Simulating Abrasive water jet nozzle behaviour

Marika

Hi to everyone. I am a new Fluent user and I am trying to simulate the behaviour of a AWj experimantal nozzle. I assumed that my case is steady, and i am trying to simulate tha case with water and air only to try to understand better all the phenomena. I am trying to use the eulerian model, but it doesn´t work. (it changes nothing in the field of phases, the water is blocked at the inlet). So i am trying to use the mixture model, and once the simulation is converged, i wanna use the results as initial condition for the euler model. But i have discovered a lot of anomalies: 1. I achieve convergence only when i don´t contemplate slip velocity, and only after 28000 iterations (a little too much?) 2. There is no way that I can use the euler model after: after few iterations I have divergence.

I have a lot of doubts, mostly cause we are talking about one nozzle with one diameter that changes along the lenght, so I am note sure about the relevant dimension that I must take for the turbukence lenght scale. I would appreciate any kind of suggestions and help. I thank anyone in advance.