Turbulence and Residual Gas Effects on Mixing, Combustion, and Emissions in Split Injection of Gaseous Fuel

Combustion and pollutant formation in split injection may be influenced by interaction between fuel pulses. Specifically, the interest here is in two aspects of that interaction: turbulence effects and residual gas effects. The objective of this work is to understand these two aspects of the interaction between multiple fuel pulses, in isolation from other effects, while employing widely accepted computational methods. Residual gas effects on combustion in the jets are studied using two combustion models: a characteristic time combustion model within Reynolds-averaged Navier-Stokes simulations and an interactive flamelet model. Findings indicate that dilution and thermal effects of residual gases are dominant. Regarding the turbulence effects, this work does not predict mixing enhancement due to turbulence from prior injection pulses. Rather, the jet is accelerated by the bulk flow field established by prior injections.