摘要
采用RNGk-ε湍流模型对扇形角(锥形角)γ为30°的垂直扇形气膜冷却单孔射流流场下游的流动和传热特性进行了详细的数值模拟,并将沿程方向的速度分布、相同吹风比下的冷却效率与相同条件下圆孔射流的计算结果进行了比较分析。结果表明:射流轨迹对横向主气流的影响主要集中在射流发生弯曲直至与主气流平行的区域内;喷孔为圆孔时,吹风比越小,射流中心线越靠近壁面,其冷却效率越好;吹风比相同,扇形喷孔的冷却效率高于圆孔的冷却效率;扇形孔的冷却效率并不随吹风比的变化而单调变化,而是在吹风比为1.0时存在最佳值。
A RNG κ-ε turbulence model is used to numerically simulate the cooling film＇ s flow field in the wake of a cooling jet, squirting out of a perpendicularly orientated single conic orifice with a diffusor angle of r = 30°. The calculated velocity distribution along flow direction, and the cooling effectiveness are compared with the calculated results performed for cylindrical orifices for same flow ratios and under the same conditions. Results show that the jet＇ s influence on the main cross-flow is concentrated in the zone where the former starts to curve, up to where it gets parallel to the latter; in case of cylindrical orifices the center flow line approaches the wall surface more readily with reducing flow ratios and with cooling effect, which gets more pronounced if diffuser shaped orifices are used instead of cylindrical ones, even for same flow ratios; the cooling effect of diffuser shaped orifices doesn＇t monotonously vary with changing flow ratio but attains an optimum with a ratio of 1,0, Figs 7 and refs 10.
出处
《动力工程》
EI
CAS
CSCD
北大核心
2006年第3期333-336,共4页
Power Engineering
基金
国家自然科学基金项目(50476037)
关键词
动力机械工程
涡轮机械
气膜冷却
紊动射流
数值模拟
冷却效率
power and mechanical engineering
turbomachinery
film cooling
turbulent jet flow
numerical simulation
cooling effectiveness
