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通过求解 N- S方程 ,数值研究了叶顶间隙对 NASA低速大尺度离心压缩机 (L SCC)三维粘性流场及气动性能的影响 ,在计算程序中采用了当地时间步长、多重网格以及隐式参差光顺来进行加速。对具有 0 .0 % ,5 0 % ,10 0 % ,2 0 0 %倍设计间隙的 4种离心叶轮的流场及气动性能进行了数值预测。研究结果表明 (1) NASA低速大尺度离心压缩机 (L SCC)半开式叶轮的低速尾迹区在压力面与轮盖的角区 ,而相应的闭式叶轮的低速尾迹区聚集在轮盖的中心位置 ;(2 )数值实验表明 ,叶顶间隙并非越小越好 ,可能存在一个最优间隙 ,使得叶轮流动损失最小
By solving the N-S equation, the effect of tip clearance on the three-dimensional viscous flow field and aerodynamic performance of NASA low-speed large-scale centrifugal compressor (L SCC) was studied numerically. Local time steps, multiple grids, Implicit gaze smoothing accelerates. Numerical simulations were performed on the flow field and aerodynamic performance of four kinds of centrifugal impellers with design gaps of 0. 0%, 50%, 100% and 200%. The results show that (1) the low speed wake zone of semi-open impeller of NASA Low Speed Large Scale Centrifugal Compressor (L SCC) is on the corner of pressure surface and wheel cover, while the low wake area of the corresponding closed impeller collects (2) The numerical experiments show that the tip clearance is not as small as possible, there may be an optimal clearance to minimize the flow loss of the impeller