横肋变截面回转通道不同肋高的流阻特性

以某型航空发动机的实际涡轮叶片内部的带肋变截面180°回转通道为研究对象,采用实验方法研究了4种不同肋高的流阻规律,并做了比较。实验模型中,矩形肋对称布置在上下两个面,肋间距为15mm,肋宽为2mm,肋与流体流向夹角为90°。定义了沿程有效压力系数,并得到了其沿程分布。实验表明,对于带90°直肋不同肋高的矩形回转通道沿程有效压力的分布趋势基本一致,由于流道截面积的不规则变化,导致有效压力有沿程逆增现象。试验还发现高径比越大的其阻力系数越大,即沿程的阻力越大。 

Influence of the rib pitch on flow resistance in a U-shaped variable cross-section channel with transverse ribs

The turn-over channel of turbine blade is an important part of the internal cooling structure of the turbine blade. Its flow performance is important for the design of cooling structure of the turbine blade.A real turn-over channel of turbine blade is simplified as an object to be studied in the present paper which studies flow performance in a 180° turn-over channel with 90° parallel different height ribs.The efficient pressure distribution in the inner part of the turn-over channel along the channel,including 90° parallel different height ribs,is shown in the paper.The result shows that the efficient pressure distribution in the inner part of these two turn-over channels with 90° parallel rib along the process is similar.Some efficient pressure increases along the channel because of the irregular changing of the channel shape.Correlation formulas of the coefficient of the efficient pressure are obtained in the paper.Resistance coefficient increases with the increase of the rib height to diameter ratio.