Design And Experimental Research Of A Low-temperature Refrigerator Based On Stirling Refrigeration Technology

It has been more than 200 years since the cryo-preservation first applied to base collection.In the past few decades,cryo-preservation has been widely researched and used in biology,medicine,bromatology and other fields with the discovery and usage of glycerin,DMSO and other antifreezes.In several years,the requirements for the device of cryo-preservation are getting higher and higher in the research domains,not only does it provide lower,more precise and easily regulated storage temperature,but also has the characteristics of energy saving and environmental protection.Stirling-cycle cryocooler has became a new cold resource applied to the low temperature refrigerator because of the high refrigeration efficiency,environment friendly refrigerant,wide cooling temperature region and the reduction of product development cost.A low temperature refrigerator using Stirling-type pulse tube cryocooler as cold source has been developed based on the design requirement of small cryogenic storage device in this paper,whose effective cubage is 2L.Design contents including thermal insulation material used in the tank and the external and internal doors,refrigerator gasket,model selection of the refrigeration system,electronic control system and the coupling structures between various systems are introduced in detail.In order to comprehensively study the distribution of air temperature field and flow field in this independently designed low temperature refrigerator,mathematical and physical models based on steady natural convection heat transfer in a three-dimension confined space have been established,and the FLUENT was used to simulate the flow and heat transfer situation in the insulating layer and the air zone inside the tank.The condensation process of steam with air near the inner wall was sucessfully modeled by applying a user defined funcion added to the FLUENT pachage at the same time.After the components of the low temperature refrigerator were developed and assembled based on the design contents,a data acquisition system was eastablished to test the cooling capacity of Stirling-type pulse tube cryocooler,the cooling performance of the refrigerator,the temperature distribution inside the box and the temperature control capability of the electronic control system.The main factor that caused the performance of the low temperature refrigerator lower than the designed index was proposed based on the comparison between the experimental results and simulation results in this paper,and it has been verified primitively by comparing the experimental results and the simulation results after correcting the numerical model.