叶片前间隙对风机性能的影响

某3台小流量氮气循环高速风机的空气试验结果差别较为明显,对比其结构参数发现叶片前间隙尺寸相差较大,而该尺寸值对风机性能有明显影响。为研究间隙值对性能的影响,对风机过流部分进行CFD三维流场数值模拟计算,其结果为:当间隙值较小时压比提升显著,间隙值对叶轮流场内部静压系数分布会产生影响,这是压比改变的原因;小间隙尺寸时叶顶间隙流动对叶片内部流场干扰较小,整机效率也会改善。间隙值的大小导致叶顶间隙流动不同,而叶顶间隙流动则会改变不同叶片高度表面载荷分布。上述研究结果对后期风机的结构改进与性能提升有很大意义。

THE INFLUENCE OF BLADE FRONT CLEARANCE ON THE PERFORMANCE OF COMPRESSORS

The air experiment results of three nitrogen cycle compressors with high speed and low flow rate showed obvious differences in performance.By comparing the structural parameters,it's found that there existed a big difference in the front clearance size of the impellers.The size has a significant influence on the performance of compressors.In order to study the influence of clearance on performance,numerical simulation of the three-dimensional flow field CFD method has been adopted for the over current fluid part of the compressor.The results indicate that the pressure ratio increased obviously when the clearance value was smaller,and the reason for the changed pressure ratio was that the reduction of clearance value would influence the distribution of static pressure coefficient inside the impeller;when the clearance value was small,the tip clearance flow had less interference on the flow field inside the blade,and the efficiency of the whole machine would also be improved.Different clearance values resulted in different tip clearance flow which would change the surface load distribution of different blade heights.The above research results are of great significance to improve the structure and performance of the fans in the later period.