Numerical Research And Optimization Of Defrost Performance Of Car Air Conditioning

The defrost performance of car air conditioners is related to consumer comfort and safety.Traffic accidents caused by poor vehicle defrost performance are common annually.Therefore,the optimization of defrost performance is very important in automobile design.At present,the most common optimization method is to test a single parameter continuously to find the optimal value of the parameter while ensuring that other structural parameters of the air conditioner are unchanged.Air conditioning has complex structure,and the defrosting performance of multi structure parameter optimization is better than that of single parameter optimization.However,the traditional optimization methods such as response surface method are difficult to solve these nonlinear multi parameter optimization problems.Therefore,this thesis conducts a thorough and systematic research on the car defrost mechanism and related optimization issues,and improves the air duct structure based on the principle of air volume distribution;a new optimization method was introduced to optimize the multi-parameter size of the automotive air-conditioning structure,thereby further improving the defrosting performance of the air-conditioning.First,the air conditioning system of a car is taken as the study subject,and a finite element simulation model is established through pre-processing such as model modification and mesh division.According to the requirements of the defrost test,simulation boundary conditions are set to analyze the vehicle's defrosting performance,including air volume distribution,steady-state wind speed,and melting state of the transient frost layer.At the same time,the test results are compared with the simulation results to verify the accuracy of the finite element model.Secondly,the finite element model is used as the study subject.Under the condition that other parameters of the vehicle remain unchanged,the air flow incidence angle and the opening length of the air outlet are adjusted continuously.Then,the simulation calculation is carried out to study and analyze the influence of the air flow incidence angle and the opening length of the air outlet on the distribution of the internal streamline of the vehicle and the internal surface wind speed of the windshield,which is the junction of the air conditioner Structure improvement provides theoretical basis.Finally,an optimization analysis is made on the air-conditioning structure.Based on the improved finite element simulation model,the parameters of air-conditioning structure are selected as the design variables,the test data are obtained through the test design.The radial basis function neural network and support vector regression are used to fit the data of air-conditioning structure parameters and nonlinear multivariable.According to the approximate model,the incident angle of the air flow and the opening length of the air outlet are optimized to improve the defrosting performance of the vehicle air conditioner.