逆向射流多斜孔气膜冷却的数值模拟

Slant multi-hole film cooling numerical simulation of reserved injection

为了使航空燃气轮机燃烧室在高于燃烧室材料许用温度的前提下能够正常工作,需对燃烧室内壁采取冷却措施,并对变吹风比和变角度下的逆向射流多斜孔气膜冷却进行了数值模拟。在贴体坐标下划分网格,采用k-ε模型模拟湍流流动,求解气膜冷却过程的数学模型。分别改变逆向射流同主流的夹角,使其为20°、30°、45°和60,°改变吹风比的变化范围为0.5到1.5等多种条件下,对多斜孔气膜冷却效果进行了数值模拟。在所研究的范围内得到了符合规律的结论。研究结果表明,当吹风比不变的情况下,减小逆向射流角度,用有效温比表示的冷却效果相应提高。当逆向射流角度不变时,增加吹风比,冷却效果也相应提高。

To accommodate higher temperatures which is higher than allowable material temperatures , cooling methods are needed to protect surface wall of inner aero gas - turbine engine＇s chamber. In this paper, numerical simulations were carried out to investigate a reversed injection to maintain flow condition with changeable blowing - ratio and changeable injection angle. Controlling equations of cooling process were resolved on body - fitted coordinate grid system using k - ε turbulence models . The cooling fluid flow reversed injection to the maintain flow for 20,30,45,60 deg, and the jet blowing - ratio is ranging from 0.5 to 1.5. Good regularity was obtained within the range investigated. When the blowing- ratio fixed, the smaller the reversed injection angle , the better cooling efficiency will be ,which represented by film effectiveness. When the reversed injection angle fixed, the bigger the blowing -ratio is, the better the cooling efficiency is.