Study On Dynamic Characteristics Of Back Pressure Recirculation Valve Of Inverter Refrigeration Scroll Compressor

With the accelerating social development and the continuous improvement of industrial development,as a new generation of displacement compressors,scroll compressors have been widely used in each field of the industry due to their advantages of small size,high efficiency and stable operation.At the same time,the working performance of the scroll compressor is also put forward higher requirements.However,back pressure recirculation valve as an important components in oil circulation of the scroll compressor,the domestic research on its content is not sufficient.Therefore,in this paper,the back pressure recirculation valve in scroll compressor will be taken as the research object,and its whole working process in a scroll compressor will be analyzed and its structure will be optimized.First of all,this paper introduces and analyzes the structural characteristics and working principle of the back pressure recirculation valve,then establishes the movement model of the valve flap after the back pressure recirculation valve is opened.Secondly,it uses Bernoulli equation and continuity equation to calculate the velocity of the fluid in different positions of the back pressure recirculation valve,the calculation formula of the fluid movement state and the recirculation pressure resistance coefficient of the recirculation valve is also deduced.Thirdly,based on the theoretical study,the moving grid technique is used to simulate the flow field distribution of the back pressure recirculation valve at different positions of the valve disc,then calculates the fluid resistance coefficient and finds out the best valve position of the back pressure recirculation valve.Finally,it calculates the spring's spring constant based on the simulation results of the analysis.When it is over,the focus is to analyze the working process after the back pressure recirculation valve is opened,the 6DOF program is prepared by using the elastic coefficient of the spring and structural parameters of the back pressure return valve,which is from the moving grid simulation and theoretical calculation.According to the boundary conditions in the actual working process,the different phases of disc motion were analyzed by the combination of dynamic simulation and steady simulation,then the change law of the flow field distribution and the coefficient of flow resistance of the back-pressure return valve were obtained in this process.Through the simulation and theoretical analysis of the flow field of the backpressure recirculation valve,it was found that when the back pressure recirculation valve is operated,the internal fluid appeared obvious vortex phenomenon at the corner of structure,which wastes a large amount of fluid energy and increases the loss of the fluid resistance.In order to avoid the generation of the vortex,the structure of the vortex should be optimized.After chamfering the position of the vortex,the internal flow field of the back pressure recirculation valve was simulated under different bevels and the flow resistance coefficient was calculated according to the simulation results.When the back pressure recirculation valve was processed at a bevel of 20°,the flow resistance coefficient is at a decrease of 15%,which means the loss of fluid resistance and the improvement of the back pressure recirculation valve.