The Optimal Thermodynamic Analysis Of Irreversible Joule-Brayton And Its Combined Cycle

On the basis of understanding and summarizing the current developments of finite time thermodynamic theory and Brayton thermodynamic cycle, By using the method of theoretical analysis and numerical calculations, this paper focus on the studies of thermodynamic optimal performance of irreversible Jouel- Brayton and its congeneratin,combined cycle with the con-sideration of the heat resistance of exchanger,irreversible losses in the compressors and turbine and heat leak.It consists of the following three main parts:The first part concentrates on making an analysis for the effects of heat transfer, the losses of internal irreversible compression and internal irreversible expansion in the piston and variable specific heats of working fluid on performance of the cycle by using the irreversible reciprocat-ing Brayton cycle as an example.Under typical circulation performance parameters, Drawn out the performance characteristics curve of the engine. Concluded that a number of important pa-rameters such as press ratio, optimize interval of temperature of working fluid.The second part concentrates on the exergy optimization of the Joule-Brayton cogeneration cycle. Considering the work and the heat is difference in quality.Exergy optimization has been carried out for the Jouel-Brayton cogeneration cycle using the theory of thermodynamics opti-mization. At first, chapter 3established the irreversible Jouel-Brayton cogeneration theoretical model of the system design parameters, considered the effects of a finite-rate of heat transfer, heat leak and internal irreversibility.Then analyzes the advantages and disadvantages of the ex-isting performance evaluation criteria forcogeneration system. Finally choose the two more rea-sonable the objective function to analysis the performance of the irreversible Jouel-Brayton co-generationsystem. That is, exergy performance coefficient and efficiency of the cogeneration. The influence of some specific parameters of the cogeneration system on its exergy performance coefficient and efficiency of the cogeneration is discussed. Gives the optimization interval of some important parameters. The third part concentrates on the ecological and efficiency optimal performance for a steady irreversible combined Brayton -Rankine cycleby solar energy through the theory of the finite-time thermodynamics. Chapter 4 uses the exergy-based ecological coefficient and effi-ciency as the objective function; at first, analyzing the steady combined cycle model of Bray-ton-Rankine with finite-rate of heat resistance, heatleakage, internal irreversibility and supple-mental combustion. The effects of the above factors on the ecological performance of the system and the efficiency of the system are discussed by detailed numerical examples.The results obtained here are closer to the performance characteristics of the actual heat en-gine. It will help to optimize the design of the heat engine and improve the performance of the heat engine.