Flow Field Analysis Of Reciprocating Compressor Cylinder Based On CFD

Reciprocating compressor as a general machinery for the transporting high-pressure gas,the pressure loss of the cylinder flow field has a significant impact on the efficiency of the compressor.With the improvement of the performance requirements of reciprocating compressors,more and more attention has been paid to the research of cylinder flow field.However,due to the narrow cylinder space,closed and high-speed operation of the cylinder gas,the experimental method is difficult to get the gas flow characteristics of the cylinder.Therefore,this thesis uses CFD method to analyze the continuous instantaneous cylinder flow field.This thesis takes a model W type reciprocating compressor as the research object.Firstly,the 3D model of cylinder flow field is established by software Pro/E 5.Secondly,the model is meshed by software ICEM 17.0.Then under the ANSYS/Fluent platform with action grid settings and simulation of cylinder flow field,the cylinder pressure field and velocity field variation are obtained.According to the simulation P-V indicated diagram,the effects of the crankshaft speed,working condition,valve area and other parameters on the flow field of the compressor cylinder were analyzed.Finally,based on the fluid solid coupling principle,the influence of the motion characteristics of valve on the cylinder flow field was also investigated.The analysis results of show that the pressure and velocity of the cylinder flow field are unevenly distributed,in which the pressure change is most obvious and the velocity is the largest at the valve port position.The increase of the crankshaft speed can reduce the fluctuation of the gas,which is beneficial to reduce the vibration of the valve plate,but the pressure loss of the cylinder flow field is increased.In the case of a certain condensation temperature,the higher the evaporation temperature,the higher the volumetric efficiency of the compressor.Increasing the flow cross section ratio of the valve can reduce the pressure loss when the gas passes through the port.Although the valve port layout will change the direction of gas flow,but the pressure loss of the cylinder flow field has little effect.The increase of valve thickness will lead to the decrease of the lift,and the pressure loss of the cylinder.The study in this thesis can provide theoretical guidance for the reasonable design of compressor parameters and optimization of the structure,so as to reduce the pressure loss of the cylinder flow field and improve the energy efficiency of the compressor.