In this work,the interactions between the environmentally friendly refrigerant propane(R290)and Polyol Ester(POE)including solubility parameters,diffusion coefficients,binding energies,and radial distribution function...In this work,the interactions between the environmentally friendly refrigerant propane(R290)and Polyol Ester(POE)including solubility parameters,diffusion coefficients,binding energies,and radial distribution functions were investigated using molecular dynamics(MD).Specifically,the effect of chain length of Pentaerythritol esters(PEC)as the representative component of POE on the interaction of PEC/R290 was discussed.The solubility parameters difference exhibits the PEC and R290 are more easily miscible as increasing chain length of PEC,and there is plateau as the chain lengths is above 8 units.In addition,it was also found that solubility parameters are various for the isomers due to the different spatial structure.Moreover,the presence of PEC would reduce the diffusion coefficient of R290 in the mixed system of R290/lubricant with the reduction of20%on average.It is also found that van der Waals forces are dominant in the R290/PEC system.The PEC molecules start to be bound to the H atoms of R290 at the first neighbor shell layer with a radius of 0.219 nm.Finally,the molecular simulation model of POE22 considering various actual components was innovatively developed.The results showed that the solubility of R290 with typical POE lubricant is affected by the composition and proportions of based oil and additives.展开更多
Considering the issues of energy saving and environment protection,the performance of refrigeration systems requires to be improved.In recent years,nano-fluids have attracted greatly attention from the researchers due...Considering the issues of energy saving and environment protection,the performance of refrigeration systems requires to be improved.In recent years,nano-fluids have attracted greatly attention from the researchers due to their outstanding thermal characteristics.In this work,the published investigations on the preparation and characterization of nano-fluids have been discussed at first.Furthermore,the key thermo-physical properties of nano-fluids,such as thermal conductivity,viscosity,specific heat and density have been summarized.Finally,the performance enhancements in different types of refrigeration systems by using nano-fluids have been reviewed.It is concluded that nano-fluids as refrigerant,lubricant or secondary fluid have wide potential application in refrigeration systems.展开更多
基金financially supported by Beijing Natural Science Foundation(3242015)the Cultivation Project Funds for Beijing University of Civil Engineering and Architecture(X23041),China。
文摘In this work,the interactions between the environmentally friendly refrigerant propane(R290)and Polyol Ester(POE)including solubility parameters,diffusion coefficients,binding energies,and radial distribution functions were investigated using molecular dynamics(MD).Specifically,the effect of chain length of Pentaerythritol esters(PEC)as the representative component of POE on the interaction of PEC/R290 was discussed.The solubility parameters difference exhibits the PEC and R290 are more easily miscible as increasing chain length of PEC,and there is plateau as the chain lengths is above 8 units.In addition,it was also found that solubility parameters are various for the isomers due to the different spatial structure.Moreover,the presence of PEC would reduce the diffusion coefficient of R290 in the mixed system of R290/lubricant with the reduction of20%on average.It is also found that van der Waals forces are dominant in the R290/PEC system.The PEC molecules start to be bound to the H atoms of R290 at the first neighbor shell layer with a radius of 0.219 nm.Finally,the molecular simulation model of POE22 considering various actual components was innovatively developed.The results showed that the solubility of R290 with typical POE lubricant is affected by the composition and proportions of based oil and additives.
基金National Natural Science Foundation of China(No.51906013)The Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture,China(JDYC20200316)。
文摘Considering the issues of energy saving and environment protection,the performance of refrigeration systems requires to be improved.In recent years,nano-fluids have attracted greatly attention from the researchers due to their outstanding thermal characteristics.In this work,the published investigations on the preparation and characterization of nano-fluids have been discussed at first.Furthermore,the key thermo-physical properties of nano-fluids,such as thermal conductivity,viscosity,specific heat and density have been summarized.Finally,the performance enhancements in different types of refrigeration systems by using nano-fluids have been reviewed.It is concluded that nano-fluids as refrigerant,lubricant or secondary fluid have wide potential application in refrigeration systems.
