Abstract
The source term model is an effective way to reduce the calculation consumption in predicting film cooling performance. The aim of this work is to develop a new source term model to consider the non-uniform in-hole flows. The internal cross flow that occurs in air-cooled blades and vanes has been shown to distinctly affect the cooling performance. In this work, the in-hole flow mechanism with the presence of the internal cross flow is studied. A topological model that divides in-hole flows into three parts and several regions is put forward. It is shown that, compared with the parallel ones, the perpendicular internal cross flows dominate the cooling performance. What is more, flows within the cooling hole are not affected by the main flow, especially in the region under a certain plane (named the R plane). This feature makes it possible for a source term model to work under various main flow conditions. Based on these understandings, a non-uniform source term model is established. It models and solves the three-dimensional in-hole flows by a two-dimensional transient solver and describes the effect of the internal cross flow as initial conditions using a vortex model. The result of the transient solver is then transformed into the axial velocity distribution at the R plane and is used as the source term. The prediction of the source term model is compared with full CFD under various VR, VRi and β, showing the ability of this model to predict the effect of the internal cross flow with discrepancy increasing with VR. Accurate modeling of the three-dimensional in-hole flows is the key point in this source term model and needs further development.
