Research On Thermodynamic Characteristics Of Reciprocating Compresser Basde On CFD Capacity Control And Valve Leakage Condition

The reciprocating compressor is a fluid machine that converts low-pressure gas into high-pressure gas and is widely used in various basic industries.Because the reciprocating compressor has high energy consumption during the working process and its displacement is fixed,this leads to a certain energy waste.For this reason,researchers have developed different capacity control adjustment methods,in which part of the stroke opens the suction valve volume.The capacity control method in which some of the strokes open the suction valve is a widely used and effective adjustment method in actual production.The gas valve is an important component of the reciprocating compressor.In the failure of the compressor,the valve failure accounts for more than 60%.Therefore,it is of great significance for the study of the thermodynamic properties of the compressor in the gas volume adjustment and the valve leakage condition.The research on the flow field and thermal working process of reciprocating compressor under various working conditions is of great significance for energy saving,and the data of the compressor in the actual working process is lacking.Some data are difficult to obtain through experiment and the risk is high.In order to deeply study the working characteristics of the compressor under normal working conditions,capacity volume control conditions and fault conditions,this paper uses computer modeling and simulation technology to work from the following aspects:(1)The structure and working principle of the reciprocating compressor are introduced.Using CFD and related software to establish a three-dimensional model of the compressor.The dynamic mesh describing the movement of the cylinder and valve fluid is constructed and the relevant boundary conditions are defined.The model is used to simulate the cylinder pressure and the valve movement law,and the model is verified by experiments.(2)The model based on full load condition simulates the operation of the compressor under different parameters.By comparing different spring stiffness and crankshaft velocity,the valve motion law of the compressor,the change of the thermodynamic parameters of the compressor and the change of the flow field characteristics in the unit.Regularity,research on the effects of different parameters on compressor operation.(3)Based on the healthy working model of the compressor,the model of the compressor under the condition of capacity volume control is established.The simulation of the variable load condition and the variable clearance condition is carried out,and the law of the valve movement is obtained.The influence of the thermodynamic performance of the cylinder and the flow field distribution.(4)The working condition of the compressor under the condition of leakage of the valve is studied.The model of the leakage of the compressor valve is established,and the model is used to test the compressor in the condition of leakage of the intake valve and leakage of the exhaust valve.The simulation is carried out to compare the effects of leakage fault on the movement law of the intake valve of the compressor,the thermodynamic parameters of the compressor and the temperature,velocity distribution and fluid flow in the flow field.The failure mechanism is compared and the theoretical basis for fault diagnosis is provided.