Flame Stabilisation Mechanism for Single and Multiple Jets in Cross-flow Using the Conditional Moment Closure

The flame stabilisation mechanism for single and multiple reacting jets in cross-flow has been investigated using Large Eddy Simulation (LES) with the Conditional Moment Closure (CMC) as the sub-grid combustion model and a detailed chemical mechanism for pure hydrogen fuel. It has been found that a single jet in cross-flow (SJICF) has higher jet penetration depth compared to multiple jets in cross-flow (MJICF). This behaviour is attributed to the proximity of the counter-rotating vortex pairs of the three jets, which induces a downward negative velocity component, thereby influencing the jet stem. The flame stabilisation mechanism has been investigated using the budget of individual terms in the CMC equation. The CMC budget analysis reveals that upstream of the reactive zone, a premixed flame structure is observed with a convection-diffusion balance, whereas further downstream, a non-premixed flame structure prevails with a balance between micromixing and chemical reactions.