【作者】 彭继军；

【导师】 杨昭；

【作者基本信息】 天津大学 ， 制冷及低温工程， 2007， 博士

【摘要】 目前的R22替代物存在诸多缺点,开发拥有自主知识产权新型环保节能R22替代物,研究替代物泄漏、扩散、安全及其它相关特性有重大意义,本文主要研究内容如下:基于CSD状态方程编制了替代工质最优化选择与计算程序,模拟计算、分析、比较多种混合工质后,确定RTJU3和RTJU4为R22替代物。和R407C相比,新替代工质具有绿色环保、滑移温度低、中高温变工况性能好等优点。实验测试和理论分析结果表明新工质RTJU3具有较高安全性能,适合用于中高温热泵中替代R22。建立储罐瞬间泄漏模型,分析了常温纯可燃工质发生瞬间泄漏条件以及发生瞬间泄漏最低条件等问题。考虑制冷剂与环境的温差换热,建立了更能反映实际储罐泄漏过程的纯工质和混合工质气液相空间动态泄漏模型,推导了判别泄漏过程中混合工质燃烧爆炸危险性增减的公式,分析了各主要内外因素对纯工质气相空间动态泄漏以及泄漏对混合工质可燃性的影响。针对储罐制冷剂质量泄漏速率变化的特点,建立了新的储罐制冷剂大空间非稳态扩散模型,通过求解模型解析解和数值解两种手段解决有限时间泄漏扩散浓度分布问题,为克服假设条件偏离实际情况的缺点修正了新扩散模型,提出一种新的重气效应修正方法,结合实例研究了新工质泄漏扩散后各种危险性以及地面火灾爆炸危险范围影响因素。研究了可燃制冷剂层流预混火焰、火焰传播机理、传播速度主要影响因素,改进了现有可燃气体爆炸极限测定试验台,测试了多种工质在常温常压空气中火焰传播速度和燃爆极限,分析了实验误差来源并提出减小误差的方法,研究了可燃纯工质和混合工质层流预混火焰传播特性与规律,提出一种新的综合评价工质燃爆危险性的方法。本文以实验和计算机仿真为手段研究开发了新型环保节能R22替代物,并开展了制冷工质泄漏扩散等其它相关研究,所用方法和得出结论可供制冷剂生产和销售厂商参考。更多还原

【Abstract】 Current substitutes for R22 have many shortcomings. It’s important to develop new environment-friendly and energy-saving R22 replacements that have self-owned intellectual property rights, and to study the leakage, diffusion, safety and other relative traits of substitutes. The main contents of this paper are as follows.Based on the CSD equation of state, a software package developed for optimal choice of alternative refrigerants is worked out. Some possible environmentally friendly alternatives for R22 were selected, and their performances were simulated. Finally, RTJU3 and RTJU4 are selected to replace R22. Compared to R407C, new refrigerants have such advantages as environmentally friendly, low slide temperature, good performances in moderately high temperature heat pump working conditions. Experimental and theoretical analyses show that RTJU3 have high security and is fit for replacing R22 in moderate-high temperature heat pumps. To obtain the instantaneous release condition of pure flammable refrigerants in tanks, an instantaneous release model is established. Considering the heat exchange between the refrigerant and environment, dynamic models of pure and mixed refrigerants leaking from vapor and liquid space were established to describe actual release processes better. A formula of judging the burnable fatalness of mix-refrigerant increase or decrease in the process of leakage is deduced.The main interior and exterior factors influencing pure refrigerants releasing from the vapor space, and the leakage’s effect on the flammability of mix-refrigerants are analyzed. Aiming at the characteristic of varied mass flow rate of refrigerants leaking from tanks, a new unsteady big-space diffusing model is put forward. The concentration of refrigerants after finite-time release and diffusion was gained by the numerical and analytical solutions of the model. To improve application value, the new diffusion model is modified, and a new modifying heavy gas effect method is set up. Through application and analyse on instance, the dangerous area of burning and blasting of new refrigerants, the factors affecting the dangerous area are investigated. Besides, this work studies the laminar premixed flame of flammable refrigerants, the mechanism of flame propagation, the main factors influencing the flame propagation velocity, improving the existed test-bed that tests the flammable limits of gas, testing the flame propagation velocity and flammable limits of many refrigerants in normal temperature and pressure air, analyzing the source of experimental error and putting forward a method to reduce it, investigating the laminar premixed flame propagation specialty and regular of flammable refrigerants, bringing forward a method to comprehensively evaluate flammable fatalness of refrigerants.New environment-friendly and energy-saving replacements for R22 are developed and the leakage, diffusion, safety and other relative characteristics of refrigerants are studied in this paper with the experiment and computer simulation as main tools. The methods and conclusions may be helpful for the producer and seller of refrigerants.更多还原