| Global warming is an urgent climate issue now,and most of the refrigerants used today are one of the sources of greenhouse gases.Therefore,promoting the replacement of new environmentally friendly refrigerants has become a common goal of the refrigeration industry.HFO refrigerants have received widespread attention due to their good performance and environmental protection characteristics.At present,some studies have analyzed the possible application scenarios of HFO refrigerants based on their properties.Among them,R1234ze(Z)studied in this paper has the same heat transfer characteristics and cycle performance as R245 fa,and can be used as its alternative refrigerant in high temperature heat pumps.In the actual replacement of refrigerants,due to the influence of lubricants on the components of the refrigeration system,lubricants for new refrigerants require proper solubility with refrigerants and good viscosity-temperature performance.Therefore,choosing lubricants suitable for HFO refrigerants and studying the viscosity of its mixed solution with lubricant has become an indispensable part of the preliminary work of promoting HFO refrigerants.(1)The main work of this paper includes several parts: For the selection of lubricants for HFO refrigerant systems,molecular dynamics simulation tools are used to establish a theoretical prediction method of solubility based on solubility parameters.The solubility of the refrigerant and lubricant can be predicted by theoretical calculation,and the lubricants that have good solubility with the refrigerant can be preliminarily selected for further experimental study.For the lubricant whose composition is unknown and cannot be modeled and calculated,an indirect method of calculating the solubility parameter is proposed,which is to determine the solubility parameter range of the lubricant by calculating the solubility parameter of the refrigerant that has been verified to have good solubility with it.(2)For R1234ze(Z),the theoretical prediction method established in(1)is used to select a high viscosity POE lubricant with good solubility with it.A measuring system for the solubility and viscosity of refrigerant and lubricant based on rotary capillary viscometer was improved.The solubility of refrigerant and lubricant are tested experimentally,and the results show that the theoretical prediction are in good agreement with the experiment.It reflects that the proposed theoretical prediction method has a certain reference for the selection of HFO refrigerants suitable for lubricants.The solubility and viscosity of R1234ze(Z)and high viscosity POE in the temperature range of 313.15 K ~ 343.15 K are measured.(3)According to the measured experimental data,the special R1234ze(Z)/POE mixed solution solubility and viscosity equations were obtained.The SEETTON mixture solubility model was used for solubility calculation,and the improved enhanced mixture viscosity calculation model was used for viscosity calculation.According to the R1234ze(Z)/POE mixed solution solubility and viscosity equations,the Daniel chart for engineering design is drawn. |
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