Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
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Chapter 5.5, Problem 79P
Air (cp = 1.005 kJ/kg·°C) is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. Air enters the heat exchanger at 95 kPa and 20°C at a rate of 0.6 m3/s. The combustion gases (cp = 1.10 kJ/kg·°C) enter at 160°C at a rate of 0.95 kg/s and leave at 95°C. Determine the rate of heat transfer to the air and its outlet temperature.
FIGURE P5–79
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Air (cp = 1.005 kJ/kg·°C) is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. Air enters the heat exchanger at 95 kPa and 20°C at a rate of 0.75 m3/s. The combustion gases (cp = 1.10 kJ/kg·°C) enter at 160°C at a rate of 0.95 kg/s and leave at 95°C. Determine the rate of heat transfer to the air and its outlet temperature.
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Air (cp = 1.005 kJ/kg·°C) is to be preheated by hot exhaust gases in a crossflow heat exchanger before it enters the furnace. Air enters the heat exchanger at 95 kPa and 20°C at a rate of 1.6 m3 /s. The combustion gases (cp = 1.10 kJ/kg·°C) enter at 180°C at a rate of 2.2 kg/s and leave at 95°C. Determine the rate of heat transfer to the air.
Air (cp = 1.005 kJ/kg·°C) is to be preheated by hot exhaust gases in a crossflow heat exchanger before it enters the furnace. Air enters the heat exchanger at 95 kPa and 20°C at a rate of 1.6 m3 /s. The combustion gases (cp = 1.10 kJ/kg·°C) enter at 180°C at a rate of 2.2 kg/s and leave at 95°C. Determine the rate of entropy generation.
Chapter 5 Solutions
Thermodynamics: An Engineering Approach
Ch. 5.5 - Name four physical quantities that are conserved...Ch. 5.5 - Define mass and volume flow rates. How are they...Ch. 5.5 - Does the amount of mass entering a control volume...Ch. 5.5 - Consider a device with one inlet and one outlet....Ch. 5.5 - The ventilating fan of the bathroom of a building...Ch. 5.5 - Air enters a 16-cm-diameter pipe steadily at 200...Ch. 5.5 - A steam pipe is to transport 200 lbm/s of steam at...Ch. 5.5 - A garden hose attached with a nozzle is used to...Ch. 5.5 - A steady-flow compressor is used to compress...Ch. 5.5 - Air enters the 1-m2 inlet of an aircraft engine at...
Ch. 5.5 - A 2-m3 rigid tank initially contains air whose...Ch. 5.5 - Air enters a nozzle steadily at 2.21 kg/m3 and 40...Ch. 5.5 - A spherical hot-air balloon is initially filled...Ch. 5.5 - Water enters the constant 130-mm inside-diameter...Ch. 5.5 - A desktop computer is to be cooled by a fan whose...Ch. 5.5 - A hair dryer is basically a duct of constant...Ch. 5.5 - Refrigerant-134a enters a 28-cm-diameter pipe...Ch. 5.5 - What are the different mechanisms for transferring...Ch. 5.5 - How do the energies of a flowing fluid and a fluid...Ch. 5.5 - An air compressor compresses 6 L of air at 120 kPa...Ch. 5.5 - A house is maintained at 1 atm and 24C, and warm...Ch. 5.5 - Refrigerant-134a enters the compressor of a...Ch. 5.5 - Steam is leaving a pressure cooker whose operating...Ch. 5.5 - How is a steady-flow system characterized?Ch. 5.5 - Can a steady-flow system involve boundary work?Ch. 5.5 - A diffuser is an adiabatic device that decreases...Ch. 5.5 - The kinetic energy of a fluid increases as it is...Ch. 5.5 - The stators in a gas turbine are designed to...Ch. 5.5 - The diffuser in a jet engine is designed to...Ch. 5.5 - Air enters a nozzle steadily at 50 psia, 140F, and...Ch. 5.5 - Air at 600 kPa and 500 K enters an adiabatic...Ch. 5.5 - Carbon dioxide enters an adiabatic nozzle steadily...Ch. 5.5 - Steam enters a nozzle at 400C and 800 kPa with a...Ch. 5.5 - Air at 80 kPa and 127C enters an adiabatic...Ch. 5.5 - Air at 13 psia and 65F enters an adiabatic...Ch. 5.5 - Refrigerant-134a at 700 kPa and 120C enters an...Ch. 5.5 - Refrigerant-134a enters a diffuser steadily as...Ch. 5.5 - Air at 80 kPa, 27C, and 220 m/s enters a diffuser...Ch. 5.5 - Air enters an adiabatic nozzle steadily at 300...Ch. 5.5 - Consider an adiabatic turbine operating steadily....Ch. 5.5 - Prob. 42PCh. 5.5 - Somebody proposes the following system to cool a...Ch. 5.5 - Air is expanded from 1000 kPa and 600C at the...Ch. 5.5 - Prob. 45PCh. 5.5 - Refrigerant-134a enters a compressor at 100 kPa...Ch. 5.5 - Refrigerant-134a enters a compressor at 180 kPa as...Ch. 5.5 - Steam flows steadily through an adiabatic turbine....Ch. 5.5 - Steam flows steadily through a turbine at a rate...Ch. 5.5 - Steam enters an adiabatic turbine at 8 MPa and...Ch. 5.5 - An adiabatic air compressor compresses 10 L/s of...Ch. 5.5 - Carbon dioxide enters an adiabatic compressor at...Ch. 5.5 - Steam flows steadily into a turbine with a mass...Ch. 5.5 - Air is compressed by an adiabatic compressor from...Ch. 5.5 - Air enters the compressor of a gas-turbine plant...Ch. 5.5 - A portion of the steam passing through a steam...Ch. 5.5 - Why are throttling devices commonly used in...Ch. 5.5 - Would you expect the temperature of air to drop as...Ch. 5.5 - During a throttling process, the temperature of a...Ch. 5.5 - Someone claims, based on temperature measurements,...Ch. 5.5 - Refrigerant-134a is throttled from the saturated...Ch. 5.5 - A saturated liquidvapor mixture of water, called...Ch. 5.5 - Prob. 64PCh. 5.5 - A well-insulated valve is used to throttle steam...Ch. 5.5 - Refrigerant-134a enters the expansion valve of a...Ch. 5.5 - Prob. 68PCh. 5.5 - Prob. 69PCh. 5.5 - Consider a steady-flow heat exchanger involving...Ch. 5.5 - Prob. 71PCh. 5.5 - Refrigerant-134a at 700 kPa, 70C, and 8 kg/min is...Ch. 5.5 - Hot and cold streams of a fluid are mixed in a...Ch. 5.5 - A hot-water stream at 80C enters a mixing chamber...Ch. 5.5 - Water at 80F and 20 psia is heated in a chamber by...Ch. 5.5 - An adiabatic open feedwater heater in an electric...Ch. 5.5 - Cold water (cp = 4.18 kJ/kgC) leading to a shower...Ch. 5.5 - Steam is to be condensed on the shell side of a...Ch. 5.5 - Air (cp = 1.005 kJ/kgC) is to be preheated by hot...Ch. 5.5 - An open feedwater heater heats the feedwater by...Ch. 5.5 - Refrigerant-134a at 1 MPa and 90C is to be cooled...Ch. 5.5 - The evaporator of a refrigeration cycle is...Ch. 5.5 - An air-conditioning system involves the mixing of...Ch. 5.5 - A well-insulated shell-and-tube heat exchanger is...Ch. 5.5 - Steam is to be condensed in the condenser of a...Ch. 5.5 - Steam is to be condensed in the condenser of a...Ch. 5.5 - Two streams of water are mixed in an insulated...Ch. 5.5 - Two mass streams of the same ideal gas are mixed...Ch. 5.5 - Water is heated in an insulated, constant-diameter...Ch. 5.5 - A 110-volt electrical heater is used to warm 0.3...Ch. 5.5 - The ducts of an air heating system pass through an...Ch. 5.5 - The fan on a personal computer draws 0.3 ft3/s of...Ch. 5.5 - Saturated liquid water is heated in a steady-flow...Ch. 5.5 - Water enters the tubes of a cold plate at 70F with...Ch. 5.5 - Prob. 96PCh. 5.5 - A computer cooled by a fan contains eight PCBs,...Ch. 5.5 - A desktop computer is to be cooled by a fan. The...Ch. 5.5 - Prob. 99PCh. 5.5 - A 4-m 5-m 6-m room is to be heated by an...Ch. 5.5 - A house has an electric heating system that...Ch. 5.5 - A long roll of 2-m-wide and 0.5-cm-thick 1-Mn...Ch. 5.5 - Prob. 103PCh. 5.5 - Prob. 104PCh. 5.5 - Argon steadily flows into a constant-pressure...Ch. 5.5 - Steam enters a long, horizontal pipe with an inlet...Ch. 5.5 - Refrigerant-134a enters the condenser of a...Ch. 5.5 - A hair dryer is basically a duct in which a few...Ch. 5.5 - A hair dryer is basically a duct in which a few...Ch. 5.5 - Air enters the duct of an air-conditioning system...Ch. 5.5 - An insulated rigid tank is initially evacuated. 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Using appropriate software,...Ch. 5.5 - Prob. 180RPCh. 5.5 - A liquid R-134a bottle has an internal volume of...Ch. 5.5 - A pistoncylinder device initially contains 2 kg of...Ch. 5.5 - A pistoncylinder device initially contains 1.2 kg...Ch. 5.5 - A pressure cooker is a pot that cooks food much...Ch. 5.5 - A tank with an internal volume of 1 m3 contains...Ch. 5.5 - In a single-flash geothermal power plant,...Ch. 5.5 - An adiabatic air compressor is to be powered by a...Ch. 5.5 - The turbocharger of an internal combustion engine...Ch. 5.5 - Prob. 189RPCh. 5.5 - Consider an evacuated rigid bottle of volume V...Ch. 5.5 - An adiabatic heat exchanger is used to heat cold...Ch. 5.5 - A heat exchanger is used to heat cold water at 15C...Ch. 5.5 - An adiabatic heat exchanger is used to heat cold...Ch. 5.5 - In a shower, cold water at 10C flowing at a rate...Ch. 5.5 - Prob. 195FEPCh. 5.5 - Prob. 196FEPCh. 5.5 - Hot combustion gases (assumed to have the...Ch. 5.5 - Steam expands in a turbine from 4 MPa and 500C to...Ch. 5.5 - Steam is compressed by an adiabatic compressor...Ch. 5.5 - Refrigerant-134a is compressed by a compressor...Ch. 5.5 - Refrigerant-134a at 1.4 MPa and 70C is throttled...Ch. 5.5 - Prob. 202FEPCh. 5.5 - Prob. 203FEPCh. 5.5 - Air at 27C and 5 atm is throttled by a valve to 1...Ch. 5.5 - Steam at 1 MPa and 300C is throttled adiabatically...Ch. 5.5 - Air is to be heated steadily by an 8-kW electric...Ch. 5.5 - Saturated water vapor at 40C is to be condensed as...
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