The Optimization On Aeroacoustic Characteristics Of Automotive Air Conditioning Systems And Passenger Compartment

The noise level is one of the main performance parameters of the automobile; it is also the main factors which affecting passengers'comfort. If the interior noise level is too high, it will has serious impact on general comfort, session definition, and the driver's ability to identify the various signals, even affect the health of the passengers. How to improve the internal acoustic environment of the automobile, which has caused the common concern of the vehicle manufacturers and consumer. With the reduction of other noise sources gradually and the continuous improvement of seal chamber, the high levels aerodynamic noise of air-conditioning system has attracted much attention to people. Thus efforts to reduce aerodynamic noise of air conditioning system have a very practical significance.In this paper, this research is base on an the China's independent innovation capacity-building platform, using commercial fluid analysis software fluent, to launch the numerical simulation of entire configuration of automotive air conditioning systems (including centrifugal fan and air conditioning ducts) and car passenger room. The flow field and sound field characteristics of centrifugal fan, air-conditioning ducts and passenger room are analyzed and researched.The relationship between the flow characteristic and aerodynamic noise is on discussion. It provides references for the following work of noise reduction.According to the results of analysis and the aerodynamic noise source of centrifugal fan, apply the Response Surface Method(RSM), the mathematical function is established between sound power level, flow, pressure and the structural parameters, optimization algorithm is used to select the structural parameters, and ultimately in conditions to ensure fan performance target to reduce noise levels.Meanwhile, according to characteristics of flow separation within the air conditioning ducts, the programs of air conditioning ducts Structure Improvement are established to improve the flow fields and aerodynamic noise level.For the research of sound absorption of automobile passenger room, firstly the sound filed of passenger compartment between roof with sound absorption material and non-absorbing materials are discussing. Secondly 5 groups are established. Respectively, roof, wall, floor, dashboard and seats. Comparing the results of numerical simulation between the 5 groups. Finally, according to the characteristics of acoustic absorption of each group and the principle of economy, the final arrangement of sound-absorbing material is developed to decrease the value of sound pressure monitoring. The guidance of acoustic noise design for the passenger compartment is provided.