Large eddy simulation of propane combustion in a planar trapped vortex combustor

Abstract

Propane combustion in a trapped vortex combustor (TVC) is characterized via large eddy simulation coupled with filtered mass density function. A computational algorithm based on high order finite difference (FD) schemes, is employed to solve the Eulerian filtered compressible Navier-Stokes equations. In contrast, a Lagrangian Monte-Carlo solver based on the filtered mass density function is invoked to describe the scalar field. The impact of injection strategy on temperature distribution and flame structure in a planar single-cavity TVC is investigated. A fuel jet and an air jet are injected directly into the cavity from the forebody and the afterbody, respectively. Different injection schemes are contemplated by altering fuel and air jet locations representing the different flow and flame structures. The temperature distribution, along with cross-sectional averaged temperature and flame structure, are compared for fuel/air injection strategies. The temperature field reveals that configurations in which both air and fuel jets are located at the cavity-walls midpoint or adjacent to the cavity inferior wall, lead to a more uniform temperature distribution and lower maximum temperature with the latter configuration performing slightly better. While, the former configuration provides the closest cross-sectional averaged temperature to the adiabatic flame temperature. The reaction rate distributions show that the configurations mentioned above lead to a more contained flame, chiefly due to more efficient fuel-air mixing at lower regions of the cavity.