【作者】 王红霞；

【导师】 李苏泷；

【作者基本信息】 南京理工大学 ， 供热、供燃气、通风及空调工程， 2009， 硕士

【摘要】 随着经济的高速发展,节能和环保已成为全球范围内的重大课题,利用可再生能源也随之而引起人们的广泛兴趣。太阳能喷射式制冷系统就是利用低品位可再生能源的一种装置,其用喷射器取代了传统蒸汽压缩式制冷系统中的压缩机,喷射器有结构简单、无运动部件,运行维护费用低等特点。但由于喷射器的喷射系数较低,实际应用还很少,喷射器的设计选型也没有统一的标准。因此如何提高喷射器的喷射系数,合理设计喷射器就成为推动喷射式制冷系统发展的关键。本文研究喷射器的结构和运行工况对喷射器性能的影响,旨在提高喷射器的喷射系数,从而提高其应用于喷射制冷系统的效率,为太阳能喷射式制冷系统的研发提供理论依据。本文以Sokolov喷射器设计理论为基础,假设定压混合,辅之以经验公式,得到了喷射器结构设计的一系列模型,利用VB语言编制了喷射器结构的设计程序,并针对某别墅太阳能喷射制冷系统,设计了喷射器结构。由于喷射器内流动复杂,简单的一维计算无法了解其内部流场细节。本文还以FLUENT软件为平台,对制冷剂R134a为工质的喷射器内流动进行了数值模拟,得到了喷射器内压力、速度和温度的分布规律。同时利用数值模拟的灵活性、可重复性、低成本的特点,通过改变工作流体压力、引射流体压力、混合流体压力等工作参数,以及喷嘴面积比、喷嘴距等喷射器几何参数,计算出不同情况下喷射器的喷射系数,通过对结果进行分析,得到了各参数对喷射器性能的影响规律。更多还原

【Abstract】 With the rapid development of economic, Energy-saving and environmental protection has become a major issue all over the world. A wide range of people are interested in using of renewable energy sources. Solar ejector refrigeration system is a device which use low-grade renewable energy. The biggest difference between this system and the traditional vapor compression refrigeration system is to use ejector instead of compressor. Ejector has a simple structure, no moving parts, and operation and low maintenance costs. But the ejector entrainment ratio is very low, and the practical applications are very few. So far there is no uniform standard for ejector design. How to improve the ejector entrainment ratio is very important for promoting the use of solar ejector refrigeration system.In this paper, studied how ejector structure and operating conditions affect on ejector, in order to improve the ejector coefficient, and to improve their application of the refrigeration system, and provide a theoretical basis for it’s widely used.This paper is based on Sokolov’s 1-D analysis, assume that mixing is constant pressure, accord to empirical formula, and get the structural design of ejector model. Make programmer by Visual Basic 6.0, and use it to calculate the ejector of a solar house ejector refrigeration system.As the ejector flow is complex, 1-D analysis can not maintain its internal flow field. Take FLUENT software as a platform, simulate ejector which use R134a as the refrigerant, acquired the distribution of pressure, velocity and temperature. At the same time, by the use of numerical simulation of flexibility, repeatability, low-cost characteristics, change working parameters such as the operating fluid pressure, second fluid pressure, mixed fluid pressure, and geometric parameters such as ejector nozzle area ratio, nozzle distance, to calculate ejector coefficient under different situations. Analysis the results, and get the parameters how to affect on the ejector performance.更多还原