Transformation And Experiment Of Low Temperature Shock Box In High And Low Temperature Based On Repid Cooling

The high and low temperature impact test system is a test equipment that can provide the high temperature and extremely low temperature environment required for the test and test of aerospace structural devices.The test chamber shall have the ability to restore the test conditions,that is,the low temperature environment,within 5 minutes of the test piece moving from the high temperature box to the low temperature box.With the current equipment capabilities,the high and low temperature box impact test equipment cannot meet the requirement of re-stabilizing the ambient temperature below-100℃within 5 minutes.Therefore,it is necessary to carry out relevant optimization and transformation of the cryogenic box system and improve the cooling capacity of the system to meet the impact test requirements of aerospace structural devices.This article first conducts related impact test research based on the cascade refrigeration system and establishes a mathematical model of the system for thermal balance analysis calculation.Based on the analysis results,a corresponding improvement plan is proposed,which is to change the characteristics of the low temperature box and increase the cooling capacity of the cold source.Fang start.According to the relevant numerical calculation analysis and the original size of the box,it was finally determined to use a solution of adding a liquid nitrogen cold source to solve the problem.Based on the response characteristics of the system,an intelligent control system for the liquid nitrogen auxiliary system was designed and established.The parameter distribution model of the cryogenic chamber system was combined with the fuzzy-PID control strategy to simulate the system.The effectiveness of the transformation scheme and control strategy was initially determined.Finally,the PLC was used for hardware control and experimental verification was carried out.The requirements of the model impact test are well met,and the separate control system has a good control response.