Pressure Gain Combustion by Using Shock Flame Interaction Pressure Rise

Pressure loss across the combustor in a gas turbine reduces the thermal efficiency and increases the specific fuel consumption. Theoretically, any pressure gain across the combustor results vice versa of the previous result. Hugoniot curve demonstrates any possibilities from an unburned state to the burned state under the conditions of 1D, no body forces, no external heat addition or loss, constant flow duct area, negligible diffusion effects, non-viscous flow and perfect gas conditions. among the possible burned state, detonation can damage the combustor and can cause irreversible entropy rise. A better option is to be between constant volume combustion and constant pressure combustion, that is ‘pressure gain combustion’. When a shock wave hits a flame, the shock refracts and a reflected wave and a transmitted wave which is a shock with a different velocity and Mach number develop. The transmitted wave hits the other end of the flame and refracts; one transmitted wave and a reflected wave develop, both them are shocks. Reflections from the walls also enhances the shock flame interaction. Each interaction causes an unsteady pressure rise in the flame.

Our work aims to obtain ‘time-averaged pressure rise across the combustor by using shock-flame interaction pressure rise’. Shock flame interaction increases the chemical heat release rate. The work consists of two parts; numerical and experimental. For numerical part, an impulsive heat addition for some time with different heat release rates within the primary zone in the 3D combustor model was defined after a quasi-steady combustion and the results were evaluated. For experimental part, we will introduce the flame with shocks with different strengths and measure the outlet and inlet pressures. Any pressure gain combustion can save billions of USD as gas turbines consume 13.9% of the total energy consumption.