A Two-Step Reaction Model for Stratified-Charge Combustion in Wave-Rotors

摘要

Testing of a wave-rotor constant-volume combustor (WRCVC) demonstrated the viability of the application of a wave rotor as a pressure gain combustor. The aero-thermal design of the WRCVC test rig had originally been performed with a time-dependent, one-dimensional model that used a single-step reaction model for the combustion of air-fuel mixture. In the present work, a two-step reaction model for the combustion process is implemented with four species variables: fuel, oxidant, intermediate and product. This combustion model is developed for a more realistic representation of the combustion process inside the WRCVC. The model allows stratified mixtures to be represented and also accounts for flammability limits that influence flame extinction for non-flammable mixtures. The combustion rate is based on the eddy-breakup model, with the chemical time scales assumed to be much faster than turbulence time scales. Experimental data for deflagrative combustion from the WRCVC test rig is used to calibrate model parameters that are not directly measured or predicted. The predicted and measured in-channel pressure traces are compared, and the predicted flame propagation in the channel is compared with experimental ion probe data.