Vortex Shedding Mechanism of Post Cyclone-Bluff Body Stabilized Combustion

Abstract

V-gutter is one of the typical bluff bodies that often used for flame stabilization in the afterburning chamber of present turbine engine. For its small range of lean/rich fuel limits, weak anti disturbance capability and low combustion efficiency which may cause the flame in combustion chamber easily to be extinguished, the V-gutter still needs to improve performance. In this paper, a new method that adding a cyclone behind the bluff body to enhance the flame stabilization by the interaction of shedding vortex of bluffs body and this cyclone is proposed. Vortex shedding mechanism of the flow around V-gutter with post cyclone is studied. The numerical result shows that the post cyclone has an important impact on the vortex shedding mechanism of the flow around V-gutter. The flow resistance and fluctuation are reduced and the length of the recirculation zone is increased, which can lead to the improvement of the flame stabilization. On the contrary, the flow resistance and fluctuation increase, and the recirculation zone become shorter when the post cyclone source is outside, which is negative to the flame stabilization. The influence of the post cyclone diameter cannot be ignored either. The flow resistance is increased, the fluctuating characteristic is strengthened, the recirculation zone is shortened and the vortex shedding frequency is decreased when the cyclone diameter is increased.