Prediction of Lean Blowout Limits for Methane-Air Bluff Body Stabilized Combustion using a Temperature Gradient Method in a Model Gas-Turbine Afterburner

Abstract

AbstractIn the present work, LBO limits for methane-air combustion stabilized by a V-Gutter have been predicted by a hybrid method using numerical simulation and empirical relations. The numerical simulations have been carried out to study the stable methane-air combustion and temperature gradients at exit and recirculation region in a model gas turbine afterburner with a planar V-Gutter as a bluff body for four inlet air pressure conditions and three V-Gutter angles. The calculated average exit gas temperature (AEGT) and the average gas temperature in recirculation region have been used for predicting the blowout conditions. An empirical method based on Feature Section Criterion has been used to determine Fuel-Air Ratio (FAR) at blowout conditions very accurately from the numerically calculated average temperature in the central recirculation zone (CRZ).The predicted Fuel-Air Ratio (FAR) at lean blowout conditions has been compared with the experimental results obtained for the same conditions and are found to be in good agreement.