Study On Air Distribution Characteristics Of An Automotive Air Conditioning Assembly

With the continuous improvement of China’s auto industry and the upgrading of people’s consumption,the thermal comfort of vehicle passenger compartment has become an important indicator for evaluating vehicle performance.Maintaining the thermal comfort of a car is largely influenced by the performance of the onboard air conditioning.The design of the internal structure of the automotive air conditioner will affect the distribution of the flow field and the distribution of air volume in the cab,and thus affect the performance of the car air conditioning.In the production and design of automotive air conditioners,the test is the most direct method to test the performance of air conditioners.Computational fluid dynamics can be used to simulate flow field distribution and discover the unreasonable design.Designers can use simulation results as an improved reference solution.In the air distribution test of a certain automobile air conditioner,it was found that the air conditioner has uneven distribution of air volume in the mode,defrost mode,and defog mode,which does not meet the design requirements.This paper numerically simulates the distribution of air volume in bilevel mode,defrost mode,and defog mode in automotive air conditioners.Through the analysis of the internal flow field of the air-conditioning cabinet under three modes,it is investigated whether there is any unreasonable design within the air-conditioning cabinet.The study found that the flow path between the mixing damper and the foot blower duct was too narrow and the inlet throat design of the foot blower duct was unreasonable.Then we optimize and improve the internal structure of the air-conditioning box,and complete the further simulation analysis of the optimization program in three modes,and compare with the design requirements of air volume ratio.The research shows that the proposed optimization scheme improves the internal flow field of the air conditioner,and the air volume at each air outlet meets the design criteria under various modes,indicating that the scheme is feasible.At the same time,aiming at the problem of heat leakage in the vent mode caused by uneven distribution of air volume in automotive air conditioners,this paper uses the FLUENT heat exchanger model to model the heating core and investigates the heat leakage inside the air conditioning box under the vent mode.By comparing and analyzing the simulation results of the heat leakage of the original and optimized air-conditioning under the vent modes,it was found that the heat leakage of the optimized automotive air-conditioning phenomenon was improved,and its leakage heat was reduced by more than 50%.Finally,after optimizing the air distribution and heat leakage problems,this paper uses the FLUENT broadband noise model to analyze the noise of the optimized air-conditioning box and air duct,and qualitatively analyzes the noise source distribution and noise intensity in the air-conditioning interior and the blowing air duct under the vent mode.The research results show that the optimized air-conditioning noise is mainly distributed in the diverging the outlet of the air-conditioning and the vent air duct,and the noise intensity meets the design requirements,further confirming the feasibility of the optimized scheme.