Research On Noise Control Based On Fluid Characteristics Of Double Suction Balanced Twin Screw Compressor

With the improvement of the manufacturing and installation level of twin screw compressors,the mechanical noise of the twin-screw compressor has been greatly reduced,and the flow-induced noise has become the main noise source.As a new structure compressor,the double-suction balanced twin-screw compressor adopts a symmetrical design,which balances the axial force of the yin and yang rotors to make the mechanical noise smaller,but because of its symmetrical structure,the flow-induced noise is also symmetrically distributed on both sides.Noise is coupled and superimposed on each other.The specific noise distribution needs to be clarified.At present,the noise research of twin screw compressors is mainly based on experimental measurements,and the method has certain limitations.In order to clarify the flowinduced noise distribution of double-suction balanced twin-screw compressors and solve the limitations of experimental measurement noise,it is particularly necessary to adopt new research methods to solve the above problems,and it is also an inevitable trend for the development of twin-screw compressors.This paper proposes the use of numerical simulation techniques to analyze the flowinduced noise of a double-suction balanced twin-screw compressor.In terms of fluid calculation,three structural parameters that have a significant impact on compressor noise are selected: inter-tooth,tooth top,and end face clearances for experimental design.CFX is used to perform computational fluid dynamics(CFD)calculations to obtain air intake,exhaust,Flow field information of the three parts of the rotor.In the sound field calculation,Actran takes the CFD calculation result as input information for frequency domain calculation.Based on the analysis of Actran's calculation of the relationship between the three major gaps,the characteristics of the noise pattern of the three major gaps on this type of twin-screw compressor are summarized.In order to further clarify the noise contribution and influence of compressors in different watersheds,Green's analysis method was used to analyze the contribution of the surface of the body to the sound pressure level at the monitoring point.Finally,based on the noise distribution characteristics of the double-suction balanced twin-screw compressor,a double-layer rotor wall noise reduction structure is designed.The objective function is optimized using Matlab,and the calculation results are substituted into Actran to verify the effectiveness of the optimized design.By analyzing the results of Actran calculations,the noise at the exhaust port of the rotor basin of the balanced twin screw compressor is greater than the noise at the intake port;the fundamental frequency of the noise in the rotor area with different tip clearances is at 500 Hz and 800 Hz respectively.Near the 1/3 octave frequency band of the center frequency;the effects of the three gaps on the compressor noise from large to small are: tooth tip,end face,inter-tooth gap,and the interaction of tooth top,inter-tooth and end face gap The effect has a certain influence on the average sound pressure level;at the same time,it is concluded that the reduction of the three major gaps can increase the volumetric efficiency but not necessarily reduce the noise generated by the compressor during operation;perform a variance analysis on the calculation results of the sound field to know the final design The double-layer rotor wall noise reduction structure can target a lower sound pressure level at a specific frequency,achieving the goal of reducing the sound pressure level.