Simulation Analysis And Experimental Study On Vibration And Noise Of Swash Plate Type Air-conditioning Compressor

With the rapid development of China’s economy, thousands of families own cars, people has higher requirement for cars. The air-conditioning system which can improve the conditions in the car has become an essential part when people buy cars. But the AC compressor as the most important part of the AC system, it also bring another problem can’t be ignored—noise and vibration. For this reason that reducing the vibration and noise of the compressor is an important part to improve the vehicle ride conditions.Earlier studies on the compressor have focused on cooling capacity and service life can directly affects the compressor’s performance. But in recent years, the requirement of ride condition has been promoted, compressor’s noise and vibration problem has been paid more and more attentions. So, the analysis and optimization about compressor’s noise and vibration is instructive, at the same time, it also can provide a reference for noise and vibration problems about other rotating mechanical and aerodynamic equipment. In this paper, we use a swash plate type air-conditioning compressor as a study case to research the compressor’s noise and vibration problem.Firstly, the refrigeration cycle of automotive AC system and the structure of ten-cylinder swash plate type compressor are introduced in this paper. Thus analyze its vibration and noise generating mechanism. According to the causes, the noise can split to mechanical noise, fluid noise and electromagnetic noise. Among them, the mechanical noise and the fluid noise have the greater influence. In this base, corresponding control principles for different forms of noise have been proposed.Secondly, have the simulation analysis on both the compressor’s modal and the compressor’s internal flow field noise. For the modal simulation part, take the constraints and the compressor’s foothold into account. The calculated result for the first order modal is small, so that the resonance is easily occurred when the car is in idle condition. For the compressor’s internal flow field noise calculate part, flow field distribution of noise are derived according to the internal flow field in the finite element modal of compressor cavity model.Thirdly, the modal test and the bench noise of compressor are introduced in this pare. The former is in tap method when the compressor is installed in the car. The result of the first modal of compressor and its foothold is similar to the calculated result, and the accuracy of the modal calculation is verified. The bench noise test is in the semi-anechoic chamber, the compressor is driven by a motor, and the near-field noise of it is measured. The experimental data is similar to the noise calculated. So the correct of fluid noise simulation is proved.Finally, according to the simulation results and experimental dates, reduce both the mechanical noise and the fluid noise. For reduce the mechanical noise, the main measure is to change the structure of the compressor’s foothold, then make the first order modal of compressor and its foothold heighten obviously, so resonance is avoided when the car is in idle condition. And at the same time, the foothold’s quality is reduced to meet the requirements of lightweight. For the fluid noise part, there are four optimization programs: improve the structure of exhaust parts, increase the diameter of the cylinder exhaust port, increase the length of the cylinder, improve the thickness of one-side discharge chamber and increased cross-sectional area of the air-way. The best program is determined after one by one analysis and the good improvement is achieved eventually.