Study On Heat Transfer Characteristics Of Refrigerator Cooled High Temperature Superconductor Cable In Space

High temperature superconducting(HTS)cables can transport large direct current without resistance.They can be used in electric power transmission from photovoltaic solar cells to microwave emitter in Space Solar Power Station,which saves the heavy power conversion equipment required by conventional conductor power transmission systems and saves rocket launch costs.To achieve the engineering application of HTS cables,the key is to ensure the normal operation of the HTS cable in the low temperature environment and thermal stability.Therefore,through the heat transfer analysis and calculation of the refrigerator cooling HTS cable in space,the temperature response of the HTS cable under different conditions is obtained.Analyze the heat transfer characteristics of refrigerator cooling HTS cables,reduce the effect of disadvantages of slow cooling,poor temperature uniformity,and low thermal shock tolerance.It can provide technical basis for the configuration of refrigerator cooling system for the application of high temperature superconducting cables in space.In this paper,according to the vacuum,low-temperature space environment and the cooling characteristics of refrigerator conduction cooling,analyze the special structure of HTS cables used for the cooling of refrigerators in space,and establishes the two-dimensional transient heat transfer analysis model for HTS cable.The finite element analysis of the heat transfer analysis model was carried out,and using MATLAB programming to achieve the finite element numerical calculation.Based on the MATLAB finite element numerical calculation method,the thermal load and transient heat transfer analysis of the HTS cable in the static cooling process,the running normal current process and the running fault current process under the cooling of the refrigerator are performed.The time of the static cooling process of the HTS cable under the cooling of the refrigerator is studied.It is found that the thickness of the cooling layer of the HTS cable has a great influence on the cooling process time.The choice of the thickness of the cooling layer needs to consider both the structure optimization and the cooling time;The temperature response of the HTS cable under normal operating current meets the thermal stability of the HTS cable during normal operation.Analyze the quantitative relationship between temperature rise,current magnitude and duration of the HTS cable under fault current,get that the HTS cable can withstand the time of different size fault currents.Finally,the finite element model of the thermal stress analysis of the HTS cable was established.The finite element numerical calculation of the thermal stress analysis was implemented using MATLAB programming.According to the results of the heat transfer analysis,the thermal stress of the HTS cable during the cooling process and the fault current was performed.Analyze and obtain the thermal stress caused by the temperature change of the HTS cable.