On combustion in a closed rectangular channel with initial vorticity

Abstract

This article examines the detailed combustion process in a theoretical model with applicability to combustion in a wave rotor or wave disc engine. The model comprises a single channel into which an initial loading of methane and air is admitted and ignited after all inlet and exit ports have been closed. Combustion takes place at constant volume. However, the initial gaseous mixture in the channel is not at rest. The initial opening and closing of the ports generates significant vorticity which influences the evolution of the combustion process. Numerical evaluations are provided for the detailed flame shape for simplified (one-step) chemistry and a simulation using the detailed 235-step San Diego scheme. Quantities examined are the evolution of vorticity, pressure fluctuations, mass consumption rate, flame surface area and the influences on combustion of adiabatic and non-adiabatic channel walls. Combustion regimes are identified and compared with simpler model studies (no initial flow). Pointwise quantities are examined to describe the various stages of burning in the channel. The focus of the study is directed towards quantities that influence overall burning rate and completeness of combustion.

Keywords:

• confined channel
• premixed
• vorticity
• transition
• detailed chemistry