【作者】 姚哲卿；

【导师】 袁竹林；

【作者基本信息】 东南大学 ， 制冷与低温工程， 2005， 硕士

【摘要】 制冷空调装置不仅与人们日常生活密切相关,而且也是影响国家在能源利用方面政策的主要因素之一。所以如何利用现代计算机科学技术,在较短的周期和较低的成本下,设计和生产出性能优良的制冷空调装置,近些年来一直是制冷空调技术领域的研究人员所探讨的热点。目前,国内外对制冷系统稳态特性的研究已较为成熟,但对动态特性的研究还存在准确性和通用性不能同时提高的矛盾。本文以压缩式制冷系统为研究物理模型,建立了虚拟数值实验平台,此平台包括系统实验装置、控制台系统、测试系统(部件测试和系统测试)、数值模拟结果在线显示以及提交实验报告等几部分;在所建立的数值模拟平台上进行了动态的数值实验,对压缩式制冷四大部件分别进行了测试,通过测试,对冷凝器和蒸发器的动态特性进行了较为深入的分析和研究,对压缩机、膨胀阀模型中的特性参数进行了修正,分别得出了它们的特性曲线。本文还通过各部件模型的数值实验结果与实际实验结果的对比进一步验证了部件模型的准确性和可靠性;在上述部件模型研究的基础上建立了虚拟制冷系统实验平台,并对系统进行了数值实验,对系统启动过程的相关动态特性进行了理论上的探讨与研究。借助此虚拟实验平台,较为详尽地分析了一些结构参数和运行参数对整个系统性能(制冷量、压缩机耗功和能效比COP)的影响情况。本文对制冷系统中的换热器(蒸发器和冷凝器)提出了分区、分流型的适时动态分布参数模型,模型建立过程中考虑到流体的物性参数和湿区含液量的适时变化、流动压力损失以及管壁蓄热等影响因素,较以往的动态模型多考虑了动量守恒的关系,即可以得出各点压力的变化。在相区的判断上也给出了详细的解决办法,使模型的准确性和通用性显著提高,模型采用适时调用函数库查取流体物性参数的办法,较拟合法求解物性参数更为准确,速度更快。利用本模型可以对各种型号的套管式换热器各个细节,如沿管长任意位置相变流体的温度、压力、两相区气液比例,无相变流体、换热管壁的温度等状态参数的适时变化都能进行单独研究,可以为部件的优化和改进提供一个良好的数值测试平台。更多还原

【Abstract】 A virtual laboratory of compression refrigeration system is established in this paper. This simulation platform includes controller, experimentation equipment of system, testing equipments of system and the four components, display equipment and experimental report. Some dynamic experiments of the heat exchangers have been done on this dummy flat. The performances of compressor, condenser, evaporator and expansion valve are analyzed and researched. The interrelated characteristic constants of compressor and expansion valve are modified and the characteristic curves are given out.The main numerical model of the system is based on the dynamic models of compressor and evaporator, as well as on the static models of condenser and expansion valve. This laboratory involves the four primary components together according to the cycle diagram. The program calculates the temperature, flowrate, density, pressure and vapor fraction at each state point in the system and the heat duty at each component. Based on this dummy flat, some influences on performance of the system caused by configuration parameters and running parameters, are analyzed.In this paper, transient mathematical models are used for condenser and evaporator. These two heat exchangers are divided into a number of control volumes. In each control volume the mass, energy and momentum conservation equations are established respectively .The details of transient parameters, vapor quality, pressure loss are considered. The simulation results are compared with the data of experiments and good agreements are found. The results indicate that the proposed models can be used to research the dynamic performances of condenser and evaporator.更多还原