叶栅端壁附面层的预测模型研究

本文对轴流压气机叶栅端壁附面层的诸种计算方法进行了详细的研制，基于实验和理论提出一种将叶片力亏损与端壁附面层主流和横流发展相关联的新的叶片力亏损模型，该模型不仅适用于叶栅通道内的附面层计算，而且适用于考虑端部间隙漏流影响的端壁附面层计算，对三种不同叶栅的计算结果表明，采用本文的力亏损模型和端壁附面层计算方法所预测的端壁附面层发展，尤其是叶片力亏损的发展，与实验结果一致性较好，这说明本文不仅通用性强而且更具有强的实用性。

New Model for Predicting End Wall Boundary Layer in an Axial Cascade

As is well known, momentum integral equations, including blade force defect, are nowgenerally uscd for predicting end wall boundary layer in axial cascade, and Head's expres-sion of entrainment [4-5] is required to close the equations. Mellor et al[3], DeRuyck etal[4-5] gave three models for predicting blade defect. It appears that no theoretical explana-tions of these three models were given. The authors' main contributions are: (1) Based on theoretical analysis, a new model is presented. This model can predict theend wall boundary layer and the blade force defect more accurately and is applicable toboth the case of tip clearance and the case of no tip clcarance. (2) Detailed theoretical analysis, which explains the new model for blade force defect,is presented. The analysis considers the development of both primary flow and transverseflow in the end wall boundary layer. The governing equations or three--dimensional endwall boundary layer in physical plane and the detailed expression of blade force defect arederived. Different velocity profile models are used respectively for end wall boudary layerwith tip clearance and that without tip clearance. (3) A revised expression of entrainment is put forward. Green et al[6], East et al[7]showed that, when the shape factor is larger than 1.6, Head's expression of entrainmentfails to give good prediction of end wall boundary layer. This shortcoming of Head's ex-pression is overcome by the authors' revised expression. (4) Much needed explanation of the great effect of tip clcarance on end wall boundarylayer and blade force defect is offered. Such a great effect was indicated by the experimentalresearch of Papailiou et al [8]. Numerical results computed by the authors' method for threehigh-load cascades are in good agreement with Papailiou's experimental data.