转速对涡轮叶顶间隙泄漏掺混的影响

Effect of Blade Rotating Speed on The Mixing of Tip Clearance Leakage Flow in Axial Turbines

转速影响着涡轮转子叶顶间隙的流场分布,泄漏流与主流之间的相互作用改变了主流通道的流场结构。对叶顶间隙大小分别为0.4 mm、1 mm,转速为0 r/min、3 500 r/min、6 000 r/min时的1.5级涡轮进行三维数值计算,结果表明:随着叶顶间隙的增大,间隙泄漏涡以及叶顶分离涡尺寸增大,对主流的阻塞作用更加明显;转速增加降低了泄漏掺混损失,0.4 mm间隙时,掺混损失与转速之间基本呈线性关系,1 mm间隙时,掺混损失随转速的增加变化相对较大,转速对掺混损失的影响更加明显。

Rotating speed has an obvious effect on the tip clearance flow field distribution of turbine blades .Interactional effect of tip leakage flow and the main flow changed the flow structure of the main flow region .Numerical research has been given to a 1.5 turbine stage which has tip clearances heights of 0.4 mm and 1 mm with rev of 0 r/min, 3 500 r/min and 6 000 r/min.Results have shown that with the increase of tip clearance height , the size of leakage vortex and tip detached vortex grow larger , which has an obvious bloc-king effect on the main flow .The increased rotating speed has reduced the mixing loss .The mixing loss has a linear relationship with the rotating speed at the clearance of 0.4 mm;while at 1 mm, the mixing loss has a significant change .