Uneven mesh
 

Hi!
I am simulating a non-premixed combustion with DPM on a rocket engine using Ansys fluent. I only enabled the flow and turbulence (in the solution controls), to simulate the cold flow before proceeding with the final simulation. The residuals (continuity, x,y and z) are fluctuating and nowhere near convergence.
I think I might have a problem with the mesh!
I have a negative pressure gradient on the throat as depicted in the figure below. So I am refining the mesh at the throat.
My problem is that I have an uneven mesh at the walls and at the exit of the geometry as shown in the figure below. So how can I solve this problem?

This looks like a problem related to geometry . make sure you have a clean surface, no divided edge . can post a screenshot of your geometry . from desigbmodeler maybe?

Geometry/DesignModeler
 

Here's the images showing the back and front of the rocket engine, and on the left (the details view) and the tree outline.
Is there something I should modify in the properties on the left pane?

can you try hexa mesh for this geometry?

tetrahedron mesh
 

I'm using a tetrahedron element with advanced size function of "proximity and curvature", and went up from 1,700,000 elements to 7,269,391 elements (in a 20 cm long geometry). Do you think that hexahedral mesh will solve the problem? take a look at the new mesh.

Hi,
Your works seems to be so good with DPM spray.
I am also working on DPM. Can you help me out with the Spray modeling in non premixed combustion model ?
I am not able to get the spray in the form of droplets which also interacts with the continuous.

Thanks a lot in advance.