Study of the Effect of the Momentum Ratio of Fuel-air Coaxial Jets on Turbulent Mixing

Momentum of the coaxial fuel and air jets is utilized for directing the flame and controlling the mixture formation which is typically the rate-limiting step of the combustion process. The momentum ratio is the ratio of the annular air jet momentum to the round fuel jet momentum. In this work, the effect of the momentum ratio on turbulent mixing of fuel and air is studied numerically, under isothermal conditions. The momentum ratio ranges from 0.25 to 24.37. Numerical results are validated against experimental data and reasonable agreement is observed. Unmixedness index is defined and used to judge the mixture quality. According to the results, mixture formation is better accomplished at lower momentum ratios.