Design by Large-Eddy Simulations of a Rich Burn – Quick Mix – Lean Burn Lab-Scale Combustion Chamber Operating in High-Pressure Conditions

Abstract The Rich burn-Quick mix-Lean burn (RQL) concept is a promising staged combustion technology that ensures flame stability at all operating conditions and significantly reduces the pollutants concentration at the outlet of a combustion chamber. The current paper aims to detail the design of an optimized RQL lab-scale combustion module equipped with large optical accesses and a new-generation Injection System from the French engine manufacturer Safran Helicopter Engines. It is intended to study soot oxidation and NOx reduction processes under realistic high-pressure conditions up to 14 bar by simultaneously investigating the Rich, Quick-mix and Lean regions by laser-based diagnostics. The design of this module is first ensured by performing Large-Eddy Simulations of the reactive flow produced by a kerosene-vapor/air mixture with the AVBP solver. Various geometric configurations of this module were tested at the nominal regime to gradually improve its performance while seeking a suitable solution optimizing flow, mechanical and thermal constraints. The main versions are first presented to show the progress made to well separate the three regions of the RQL combustor while preserving an ability to perform a detailed optical investigation. A reactive two-phase flow LES with liquid fuel kerosene is finally performed to validate the adopted design of the RQL module.