MIXING IN CO-FLOWING TURBULENT JETS

摘要

The present investigation deals with the results of single and multiple jets in co-flowing streams. The shapes include the plane slot, circular, square and three-dimensional orifices. A feature that is common to the point-source method, adopted herein, and the CFD simulation is that the flow field need not be considered as two distinct parts- the developing and the developed zones. Of the various turbulence model options available in FLUENT, the realizable k-e model was selected for the simulation. It was found that the mean flow features like the decay of the maximum velocity-excess can be predicted with comparable accuracy by the two methods, especially in the developed zone, i.e. x/d ＞ 10. In the near field, significant differences exist between the results of the two predictions. The predicted CFD spread rates for all the jets investigated in this study were seen to be higher than the experimentally observed values. The point-source results seem to agree better with the experimentally observed velocity excess and the tracer concentrations.