低温余热有机朗肯循环发电系统稳态特性仿真及性能研究

发布时间：2018-08-27 19:53

【摘要】：摘要：国内外学者在低温余热ORC发电系统研究中主要以理论计算和实验研究为主,理论计算由于精度低非常不可靠,实验研究则具有成本高、不易优化等缺点。而采用计算机进行模拟仿真是一种非常好的方法,能够有效的克服理论计算和实验研究带来的弊端。本文提出利用模拟仿真的方法研究不同的外界参数对低温余热ORC发电系统其他参数和性能参数的影响,主要做了以下工作：首先,本文概述了低温余热ORC发电系统的研究现状,介绍了其原理及组成结构,对比分析了四种常用的低沸点干性工质对系统的不同影响,理论计算表明R600a优于其他三种工质。选取R600a作为循环工质,设计了一套低温余热ORC发电系统的物理原型,并选取了该物理原型中的膨胀机、蒸发器、冷凝器、工质泵的型号。其次,以ORC物理原型为研究对象,利用稳态集中参数法对其建立了四大主要部件的数学模型,并分别给出了每个部件数学模型的具体算法。其中膨胀机和工质泵采用集中参数法建模,冷凝器和蒸发器采用分区集中参数法建模,针对较复杂的蒸发器仿真数学模型的可靠性选取了某文献中的数据对其进行了验证,结果表明所建模型仿真计算值与文献中数据最大相对误差不超过9%,模型是可靠的。最后利用质量、动量和能量方程将四大部件耦合进行求解,本文给出了耦合求解的具体算法流程。基于ORC系统的算法及物性软件Refprop,利用Visual fortran软件编制了ORC系统的仿真计算程序。最后,利用以上建立的ORC系统稳态仿真的数学模型对不同热源温度,热源流量、冷却水温度、冷却水流量以及工质流量条件下ORC系统其他内部参数和性能参数变化进行仿真,根据仿真计算的结果定量地分析和研究热源温度,热源流量、冷却水温度、冷却水流量以及工质流量对低温余热ORC发电系统的蒸发温度、冷凝温度以及膨胀比等内部参数和输出功率、循环效率等性能参数的影响,仿真计算的结果为ORC发电系统的设计和优化提供了重要的数据参考依据。
[Abstract]:Abstract: domestic and foreign scholars mainly focus on theoretical calculation and experimental research in the research of low-temperature waste heat ORC power generation system. The theoretical calculation is very unreliable because of its low precision, but the experimental research has the disadvantages of high cost and difficult to optimize. Computer simulation is a very good method, which can effectively overcome the shortcomings of theoretical calculation and experimental research. In this paper, the influence of different external parameters on other parameters and performance parameters of low-temperature waste heat ORC power generation system is studied by means of simulation. The main work is as follows: first, This paper summarizes the research status of low temperature waste heat ORC power generation system, introduces its principle and structure, compares and analyzes the different influences of four commonly used dry working fluids with low boiling point on the system. The theoretical calculation shows that R600a is superior to the other three working fluids. A physical prototype of a low-temperature afterheat ORC power generation system is designed by using R600a as a circulating working medium. The models of expander, evaporator, condenser and working fluid pump in the physical prototype are also selected. Secondly, taking the physical prototype of ORC as the research object, the mathematical models of the four main components are established by using the steady-state lumped parameter method, and the specific algorithms of the mathematical models of each component are given respectively. The expander and the working fluid pump are modeled by lumped parameter method, and the condenser and evaporator are modeled by zonal lumped parameter method. The reliability of the complicated mathematical model of evaporator simulation is verified by the data in some literature. The results show that the maximum relative error between the calculated value and the data in the literature is less than 9 and the model is reliable. Finally, the coupling of the four components is solved by the mass, momentum and energy equations. The detailed algorithm flow of the coupling solution is given in this paper. Based on the algorithm of ORC system and the physical property software Refprop, the simulation program of ORC system is compiled by using Visual fortran software. Finally, the mathematical model of steady state simulation of ORC system is used to simulate the change of other internal and performance parameters of ORC system under the conditions of different heat source temperature, heat source flow, cooling water temperature, cooling water flow and working fluid flow. According to the results of simulation, the evaporation temperature of heat source temperature, heat source flow rate, cooling water temperature, cooling water flow rate and working fluid flow rate on low temperature waste heat ORC power generation system are quantitatively analyzed and studied. The effects of internal parameters such as condensing temperature and expansion ratio, output power, cycle efficiency and other performance parameters are discussed. The simulation results provide an important data reference for the design and optimization of ORC power generation system.
【学位授予单位】：中南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM617

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