Numerical Investigation of Diffusion Flame in Transonic Flow with Large Pressure Gradient

TL;DR

This paper develops a finite-volume method for simulating steady, compressible reacting flows with large pressure gradients, revealing chemical reactions' impact on turbulence and examining vitiated air effects on combustion and turbine performance.

Contribution

It introduces a steady-state preserving splitting scheme for stiff chemical source terms in Navier-Stokes equations and applies it to turbulent reacting flows with large pressure gradients.

Findings

Chemical reactions enhance turbulent transport and increase turbulent viscosity.

Vitiated air influences combustion efficiency and aerodynamic performance.

Results support the viability of the turbine-burner concept.

Abstract

A finite-volume method for the steady, compressible, reacting, turbulent Navier-Stokes equations is developed by using a steady-state preserving splitting scheme for the stiff source terms in chemical reaction. Laminar and turbulent reacting flows in a mixing layer with large streamwise pressure gradient are studied and compared to boundary-layer solutions. It reveals that chemical reaction strongly enhances turbulent transport due to intensive production of turbulence by the increased velocity gradients and thus produces large turbulent viscosity in the reaction region. Influence of vitiated air on the combustion process and aerodynamic performance is also investigated for the cases of turbulent mixing layer and highly-loaded transonic turbine cascade. Both cases indicate viability for the turbine-burner concept.