结构参数对CO_(2)离心压缩机的性能影响分析

Analysis of influence of structural parameters on performance of CO_(2) centrifugal compressor

为研究各关键结构参数对CO_(2)离心压缩机性能的影响,针对某MW级压缩CO_(2)储能系统低压段中的一级进行了一维设计和三维数值模拟。基于该模型研究了叶片数、叶顶间隙、叶片出口安装角和叶轮出口相对宽度4种关键结构参数对压缩机性能的影响。研究结果表明:叶片出口安装角和叶顶间隙对离心压缩机性能的影响最大,其次是叶片数和叶轮出口相对宽度;增加叶片出口安装角度可显著提高压缩机的做功量及压比,但过大角度会使得流动损失增大而造成效率的降低;随着叶顶间隙的增大,泄漏流动会更加严重,从而影响压缩机的性能;减少叶片数量会减小叶片对流体的约束,更易产生流动分离;叶轮出口相对宽度与压缩机设计流量相关,过小的相对宽度会增大摩擦、泄漏等损失,进而影响压缩机性能及运行工况范围。

To study the influence of key structural parameters on the performance of CO_(2)cen-trifugal compressor,one-dimensional design and three-dimensional numerical simulation were car-ried out for the first stage in the low pressure section of a MW-level compressed CO_(2) energy stor-age system.Based on the model,the influence of four key structural parameters,namely the number of blades,the top clearance,the installation angle of the blade outlet and the relative width of the impeller outlet,on the compressor performance was studied.The results show that the installation angle of the blade outlet and the top clearance have the greatest impact on the perform-ance of the centrifugal compressor,followed by the number of blades and the relative width of the impeller outlet.Increasing the installation angle of the blade outlet can significantly improve the working capacity and pressure ratio,but too large the angle will increase the flow loss and reduce the efficiency.As the top clearance increases,the leakage flow will become more serious,which will affect the performance of the compressor.Reducing the number of blades will reduce the fluid constraint of the blades,and it is easier to produce flow separation.The relative width of the im-peller outlet is related to the design flow rate of the compressor,and too small the relative width will increase the loss of friction and leakage,which in turn will affect the performance of the com-pressor and the range of operating conditions.