Large eddy simulation of scalar mixing in jet in a cross-flow

Jet in a Cross-Flow (JICF) is a flow arrangement found in many engineering applications, especially in gas turbine air-fuel mixing. Understanding of scalar mixing in JICF is important for low NOx burner design and operation, and numerical simulation techniques can be used to understand both spatial and temporal variation of air-fuel mixing quality in such applications. In this paper mixing of the jet stream with the cross-flow is simulated by approximating the jet flow as a passive scalar and using the Large Eddy Simulation (LES) technique to simulate the turbulent velocity field. A posteriori test is conducted to assess three dynamic Sub-Grid Scale models in modelling jet and cross-flow interaction with the boundary layer flow field. Simulated mean and Reynolds stress component values for velocity field and concentration fields are compared against experimental data to assess the capability of the LES technique, which showed good agreement between numerical and experimental results. Similarly, time mean and RMS values of passive scalar concentration also showed good agreement with experimental data. In addition, LES results are further used to discuss the scalar mixing field in the downstream mixing region.