| The high and low temperature environment test box is a kind of test equipment which simulates the temperature environment artificially.The test chamber can continuously complete the high and low temperature transformation with controllable temperature conversion rate,which can significantly shorten the test period and improve the test efficiency compared with the test in natural environment.In this paper,according to the environmental test requirements of lithium batteries and related electronic products,the high and low temperature simulation experiment system was designed in cooperation with relevant enterprises according to the technical requirements.The systems of the high and low temperature test chamber are designed,and the key problems such as temperature uniformity and inlet parameters of the high and low temperature test chamber are studied and optimized through theoretical analysis,simulation analysis and experimental research.Firstly,the circulation mode of air duct is compared and analyzed.On this basis,the shape and structure layout of the test box are designed with the modular design idea.The main body adopts sheet metal to reduce the processing difficulty and cost.According to the technical requirements to calculate the design load of the high and low temperature test box,and according to the calculation results of the refrigeration system selection design.Through the use of control requirements and user requirements for the PC software,and master of high and low temperature box system design,this paper adopts PID control principle,the PC using carrying WIN 10 system of PC,PC software using VC programming to design according to the actual requirements of the users,upper machine and the main control system adopts RS485 communication in real time.After the design of high and low temperature chamber,the air distribution was studied by numerical simulation.Firstly,the simplified physical model is established,the mathematical model is established according to the actual engineering problems,and the boundary conditions are set for solving by ANSYS.After that,the calculated data obtained by the software are processed with the post-processing software to obtain the temperature cloud diagram and flow field diagram under different inlet parameters and operating conditions.Through the analysis of simulation results,it is found that the energy transferred by the front end at low inlet circulation wind speed is insufficient,the load near the wall is not easy to balance,it is difficult to form a adherent cycle at a large inlet Angle,and the temperature uniformity is poor.After forming a good adherent cycle,the middle part of the two sides of the wall is difficult to balance the load.In order to verify the reliability and correctness of the simulation theory,an experimental platform was built by using the design object.Representative entrance parameters were selected for experimental verification,and the average temperature value of the experimental results was slightly deviated from that of the simulation through experimental comparison,which was caused by the physical simplification of the simulation.However,the trend of the simulation results was consistent with the experimental results.The analysis shows that the simulation theory is correct and the temperature field uniformity of the high and low temperature test chamber can be predicted.Figure[47]table[13]reference[68]... |
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