扩压叶栅最佳弯叶片生成线与展弦比的关系

Relationship of Optimum Curved Blade Stack Line and Aspect Ratio in Linear Compressor Cascade

为了研究亚声速扩压叶栅最佳弯叶片参数与叶栅展弦比的关系,在7个不同展弦比下对7组共49个方案进行数值模拟。数值模拟结果表明:在同一个弯角下,叶栅损失随弯高的增大而减小,50%弯高时叶栅损失最小,弯叶片最佳弯高为50%;弯叶片弯高相同时,叶栅损失随弯角增大呈现抛物线型变化规律,损失随弯角增大先减小再增大,存在一个最佳弯角(αopt)使叶栅损失最小。最佳弯角与直叶片的负荷展向不均匀度正相关,总体趋势上两者都随叶栅展弦比的增大而减小。但是,展弦比越小端区流动对叶展中部的影响越大,叶片中部的叶型损失增大越明显,弯叶片的弯角越大叶型损失增加越明显,所以小展弦比时最佳弯角随展弦比增大有小幅度增大。

ABSTRACT:In order to research the relationship of optimum curved blade stack line and cascade aspect ratio in linear compressor cascade, 49 schemes at 7 different aspect ratio were simulated. Numerical results show that cascade loss decreases with the increase of curved height at the same curved angle, and the optimum curved height is 50%. Loss variation with curved angle presents an approximate parabola type at the same curved height. There is an optimum curved angle with the increase of curved angle, at which the total loss is minimal. The optimum angle is positively correlated with the local blade loading variation along span wise, and both of them decrease with the increase of aspect ratio in the overall trend. Profile loss at mid span increases because of the influence of end wall flow, the smaller the aspect ratio, the larger the profile loss;the larger the curved angle, the larger the profile loss. The optimum curved angle could modestly increases with aspect ratio increasing.