燃气透平凹槽状叶顶气膜冷却特性研究

Investigations on the Film Cooling Characteristics of the Gas Turbine Blade with Squealer Tip

采用数值求解三维Reynolds-Averaged Navier-Stokes(RANS)和k-ω紊流模型的方法研究了燃气透平凹槽状叶顶气膜冷却特性。通过比较4种紊流模型的数值结果与GE-E3实验数据,验证了采用标准k-ω紊流模型可以有效地模拟叶顶间隙的流动换热特性。计算分析了无气膜冷却时凹槽深度对叶顶间隙流动传热的影响特性。开展了凹槽状叶顶的气膜冷却几何结构参数气膜孔直径、气膜孔间距比、位置和吹风比对叶顶流动传热特性的影响。研究结果表明:无气膜冷却时,在1.5%叶高的叶顶间隙条件下凹槽深度为2%叶高时叶顶平均换热系数最高,凹槽深度继续增加,表面平均换热系数迅速降低。对于凹槽状叶顶气膜冷却特性的研究表明:在气膜孔叶顶中弧线布置方式下,吹风比为1.0时气膜冷却效率最好;在气膜孔叶顶中弧线布置方式和吹风比为1.0时气膜孔直径越大冷却效果越好;在吹风比是1.0时气膜孔布置在靠近吸力面侧时冷却效果最差;在气膜孔叶顶中弧线布置方式和吹风比是1.0时,间距比为5时凹槽状叶顶的气膜冷却效果达到最佳。

The film cooling characteristics of gas turbine blade with squealer tip were numerically investigated using three -dimensional Reynolds-Averaged Navier-Stokes（RANS） and k-ωturbulent model.The availability of the utilized numerical approach with standard k-ωturbulent model for analysis the heat transfer performance of blade tip was demonstrated by comparisons of numerical results with four kind of turbulent model and experimental data .The effect of the squealer tip depth on the heat transfer performance was conducted without consideration of film cooling .The film cooling performance on gas turbine blade with squealer tip was numerically studied at different geometrical parameters of film cooling structure diameter of film cooling hole , spacing ratio and arrangements , as well as blow ratios.The numerical results show that the averaged heat transfer coefficients of blade squealer tip without consideration of film cooling at 1.5%span tip clearance and 2%depth is highest.The averaged heat transfer coefficients of blade squealer tip decreases with in -crease depth.Regarding to the blade squealer tip with film cooling structure , the best film cooling performance of blow ratio with 1.0 for the film cooling camber arrangement is obtained .The film cooling efficiency increases with increasing of the hole diameter at the camber line arrangement and blow ratio with 1.0.The film cooling near the suction side arrangement shows the lowest cooling efficien -cy.The comprehensive best cooling efficiency of film cooling spacing ratio with 5 at the camber line arrangement and blow ratio 1.0 is captured.