Boundary condition for supesonic nozzle simulation
 

Hi all, I am doing 3d simulation of convergence-divergence nozzle with supersonic flow. Mach no. around 2. I am using std K-e model. I would appreciate if someone can suggest me what would be the proper wall conditions for the nozzle. The average thickness of my nozzle is 0.1 inch. I went to couple of research paper, some have used adiabatic wall and some as constant temperature wall. Since this is supersonic flow simulation, I am not sure what to use as wall condition. I will really appreciate any suggestion on this. Thank you in advance. Abhinav

Re: Boundary condition for supesonic nozzle simula
 

Both wall conditions are right. A adiabatic wall can be maintained at constant temp.

Re: Boundary condition for supesonic nozzle simula
 

Hi Hirdesh, Thank for replying so quick. What you say adiabatic wall will be good or convective wall with specific heat transfer coefficient will be the good option for me. As flow is supersonic and mtl of nozzle is steel with 0.1 inch thickness.

Once again thank you very much for reply. Abhinav

Re: Boundary condition for supesonic nozzle simula
 

Hi, I think solid wall can't be convective. So better to take adiabatic wall.

Hirdesh

Re: Boundary condition for supesonic nozzle simula
 

What exactly do u need at the wall are u planning to study the flow properties or the heat transfer across the wall. if your interest is only flow you can have only no slip condition at the wall and leave the default options of wall boundary condition as it is or if u need to study the heat transfer coefficient then u need to bother about it as maintaining the wall at constant temp or adiabatic

it entirely depends on ur problem definiton

Re: Boundary condition for supesonic nozzle simula
 

My main aim to analyze flow and in particular shock waves ... So I wanted to keep boundary condition simple still realistic ... What you suggest I should use as Boundary condition, as boundary condition is important for realistic results. Thank you.

Dear Abhinav and all
I am also trying to simulate 3d CD nozzle flow. But I am very bad in grid generation. I use GAMBIT for grid generation. If you have any example of 3d CD nozzle grid generation and FLUENT simulation, help me please. I wonder if you make reply to me. my email is tunzawcn@gmail.com