Simulation And Experimental Study On Regenerator Of High Cooling Power Stirling Cryocooler

With the rapid development of high-temperature superconducting technology,liquefied air technology and low-temperature liquid preservation technology,the demand for large-capacity low-temperature refrigeration is increasing.Because of its advantages such as high efficiency,low noise and safety,the Stirling cryocooler has played an important role in the field of low temperature refrigeration.At present,the calculation of the regenerator of the large-capacity Stirling cryocooler depends on the old empirical formula obtained,and lacks a more specific and quantified method to improve the calculation accuracy;the interaction mechanism between the structural parameters and the working parameters of the regenerator needs further exploration.In this paper,all numerical simulation and experimental research of cryocoolers and regenerator is rely on a four-cylinder high-cooling Stirling cryocooler driven by a crank connecting rod.Simulation calculation were undertaken using Sage software,and the experimental high cooling power four-cylinder Stirling cryocooler was converted from a Stirling engine.Stirling cryocooler simulation calculations show that,with the increase of wire diameter or porosity can reduce the resistance loss of regenerator and increase the enthalpy flow loss.There is a porosity in each wire diameter that causes a sudden change in enthalpy flow loss.The main loss is resistance loss.Variable porosity regenerator hot end to cold end porosity should be increased to reduce losses.Analyze the impact of the two conditions of the refrigerator's charging pressure and operating frequency on the performance of the cryocooler.There is an optimal working state to minimize the losses.COP decreases with the increase of inflation pressure.When the inflation pressure is low,COP decreases first and then increases with the operating frequency,and the lowest point is between 20 and 25 Hz.When the inflation pressure is high,COP increases with the increase of operating frequency.In the experiment,when the inflation pressure is 1.5 MPa,the input power is 18 k W,it takes 2500 s to cool the cold end of the refrigerator from room temperature to120 K,and the minimum temperature is stable to 100 K,and get 663 W cooling capacity.As the inflation pressure increases,the cooling capacity increases,and the minimum cooling temperature decreases.The experimentally measured changes in cooling capacity and COP with pressure and frequency are consistent with the simulation results,but there is a gap between the experimental value and the analogvalue,the main reason are simulation calculation errors,mechanical friction loss,and working fluid pollution loss.The refrigeration experiments compared the performance of R1 and R6 regenerators under different working conditions,under high-voltage and low-frequency working conditions,R6 performance is better,under low-frequency and high-frequency operating conditions,R1 performance is superior.The empirical formulas of the friction coefficients of the two regenerators are fitted.