Numerical Simulations of Rich Burn Quick Mix Lean Combustor

Abstract

Objectives: This paper aims to present a summary of Nitrogen oxide formation in designed Rich Burn Quick Mix Lean Burn Gas Turbine Combustor. The combustor uses Hydrogen as a fuel and designed for 20 kW power output. Methods/Statistical Analysis: The numerical study has been carried out for designed combustion chamber by using Modified O’Conaire Mechanism. The output of numerical study concludes that the design combustion chamber has high velocities of the order of 600m/s in the quick mix zone which in turns suggest very high pressure drop. The highpressure drop is not advisable for gas turbine engine. The modifications in quick mix zone are redesigned to reduce the velocities and in turn reduce pressure drop. Redesign of quick mix zone is carried out providing diffuser at the exit of quick mix zone. The redesigned combustor is numerically simulated at different overall equivalence ratio. Findings: The results suggest low velocity levels in the rich zone leading to better mixing of fuel and air streams, near uniform temperature distribution in annulus liner, flame blow out in quick mix zone, and stable combustion in lean zone. Application/Improvements: Modified Combustion chamber was numerically tested for different altitude condition and different equivalence ratio for stable operation during real life condition. Keywords: Equivalence Ratio, NOx, Numerical Simulations, RQL