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基于压力敏感漆(PSP)实验技术,本文研究了某F级重型燃机一级动叶平面叶顶和凹槽叶顶在不同冷却射流与主流质量流量比,不同密度比和不同叶顶间隙大小等多参数影响下的气膜冷却特性。平面叶顶冷却射流在气膜孔后往吸力面覆盖,凹槽叶顶在槽内形成回旋涡,冷却射流往压力面覆盖并向尾缘形成累积效应。平面叶顶和凹槽叶顶气膜冷却效率均随质量流量比的增大而增大。密度比增大,冷却射流出口动量减小,抑制了叶顶气膜垂直射流的吹离趋势,从而提高气膜冷却效果。叶顶间隙与叶顶形状、质量流量比等参数对气膜冷却效率有关联影响;间隙增大,气膜冷却效率在不同工况下的表现不同。另外凹槽叶顶的整体气膜冷却效果优于同等条件的平面叶顶。
Based on the pressure-sensitive paint (PSP) experimental technique, this paper studies the effect of the tip-top and the groove tip of a moving blade on the top of a F-class heavy-duty gas turbine at different cooling jets and mainstream mass flow rates, different density ratios and different tip clearances And other parameters under the influence of the film cooling characteristics. The flat tip cooling jets cover the suction surface after the film holes, and the tip of the groove forms a whirlpool in the groove. The cooling jet covers the pressure surface and forms a cumulative effect toward the trailing edge. The film cooling efficiency of the flat blade tip and the grooved blade top increases with the increase of mass flow rate. When the density ratio increases, the momentum of the exit of the cooling jet decreases, which suppresses the tendency of the vertical jet of the tip gas film to blow off, thereby improving the cooling effect of the film. The relationship between the tip clearance and the shape of the tip, the mass flow rate and other parameters have an impact on the cooling efficiency of the gas film. The gap increases and the cooling efficiency of the film varies under different operating conditions. In addition, the integral air film cooling effect of the groove top is better than that of the plane roof under the same conditions.