多元混合物的热力性质及绿色环保制冷工质的研究

发布时间：2018-06-22 11:24

本文选题：制冷剂替代 + HFOs　；参考：《武汉纺织大学》2017年硕士论文

【摘要】：从欧盟在2006年提出的F-gas法规及其在2014年对法规所作的修订(NO 517/2014)可以看出,人类愈加重视对制冷剂GWP的控制。由于我国是世界上最大的HCFCs生产和消耗国,而且传统的HCFCs替代制冷剂如R134a、R410A、R407C等的GWP值较高。寻找绿色环保替代制冷剂已成为我国制冷空调领域实现可持续发展战略的重要任务之一。本文以目前汽车空调中常用的R134a为例进行混合工质的替代物理论研究,选择对R134a、R1234yf、R1234ze(E)、R32、R152a、R600a及其混合物进行热力性质分析。本文根据热力学微分关系式,用CSD、MH方程结合饱和液体密度方程、饱和蒸汽压方程和理想气体比热方程获得了各单工质的热力性质。为方便分析各单工质的汽车空调制冷循环性能,在编制热力性质计算程序的基础上运用VS2010建立了理论循环计算平台。经验算比较,平台的计算精度较高,满足工程计算需求。在此基础上对比了各工质与R134a的循环性能差异。通过比较,发现R1234yf有助于实现直接灌注式替代且获得了工质的可能配比方案。本文使用RKS、PR、MH-81方程结合多种混合法则建立了混合工质的热物性模型。在对各二元混合物模型的VLE计算结果进行比较后,根据计算精度和稳定性选取由PR+vdW建立的热物性模型分析混合物的气液相平衡特性。分析发现,R1234yf/R134a、R1234yf/R600a、R1234ze(E)/R600a、R1234yf/R134a/R152a、R1234yf/R134a/R600a为共沸混合物;R1234yf/R152a、R1234ze(E)/R152a为近共沸混合物;R1234yf/R32为非共沸混合物。之后,结合余函数法计算出混合工质的热力性质。为获得混合工质的理论循环性能,本文在单工质循环计算程序的基础上编制了混合工质的制冷循环计算程序。通过对不同摩尔组分比下混合工质的泡、露点压力、在汽车空调典型工况下的循环性能和GWP设定筛选条件,确定适宜摩尔组分比范围。然后,将处于适宜摩尔组分比范围的混合工质的循环性能与R134a和R1234yf进行比较,得出R1234yf/R134a(0.89/0.11)、R1234yf/R152a(0.80/0.20)、R1234yf/R134a/R152a(0.71/0.12/0.17)、R1234yf/R134a/R600a(0.74/0.21/0.05)具有较高的直接替代R134a的潜力,且其COP高于R1234yf。最后,通过比较混合工质制冷系统的性能与过冷度、过热度及冷凝温度的关系,指出替换工质在制冷系统中提高性能的优化途径。
[Abstract]:From the F-gas regulation proposed by the European Union in 2006 and its revision in 2014 (no 517 / 2014), it can be seen that more attention has been paid to the control of the refrigerant GWP. Since China is the largest producer and consumer of HCFCs in the world, the GWP values of traditional HCFCs substitute refrigerants such as R134aC410ANR407C are higher. It has become one of the important tasks of the sustainable development strategy in the field of refrigeration and air conditioning in China to find green environmental alternative refrigerants. In this paper, taking R134a commonly used in automobile air conditioning as an example to study the substitution theory of the mixed working fluid, the thermodynamic properties of R134a1 / R1234yfU R1234ze (E) / R32C / R152a / R600a and its mixture are analyzed in terms of thermodynamic properties of R134a, R1234yfU, R1234ze (E) and its mixture. According to the differential equation of thermodynamics, the thermodynamic properties of each working medium are obtained by using CSD MH equation combined with saturated liquid density equation, saturated vapor pressure equation and ideal gas specific heat equation. In order to analyze the performance of automobile air conditioning refrigeration cycle with single working fluid, a theoretical cycle calculation platform was established by using VS2010 on the basis of compiling the calculation program of thermodynamic properties. Compared with empirical calculation, the accuracy of the platform is high, which meets the need of engineering calculation. On the basis of this, the cyclic performance of each working fluid is compared with that of R134a. By comparison, it is found that R1234yf is helpful to realize the direct perfusion substitution and to obtain the possible formula of the working medium. In this paper, the thermal physical properties model of mixed working fluids is established by using RKSU PRN MH-81 equation and several mixing laws. After comparing the VLE calculation results of the binary mixture models, the vapor-liquid equilibrium characteristics of the mixture are analyzed according to the accuracy and stability of the calculation. The thermal physical properties model established by PR VDW is selected to analyze the equilibrium characteristics of the mixture. The analysis found that R1234yfr / R1234yf / R600av R1234ze (E) R1234yfr / R1234yfr / R1234yfr / R1234yfr / R134aR600a is an azeotropic mixture, R1234yf / R152a (E) / R152a is a nonazeotropic mixture, R1234yrr32 is a non-azeotropic mixture. After that, the thermodynamic properties of the mixed working fluid are calculated by using the residual function method. In order to obtain the theoretical cycle performance of the mixed working fluid, the calculation program of the refrigeration cycle of the mixed working fluid is compiled on the basis of the calculation program of the single working fluid cycle. The suitable range of mole ratio was determined by setting the conditions of selection of foam, dew point pressure, cycle performance and GWP under typical working conditions of automobile air conditioning system under different molar fraction ratios. Then, by comparing the cycle performance of the mixed working fluid in the appropriate molar ratio range with R134a and R1234yf, it is concluded that R1234yfr / R134a (0.89 / 0.11) R1234yfP / R152a (0.80 / 0.20) / R1234yfP / R134a / R152a (0.71r / 0.120.17) / R1234yf / R134a / R600a (0.74 / 0.21 / 0.05) has a higher potential to replace R134a directly, and its cop is higher than that of R1234yfR / R1234yf. Finally, by comparing the relationship between the performance of mixed refrigerant refrigeration system and supercooling degree, superheat degree and condensing temperature, the optimized way to improve the performance of refrigerant in refrigeration system is pointed out.
【学位授予单位】：武汉纺织大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U463.851;TB64

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