Study On Noise Radiation Characteristics Of Suction And Exhaust Of Reciprocating Refrigeration Compressor

As one of the most important components of refrigerator,reciprocating compressor occupies a large share in the industry of small and medium refrigeration equipment,which is also a significant source of noise.With the rapid development of economy and the continuous improvement of science and technology,people are pursuing higher-quality life and paying more attention to the noise level of refrigerators.Low noise and high efficiency refrigerators are more in line with the needs of people,and their market share is also increasing.In the process of compressor operation,the non-uniform variation of gas flow in pipeline caused by intermittent suction and exhaust is the main cause of energy loss and aerodynamic noise.It is difficult to obtain the flow field characteristics in the cylinder of the whole compressor through experiments for the refrigeration compressor is compact and fully enclosed.In this paper,the flow field of reciprocating compressor is simulated and analyzed by CFD simulation software.Based on the theory of jet noise,the variation and radiation characteristics of monopole source and turbulent quadrupole source caused by unsteady mass flow in the process of suction and exhaust are studied.It is of great significance to improve the refrigeration efficiency and reduce the noise of the compressor.Initially,the characteristics of compressor suction and exhaust sound sources are analyzed in theory.The basic theory of aerodynamic noise and the types of sound sources are introduced,and the flow field control equation and turbulence model used in the simulation of compressor suction and exhaust flow field are briefly introduced,which lays a foundation for the simulation calculation in the following chapters.After that,under the guidance of theoretical analysis,the compressor cylinder model is developed,and the model is meshed by software ICEM 15.0.Then the dynamic grid of the cylinder flow field is set up and simulated by ANSYS/Fluent platform,and the change of the cylinder pressure field and velocity field is obtained.This paves the way for solving the flow field and sound field in the process of suction and exhaust of compressor.Next,the large eddy turbulence model is used in the CFD software to solve and analyze the transient flow field of the gas flow through the suction and exhaust valves,and the flow field distribution,such as fluctuating pressure and velocity data,is obtained.The data from CFD calculation are imported into the professional acoustic software for joint simulation to generate the aerodynamic noise source terms,including dipole and quadrupole sources,and the aerodynamic noise generation and propagation model is established.Aerodynamic noise and radiation directivity of dissolved gas flowing through valve plates.Finally,based on the above theory and results analysis,the structure of the compressor valve plate is optimized.It is found that the arc curvature of the diversion surface has a greater impact on the pressure loss and noise of the suction valve orifice when the flow area ratio between the inlet and outlet is fixed.The optimal arc curvature is obtained by comparing the simulation experiments,and the purpose of reducing compressor noise is achieved.