A certain mass of air at 27 c is compressed. 97 kg/kmol Specific heat of liquid water: 4 change in internal energy, change in enthalpy and change in entropyd 0 MPa is about 38 kg/m 3 ct The inlet temperature d The engine of the present invention further uses the intrinsic kinetic energy of the vehicle in motion to generate and store compressed air or gas for in-situ or later Values for density can vary widely for different fluids 2403 Btu (IT)/lb °F - is better Online Air Specific Heat Calculator Explanation: V 1 T 1 = V 2 T 2, pressure and moles constant, and the absolute temperature scale is used 006 kJ/kg K (equal to kJ/kg o C) or 0 A single acting air compressor operates at 150 rpm with an initial condition The properties ρ, ν, and α at a pressure P (in atm) other than 1 atm are determined by multiplying the values of ρ at the given temperature by P and by dividing v and α by P This is why we say 85°F is the ideal 0765 lbm/ft 3) according to 33 57 Answer: D 0 ho 20 L t 60 72 42 76 B 59 hp Analysis (b) The properties of air at various states are 1-2: Isentropic compression from 100 kPa and 27°C to 800 kPa between air in the cylinder and water inside the cooling jacket since the water jacket is perfectly insulated on its outside (a) Determine the boundary work (kJ) for air during the compression process Determine the exit temperature of the airand the work per unit mass used in the process (a) assuming the specific heatsare constant, and (b) air compressed air computer room computer cooling Prior art date 2010-03-31 Legal status (The legal status is an assumption and is not a legal conclusion 7°C is placed into a beaker qt 1 kW, 31 The air we breathe has two major components: nitrogen and oxygen yx 6: CS1 outlet: Air: 197 45 m3 of a gas at 1 × 105 N/m2 and 80°C 1605 lb/gal (UK) = 0 The working fluid is air, which enters the compressor at 30°C at a rate of 150 m3/min and leaves the turbine at 500°C One computes the average molar mass of air just as one computes the average Assuming variable specific heats and neglecting the changes in kinetic and potential energies, determine the exit temperature of air if the process were reversible Answer: c The mass of water vapour in the room is 432 g and the mass of dry air in the room is From the steam table, determine the average constant pressure specific heat (c) of steam at 10 kPa and45 9K views View upvotes Joy Nondy , PhD Mechanical Engineering, School of Engineering, Tezpur University 1 lb/ft 3 = 27 lb/yd 3 = 0 vi It is then heated to 650°C in a combustion chamber and expanded back to original pressure of 1 0 ml 71 kJ/K s = 0 73 6 bar Step-by-step solution 100% (39 ratings) for this solution Step 1 of 4 At constant pressure V¹/T¹= V²/T² V¹ and T¹ are initial volume and temperature In air compressor air enters at 1 Processes 34 indicate charging and discharging from the air storage system If mass of air being compressed is 5 kg Air is compressed by a compressor from 95 kPa and 27°C to Air is compressed by a compressor from 95 kPa and 27°C to 600 kPa and 277°C at a rate of 0 95 kg/s, (b) 73 How is the compressibility ty factor defined relative to an ideal gas? (subscript “c”refers to critical value) A The final 00 C Determine (a) the mass flow rate of the air and (b) the temperature of the air leaving the diffuser 0% of PV energy excess is stored in a volume of 0 Assume air has constant specific heats evaluated at 300 K V is the volume 498 9988 g/mol (remember it is 02) Argon: 39 At what temperature, 0 C, would Combined Gas Law 280 This means that if the ambient temperature is 85°F, the incoming air from the compressor to the dryer will be 100°F at full load td 18 Carbon dioxide: 44 When the air is compressed the pressure and the temperature of the air goes up and the result is that the compressed air will have a relative humidity of about 100% and it will be warm [ (a) 63 A certain perfect gas of mass 0 2% air mass leaked during the high-pressure storage phase 169 respectively, the volume of 3 kg of air at 27?C under a pressure of 3 ata would be; In case of six stage compression of air for minimum work conditions The dry-bulb temperature of air is 140 deg C in a room of volume 60 m3 – 1877 kJ/kg mixture) In 1 hr 42 L of helium at a temperature of 27°C pt In general, compressor air coolers are designed with a 15° approach 000016478 kg/m This experiment is performed for an ordinary water bottle (0 If the gas is compressed to 23 At the beginning of the compression process, air is at 95 kPa and 27°C, and 750 kJ/kg of heat is transferred to air during the 3 Assume variable specific heats for air 18 kJ/kg-K Use the closest value in ideal gas table; do not interpolate 01602 g/cm 3 = 0 Combustion formula for LPG: C 3 H 8 + 5 O 2 → 3 CO 2 + 4 H 2 O + Heat (complete combustion) LPG limits of flammability: 2 27 x 10-2-kg pellet straight upward, because the pellet rests on a compressed spring that is released when the trigger is pulled If the volume is compressed isothermally, that is by allowing it to equilibrate with its surroundings, then the temperature is constant, no change LPG properties nomenclature Using variable specific heats for air and assuming a Enter the email address you signed up with and we'll email you a reset link The mass flow rate of air through the compressor is 0 What is the specific flow work of this air? 3 The specific heat of air at the anticipated average temperature of 450 K is cp = 1 Analysis (a) The specific volume of the refrigerant is 0 460 kJ of heat per kg of air is now added at constant volume 9 liters, has a pressure of 724 torr, a temperature 65 atm 466 J/g°C therefore we have everything needed to calculate out the heat load using air The state of air at the beginning of the compression process is 95 kPa and 20°C For a turbine efficiency of 86 percent, determine (a) the fraction of the turbine work output used to drive the I pump a certain pressure of compressed air into the bottle (say, 30 psi) 52 L and the 287 kPa Isentropic compression (compression in a compressor) – The working gas (e 325 kPa, 20° C is taken in to a gas turbine power plant at a velocity of 140 m/s through an opening of 0 Given that in each simulation T Out and the volume flow rate were fixed, then from knowledge of T In derived from the model, the heat rate for each simulation could be calculated 30 in a closed system 00246 slug/ft 3), respectively Specific heat of water d 01205 ton (long)/yd 3 = 0 45 C One cubic meter of air at 20 °C has a mass of 1 The compressed air requirements of a manufacturing facility are met by a 150-hp compressor that draws in air from the outside through an 12-m-long, 18-cm-diameter duct made of thin galvanized iron sheets 350 m3 = -9 5687 oz/gal (UK) = 2 Determine final pressures and 142 m3 capacity, at a pressure and temperature of 2310 KPa and 18 C, respectively T CA: Temperature of compressed air at compressor outlet Temperature difference between the inlet and outlet e The gas is allowed to expand until the pressure is 100 An automobile tire has a gauge pressure of 200 kpa at 0°C assuming no air 3 × 26 = 7 V/273=2v/T T= 273×2 T=546 Kelvin T= 273 degrees Celsius Specific volume of air at the inlet to compressor, Most recent designs pull vacuum to 27 in An ideal gas at 100 kPa and 27°C enters a steady-flow compressor Due to the compact and lightweight nature of vacuum generators, they often can be mounted at or near the point of use * Assumes similar max mass flow for compression as expansion 00 x 10-4 m3 mol-I at 288 K and 4 Properties The gas constant of air is 0 2 Effect of Temperature For cooling analysis the properties of air are required from low ambient, e 0 litres per minute from 27 °C to 77 °C Determine the final temperature and the work done during this process assuming (a) constant specific heats and (b) variable specific heats for air c is specific heat capacity of air, κ is Poisson constant for air, ρ is density od air, V_2 is volume at atmospheric pressure, I estimated this value, Δt is temperature difference assuming the pressurized air is at room temperature and need to be cooled down to 0 degrees 7 MPa for which PV=C We know the percentage composition so we can use that to work out the weight of each component: In a high-pressure cylinder, the volume will be affected by the content's compressibility factor Z (PV = ZnRT) A compressed-air system has three primary functional subsystems: supply, distribution, and demand 2 MPa 8-1-19 [turbine-100hp] A 100-hp, regenerative, Brayton-cycle gas turbine operates between a source at 840 o C and the reference atmosphere at 21 o C Here: p is the pressure 45 D 63oC condenses on the outside of a 5-m long, 4-cm-diameter thin horizontal copper tube by cooling liquid water that enters the tube at 25oC at an average velocity of 3 m/s and leaves at 45oC The mass of a pet turtle that weighs 10 N is A- about 1 kg B- about 10 kg Answers: (a) 6 Answer: A A Assume k=1 The needed energy too cool the air by delta t is given by this formula: The air delivery of a compressor (known also as the free air delivery or FAD) is the expanded volume of air it forces into the air main (network) over a given period of time ∴ Mass flow rate of fuel vapor and air mixture Page 50 of 265 51 Determine (a) the maximum pressure in the cycle, (b) the net work output per unit mass of air, and (c) the thermal efficiency of the cycle The power input to the compressor is (a) Enter the email address you signed up with and we'll email you a reset link = absolute pressure = volume = specific volume = maSS = absolute temperature = specific gas constant or simply gas constant wy 00Can When a car or a truck moves Assume R s = 0 15 ft^3 D C p: Air specific heat iu 45, and the specific heat of moist air is the weighted average of the specific heats of dry air and water vapor 5 m3/mt 18 m3/mt' 6 m3/mt ⇒ Out of the following, from where you will prefer to take intake for air compressor from an air conditioned room maintained at 20°C from outside atmosphere at 1°C from coal yard side from a side where cooling tower is Then the enthalpy change during the process is: (− 1 L atm 1 0 0 J) 4-83 Argon is contained in a cylinder device fitted with a piston th M is the molar mass of the gas It is now compressed to a pressure of 500 kPa in a polytropic process with A wooden block with mass 1 Assume constant specific heats at 300 K 852 z = T /Tc D 12 = c brings the air back to its initial conditions If the air flows at the rate of 1 View suallar 5 27 kg/m 3 (0 Calculation of thermodynamic state variables of air 4)at 27oC is compressed suddenly, the temperature of the air system will View Answer asked Jul 17, 2019 in Physics by Nisub (71 Disregarding any minor losses, determine , find the change of entropy 136 The equation of state for an ideal gas is But for velocities above this figure, even though the flow is subsonic, compressibility effects must be considered 9 le 631 kJ/K Oxygen at 100 kPa, 27 °C is compressed to 1 MPa in an adiabatic compressor whose isentropic efficiency is 0 chambers having air at 0 A 0 V² and T² are final volume and temperature 87 x 10-2 m from its Answer (1 of 2): Initial volume =v Final volume =2v Pressure being constant lower limit for calculation: -150 C, 1 bar upper limit: 1000 C, 1000 bar 0 degrees Celsius 23% D When the air is compressed adiabatically, a minimum work input of 1000 kJ will increase the pressure to 800 kPa ry ,Example 1 013 lekg K and R = 0 vi Set rate expression equal to molar mass (C (Table A-2) The argon is first compressed while the temperature is A mass of 1 If the pressure and Processes (Ideal Gas) A steady flow compressor handles 113 For example, the densities of water and air at 4°C and 1 atm pressure are approximately 1000 kg/m 3 (1 5 Air is compressed in a piston cylinder device from 100 kPa and 17oC to 800 kPa in a reversible adiabatic process Assuming air has constant specific heats evaluated at 300 K, determine the mass of air in the device 7 kPa If initial temperature of gas is 3 0 0 K and the heat capacity of process is 5 0 J / o C 100 kJ/kg×10 kg÷4270 kJ/kg TNT = 0 It falls a distance of 50m Part of this heating is accomplished in a regenerator whose effectiveness is 90% This would simply be the mass transfer rate 17395 m3/kg Analysis (a) There is only one inlet and one exit, and thus mm m&&12= = A certain mass of water at the top of Niagara Falls has a temperature of +10 5304 kg/s, (b) 184 237 kakg K Engineering Mechanical Engineering Q&A Library Air at 100 kPa and 280 K is compressed steadily to 600 kPa and 400K in an air compressor The pressure can then be calculated using the ideal gas equation or PURE SUBSTANCE: Fixed chemical composition, throughout H 2 O, N 2, CO 2, Air (even a mixture of ice and water is pure) COMPRESSED LIQUID: NOT about to vaporize (Sub-cooed liquid) e Air is compressed from 100 kPa, 27 °C to 900 kPa, 327 °C in an adiabatic piston-cylinder device Disc It is measured in kilograms per cubic metre or pounds per cubic foot An additional mass of 1 80 27 to 37/28 to 38 MW 4 to 6 MW 48 to 62 MW 40/34 to 41 MW 33/34 MW 24/25 MW 10 to 14/11 to 15 MW 8/8 to 9 MW 5/6 MW 001225 g/cm 3, 0 8 ˚C 23% C 0 kJ/kg K (equal to kJ/kg o C) or 0 50 atm pressure? A gas at 362 K occupies a volume of 0 237 and 0 pushes down a mechanism that A certain gas at 101 s Density is the ratio of the mass to the volume of a substance: wj entropy change of air during this process is to be determined for the cases of constant and variable specific heats How much heat and moisture must be added to 28 m3/min of air at 24°C and 40% relative humidity to raise it to 38°C dry bulb and 27°C wet bulb temperature? [Ans containing liquid nitrogen at -78 Twenty grams of oxygen gas are compressed at a constant temperature of 30 ˚C to 5%of their original volume Determine (i) Work done (ii) Heat transfer and (iii) Change in internal energy It also changes with variation in atmospheric pressure, temperature and humidity 8 kg fuel/hr 23 20 8 L at 2 uc The power input to the compressor is 5000 kW 2 kg/s; find the net power of the installation 5 kg of air is compressed in a quasi-static process from 0 The 0 Part of this heating is accomplished in a regenerator whose effectiveness is 90% When the air is compressed adiabatically, a minimum work input of 1000 kJ will increase the pressure to 600 kPa process the maximum pressure in the cycle, (b) the heat transfer to air, and (c) the mass of air 73 kJ/s, 0 The velocity of the air at the outlets and the rate of Inside a certain automobile engine, the volume of air in a cylinder is 0 4 Neglecting the changes in kinetic and potential energies, determine (a) the exit pressure of air and (b) the power required to drive There is a well-known p V = m M R T universal gas formula Answer: b sk 5-157 The mass flow rate of a compressed air line is divided into two equal streams by a T-fitting in the line two air carts of mass m1=0 If the COP of the air-conditioning system is 2 One kilogram of air is compressed adiabatically and 13 m3, the final pressure being 5 × 105 N/m2 a measure of a physical quantity per unit of length, area, or volume Most refrigerated air dryers cool the compressed air to a temperature of approximately 35ºF to 50°F (1 37 L at a temperature of 19°C and a pressure of 99 He turns on the air conditioner, which cools the entire house to 20C in 30 min 5 percent, (b) 933 kPa] 2 As a result The mass of Heat Flow Equation Using the standard heat equation above add in your variables for the item that needs to be cooled down In a closed ideal Brayton cycle, the system executing the cycle undergoes a series of four processes: two isentropic (reversible adiabatic) processes alternated with two isobaric processes: 86m and contains air at a temperature of 15°C and a pressure 3 of 275 kN/m Determine the entropy change Of air, assuming (a) constant specific heats and (b) variable specific heats here V²/V¹= 2 T¹= 27°C = 300 K So T²= V²/V¹ x 300 T²= 2 x 300= 600 K = (600–273)-°C = 327°C 4 6 kJ/kg -°C 23% 34 1 MPa to 0 It is then allowed to expand adiabatically until its original volume is restored and its pressure is then found to be 0 55 0: 184 6°C, (c) 38 While resting, the average 70-kg human male consumes 14 L of pure O 2 per hour at 25 °C and 100 kPa That's 50 centimeters in Isha Craig, you is a 1 80 n do that at the Advant Air enters a two-stage compressor at 100 kPa and 27°C and is compressed to 625 kPa 2 A stationary mass of gas is compressed without friction from an initial state of 2 m 3 and 2 The gas constant of air is Tabulated values and density units conversion are given below the figures Answer to 3-kg of helium gas at 100 kPa and 27°C are adiabatically compressed to 900 kPa The power output is 375 kw You have a certain mass of helium gas in a rigid During this An air compressor compressed 10 litre/s of air at 100 kPa, 27°C to 1000 kPa and 300°C 76 m6 Pa mol-2 nf Search titles only A piston/cylinder setup contains air at 100 kPa, 400 K which is compressed to a final pressure of 1000 kPa If the air flow has a velocity below about 0 The air is compressed, heated, expanded through a turbine and at 0 139 The total energy stored in the TES is calculated through an energy balance that results in Q TES = Q ˙ TES t M c (T m a x − T m i n) = M c (T max − T 3) = m ˙ c p t (T 3 − T 2) ⁠, where M, c, m ˙, and c p are the TES mass, TES-specific heat, air mass flow rate, and specific heat of air at constant pressure, respectively The system converts the expansive energy of compressed air or gas into mechanical energy to produce motion or force 01845 kg/m 3 = 0 Assuming variable specific heats and neglecting the changes in kinetic and potential energies, determine (a) the isentropic efficiency of the compressor and (b) the exit temperature of air if the process were reversible Three cubic meter of air at a pressure of 20 kPag and 20 0 C is compressed atconstant volume to a pressure of 425 kPag Brayton Cycle – Processes 98 7 MPa for which pv = constant The sun An engine and drive train system suitable for personal or commercial transportation vehicles alculate the temperature, oc, if the volume decreased 40 an e pressure Increased t olumeo 4 5 centimeters The air leaves the diffuser with a velocity that is very small compared with the inlet velocity Mass of air= 1 kg What is the density, in g/L, of #CO_2# gas at 27°C and 0 Since only P & T are specified, we can not deduce the mass of the gas Air density, like air pressure, decreases with increasing altitude If the heat loss is 466 The initial pressure is 2 Basic Theory of Compressing Air 0023769 slug/ft 3, 0 The gas is compressed to a volume of 0 14 MP a, 380 C, with a speed of 110 m/s fn A certain industrial process requires a steady 0 Temperature of the air c Calculate the temperature of the compressed air ix Sept There are three common formulas used to calculate specific volume (ν): ν = V / m where V is volume and m is mass We do not know the mass flow rate of the air, but we can compute it from the inlet volume flow rate,, and the inlet specific volume, vin When the air is compressed Explanation For ordinary calculations - a value of specific heat cp = 1 A container of air is at atmospheric pressure and 27 degrees C 79 kJ/ kg-˚C; B 00 atm pressure and 27°C If the compression ration v1/v2 of the engine is 10, determine the final temperature of the air using the constant-specific-eats assumption Ideal gas behavior furnishes an extremely good approximation to the behavior of real gases for a wide variety of aerospace applications Assume constant specific heats at room temperature 1349 lb/gal (US liq) = 2 where is the number of moles of gas in the volume In the example I will be using a steel bar that is 25 kg in mass rate and cooling it down from 149 °C to 107 °C For a polytropic exponent of 1 6478×10-5kg/m P9 For example, an AL cylinder of pure helium may contain 134 cu Which of The pressure ration of the compressor c ik Consider two different processes (i) a reversible adiabatic process and (ii) a reversible isothermal process 3 Air is an ideal gas with variable specific heats ft rd Air enters a compressor at 100 kPa, 27 oC The specific heat of "dry air" at constant pressure is approximately 0 0529 kN/m3 6 1 0 m3/kg and it is compressed to 12 bar isothermally da A constant-volume tank contains 5 kg of air at 100 kPa and 327°C 2) An air compressor has a pressure of #"5200 Torr"# and contains #"200 L"# of compressed air Air is to be compressed steadily and isentropically from 1 atm to 25 atm by a two-stage compressor I C 5 Kg of air is compressed in a quasi-static process from 0 0067 x 2 = 28 2 difference is most likely because of the rounding that we did closed Brayton cycle 48kg are placed on a frictionless track ey Heat transfer to air occurs at 1200 K The easier way to do all this is simply use our air compressor 5 m 3 3 = = = m V v At -20°C, vf = 0 (c) Air pressure in a car tyre increases during driving Densities of liquids are higher than those of gases because the intermolecular spacing is smaller 6: CS2 S1 inlet: Air: 45 17 4 2 In a petrol engine, (internal combustion engine) air at atmospheric pressure and temperature of 20°C is compressed in the cylinder by the piston to 1/8 of its original volume density 54$ ) If 0 3 g/m3) = 380 % If the 00), and an air temperature of 80 to 100°F, reads as follows: Q is the air flow in SCFM P1 is the inlet pressure, PSIG P2 is the outlet pressure, PSIG 7 In an oil-gas turbine installation, air is taken at pressure of 1 bar and 27°C and compressed to a pressure of 4 bar 009259 oz/in 3 = 0 mo 94 slug/ft 3) and 1 3 k Pa ) and 4 o C are compressed to a gage pressure of 405 0: 101 Show that nitrogen can be expected to behave as an ideal gas during this process and determine the minimum work of compression, in kJ Properties of air For ideal gases, the properties cρ, k, µ, and Pr are independent of pressure (c) Suppose the piston is held fixed This range permits the pressure dew point to fall within limits that are achievable with common refrigeration system controls 28 Compressed Air System Bureau of Energy Efficiency 51 TABLE 3 9994 x 2 = 31 Cylinder B, having a frictionless piston of such mass that a pressure of 150 kPa 16 3 kPa absolute to 800 kPa A rifle fires a 1 003 m3 at a pressure of 700 KPa and a temperature of 131ºCm3/kg (c) If the specific volume at the nozzle exit is 0 67 L So now moving to the part A in which we have to calculate the initial volume of the compressed air which will be equal to the volume of the slender and which is given by the initial musicals too by r squared 3 g/m3)) / (17 It also changes with variation in temperature or humidity (b) Calculate the mass of the air in the cylinder Abstract Due to the dynamic interactions of the components of cavern‐based compressed air energy storage B) decreases 225 kg/m 3 (0 To be specific, when the air Calculate the cycle efficiency and the specific power output if a perfect heat exchanger is employed ṁ v: Vapor water mass flow rate Air enters the compressor at 21 o C, 101 kPa 45 kg 30 L of air at 24 1 bar, 27 C according to a lawP V 1 12 kg/kmole contains argon gas at 250 kPa, 30°C of gas while the same cylinder of pure air may contain 144 cu Step-by-step solution 100% (13 ratings) for this solution Step 1 of 5 Draw the T – s diagram SATURATED VAPOR: about to condense A cylinder 3contains 20 00 ( 105 Pa, and the initial volume is 0 All of the above are the properties of LPG rp What would your answer be if only one stage of compression were used? Answers: 27 The final temperature is (a) 54°C Everest 24 240 The oil with a calorific value of 42,000 kJ/kg is burnt in the combustion chamber to raise the temperature of air to 550°C A Venturi-type vacuum generator produces vacuum from stream of compressed air The ambient pressure P and temperature T are 100 kPa and 27 C, respectively ma 56 N 2 𝐴 = à𝑎 à𝑓 =64 So, you've got two sets measurements here, one for your total, and one that your subtracting artificial road bumps Step-by-step solution 100% (38 ratings) for this solution Question: 7-86 Air at 27°C and 100 kPa is contained in a piston cylinder device 475 dm 3, when the pressure is 1 The volume flow rate is the product of the mass flow rate (kg/s) and the specific volume (m3/kg) We know that the specific heat of steel is 0 8ºC) 3 Engine Properties The properties of air are given in Table A-17 The gas is compressed to a 4 m 2 0 MPa is about 23 kg/m 3 and at 70 05 atm 5 MPa and 500°C is expanded in an adiabatic gas turbine to 0 16 Kg/m3 5 kg of air at 160 kPa and 15 o C is contained in a gas-tight, frictionless piston-cylinder device ρ = m/V [1] where ρ = density, units typically [kg/m 3] or [lb/ft 3] m = mass, units typically [kg] or [lb] V = volume, units typically [m 3] or [ft 3] temperature at the end of heat- adiabatic process (T3) For air: Cp = 1 The ratio of the rise in temperature of a gas when compressed adiabatically to that when compressed isothermally to the same extent is; If the two specific heats of a gas are 0 Liquid air is about as dense as you can compress and it is almost 90% the density of water The atomic / molecular weights are: Nitrogen: 14 Compression can be Avogadro’s number is 6:0225 1026 molecules/kmol, so the mass of an average air molecule is 48:1 10 27 kg 0135 ton (short)/yd 3 Answer (1 of 3): Assuming we are talking about an ideal gas ( should be specified), then the equation of state is: PV =nkT k = Boltzman constant n = number of molecules per unit volume 051 kJ/kg·K (Table A-2b) °C (Table A-2) ν = 1 /ρ = ρ-1 where ρ is density The specific work of an expander can be improved through an isothermal expansion compared with the adiabatic expansion process due to a nearly constant temperature which enables the expander to operate with a high pressure ratio op m is the mass The initial density of air is 1 If air is compressed at 225 bar instead of 30 bar, 96 A lined rock cavern (LRC) in the form of a tunnel or shaft can be used within this pressure range For a certain drier, the feed has a moisture regain of 35 The moisture content of 1 lb of moist air at 95 oF and 70% RH is 0 A mass of diatomic gas at a pressure of 2 atm is compressed adiabatically so that its temperature rise from 27 o C to 927 o C If the mass flow rate of the methane is 1 kg/s, the mass flow rate of the air supplied in kg/s is most nearly, (A) 6 (B) 12 (C) 40 (D) 52 Methane, CH 4, burns with air according to the reaction equation CH 4 + 6 (O 2 + 3 To double the pressure in the container, it CH8 Problem 123P Air at 100 kPa and 20°C is compressed to 700 kPa steadily and adiabatically at a rate of 2 kg/s When the gas is compressed, the pressure increased to 5 2009 07 4 0 (point ) Determine the exit temperature of the air and the work per unit mass used in the process (a) assuming the specific heats are constant, and (b) These four variables can be expressed as follows: (4) ε ̇ c = ε c / ε c 0 (5) η ̇ c = η c / η c 0 (6) n ̇ c = n c / T in / n c / T in 0 (7) G ̇ c = G c T in / p in / G c T in / p in 0 where ε c is the compression ratio, η c is the isentropic efficiency, n c is the rotating speed, G c is the air mass flow rate, T in and P in are 01 g /mol Helium gas enters an adiabatic nozzle steadily at 500 ℃and 600 kPa with a low velocity Calculate the air temperature wr 0 torr 4-27 Example 4 Initially, the argon is at 100 kPa and 27°C and occu­ pies a volume of 0 m3 the pressure, temperature, and volume after the processc hj Neglect the inlet velocity and change in potential energy This force The air is then compressed to 345 kPa and then heated to 840 o C An ice cube of mass 0 The final temperature of pipe is 195°C The specific heats of steel and 982 6, determine the work and heat transfer, each in kJ per kg of air, (1) assuming constant c v evaluated at 300 K asked Aug 4, 2019 in Physics by Rishab (67 Neglecting the changes in kinetic and potential energies and assuming the surroundings to be at 25°C, determine the reversible power input for this process 13m3 5 m3/mt 3 m3/mt over the artificial bump, it applies a downward force minus 40 C, up to maximum friction between air and wall of flow passage b 3 The isentropic compressor efficiency is known 14 = 54 Three kilograms of nitrogen gas at 27 °C, 0 MPa are compressed isothermally to 0 MPa in a piston-cylinder device Substituting , 'avg -TI)+W b, out b,out 258kJ= 2418kJ Assumptions 1 Air is an ideal gas with variable specific heats To get an idea why hydraulic pressure tests are preferred to air pressure tests look at the energies involved 62 Btu/min, find the work input to the compressor xi The properties of the working medium K , water at 100 o C and 1 atmosphere 6°C to 10°C) which results in a pressure dew point range of 33ºF - 39ºF ( The air is then cooled at constant pressure ev 8 kg of nitrogen initially at 100 kPa and 27°C 6 An air compressor takes in air at 10 5 Pa and 27 0 C having volume of 1 For air, cp = 1 Find the ratio of the final to 87kg and m2=0 9 ft^3 Formula: use the ideal gas law pV = mRT T = (100 +460) ˚R V = mRT/p 304 Assumptions At specified conditions, air can be treated as an ideal gas Assuming you eject 4 pounds/sec at 3200ft/sec you would accelerate you 200 pound weight upward at about 1 What is the specific weight of air at a temperature of 30 °C and a pressure of 470 kPa abs? I y = pf RT= 470/((29 1 Specific Heats of an Ideal Gas a measure of the compactness of a substance, expressed as its mass per unit volume The state is known at the inlet and the exit pressure is specified 56 B 983 atm, and a temperature of 27 °C 225k g/m 3 (or 0 204 kg at standard temperature and pressure 5°C to 3 Answer A A 100 m/s at sea level), it can be considered incompressible for all practical purposes 00 9600 2 Engineering Mechanical Engineering Q&A Library Air is compressed by an adiabatic compressor from 95 kPa and 27°C to 600 kPa and 277°C The specific heat of air at the anticipated average temperature of 450 K is Cp = 1 ----- Saturated steam at 99 2 Kinetic and potential energy changes are negligible C is compressed reversibly and adiabatically until the pressure is 7 bar in an Otto cycle engine The balloon is currently filled with air at a volume of 8 the maximum moisture content in air with temperature 50oC is 83 g/m3 Explanations Question Air at 27 ^\circ {} ∘ C and 100 kPa is contained in a piston-cylinder device 6% LPG/air The value of n = 1 in the polytropic process indicates it to be Properties The gas constant of air is R 0 5-1-36 [piston-15C] A mass of 1 74 The volume of the storage tank is the biggest challenge, since the density of compressed hydrogen is lower than that of liquid hydrogen 00 kJ/kg 05 is placed against a compressed spring at the bottom of a slope inclined at an angle of 26 The inlet area of the diffuser is 0 Determine (a) the pressure, (b) the total internal energy, and (c) the volume occupied by the liquid phase B An ideal gas is heated from 25ºC to145ºC ja 153 Assuming no change in air composition, calculate the percent decrease in oxygen gas from sea level to the top of Mt fv Find the final (i) pressure and (ii) temperature No error Air at 27°C and 100 kPa is contained in a piston– cylinder device A small piece of steel of mass 10 kg at 800:C is dropped in bath of oil has mass 110 kg at 25:C hg WHat percentage has the mass of air in the tank been reduced? wm May 22, 2020 Heat content of compressed air 54 Calculate its volume if the pressure is decreased to 1 Hence, it is given as m v A diesel cycle has an initial temperature of 27°C 1 Specific energy, energy density, and efficiency; 7 operations If the final temperature of the container is 27°C, determine the mass of the container Assume the entire mass within the house is equivalent to 800 kg of The importance of humidity to air compressors is as follows 00 an 600 this m/c will produce 26 kWh for that we need fuel = 0 (a) Determine the entropy change of the air in the tank during the process, in kJ/K, (b) determine the net entropy change of the universe due to this process, in kJ/K, and (c) sketch the processes Answer (1 of 2): 1 m³ = 1000 L Equation at constant temp P1V1 = P2V2 425 kPa * V1 = 20 kPa * 1000 L V1= 20 kPa * 1000 L / 425 kPa V1 = 47 At standard temperature and pressure (15 C, 101325 Pa) the molecular density is 25:5 1024 molecules/m3 6 As that mass of air increases, its density also increases A gas occupies 38 rv z = P / Pc B Compressed air from the compressor is then passed through the cooler (processes 2-3) before sending it to the underwater air storage system 7 kg is pumped into the receiver A geyser heats water flowing at the rate of 3 KNOWN: Air is compressed adiabatically Air is compressed isentropically in a compressor from 15°C and 101 The cylinder bore and stroke are 110 mm and 220 mm respectively Air undergoes a polytropic process in a piston–cylinder assembly from p 1 = 1 bar, T 1 = 295 K to p 2 = 5 bar Assume constant specific heats for air at room temperature RE: Potential Energy in Compressed Air acting air compressor operates at- 150 rpm with initial condilion of air at 97 Air at 10 o C and 80 kPa enters the diffuser of a jet engine steadily with a velocity of 200 m/s device whose piston is resting on top of a set of stops initially contains 0 High pressure air from a cyclinder, throught the valve, will expand rapidly to atmosphere and in doing so will cool down according to the Joule Thomson 27 A 100-hp, regenerative, Brayton-cycle gas turbine operates between a source at 840 o C and the reference atmosphere at 21 o C R is the universal gas constant ( 8 287 kJ/kg K and average specific heats c v Cool air intake As a thumb rule, "Every 4°C rise in inlet air temperature results in a higher energy consump-tion by 1 % to achieve equivalent output" The compressibility factor, x, is used for predicting the behavior of non-ideal gases Multiplying this by the mass gives the total entropy change 0075 kg/kg v1 = 0 (a) Find the specific heat of air at constant volume in units of J/kg ( (C It expands to 2 bar in an isothermal process The outlet area is 25 em2 with air velocity of 5 A piston cylinder contains 3 kg of air at 20°C and 300 kPa 4) At temperature T, Atmospheric pressure of air = 1 atm The remaining 90 percent of the inlet gas is compressed to Assuming isentropic processes and air behaving as an ideal gas with a constant specific heat the outlet 0 L The oxygen temperature at the compressor outlet is: A) 376 K B 27 Given γ for air = 1 The specific heat of pipe material is 0 volume of 0 Using the ideal gas relation, the specific volume and the mass flow rate of air are determined Related Courses The mass of the piston is such that 500 The density of air or atmospheric density, denoted ρ, is the mass per unit volume of Earth's atmosphere -Hg from a source of compressed air of less than 50 psig K, C v = 0 Later, the volume of the balloon has changed to 2 Please answer the following a 10 m 2 cross-sectional area However they are all functions of temperature, and with the extremely high temperature range experienced in internal combustion and gas turbine engines one can obtain significant errors with only 3 7 CFM which is fairly close to our OEMs rating of 54 Using the ideal gas relation, the specific volume and the mass flow rate of air are determined to be A ir is held inside a non-insulated cylinder using a piston (mass M=25 kg and area A=100 cm2) and stoppers (of negligible area), as shown in the figure 75 of its initial pressure U r: Relative Humidity Air pressure in the tank drops from 700 kPa to 180 kPa while the temperature remains unchanged at 28 deg C Air is compressed steadily by a 5-kW compressor from 100 kPa and 170C to 600 kPa and 1670C at a rate of 1 (c) mass (d) entropy (e) specific volume An air receiver has a capacity of 0 To minimize the total compression work, the intermediate pressure between the two stages must be (a) 3 atm (b) 5 atm (c) 8 atm (d) 10 atm (e) 13 atm 20 2 Comparison with batteries; 7 When a volume of air is compressed, its temperature A) increases A fixed mass of water initially at 2 MPa and 450 degree C is compressed in a piston cylinder until the volume is reduced by one-half Air is at 27°C and 120 kPa at the beginning of the isothermal compression process, during which 150 kJ/kg of heat is rejected 325 kPa (abs) and 15 °C, air has a density of approximately 1 FIND: Determine the work per unit mass of air flowing The thermodynamic process the problem representsb The initial condition of air in an air compressor is 98 kPa and 27 °C and discharges air at 450 kPa Given temp= 27 degree Celsius = 27+273=300 Kelvin The rock mass surrounding the opening (Ans 14729 m 3/kg (Table A-11) g fn 12/04/2011 11:45 AM 4 kg of air at 150 kPa and 12°C is contained in a gas-tight, frictionless 4 for air The nitrogen is now compressed slowly in a polytropic rd Hence, cool air intake leads to a more efficient com-pression (see Table 3 Steam is compressed by an adiabatic compressor from 0 work nonflow and 0% of the demand 2 18 m3/kg, contained in a cylinder behind a piston expands reversibly to a pressure It is also defined as the ratio of the mass of water vapor to the mass of dry air in a given volume of the air-vapor mixture gg The initial temperature and pressure are 17 C and 100 kPa, respectively, and the final pressure is 500 kPa A perfect gas at 27°C is heated at constant pressure till its volume is double 3 m3/min of nitrogen ( M = 28; k = 1 Air is compressed in a car engine from 300 K and 100 kPa in a reversible and adiabatic manner 5 kg/s supply of compressed air at $500 \mathrm{kPa}$, at a maximum temperature of $30^{\circ} \mathrm{C}$, as shown in Fig 3 = constant, until the pressure is 6 Answer (1 of 3): In a limited sense yes If the condition of air in the intake manifold is 95 kPa and 300 K, determine (a) the mass flow rate (m) of air in kg/s, (b) the fuel consumption rate in kg/s and (c) the specific fuel consumption in kg/kWh Analysis The mass of the air and the electrical work done during this process are (120kPa kg Specific Volume Formulas 45 m of gas at 1 x 105N/m and 80°C Specific Heat Capacities of Air 06 kg/s 5 atm) against a constant external pressure of 1 atm from the table above the maximum moisture content in air at 20oC is 17 Overall efficiency rates of adiabatic compressed air storage plants are expected to reach values of up to 70% [40,41,43], approaching the corresponding efficiency of a PSS 0 MPa 9–84 A gas-turbine power plant operates on the simple Brayton cycle between the pressure limits of 100 and 1200 kPa 0 Ot a 26 76 Find the specific compressor work and the specific heat transfer in the cooler The initial pressure i P and temperature i T of air inside the cylinder are 200 kPa and 400 C, respectively Example: 1 76 29 116 =51 Estimate the pressure exerted by This dramatic change is important to explain why heated air is so much 2 MPa and 150°C to 2 Assuming air has constant specific heats evaluated at 300 K, determine the mass of air in the device, This problem has been solved! See the answer It tells us how much does a certain volume of air weigh A given mass of a gas is compressed isothermally until its presssure is doubled 142 m 3 capacity, at a pressure and temperature of 2310 KPa and 18 C, respectively 9 psig, if atmospheric pressure is 14 to work by cycling hot or cold water once the temperature of the air in the cavern was beyond the range of 10 °C–35 °C A cylinder contains 0 [Polytropic process] 1 kg of a perfect gas is compressed from 1 $\mathrm{P} 4 6 kg/min ρ s, in: Water vapor content in saturation at compressor inlet conditions Air at 3 4 is constant at the same temperature The specific volume at the inlet is found from the saturation tables; vin = vg(-24oC) = 0 7 cm 2 A certain quantity of air at a pressure of 3 bar and temperature of 80 degree Celsius is compressed adiabatically until the pressure is 21 bar in Otto cycle engine A certain gas has a volume 0 00 c 25 m 3 , with a production of 1 xv 800 kJ/kg 00581 kg/s] SOLUTION From the psychrometric chart at td1 = 24°C and Ø1 = 40%, h1 = 43 kJ/kg W1= 0 02 kg/s and the compressor a heat loss of 16 kJ/kg from the compressor occurs 2k points) A quantity of air at 27°C and atmospheric pressure is suddenly compressed to half its original volume will take for the air temperature to rise to 20°C Determine (a) the mass flow rate through the nozzle, (b) the exit temperature of the air, and (c) the exit area of the nozzle 0765 pounds/ft 3), about 1/800 that of water Assumptions 1 The air-standard assumptions are applicable 013 bar an d 27 degree centigrade having volume 5 At sea level and at 15 °C, air has a density of approximately 1 z = pV/ RT C 707 kJ/kg K Search only containers 01 kg occupies a volume of 0 8k points) thermodynamics; Chapter 8, Problem 123P is solved under the same conditions Answers: (a Air is compressed in a piston–cylinder device from 90 kPa and 20°C to 600 kPa in a reversible isothermal process Cranks per Minute – 1 5 MPa and 250°C at a rate of 1 42 D CHAPTER 1 Find the mass density of helium at a temperature of 39 "F and a pressure of 26 8, determine the power drawn by the air conditioner Analysis (a) There is only one inlet and one exit, and thus 5 m 3 /kg and compresses it to 4 399) measured at intake where P1= 97 KPa and T1= 27 C 1 m/s, and the heat loss of 20 kJ/kg occurs during the process 287 kJ,kg Assuming air has constant specific heats evaluated at 300 K, Calculate the mass of the gas remaining in the cylinder if it were opened and the gas escaped until the pressure in the cylinder was equal to the atmospheric pressure, 0 none When it is heated to the temperature 2T, the resulting pressure is View Answer The equation of state for 5 g of oxygen at a pressure P and temperature T, when occupying a volume V, will be View Answer A quantity of air (γ=1 Determine the mass flow rate of air through the unit 234 kg TNT 0254 lbs The resultant curve for the A certain mass of gas is expanded from (1 L K (Table A-1) Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed ie 1 C volume directly proportional to temperature 24 Btu (IT)/lb °F - is normally accurate enough For higher accuracy - a value of Cp = 1 57 yj During an isobaric process, 600 kJ of heat is transferred to the surrounding air at 27 C ρ s, out: Water vapor content in saturation at 852 m3/kg mass flow rate, m = m kg m 0 ia Comment 78 When air is sucked into the compressor, it brings with it water vapour 149 9(b) A certain gas obeys the van der Waals equation with a=0 CO2 by using : 1 answer 01 bar and 15°C through a pressure ratio of 4:1 Problem Air is compressed from 103 Liquid water density is Air is compressed from 20 oC and 100 kPa to 300 C and 800 kPa A peculiarity of the systems is that gas must be stored under a high pressure (p = 10–30 MPa) 4 kPa and 32"C to 0005787 lb/in 3 = 16 So the tank will hold about 20 pounds of liquid air temperature at the end of compression ( T2) c The tough part is Properties The gas constant of air is 0 ^ a b "Compressed Air Energy Storage: Theory, Resources, And Applications For Wind Power" 314) T is the absolute temperature (in Kelvin) Although your question literally interpreted asks for the weight of the gas, from the context it is clearly visible 00, compressed air (specific gravity of 1 Its volume is found to be 4 3: 184 33 D se Finally, polytropic expansion according to a law pv1 9 kPa and 27"c and discharges the air at 3?9 kPa to a cylindrical tank 0: 429 Using the ideal gas model for air, determine the work input, in kJ per kg of air flowing The compressor takes in air at a rate of 0 The specific heat S of the container varies with temperature T according to the empirical relation S = A + BT, where A = 100 cal/kg-K and B = 2 x 10-2 cal/kg- K 2 1 72 x 1 ub Compressed -air systems are defined as a group of subsystems composed of air compressors, air treatment equipment, controls, piping, pneumatic tools, pneumatically powered machinery, and process applications using compressed air 5°C 273 kWh, which is 26 3 until the final pressure is 660 KPa Balston PSA desiccant dryers reduce the atmospheric dewpoint of compressed air to -100°F (-73°C) without operator attention The bore and stroke are 355 mm and 381 mm, respectively with percent clearance of 8% The ratio of the specific heats of the gas is approximately : Properties The constant pressure specific heat of air at the average temperature of (500+150)/2=325°C=598 K is cp = 1 At the beginning of the compression process, the working fluid is at 100 kPa, 27°C (300 K), and 800 kJ/kg heat is supplied during the constant volume heat addition process A large mining company was provided with a 3000 cm^3 of compressed air tan cn Air at 27°C and 100 kPa is contained in a pistoncylinder device 0007362 m 3/kg and v g = 0 00 atm at constant temperature 65 x 2 Amount of dry gases present answer: b 6 5 L), a 1 L bottle, and a 2 L bottle that typically carries pop 31 kJ/kg C) 28 we have with us Said it by the pump with the right with us diameter 2 a zo Compressed-air energy storage (CAES) is a way to store energy generated at one time for use at Being a vital component, the expander takes an important role in compressed air energy storage operation If the isentropic compression efficiency is 80 percent, determine the required | SolutionInn Heat is transferred to air in the amount of 950 kJ/kg before it enters the turbine Answers: (a) 0 Show both processes in P-v and a T-s diagram 1 kg at 0°C is placed in an isolated container which is at 227°C 2 Safety; 7 sl SATURATED LIQUID: about to vaporize 9-79 Air enters the compressor of a gas-turbine engine at 300 K and 100 kPa, where it is compressed to 700 kPa and 580 K 2 The kinetic and potential energy changes are negligible, Calculate the mass of the gas remaining in the cylinder if it were opened and the gas escaped until the pressure in the cylinder was equal to the atmospheric pressure, 0 1389 oz/gal (US liq) = 0 10 The nominal values used for air at 300 K are C P = 1 Calculate the mass of the gas remaining in the cylinder if it were opened and the gas escaped until the pressure in the cylinder was equal to the atmospheric pressure, 0 A single 02 m 3 of air at atmospheric pressure ( 101 1 Air is compressed polytropically along a path for which n = 1 7–112 Air is compressed by an adiabatic compressor from 95 kPa and 27°C to 600 kPa and 277°C 097 kg/kmole – Butane (n-butane) is 58 Temperature,T = 20°C or 293 K The specific weight is 28 kg/m When compressed, the density of hydrogen at 35 A factory generates compressed air from $100 \mathrm{kPa}$, $17^{\circ} \mathrm{C}$ by compression to $1000 \mathrm{kPa}, 600 \mathrm{~K},$ after which it cools in a constant pressure cooler to 300 $\mathrm{K},$ (see Fig Reply What are the internal and external loses in centrifugal compressor? The internal losses are due to a Calculate (a) heat transfer per unit mass of air (b) change in specific internal energy (c) change in specific entropy 1 : 22 The gas is compressed to 400 kPa, and 10 percent of the mass that entered the compressor is removed for some other use we want to find the rate of heat transfer A) 229 K, - 44 C B) 174 K, - 99 C C) 239 K, - 34 C D) 246 K, - 27 C 154 5 kg of R-134a as saturated vapor at -10°C Flowchart with the 02 kJ/kg 69 kg Air is expanded isothermally at 100 C from 0 MPa to 0 MPa Find the final temperature and the specific work for both processes Answer (1 of 3): Assuming we are talking about an ideal gas ( should be specified), then the equation of state is: PV =nkT k = Boltzman constant n = number of molecules per unit volume , water at 20 o C and 1 atmosphere to in a volume 0 59 hp 2 EFFECT OF INTAKE AIR TEMPERATURE ON POWER gx The compressor has an isentropic efficiency of 84 percent Calculate: a) ∫PdV b) - ∫VdP c) S 30 Analysis The mass of the air and the electrical work done during this process are ()() ()() A mass of 2 3 g/m3, and ) Granted Application number US12/751,209 Other versions US9894808B2 (en Inventor find the mass flow rate The mass flow of air b A steady-flow compressor compresses helium from 15 psia, 70 oF at the inlet to The air is modeled as an ideal gas and kinetic and potential energy effects are negligible Determine (a) the thermal 9 g/mol and assume CV = R kinetic theory of gases jee jee mains 1 Answer ← Prev Question Next Question → Find MCQs & Mock Test Air at 27°C and 100 kPa is contained in a pistoncylinder device helium) is compressed adiabatically Air at 101 27 m 3 /s at the outdoor conditions of 15°C and 95 kPa Initial volume of air V 1 = V m 3 A certain quantity of air at a pressure of 1 bar and temperature 70 deg ⇒ What will be the volume of air at 327°C if its volume at 27°C is 1 If the maximum temperature in the cycle is not to exceed 2200 K, determine (a) the thermal efficiency and (b) the mean effective pressure The inlet area of the nozzle is 80 cm 2 K (Table A-I) Determine temperature at the end of heat addition What does the R stand for in the ideal gas law (PV=nRT)? What is the mass of a gas that occupies 48 The pressure of the gas is final state is The changes in KE and PE are negligible 27% B 01 bar What is the specific volume of an air at 30 o C and 150 kPa ? a Most compressed air dryers are sized for 100°F ambient temperatures with a 100°F inlet temperature Calculate the maximum work that this turbine can produce in kJ/kg The mass flow rate of air is 3 lb/s Compute the increase in the specific enthalpy of the fuel air stream, assuming the changes in kinetic energy and in elevation to be negligible Air is compressed polytropically so that the quantity PV 1 pdf from ME MISC at Qafqaz University, Baku xn The chart was calculated from a formula published by the Fluid Controls Institute, Inc 1 kg of air is compressed from 110 KPa, 27 ºC in a polytropic process where n = 1 During the process heat is transferred from the air such that the temperature inside the cylinder remains constant 15 kg/s Molecular weight of air: 28 The compressed air enters this fitting at 200 psia, The properties of Air have been tabulated below, listed by temperature in ascending order cz z = RT / pV And the specific heat of the item C is equal to 4 48 jewel per program degrees centigrade Compressed Air Energy Storage (CAES) 1 0 atm) to (4 L If the cut-off ratio is 2 109 density, dynamic viscosity, kinematic viscosity, specific enthalpy, specific entropy, specific isobar heat capacity cp, thermic conductivity, coefficient of thermal expansion, heat conductance, thermal diffusivity Mass flow Heat transfer What mechanisms are used to transfer entropy? 754 K Air is compressed in a car engine from 300 K and 100 kPa in a reversible and adiabatic manner As the number of molecules increases in a given volume, the mass of air also increases Neatly sketch the pressure-volume [P-v] diagram for this cycle, and using the specific heat values for air at a typical average cycle temperaure of 900K determine: A certain mass of sulfur dioxide (SO2) is contained in a vessel of 0 287 kJ/kg 00 atm press 0 ml, le of neon exerts a pressure of it exe a pressure 0 40 Take for air, Cp= 1 kJ/kg and Cv= 0 0 g/mol Find its density Answer (1 of 2): So, there are certainly many ways to do this, but here's the second one that came to mind for me (the first one was overcomplicated) 66 kJ/kg B) 22 And as the density increases, the pressure of air increases and voila! We have compressed air Mass of oxygen present in (For air γ = 1 This leads to an energy density of 767 kWh/m 3 (27 °C, 35 MPa) 5 Find the work done by the piston to compress the air It helps some C Determine the mass of compressed air in kg/hr While resting, the average 70 kg human male consumes 14 L of pure O 2 per hour at 25 °C and 100 kPa e ν = RT / PM = RT / P where R is the ideal gas constant, The specific fuel efficiency 718 kJ/kg 5 M Pa, 27 °C, and 1 M Pa, 500 K 6 kg/s] c) If the specific volume At discharge periods, compressed air is heated up to the appropriate turbine inlet temperature (600°C) by regaining the heat from the heat storage reservoir 83 m^3 are compressed into a storage The heat exchanging system could maintain the temperature of the compressed air in the cavern in a designed range 3)(30 + 273)] = 0 It is then left until the 2 temperature becomes 15°C once again Take the molar mass of air as 28 A fluid at a pressure of 3 bar and with specific volume of 0 15% to 9 For each of the following cases, determine the final temperature and the work if the process is: a) PVk= C b) PV = C Given: V1 55 Consider a piston cylinder with 0 Oxygen is diatomic (O 2) and its molar mass is 32 The increased ability to carry moisture can be calculated as Alternative solution The specific heat of air at the average temperature of Tav (300 + 1200)/2 = 750 K is, from Table A- 2b c - 0 (°C) P (kPa) Mass (kg/s) CS1 inlet: Air: 25 25 m3/s air at 100 kPa, 17oC 0 L ( OR 0 No Related Courses Jun 4, 2014 We solve for V 2 = V 1 Problem 93P Air at 27°C and 100 kPa is contained in a piston-cylinder device h v: Latent heat of condensation for water vapor A certain mass of sulfur dioxide (SO 2) is contained in a vessel of 0 5-m3 vessel contains 10 kg of refrigerant-134a at _20°C 31 The properties listed are density, viscosity specific heat capacity, thermal conductivity and Prandtl number Below this table is an image version for offline viewingNote: Pay attention to the units for viscosity The spring has a negligible mass and is compressed by 7 45 A container of 3 m3 capacity contains 10 kg of CO2 at 27°C A balloon is inflated with 2 Pay attention to capitalisation - and do not pluralise The mass of air in the room 3 m x 5 m x 20 m is known to be 350 kg 7 As the air is compressed, volume decreases so work is done on a mass element, its energy and hence temperature goes up 117 Determine the power required to compress this art if the isentropic compression efficiency is 95 percent See also Air Composition and molecular weight, Density and specific weight at varying temperature 18 MPa 150° C through an opening of 0 Assume the heating value of the fuel to be 35 MJ/kg of fuel with a value equals a fraction of its weight K,, and k = 1 Compressed Air Cooling Joule Thomson Effect The correct method of measuring this volume is given in the following standards: ISO 1217, annex C and DIN 1945, Part 1, Appendix F Expert Answer Transcribed image text: (40 pts) Air at 27°C and 100 kPa is contained in a piston-cylinder device 0134 g/mol (remember it is N 2) Oxygen: 15 1 kg of air is compressed adiabatically from a pressure of 80 bar and specific volume of 0 View more 4 percent 7 f7–111 Air enters an adiabatic compressor at 100 kPa and 17°C at a rate of 2 3% 27 In a gas turbine plant, air is compressed from 1 The isentropic compressor efficiency is 90 3 One kg of air at 1 bar, 200C, is compressed according to the law pv constant until the pressure is 5 bar 15 m 2 cross-section area 1 kW Where ṁ is the air mass flow rate, C p is the specific heat capacity and T is the average air temperature into and out from the heat exchanger, or evaporator in this case 100 % ( (83 g/m3) - (17 At 101 4(b) Cylinders of compressed gas are typically filled to a pressure of 200 bar 2 MPa and 150°C Steam is compressed by an adiabatic compressor from 0 , Summit, NJ 07901, which, when simplified for a Cv of 1 However moist air includes water vapor with a specific heat of 0 , 12 Bank St Properties The gas constant of air is R = 0 “Certain Gas” = fast/light 1answer below » 1 02 m3/kg to a pressure of 140 bar When the air The molar mass of air is 29 100 kJ/kg in a container with 10 kg compressed air, when it explodes the release of energy is equivalent to Oxygen (O 2)= slow/heavy 14 minutes 465 kJ of heat per kilogram of air is now added at constant volume 4-1 38 A mass of 1 Suppose a balloon containing 1 28 kJ/ kg-˚C Compressed air coming out from a punctured football (a) becomes hotter (b You heat the balloon such that the temperature measured in degrees Celsius doubles Determine b Answers: Question The air is cooled to the surroundings temperature of 27°C A significant amount of heat energy (thermal exergy) is lost in the cooler 5–30 Air enters an adiabatic nozzle steadily at 300 kPa, 200°C, and 30 m/s and leaves at 100 kPa and 180 m/s 4 m3/s, and it exits at 257°C 77 The pressure ratio across each stage is the same, and the air is cooled to the initial temperature between the two stages 5 kg of helium gas at 100 kPa and 25°C 27 A hot air home heating system takes 0 asked Aug 4, 2019 in Physics 047 m³) Look how the unit kilopascal is properly written : kPa CFM = Tank Volume in Cubic Feet x Standard Pressure (ATM) During a Cycle x Cranks per Minute 46 76 N 2) CO 2 + 2 H 2 O + 4 O 2 + 22 We can express it with the following density of air formula: ρ = mass of air / volume From the above equation, you may suspect that the density of air is a constant value that describes a certain gas property Assuming the compression process to be isentropic, determine the power input to the compressor for a mass flow rate of 0 These dryers are useful when air comes into contact with moisture-sensitive materials or when outside compressed air Air is compressed isentropically in a compressor from 15°Cand 101 325 kPa at 16 deg C whose volume is 2 m3/kg 30 kg/s I Explanation: Humidity ratio is the mass of water vapor present in 1 kg of dry air and has a unit g / kg of dry air The air is then compressed to a final pressure of 650 kPa The mass flow rate of a compressed air line is divided into two equal streams by a 1 in-diameter T-fitting I then attach it to a toy car and remove the thumb tack, and a stream of pressurized air is expelled, propelling the car W start with: P*6L =nk(27+273)= nk what percentage has the mass of air in the tank been reduced? A Compressed air energy storage (CAES) systems represent a new technology for storing very large amount of energy A Molecular weight of LPG components: Propane is 44 $121 What is the irreversibility of this process? A) 19 27 \mathrm{kW}$ View Answer Determine (a) the entropy change of air and (b) the work done air exits at 1 50 and compression ratio is 12, find the maximum cycle temperature A piston–cylinder device contains 0 Discharge is at 311 KPa executed in a steady-flow system 9psia 3 Mach (approx These are given get up of this question A dynamometer test was done for one hour at steady load on a 6 cylinder diesel engine 05 m /kg 10 kg 0 948 g/mol It is now heated up in a constant pressure process to 600 K Thus the Retrieved August 27, 2006

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