Converging diverging nozzle

Aim - Simulation of flow through a C-D Nozzle.

Tool used - Ansys Fluent

Procedure

1. Geometry creation

Inlet, throat and outlet radius are known.

A three point arc passing through these points would give us a smooth curve, which will act as the wall of the C-D Nozzle.

2. Mesh generation and providing named selections

Auto generated mes, in this case it is a hybrid mesh which is a combination of structured and unstructured mesh types.

3. Solving

Density based (Air-compressible at high velocity)

Steady state (Intrested in end results)

Viscous - Inviscid/Turbluent

Energy equation

4. Results

Conclusion

• Since pressure at inlet an doutlet is predefined, the pressure inside the C-D nozzle falls in the intermediate range of these extrimites.
• The temperature gradually reduces as it passes through the C-D nozzle. This is quite counter-intuitve. One would expect the temperature to rise as the flow is speeding up.
• The velocity and Mach number plots follow the increasing trend.
• Mach becomes 1 at throat or right after the throat, the flow is chocked here.