Static And Dynamic Characteristics Analysis Of Local Flow Field In Ultra-High Pressure Reciprocating Compressor

As a clean energy source,natural gas is a key technology because of its small density,large space,and accidents during collection and transportation.The pressure required for the compression of LNG is ultra-high pressure,which is not achievable by general compressors.In order to solve the problem of compression storage,it is extremely urgent to develop ultra-high pressure compressors.In order to understand the safety and stability of the working performance of the UHP compressor,it is necessary to analyze the internal flow field during its working process.Because it is difficult to measure the gas flow in the cylinder through the experimental method,the gas parameters of the cylinder and gas valve at different times are obtained by dynamic simulation of the internal flow field of the ultrahigh pressure reciprocating compressor.Taking an ultra-high pressure double-acting reciprocating compressor as an example,SolidWorks software is used to model the three-dimensional model of the compressor and the intake and exhaust valves.MATLAB is used to calculate the dynamics of the valve plate to obtain the motion law of the valve.The movement of the gas valve is coupled with the cylinder,and the flow field variation in the cylinder and the gas valve is obtained by the CFD method.The main research work has the following aspects:Firstly,through the introduction and analysis of the research status,the dynamics research method of the valve and the flow field coupling of the compressor are obtained.The idea and theory of the transient flow field calculation of the reciprocating compressor are analyzed,and mathematical models and calculation methods for fluid analysis were determined.Secondly,the structure of the compressor and the valve are analyzed in detail,and the detailed parameters of the compression machine are introduced and the three-dimensional modeling is carried out.The classification of the gas valve and the type of valve used in the compressor are outlined.Finally,the valve is modeled and scaled to allow the valve to accommodate the assembly of the compressor.The working principle of the valve is analyzed,the mathematical model of the valve motion is derived,and the SUMULINK is used to build and calculate the computer model.The algorithm is optimized to obtain the displacement curve of the valve.The valve channel is extracted and the grid is divided.The internal flow field of the valve is calculated by FLUENT to obtain the pressure and temperature changes.Finally,the hybrid flow grid is divided into the compressor flow field,and the three-dimensional dynamic mesh model is introduced.The UDF function is used to control the motion of the piston.The change of gas flow velocity and pressure inside the cylinder during the working process is obtained by CFD calculation.