涡轮叶片型面气膜冷却效率的计算模型

A new model for film cooling effectiveness computation on blade surface in a turbine cascade

关键词:  涡轮叶片  气体冷却  薄膜冷却  喷射混合流  计算

Key words:  Turbine blade  Gas cooling  Film cooling  Jet mixing flow  Computation

摘要:

研究并发展了以低雷诺数k ε紊流模型为基础的气膜冷却效率计算方法,将前人针对平板气膜冷却提出的掺混模型推广应用于涡轮叶片型面。计算结果表明,导向叶片型面存在四个典型区域,每个区域自气膜孔喷出的冷气射流与主流的相互作用的规律不同,对于四个典型区域分别建立质量喷出率φ和三维掺混系数γ两个经验参数随冷气吹风比变化的规律,并用所得的规律计算叶片上单排气膜孔下游的冷却效率,与实验数据符合良好。

Abstract:

Predictions of span-wise averaged effectiveness were made with a two-dimensional boundary layer code using the low Reynolds number k-ε two-equation turbulent model. A new injection model, which was incorporated in the code, for describing the discrete-hole injection process were suggested. The code can be used to calculate the film cooling effectiveness on the turbine blade surface. The computational results show that there are four typical regions on blade surface. The correlations between empirical parameters and blowing ratios are developed at different regions independently and it is used to compute the cooling effectiveness downstream of single row gas holes on blade surface. The calculated results agree very well with test data.