Quarter section volume of Converging Diverging nozzle

Assumption and approach:-

• This compressible flow is a turbulent analysis that uses the Fluid 142 - 3D fluid-thermal element.

(But Fluid 141 - 2D fluid-thermal element is also used for initial meshing of area to get fine mesh through out the full volume of CD nozzle)

• The analysis assumes atmospheric pressure condition at the outlet. It assumes nominal temperature = 550 K and stagnation temperature = 550 K.
• The wall of CD nozzle assumed to be adiabatic.
• Fluid after passing through converging section, its velocity further increases in diverging section of CD nozzle due to its decrease in density.

• The whole analysis is carried out in 800 iteration (10 load-steps).

Fluid 142 - 3D and Fluid 141 - 2D fluid-thermal elements

Boundary conditions

Solve

Full volume of CD nozzle

Quarter section volume of CD nozzle

Path status

Path selected for graph results is between Node_1 (at the inlet section of axisymmetry) and Node_1401 (at the outlet section of axisymmetry) in both volume types

Mach no animations and graph

Fluid velocity animations and graph

Fluid effective viscosity animations and graph

Total stagnation pressure animations and graph

Temperature animations and graph

Pressure animations and graph

As, it can seen in pressure graph, mach no graph, fluid velocity graph, temperature graph and density graph of full volume of CD nozzle that is no significant changes in between the region of throat and exit which shows presence of normal shock except in case of total stagnation pressure graph it's irreversibility is needed to study further. Overall it can be considered that back pressure must be less than exit pressure, hence normal shock might be formed outside the diverging section(exit).

Vector plot animations

Load-step 10 vector plot images and particle flow animation

Ansys analysis obtained values can be verified at throat condition using following formulas :-

Thank you

Happy to discuss more in detail.

Guide me and let me know my mistakes