tailieunhanh - Lecture Companion site to accompany thermodynamics: An engineering approach (7/e): Chapter 10 - Yunus Çengel, Michael A. Boles

Chapter 10 - Vapor and combined power cycles. The objectives of Chapter 10 are to: Analyze vapor power cycles in which the working fluid is alternately vaporized and condensed, analyze power generation coupled with process heating called cogeneration, investigate ways to modify the basic Rankine vapor power cycle to increase the cycle thermal efficiency. | Chapter 10 Vapor and Combined Power Cycles Study Guide in PowerPoint to accompany Thermodynamics: An Engineering Approach, 7th edition by Yunus A. Çengel and Michael A. Boles Overview of a steam power plant Photo courtesy of Progress Energy Carolinas, Inc. We consider power cycles where the working fluid undergoes a phase change. The best example of this cycle is the steam power cycle where water (steam) is the working fluid. For more information and animations illustrating this topic visit the Animation Library developed by Professor S. Bhattacharjee, San Diego State University, at this link. Carnot Vapor Cycle The heat engine may be composed of the following components. The working fluid, steam (water), undergoes a thermodynamic cycle from 1-2-3-4-1. The cycle is shown on the following T-s diagram. The thermal efficiency of this cycle is given as Note the effect of TH and TL on th, Carnot. The larger | Chapter 10 Vapor and Combined Power Cycles Study Guide in PowerPoint to accompany Thermodynamics: An Engineering Approach, 7th edition by Yunus A. Çengel and Michael A. Boles Overview of a steam power plant Photo courtesy of Progress Energy Carolinas, Inc. We consider power cycles where the working fluid undergoes a phase change. The best example of this cycle is the steam power cycle where water (steam) is the working fluid. For more information and animations illustrating this topic visit the Animation Library developed by Professor S. Bhattacharjee, San Diego State University, at this link. Carnot Vapor Cycle The heat engine may be composed of the following components. The working fluid, steam (water), undergoes a thermodynamic cycle from 1-2-3-4-1. The cycle is shown on the following T-s diagram. The thermal efficiency of this cycle is given as Note the effect of TH and TL on th, Carnot. The larger the TH the larger the th, Carnot The smaller the TL the larger the th, Carnot To increase the thermal efficiency in any power cycle, we try to increase the maximum temperature at which heat is added. Reasons why the Carnot cycle is not used: Pumping process 1-2 requires the pumping of a mixture of saturated liquid and saturated vapor at state 1 and the delivery of a saturated liquid at state 2. To superheat the steam to take advantage of a higher temperature, elaborate controls are required to keep TH constant while the steam expands and does work. To resolve the difficulties associated with the Carnot cycle, the Rankine cycle was devised. The steam power plant is composed of several distinct componets. Steam generator or boiler Turbine and electric generator Condenser and cooling water system Pumps Steam generator or boiler. Down comer and riser tubes Pulverized Coal and air injectors Heat exchangers for superheating, reheating, and water economizers Air preheater .