An Experimental Study on the Causes of the Combustion Instability in a Dump Combustor

Abstract

The stabilization of turbulent flames, together with the emission of combustion products, is the most important problem of the gas turbine combustor. In this study, we made a model gas turbine combustor which has a dump plane and investigated the combustion phenomena with various experimental conditions such as the variation of equivalence ratio, various mixing process of the fuel and air, and fuel injection method. The heat release rate of the flame, the stabilization region of the flame, and the pressure fluctuation of the flow are closely connected to one another in the instability mechanism. We changed the fuel flow modulation, the heat release rate with the load change of the gas turbine and the equivalence ratio variation of the mixing process. We found that the role of the vortex flow near the flame, the modulation of the reactant flow and the flame stabilization mechanism are the key parameters of the combustion instability of the gas turbine combustor.