Practical Aspects of Computational Fluid Dynamics for Turbomachinery

Abstract

The following dissertation examines several aspects of numerical simulations for turbomachinery flows modeled with an in-house Reynolds-averaged Navier-Stokes solver. The impact of the turbulence model on the solution is also explored in this work. Additionally, the effects of different solution limiters, including both a new and modified limiter, are examined.

This dissertation also presents a new grid generator that was tailored for turbomachinery geometries. The grid generator uses a combination of structured grid blocks to discretize a single blade passage domain. Structured grid blocks can also be placed at the blade tip, allowing for the modelling of tip leakage flows.

A number of canonical cases were used to validate the additions and modifications to the flow solver. Among these cases were the inviscid flow through a convergent-divergent nozzle and a turbulent flat plate. It is shown that the new and modified limiters perform similarly to the existing limiter functions, and in some cases, out-perform their predecessors.

The flow solver is further validated against two turbomachinery cases: an annular turbine vane and a transonic fan. Comparisons with experimental data are made in both cases. The effects of turbulent inlet conditions and the under-relaxation of the turbulence equations are examined for the turbine vane geometry. Two novel rubbing configurations are presented and examined in the turbulent transonic fan case. Additionally, a transonic fan case, which includes the tip leakage flow, is also presented and compared against the rubbing cases.