Learning Forum

[vijaykumarom15]

Hi,

I am currently working on a cold spray analysis which is a process to make coatings on a substrate with low porosity, high strength and at low temperature conditions. Compressed air and particles(that will form coating) are bombarded through a nozzle to the substrate. The spray parameters are an important factor in making coating effective and optimized. Hence, ihave started my analysis with nozzle. In ansys fluent, I am getting the floating point errors in calculation part. Dont know the reason.

The complete analysis including geometry, meshing , fluent analysis done till now is shown below:

GEOMETRY

[vijaykumarom15]

(Continued)

2.Make the energy eq on, realizable k-epsilon as a viscous model, As there is injection of particles in the nozzle inlet so considered discrete phase on with all parameters given below. Also considered spherical as drag law.




3.Assign the material with properties shown.
4.Boundary conditions are also specified well with inlet and outlet given pressure values and and heat flux 0 for wall. Temperature=300K.





SOLUTION
1.First order considered for stability of solutions and other parameters shown in below pics.




3.Hybrid initialization considered.
4.Created the solution data export as well as the particle export data report.



5.Run calculation assigned values:

After clicking on calculate the following message appears:

This was all i had done. Plz explain where is the issue. Any manipulations i have to do?
Also my gut feeling says that my mesh qualities are not up to mark. But also i have tried to vary that but no result. Is there any change I need to make in my modal or in meshing or is there something I am missing out. Kindly clarify.

[Rob]

Start with some mesh refinement. You want 10-15 cells across the throat. Have a look at the mesh options to use a pave mesh: mapped will cause problems as the mesh squashes into the throat. Also review the particle size relative to the cell size: read the DPM theory to see why.

[vijaykumarom15]

@Rob
Dear Sir I have changed the geometry a bit and had done the mesh refinement and also used a paved mesh(shown in fig below). The cells around the throat are more than 15.The cell size also i have optimized such that it is more than particle size. But still the error is coming. Can u tell specifically where is the problem? .Also please provide any links as an reference to help me in this issue if required.

[DrAmine]

Double check the velocity straight after the initialization. Is that what you expect? Ignore first the particles: you need first to assess the fluid dynamics...