Numerical Simulation Of Internal Flow Field In Supercritical Carbon Dioxide Centrifugal Compressor

Climate change is a global challenge facing mankind.In order to reduce carbon dioxide emissions,my country has proposed carbon peak and carbon neutral goals,and the application of supercritical carbon dioxide in the Brayton cycle can effectively reduce carbon dioxide emissions.As a key component of the Brayton cycle,the supercritical carbon dioxide centrifugal compressor has a simple structure and easy maintenance.It has broad prospects in industries such as distributed power generation and cogeneration,and can effectively deal with energy consumption and energy utilization problems.Based on the CFD numerical simulation method,this paper has carried on the relevant analysis to the supercritical carbon dioxide centrifugal compressor.The influence of RGP tables with different resolutions on simulation results and internal flow fields is explored.On this basis,the influence laws of different inlet flow,pressure,temperature and speed on the performance and internal flow field of the supercritical carbon dioxide centrifugal compressor under appropriate resolution were analyzed.This article first introduces the basic principles of computational fluid dynamics,control equations,and gives the model,meshing and model verification of a supercritical carbon dioxide centrifugal compressor.Then the numerical simulation of supercritical carbon dioxide centrifugal compressors with different RGP tables is carried out.The calculation is optimized from three different directions of pressure and temperature resolution,and the calculation accuracy and internal of supercritical carbon dioxide centrifugal compressors with different resolutions are analyzed.The law of flow field distribution,research has found that a small change in the resolution table will have a huge impact on the accuracy of the calculation results and the accuracy of the flow simulation of the internal flow field of the compressor.Finally,the effect of different inlet flow,pressure,temperature and speed on the performance of supercritical carbon dioxide centrifugal compressor was studied,and it was found that the increase of inlet flow and temperature can improve the isentropic efficiency but will bring about the decrease of pressure ratio.The increase in pressure will reduce the isentropic efficiency but the pressure ratio will increase.There is an optimal speed to make the isentropic efficiency the highest.And analyzed the change law of the internal flow field of the centrifugal compressor under these different inlet conditions.For the simulation in this paper,there is an optimal inlet temperature and pressure to minimize the low temperature and low pressure area in the impeller.As the flow rate and speed increase,the range of the phase change or condensation zone further increases.The research results of this paper provide certain reference value for the accuracy of numerical simulation of the internal flow field of supercritical carbon dioxide centrifugal compressors and the design and development of supercritical carbon dioxide centrifugal compressors.