A Multilayer Insulation Thermal Performance Test System With Cryocooler Cooling

To meet the requirements of cryogenic and efficient thermal insulation for the efficient storage,transportation and use of cryogenic clean fuels（liquid hydrogen and LNG）,a calorimetric characterization method based on the performance of cryocooler is proposed to indirectly measure the thermal insulation performance of vacuum multilayer materials.On this basis,a multilayer insulation performance test system for cryocooler cooling is designed and built.The test system can test the thermal insulation performance of multilayer materials in the temperature range of above liquid hydrogen region（>15K）,and provide practical and reliable data for the design of cryogenic clean fuel storage and transportation equipment,so as to ensure the safe and reliable operation of relevant equipment.（1）Construction of a method for characterizing radiant heat transfer rate based on cryocooler performanceFirstly,the radiation heat transfer rate model in the closed cavity is established in this paper.The radiation heat transfer rate of the test chamber is obtained by solving the model with COMSOL software.The experimental verification is carried out by using the liquid nitrogen temperature region apparent thermal conductivity test system.The relative error between the theoretical calculation and the experimental test is 0.98%.It is proved that the radiation heat transfer model can be used to calculate the radiation heat transfer between the surfaces of the closed cavity in the actual experiment.According to the radiation heat transfer model,a characterization method of radiation heat transfer based on cryocooler performance is established,which lays a theoretical foundation for the development of a new test system.（2）Research and development of multi-layer insulation material performance test system for cryocooler coolingBased on the characterization method of radiant heat transfer of cryocooler performance.Through thermodynamic analysis and mechanical performance analysis,the size of the main test component cold cylinder is designed,the appropriate cryocooler and vacuum unit are selected,the man-machine interface is designed by Lab VIEW software,the automatic data acquisition is realized by programming,and the multilayer insulation performance test system for cryocooler cooling is developed,The operation steps of the system are determined.（3）Performance analysis of multilayer insulation material performance test systemIn order to verify the accuracy of the multilayer insulation performance test system cooled by the cryocooler,the cold cylinder high vacuum radiation heat transfer test experiment is carried out on the test system.Compared with the calculation results of the radiation heat transfer model in the closed chamber,the relative errors of temperature distribution and radiation heat transfer are within 5%,which meets the design requirements.The thermal insulation performance of the multilayer materials provided by FORSTAR was tested.The apparent thermal conductivity of the multilayer insulation was measured at 16 K、48 K and 77 K,which were respectively 4.43×10^-4W/（m·K）、4.64×10^-4 W/（m·K）and 4.51×10^-4 W/（m·K）。...