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首页> 外文期刊>Journal of Heat Transfer >Increasing Adiabatic Film-Cooling Effectiveness by Using an Upstream Ramp
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Increasing Adiabatic Film-Cooling Effectiveness by Using an Upstream Ramp

机译：通过使用上游斜坡提高绝热膜冷却效果

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A new design concept is presented to increase the adiabatic effectiveness of film cooling from a row of film-cooling holes. Instead of shaping the geometry of each hole; placing tabs, struts, or vortex generators in each hole; or creating a trench about a row of holes, this study proposes a geometry modification upstream of the holes to modify the approaching boundary-layer flow and its interaction with the film-cooling jets. Computations, based on the ensemble-averaged Navier-Stokes equations closed by the realizable k-ε turbulence model, were used to examine the usefulness of making the surface just upstream of a row of film-cooling holes into a ramp with a backward-facing step. The effects of the following parameters were investigated: angle of the ramp (8.5 deg, 10 deg, 14 deg,), distance between the backward-facing step and the row of film-cooling holes (0.5D,D), blowing ratio (0.36, 0.49, 0.56, 0.98), and "sharpness" of the ramp at the comers. Results obtained show that an upstream ramp with a backward-facing step can greatly increase surface adiabatic effectiveness. The laterally averaged adiabatic effectiveness with a ramp can be two or more times higher than without the ramp by increasing upstream and lateral spreading of the coolant.
机译：提出了一种新的设计概念，以提高从一排薄膜冷却孔中冷却薄膜的绝热效果。而不是塑造每个孔的几何形状；在每个孔中放置翼片，支柱或涡流发生器；或在一排孔周围形成沟槽，这项研究提出了在孔上游进行几何形状修改的方法，以修改接近的边界层流及其与薄膜冷却射流的相互作用。基于由可实现的k-ε湍流模型封闭的整体平均Navier-Stokes方程进行的计算，用于检验将一排薄膜冷却孔上游的表面制成具有向后倾斜的坡道的有用性步。研究了以下参数的影响：坡道角度（8.5度，10度，14度），向后台阶与成排的薄膜冷却孔之间的距离（0.5D，D），吹塑比（ 0.36、0.49、0.56、0.98）和拐角处的坡度“清晰度”。获得的结果表明，带有向后台阶的上游斜面可以大大提高表面绝热效果。通过增加冷却剂的上游和横向扩散，具有斜坡的横向平均绝热效率可以比没有斜坡的绝热效率高两倍或更多倍。

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