[CrazyF]

Hi friends,

I am doing some simulation on Spray G with CONVERGE. In the CONVERGE example case of Spray G, the KH-RT model (RT model with breakup length) is recommended. But the Modified KH-RT model (RT model without breakup length) is recommended for Spray A. Does anyone know the reason for the different choice? I found the vapor penetrations are comparable while the liquid penetrations have a significantly different.

Thanks in advance

[alexzhangyu]

Regarding the options of different breakup models that have been used in the Spray A and Spray G example, it is related to the fuel and the injection conditions. For Spray G example, the fuel is gasoline, the injection pressure is about 220 bar, while for the Spray A example, the fuel is diesel, and the injection pressure is about 1600 bar, these lead to a much higher injection velocity in the Spray A example, and therefore different break-up process, e.g. the effect of aerodynamic instability is more dominate for the higher injection velocity condition. With these considerations, we used different break-up models in the two examples, and therefore leads to different simulation results. For example, for the RT model with breakup length, within the breakup length, only the KH model is activated.

If you want know more details about the spray breakup models, please refer to our user manual, or our advanced training materials about the spray modeling (you can download them from https://hub.convergecfd.com/).

In the meanwhile, in the Spray modeling configuration panel, we provided some recommendation model parameters w.r.t fuel and operation conditions. It is a good reference starting point for your own application.

Hope it helps.

- Yu Zhang
CONVERGE support