振动平板气膜冷却的数值分析

Numerical Analysis of Film Cooling on Vibrating Flat Plates

采用数值方法模拟振动平板单孔气膜冷却过程,对比不同振动频率、不同振幅和不同吹风比下气膜孔中心线下游绝热壁面的有效温比曲线,并分析了气膜孔周围壁面相对静压分布.结果表明:振动会削弱气膜冷却效果;在吹风比λ=1.0下,不同振幅、不同振动频率振动时绝热壁面的有效温比比稳态时小,且在x/D>10时,2种情况下有效温比的差距更明显;同一振动下,在吹风比小于0.6,x/D<5振动时绝热壁面的有效温比比稳态时大,在x/D>5振动时的有效温比比稳态时小;在吹风比大于0.6振动时的有效温比始终比稳态时小;振动时气膜孔周围壁面相对静压会出现周期性变化.

The single-hole film cooling process on a vibrating flat plate was numerical studied, so as to com- pare the curves of adiabatic film cooling effectiveness in the downstream of jet hole centerline obtained at different vibration frequencies, amplitudes and different blow ratios ;t, and to analyze the distribution of relative static pressure around the jet hole. Results show that vibration weakens the effectiveness of film cooling. In the case of λ= 1.0, the adiabatic film cooling effectiveness at different amplitudes and frequen- cies of vibration （FCEV） is larger than that at steady state （FECS）, and if x/D）lO, the difference be- tween above two states will become more obvious. Under same vibration conditions, and for λ〈0.6, the FCEV will be larger than the FECS in the case of x/D%5, and the FCEV will be smaller than FECS in the case of x/D）5. The FCEV will always be smaller than the FECS under the condition of λ〉0.6. The dis tribution of relative static pressure around jet hole appears periodic changes under vibration conditions.