平板振动对气膜冷却及流场特性影响的数值研究

Numerical study on the effect of plate vibration on film cooling and flow field

对平板在振动状态下的气膜冷却进行数值研究,比较在不同振动条件下吹风比为1时气膜孔下游中心线上绝热壁面的冷却绝热效率,同时分析了气膜孔下游壁面在不同振动条件下的静压及静压随相位角的变化。结果显示:振动会使平板气膜冷却效果恶化,在不同振动条件下振动时绝热壁面的冷却绝热效率均比稳态时低,在x/d>7时,不同振动频率下的冷却绝热效率相差较大,且频率越大冷却绝热效率越小,不同振幅下的冷却绝热效率相差较小。振动时气膜孔下游上下壁面静压呈周期性变化。靠近气膜孔截面贴壁区域各相位下均存在明显的二次流,在x/d=5和x/d=10截面内,y/d<4范围内各相位均存在速度峰值,90°和180°速度峰值大于稳态时速度,0°和270°速度峰值小于稳态时速度。

The film cooling of a flat plate in vibration was numerically studied.The adiabatic cooling efficiency of adiabatic wall at the downstream centerline of the film hole was compared under different vibration conditions with blow ratio 1,and the variation of static pressure with angle was analyzed.Results showed that vibration deteriorated the flat film cooling,the adiabatic cooling efficiency at different vibration conditions were lower than that at steady state.When x/d>7,larger variations of cooling efficiency were found at different frequencies of vibration,and the adiabatic efficiency decreased with the increase in frequency.The effective temperature ratio differs at different amplitudes.The static pressure of the upper and lower wall surfaces downstream of the film hole changes periodically during vibration.There is obvious secondary flow near the phase of the adherent area of the gas film hole section.Within x/d=5 and x/d=10 sections,The maximum speed exists in each phase in the range of y/d<4,90°and 180°speed peaks are greater than steady state,0°and 270°speed peaks are less than steady state.