扫掠冲击-气膜冷却结构的气动传热特性数值研究

Numerical Investigation on Aerodynamic and Heat Transfer Characteristics of Sweeping Impingement and Film Composite Cooling Structure

关键词:  涡轮  叶片  气膜冷却  复合冷却  气热耦合  冷却效率

Key words:  Turbine  Blade  Film cooling  Composite cooling  Conjugate heat transfer  Cooling effectiveness

摘要:

为了揭示“扫掠冲击-气膜”冷却结构的换热机理，采用气热耦合方法和SST k-ω湍流模型，对比分析了吹风比为1，2，3，4和气膜孔角度为30°，45°，55°，65°等条件下，“直接冲击-气膜”组合方式和“扫掠冲击-气膜”组合方式在平板模型上的气动传热特性。结果表明，流体激振器的扫掠频率、冲击靶面上的Nu数随吹风比增大而增大，并且几乎不受气膜孔角度影响。两种组合方式的总压损失系数和综合冷却效率随吹风比增大而增大，并且随气膜孔角度的增大而略微减小。尽管在使用相同冷气流量时“扫掠冲击-气膜”组合方式的冷气进口静压较高，但是其具有冲击靶面上Nu数分布均匀、综合冷却效率更高且分布面积更大的优势。

Abstract:

In order to reveal the heat transfer mechanism of "sweeping impingement & film" composite cooling， the aerodynamic and heat transfer characteristics of "direct impingement & film" composite cooling and "sweeping impingement & film" composite cooling on a flat plate model were compared and analyzed by using SST k-ω turbulence model and conjugate heat transfer method under the conditions of blowing ratio of 1， 2， 3， 4 and film hole angle of 30°， 45°， 55° and 65°. The results show that the sweep frequency of the fluidic oscillator and Nusselt number Nu on the impinging surface increase with the increase of the blowing ratio， and are hardly affected by the angle of film holes. The total pressure loss coefficient and overall cooling effectiveness of the two composite cooling increase with the increase of blowing ratio， and slightly decrease with the increase of film hole angle. Although the coolant inlet static pressure of "sweeping impingement & film" composite cooling is high when using the same coolant flow， it has the advantages of uniform Nu distribution on the impinging surface， higher overall cooling effectiveness and larger distribution area.