Parametric Analysis of Annular Twin Cavity Trapped Vortex Combustor Using Numerical Simulations

Small turbojet engines require lightweight and compact combustors to stabilize the flame over a wide range of operating conditions. A cavity-based flame stabilization is a suitable choice due to the high residence time in the physical cavity. F-24 jet fuel-powered annular twin cavity configuration with forward and backward cavity air injection for a stable dual vortex structure is investigated. A previously validated Unsteady Reynolds Averaged Navier-Stokes-based numerical model is used to study the effects of flow velocities on the combustor performance and optimize the combustor operation. A geometric variation with obstructions in the main flow is also considered for enhancing the cavity-main flow mixing, which provides the additional advantage of the ease of combustor ignition. Enhanced mixing of the cavity and main flow is observed in the wake region of the main flow path because of the reorientation of the vortex structure in the cavity and main flow. The proposed geometry and operating conditions are used to develop a small-scale gas turbine combustor.