Applications of finite-time thermodynamics in thermodynamic cycles
| Autor: | Ching-Yang Cheng, 鄭慶陽 |
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| Rok vydání: | 1996 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 84 In this study, a steady-flow approach in finite-time thermo- dynamics has been used to study on the performance optimizations of heat engines and heat pumps from the viewpoints of various ob- jective functions. The topics studied include: (1) ecological- criterion-function optimizations of endoreversible Brayton heat engines with isothermal heat sources, (2) power optimiztions of endoreversible regenerative Brayton heat engines with isothermal heat sources, (3) power optimizations of endoreversible inter- cooled Brayton heat engines with isothermal heat sources, (4) performance-of- coefficient optimizations of irreversible Carnot heat pumps with isothermal heat sources, (5) power optimizations of irreversible Brayton heat engines with isothermal heat sour- ces,(6) efficiency optimizations of irreversible Brayton heat en- gines with isothermal heat sources, (7) ecological- criterion- function optimizations of irreversible Carnot heat engines with variable-temperature heat sources. The results obtained are: (1) The better design point of a heat engine is positioned between the maximum-power point and the maximum- efficiency point, and with ecological criterion functions as objective functions, a heat engine has a balance between its power output, thermal efficiency and entropy gene- ration rate. (2) The irreversible models consider three types of irreversibilities: finite thermal conductance between the working fluid and reservoirs, heat leaks between the resevoirs and irreversibilities in the processes of expansion and com- pression, and the power-efficiency relationship obtained by this model is a closed loop-like curve, similar to the charac- terisitic curves of real heat engines. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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