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 9.12, Problem 117P
To determine
State the reason why the multistage compression reduces the compression work as a result of inter-cooling and the multistage expansion increases the turbine work as a result of reheating for a specified pressure ratio.
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2. A freezer of 20 TR capacity has evaporator and condenser temperatures of 30°C and
25°C respectively. The refrigerant R-12 is sub-cooled by 4°C before it enters the expansion
valve and is superheated by 5°C before leaving the evaporator. The compression is
isentropic and the valve throttling and clearance are to be neglected. If a six-cylinder, single
acting compressor with stroke equal to bore running at 1000 r.p.m. is used, determine:
A- C.O.P. of the refrigerating system,
B- Mass of refrigerant to be circulated per min,
C- Theoretical piston displacement per minute and
D- Theoretical bore and stroke of the compressor.
For a specified pressure ratio, why does multistage compression with intercooling decrease the compressor work, and multistage expansion with reheating increase the turbine work?
In a marine gas turbine unit, a high-pressure stage turbine drives the compressor and a low-pressure stage turbine drives the propeller through suitable gearing. The overall pressure ratio is 4/1 and the maximum temperature is 650 oC. the isentropic efficiencies of the compressor, H. P. turbine, L. P. turbine are 0.8, 0.83 and 0.85 respectively and the mechanical efficiency of both shafts is 98 %. Sketch the process on the T-s diagram
Calculate the pressure between turbine stages when the air intake conditions are 1.01 bar and 25 oC.
Calculate also the thermal efficiency and the shaft power when the mass flow is 60 kg/s.
NB: Neglect kinetic energy changes and the pressure loss in combustion.
Chapter 9 Solutions
Thermodynamics: An Engineering Approach
Ch. 9.12 - What are the air-standard assumptions?Ch. 9.12 - What is the difference between air-standard...Ch. 9.12 - Prob. 3PCh. 9.12 - How does the thermal efficiency of an ideal cycle,...Ch. 9.12 - How are the combustion and exhaust processes...Ch. 9.12 - What does the area enclosed by the cycle represent...Ch. 9.12 - Prob. 7PCh. 9.12 - Can the mean effective pressure of an automobile...Ch. 9.12 - What is the difference between spark-ignition and...Ch. 9.12 - Prob. 10P
Ch. 9.12 - Prob. 11PCh. 9.12 - Can any ideal gas power cycle have a thermal...Ch. 9.12 - Prob. 13PCh. 9.12 - Prob. 14PCh. 9.12 - Prob. 15PCh. 9.12 - Prob. 16PCh. 9.12 - Prob. 17PCh. 9.12 - Prob. 18PCh. 9.12 - Prob. 19PCh. 9.12 - Repeat Prob. 919 using helium as the working...Ch. 9.12 - The thermal energy reservoirs of an ideal gas...Ch. 9.12 - Consider a Carnot cycle executed in a closed...Ch. 9.12 - Consider a Carnot cycle executed in a closed...Ch. 9.12 - What four processes make up the ideal Otto cycle?Ch. 9.12 - Are the processes that make up the Otto cycle...Ch. 9.12 - How do the efficiencies of the ideal Otto cycle...Ch. 9.12 - How does the thermal efficiency of an ideal Otto...Ch. 9.12 - Why are high compression ratios not used in...Ch. 9.12 - An ideal Otto cycle with a specified compression...Ch. 9.12 - Prob. 30PCh. 9.12 - Prob. 31PCh. 9.12 - Determine the mean effective pressure of an ideal...Ch. 9.12 - Reconsider Prob. 932E. Determine the rate of heat...Ch. 9.12 - An ideal Otto cycle has a compression ratio of 8....Ch. 9.12 - Prob. 36PCh. 9.12 - A spark-ignition engine has a compression ratio of...Ch. 9.12 - An ideal Otto cycle has a compression ratio of 7....Ch. 9.12 - Prob. 39PCh. 9.12 - An ideal Otto cycle with air as the working fluid...Ch. 9.12 - Repeat Prob. 940E using argon as the working...Ch. 9.12 - Someone has suggested that the air-standard Otto...Ch. 9.12 - Repeat Prob. 942 when isentropic processes are...Ch. 9.12 - Prob. 44PCh. 9.12 - Prob. 45PCh. 9.12 - Prob. 46PCh. 9.12 - Prob. 47PCh. 9.12 - Prob. 48PCh. 9.12 - Prob. 49PCh. 9.12 - Prob. 50PCh. 9.12 - Prob. 51PCh. 9.12 - Prob. 52PCh. 9.12 - Prob. 53PCh. 9.12 - Prob. 54PCh. 9.12 - Prob. 55PCh. 9.12 - Prob. 56PCh. 9.12 - Prob. 57PCh. 9.12 - Repeat Prob. 957, but replace the isentropic...Ch. 9.12 - Prob. 60PCh. 9.12 - Prob. 61PCh. 9.12 - The compression ratio of an ideal dual cycle is...Ch. 9.12 - Repeat Prob. 962 using constant specific heats at...Ch. 9.12 - Prob. 65PCh. 9.12 - Prob. 66PCh. 9.12 - Prob. 67PCh. 9.12 - An air-standard cycle, called the dual cycle, with...Ch. 9.12 - Prob. 69PCh. 9.12 - Prob. 70PCh. 9.12 - Consider the ideal Otto, Stirling, and Carnot...Ch. 9.12 - Consider the ideal Diesel, Ericsson, and Carnot...Ch. 9.12 - An ideal Ericsson engine using helium as the...Ch. 9.12 - An ideal Stirling engine using helium as the...Ch. 9.12 - Prob. 75PCh. 9.12 - Prob. 76PCh. 9.12 - Prob. 77PCh. 9.12 - Prob. 78PCh. 9.12 - Prob. 79PCh. 9.12 - For fixed maximum and minimum temperatures, what...Ch. 9.12 - What is the back work ratio? What are typical back...Ch. 9.12 - Why are the back work ratios relatively high in...Ch. 9.12 - How do the inefficiencies of the turbine and the...Ch. 9.12 - A simple ideal Brayton cycle with air as the...Ch. 9.12 - A stationary gas-turbine power plant operates on a...Ch. 9.12 - A gas-turbine power plant operates on the simple...Ch. 9.12 - Prob. 87PCh. 9.12 - Prob. 88PCh. 9.12 - Repeat Prob. 988 when the isentropic efficiency of...Ch. 9.12 - Repeat Prob. 988 when the isentropic efficiency of...Ch. 9.12 - Repeat Prob. 988 when the isentropic efficiencies...Ch. 9.12 - Air is used as the working fluid in a simple ideal...Ch. 9.12 - An aircraft engine operates on a simple ideal...Ch. 9.12 - Repeat Prob. 993 for a pressure ratio of 15.Ch. 9.12 - A gas-turbine power plant operates on the simple...Ch. 9.12 - A simple ideal Brayton cycle uses argon as the...Ch. 9.12 - A gas-turbine power plant operates on a modified...Ch. 9.12 - A gas-turbine power plant operating on the simple...Ch. 9.12 - Prob. 99PCh. 9.12 - Prob. 100PCh. 9.12 - Prob. 101PCh. 9.12 - Prob. 102PCh. 9.12 - Prob. 103PCh. 9.12 - Prob. 104PCh. 9.12 - A gas turbine for an automobile is designed with a...Ch. 9.12 - Rework Prob. 9105 when the compressor isentropic...Ch. 9.12 - A gas-turbine engine operates on the ideal Brayton...Ch. 9.12 - An ideal regenerator (T3 = T5) is added to a...Ch. 9.12 - Prob. 109PCh. 9.12 - Prob. 111PCh. 9.12 - A Brayton cycle with regeneration using air as the...Ch. 9.12 - Prob. 113PCh. 9.12 - Prob. 114PCh. 9.12 - Prob. 115PCh. 9.12 - Prob. 116PCh. 9.12 - Prob. 117PCh. 9.12 - Prob. 118PCh. 9.12 - Prob. 119PCh. 9.12 - Prob. 120PCh. 9.12 - A simple ideal Brayton cycle without regeneration...Ch. 9.12 - A simple ideal Brayton cycle is modified to...Ch. 9.12 - Consider a regenerative gas-turbine power plant...Ch. 9.12 - Repeat Prob. 9123 using argon as the working...Ch. 9.12 - Consider an ideal gas-turbine cycle with two...Ch. 9.12 - Repeat Prob. 9125, assuming an efficiency of 86...Ch. 9.12 - A gas turbine operates with a regenerator and two...Ch. 9.12 - Prob. 128PCh. 9.12 - Prob. 129PCh. 9.12 - Prob. 130PCh. 9.12 - Prob. 131PCh. 9.12 - Air at 7C enters a turbojet engine at a rate of 16...Ch. 9.12 - Prob. 133PCh. 9.12 - A turbojet is flying with a velocity of 900 ft/s...Ch. 9.12 - A pure jet engine propels an aircraft at 240 m/s...Ch. 9.12 - A turbojet aircraft is flying with a velocity of...Ch. 9.12 - Prob. 137PCh. 9.12 - Prob. 138PCh. 9.12 - Reconsider Prob. 9138E. How much change would...Ch. 9.12 - Consider an aircraft powered by a turbojet engine...Ch. 9.12 - An ideal Otto cycle has a compression ratio of 8....Ch. 9.12 - An air-standard Diesel cycle has a compression...Ch. 9.12 - Prob. 144PCh. 9.12 - Prob. 145PCh. 9.12 - Prob. 146PCh. 9.12 - Prob. 147PCh. 9.12 - A Brayton cycle with regeneration using air as the...Ch. 9.12 - Prob. 150PCh. 9.12 - A gas turbine operates with a regenerator and two...Ch. 9.12 - A gas-turbine power plant operates on the...Ch. 9.12 - Prob. 153PCh. 9.12 - An air-standard cycle with variable specific heats...Ch. 9.12 - Prob. 155RPCh. 9.12 - Prob. 156RPCh. 9.12 - Prob. 157RPCh. 9.12 - Prob. 158RPCh. 9.12 - Prob. 159RPCh. 9.12 - Prob. 160RPCh. 9.12 - Prob. 161RPCh. 9.12 - Consider an engine operating on the ideal Diesel...Ch. 9.12 - Repeat Prob. 9162 using argon as the working...Ch. 9.12 - Prob. 164RPCh. 9.12 - Prob. 165RPCh. 9.12 - Prob. 166RPCh. 9.12 - Prob. 167RPCh. 9.12 - Consider an ideal Stirling cycle using air as the...Ch. 9.12 - Prob. 169RPCh. 9.12 - Consider a simple ideal Brayton cycle with air as...Ch. 9.12 - Prob. 171RPCh. 9.12 - A Brayton cycle with a pressure ratio of 15...Ch. 9.12 - Helium is used as the working fluid in a Brayton...Ch. 9.12 - Consider an ideal gas-turbine cycle with one stage...Ch. 9.12 - Prob. 176RPCh. 9.12 - Prob. 177RPCh. 9.12 - Prob. 180RPCh. 9.12 - Prob. 181RPCh. 9.12 - Prob. 182RPCh. 9.12 - For specified limits for the maximum and minimum...Ch. 9.12 - A Carnot cycle operates between the temperature...Ch. 9.12 - Prob. 194FEPCh. 9.12 - Prob. 195FEPCh. 9.12 - Helium gas in an ideal Otto cycle is compressed...Ch. 9.12 - Prob. 197FEPCh. 9.12 - Prob. 198FEPCh. 9.12 - In an ideal Brayton cycle, air is compressed from...Ch. 9.12 - In an ideal Brayton cycle, air is compressed from...Ch. 9.12 - Consider an ideal Brayton cycle executed between...Ch. 9.12 - An ideal Brayton cycle has a net work output of...Ch. 9.12 - In an ideal Brayton cycle with regeneration, argon...Ch. 9.12 - In an ideal Brayton cycle with regeneration, air...Ch. 9.12 - Consider a gas turbine that has a pressure ratio...Ch. 9.12 - An ideal gas turbine cycle with many stages of...
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