The Effects of 3D Flow on Turbomachine Boundary Layers

叶片表面损失与耗散系数乘以速度的立方成正比。在二维湍流边界层中，这些损失被很好地理解，并且存在计算损失的模型。然而，在叶片通道中，横向压力梯度导致三维边界层，其中的损失尚未得到很好的理解。本项目旨在定义涡轮机械中的三维边界层，量化边界层的三维性，并测量三维耗散系数的变化。该项目还旨在了解任何增加损失背后的机制，并调查边界层上的3D效应是否会影响向湍流的转变。三维边界层的耗散系数以前没有测量过，本项目将进行实验测量。增加损失的机制将使用高保真计算流体动力学进行研究。

Blade surface losses are proportional to the dissipation coefficient multiplied by velocity cubed. In a two-dimensional turbulent boundary layer these losses are well understood and models exist to calculate the loss. However, in a blade passage, transverse pressure gradients result in three-dimensional boundary layers in which the losses are not well understood. This project aims to define the three-dimensional boundary layer seen in turbomachinery, quantify three-dimensionality of a boundary layer and measure the change in dissipation coefficient with three-dimensionality. The project also aims to understand the mechanisms behind any increased loss and to investigate whether 3D effects on boundary layers impact transition to turbulence. The dissipation coefficient of a 3D boundary layer has not been measured before and this project will measure this experimentally. The mechanisms of increased loss will be investigated using high fidelity computational fluid dynamics.