THE EFFECT OF H2 ADDITION ON CNG/H2-AIR FLAME SHAPE TOPOLOGY IN A LEANPREMIXED SWIRL STABILIZED GAS TURBINE COMBUSTOR

The present study investigates the flame shape topology in a lean premixed swirl stabilized combustor for various hydrogen thermal powers (P-th.H2) and equivalence ratios (phi) using CNG/H-2-air mixtures at atmospheric conditions. High-speed OH*-chemiluminescence (OH*- CL) imaging is employed to study flame dynamics. It is found that at a fixed value of hydrogen mole fraction (XH2), an intense and short flame is found for a higher value of phi. Also, at a fixed value of phi, flame length shortens, and an enhanced heat release is observed near the burner exit with an increase in X-H2. A V-shaped flame with the flame tip pointing toward the exhaust port is witnessed at low values of phi and X-H2. Moreover, the V-shaped flame transitioned into an M-shaped flame with a flickering flame tip near the wall with an increase in phi and X-H2. Further, the heat release zone gets extended and distributed over the entire length of the combustion chamber for small values of phi and X-H2. Finally, the stable flame topology is correlated to the non-dimensional parameters Damkohler number (Da), and the wall temperatures (T-w).