Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 10.9, Problem 13P
The entropy of steam increases in actual steam turbines as a result of irreversibilities. In an effort to control entropy increase, it is proposed to cool the steam in the turbine by running cooling water around the turbine casing. It is argued that this will reduce the entropy and the enthalpy of the steam at the turbine exit and thus increase the work output. How would you evaluate this proposal?
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Chapter 10 Solutions
Thermodynamics: An Engineering Approach
Ch. 10.9 - Why is the Carnot cycle not a realistic model for...Ch. 10.9 - Why is excessive moisture in steam undesirable in...Ch. 10.9 - A steady-flow Carnot cycle uses water as the...Ch. 10.9 - A steady-flow Carnot cycle uses water as the...Ch. 10.9 - Consider a steady-flow Carnot cycle with water as...Ch. 10.9 - Water enters the boiler of a steady-flow Carnot...Ch. 10.9 - What four processes make up the simple ideal...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...
Ch. 10.9 - How do actual vapor power cycles differ from...Ch. 10.9 - Compare the pressures at the inlet and the exit of...Ch. 10.9 - The entropy of steam increases in actual steam...Ch. 10.9 - Is it possible to maintain a pressure of 10 kPa in...Ch. 10.9 - A simple ideal Rankine cycle with water as the...Ch. 10.9 - A simple ideal Rankine cycle with water as the...Ch. 10.9 - A simple ideal Rankine cycle which uses water as...Ch. 10.9 - Consider a solar-pond power plant that operates on...Ch. 10.9 - Consider a 210-MW steam power plant that operates...Ch. 10.9 - Consider a 210-MW steam power plant that operates...Ch. 10.9 - A simple ideal Rankine cycle with water as the...Ch. 10.9 - A simple ideal Rankine cycle with water as the...Ch. 10.9 - A steam Rankine cycle operates between the...Ch. 10.9 - A steam Rankine cycle operates between the...Ch. 10.9 - A simple Rankine cycle uses water as the working...Ch. 10.9 - The net work output and the thermal efficiency for...Ch. 10.9 - A binary geothermal power plant uses geothermal...Ch. 10.9 - Consider a coal-fired steam power plant that...Ch. 10.9 - Show the ideal Rankine cycle with three stages of...Ch. 10.9 - Is there an optimal pressure for reheating the...Ch. 10.9 - How do the following quantities change when a...Ch. 10.9 - Consider a simple ideal Rankine cycle and an ideal...Ch. 10.9 - Consider a steam power plant that operates on the...Ch. 10.9 - Consider a steam power plant that operates on the...Ch. 10.9 - An ideal reheat Rankine cycle with water as the...Ch. 10.9 - Steam enters the high-pressure turbine of a steam...Ch. 10.9 - An ideal reheat Rankine cycle with water as the...Ch. 10.9 - A steam power plant operates on an ideal reheat...Ch. 10.9 - Consider a steam power plant that operates on a...Ch. 10.9 - Repeat Prob. 1041 assuming both the pump and the...Ch. 10.9 - Prob. 43PCh. 10.9 - Prob. 44PCh. 10.9 - How do open feedwater heaters differ from closed...Ch. 10.9 - How do the following quantities change when the...Ch. 10.9 - Cold feedwater enters a 200-kPa open feedwater...Ch. 10.9 - In a regenerative Rankine cycle. the closed...Ch. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - Consider an ideal steam regenerative Rankine cycle...Ch. 10.9 - Consider a steam power plant that operates on the...Ch. 10.9 - Consider a steam power plant that operates on the...Ch. 10.9 - Consider a steam power plant that operates on the...Ch. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - Repeat Prob. 1060, but replace the open feedwater...Ch. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - A simple ideal Rankine cycle with water as the...Ch. 10.9 - Prob. 64PCh. 10.9 - An ideal reheat Rankine cycle with water as the...Ch. 10.9 - Consider a steam power plant that operates on a...Ch. 10.9 - Prob. 67PCh. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - The schematic of a single-flash geothermal power...Ch. 10.9 - What is the difference between cogeneration and...Ch. 10.9 - Prob. 71PCh. 10.9 - Prob. 72PCh. 10.9 - Consider a cogeneration plant for which the...Ch. 10.9 - Steam is generated in the boiler of a cogeneration...Ch. 10.9 - A large food-processing plant requires 1.5 lbm/s...Ch. 10.9 - An ideal cogeneration steam plant is to generate...Ch. 10.9 - Steam is generated in the boiler of a cogeneration...Ch. 10.9 - Consider a cogeneration power plant modified with...Ch. 10.9 - Prob. 80PCh. 10.9 - Why is the combined gassteam cycle more efficient...Ch. 10.9 - The gas-turbine portion of a combined gassteam...Ch. 10.9 - A combined gassteam power cycle uses a simple gas...Ch. 10.9 - Reconsider Prob. 1083. An ideal regenerator is...Ch. 10.9 - Reconsider Prob. 1083. Determine which components...Ch. 10.9 - Consider a combined gassteam power plant that has...Ch. 10.9 - Prob. 89PCh. 10.9 - What is the difference between the binary vapor...Ch. 10.9 - Why is mercury a suitable working fluid for the...Ch. 10.9 - Why is steam not an ideal working fluid for vapor...Ch. 10.9 - By writing an energy balance on the heat exchanger...Ch. 10.9 - Prob. 94RPCh. 10.9 - Steam enters the turbine of a steam power plant...Ch. 10.9 - Consider a steam power plant operating on the...Ch. 10.9 - A steam power plant operates on an ideal Rankine...Ch. 10.9 - Consider a steam power plant that operates on a...Ch. 10.9 - Repeat Prob. 1098 assuming both the pump and the...Ch. 10.9 - Consider an ideal reheatregenerative Rankine cycle...Ch. 10.9 - Prob. 101RPCh. 10.9 - A textile plant requires 4 kg/s of saturated steam...Ch. 10.9 - Consider a cogeneration power plant that is...Ch. 10.9 - Prob. 104RPCh. 10.9 - Prob. 105RPCh. 10.9 - Reconsider Prob. 10105E. It has been suggested...Ch. 10.9 - Reconsider Prob. 10106E. During winter, the system...Ch. 10.9 - Prob. 108RPCh. 10.9 - Prob. 109RPCh. 10.9 - A steam power plant operates on an ideal...Ch. 10.9 - A Rankine steam cycle modified for reheat, a...Ch. 10.9 - Show that the thermal efficiency of a combined...Ch. 10.9 - Prob. 118RPCh. 10.9 - A solar collector system delivers heat to a power...Ch. 10.9 - Starting with Eq. 1020, show that the exergy...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Consider a simple ideal Rankine cycle. If the...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Consider a simple ideal Rankine cycle with fixed...Ch. 10.9 - Consider a steady-flow Carnot cycle with water as...Ch. 10.9 - Prob. 126FEPCh. 10.9 - Prob. 127FEPCh. 10.9 - A simple ideal Rankine cycle operates between the...Ch. 10.9 - Pressurized feedwater in a steam power plant is to...Ch. 10.9 - Consider a steam power plant that operates on the...Ch. 10.9 - Consider a combined gas-steam power plant. Water...
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- An isentropic (s1 = s2) turbine in a steam generating plant receives steam at a pressure of 7 MPa and 550 0C, and exhaust at 20 kPa. The turbine inlet is 3 m higher than the turbine exit. The inlet steam velocity is 15 m/sec and the exit velocity is 300 m/sec. Calculate the turbine work per unit mass of steam. (Hint: s1 = s2 = sf2 + x2sfg2)arrow_forwardHow do the inefficiencies of the turbine and the compressor affect the thermal efficiency of a gas-turbine engine?arrow_forwardIn an air standard gas turbine cycle, air at 14.5 psia and 70 F is first compressed to 80 psia in a compressor of 82 percent efficiency. The hot air leaving the combustion chamber at 1250 F is expanded back to 14.5 psia in a turbine of 85 percent efficiency. If a regenerator is inserted into the cycle to heat the air leaving the compressor to 650 F, determine the thermal efficiency of the cycle and the effectiveness of the regenerator.arrow_forward
- Discuss the reversible, irreversible, and impossible process of the Carnot cycle.arrow_forwardCan you imagine a steam power plant working without steam condenser, letting the turbine throw its exhaust steam away into the ambient air? Discuss the consequences of such stupid idea.arrow_forwardhow does mechanical efficiency affect net power output calculation of a gas turbine power plant. does it only affect the compressor work. does it have an effect on the net work.arrow_forward
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