Computational study of trapped-vortex combustors

This research aims to study a novel combustor concept which utilises on the effect on trapped-vortex in a cavity. The Trapped-Vortex Combustor (TVC) will help to stabilise combustion by providing a continuous source of ignition in the cavity. It can bring about many advantages like better combustion efficiency and lower NOX emissions. In this study, the numerical investigations of a TVC were been performed using FLUENT V14.5. The fuel injector size was varied (30mm, 35mm, 40mm) and its effects were investigated. An axis-symmetric TVC with cavity on the walls of the combustor was studied. The fuel used for mixing and combustion was methane. The cold flow field was first investigated. The increasing injector size resulted in a decrease in MFR. This in turn allowed more fuel to enter the cavity of the TVC but had poorer mixing performance. In addition, the equivalence ratio was too high at certain regions of the combustor. Next, the combustion model was investigated. It is found that the 30mm injector size produced the best combustion performance due to good mixing. On the other hand, the 35mm injector was able to provide a better pilot flame zone in the cavity as a better equivalence ratio was observed in the cavity. The 40mm injector had the worse mixing and combustion performance. In summary, this research aims to provide a better understanding to the concept of using trapped vortex in combustors. It also serves to demonstrate the advantages of this concept.Bachelor of Engineering (Aerospace Engineering