A Lattice Boltzmann Method for Turbomachinery Simulations

Abstract

In the last decade, a relatively new method for fluid dynamics simulations, the Lattice Boltzmann (LB) method has been successhlly developed into a promising alternative of the traditional CFD method. Simulations of many flow phenomena have been demonstrated. However, most of those LB simulations were laboratory type simulations and applications of the LB method to real-life problems have been few. In the present work, a new compressible LB model is developed for turbomachinery simulations, specifically, simulation of cascades. The traditional LB models were restricted to simulations of small Mach numbers. The present authors proposed an LB model that lifted the small Mach number restriction and could simulate flows with an arbitrary Mach number. In the current work, this model has been extended successfully to the simulation of cascades. In order to handle the complex geometry in cascade simulations, several new techniques have been successfully developed. A new boundary treatment has been introduced to the current LB model to simulate the slip wall boundary. A new mesh treatment has also been devised in current work to cover an irregular computational domain with a regular mesh. Simulations have been carried out for two different cascades, including, the wedge cascadqand a C3X cascade. Comparisons were made between the current results and both experimental results and numerical results of pervious simulations using the traditional CFD method. Good agreements between the current result and both the experimental and the numerical results have been shown. This is the first time that a LB simulation of turbomachinery has been reported.