[rootbeer_cigarettes]

Hello everyone,

I am working on a project to design a hybrid rocket engine. I am having some difficulties with simulation compressible flow through the nozzle.

I have a 2D surface imported from SolidWorks which includes the axis-symmetric nozzle and a large air domain.

I am using ANSYS 19 with a student license.

Energy Equation is on
Viscous Model is K-Omega & SST
The working fluid is air
Density is ideal-gas
Cp -> Piecewise-Polynomial
Viscosity -> Sutherland -> 3 Coefficient Method
Cell Zone Cond's -> Set to 0 Pa
Boundary Conditions:
inlet -> Pressure Inlet
Gauge Total Pressure -> 1896100 Pa
Initial Gauge PRessure -> 1895900 Pa
Thermal -> 3394.32K
outlet -> Pressure Outlet
Gauge Pressure -> 0.6 Pa (Mars surface pressure)
Thermal -> 350K
Reference Values -> Compute from inlet

The results are a little troubling. The velocity magnitude is good and the Mach contours also seem reasonable but the temperature contours don't make sense. I have a region of very gold gas that develops well within the nozzle. The static pressure contours are also wrong. I have reasonable pressure in the subsonic portion of the nozzle but everything past the throat and into the air domain is a uniform low pressure. Additionally, should I be looking at static pressure or one of the other pressure options?

I apologize for the wall of text but any and all feedback will really be appreciated. Thanks a lot!

imgur link with screen shots of my results

[AlexanderZ]

youtube -> rocket nozzle ansys fluent ->
https://www.youtube.com/watch?v=oY_3_c0rDiw

spent time: 15 sec

best regards

[rootbeer_cigarettes]

Thanks for the quick response. I'll try modifying the parameters according to this video although I'm not sure what the issue is with how I've set up my simulation so far. The velocity plot looks pretty good; it's Just the temperature and pressure plots that are giving me issues.

Originally Posted by AlexanderZ

spent time: 15 sec

Are you saying it only took you 15 seconds to find that video? Yes, I'm sure it's easy to find something when you already know what you're looking for.

EDIT: Corrected formatting