“冲击-气膜”复合式结构冷却效果数值研究

Numerical simulation on cooling effectiveness of combined impingement and film cooling

分析了六种不同的"冲击-气膜"复合式冷却结构,将其应用在燃气轮机涡轮导向器叶片中弦区并对其内部流体的流动和换热进行了数值模拟。计算条件采用某燃气轮机的典型工况,流体物性参数随温度变化。将不同"冲击-气膜"复合式冷却结构的计算结果进行对比得出:冲击孔与气膜孔在展向的排列形式对冷却效果有较大影响,叉排明显优于顺排;随着冲击孔的后移,冷却气体对腔内壁的覆盖面积逐渐减小,冷却效果逐渐降低,流阻逐渐增大;在来自冲击冷却和气膜冷却多种影响因素的共同作用下,气膜孔角度和所在面曲率对冷却效果和流阻的影响被大幅度削弱。

The effect of structure on the flow and heat transfer of combined impingement and film cooling was studied with numerical simulation. This new cooling configuration was applied in the middle section of modern gas turbine nozzle blade under the typical condition of a gas turbine engine. Parameters of fluid were applied as functions of temperature. The simuZation was calculated with a three-dimensional Navier-Stokes equation, the standard k-~ turbulence model and wall functions. The results show that： the arrangement manner of film Cooling holes and impingement cooling holes has strong influence on cooling effectiveness of the whole configuration. The maximum cooling effectiveness was localized at a distance of 10d from the leading edge of the cavity to impingement hole. In addition, angle of film cooling hole and curvature have little effect on cooling effectiveness.