Supersonic nozzle
Introduction
This is an example of solving an axisymmetric supersonic nozzle flow using a density-based solver.
The computational conditions are as follows
- solver : TSLAeroFoam
- turbulence model : $SST$ $k-omega$
- nozzle inlet total pressure : 4e+5 Pa
- nozzle inlet temperature : 3000 K
- farfield pressure : 1e+4 Pa
- farfield temperature : 300 K
Start BaramFlow and load mesh
Run the program and select ‘New Case’ from the launcher. In the launcher, select [Density-based] for [Solver Type].
Use the given polyMesh folder. In the top tab, click [File]-[Load Mesh]-[OpenFOAM] in that order and select the polyMesh folder.
launcher
General
Set [Operating Conditions] as 0.
Models
For this example, we’ll use $SST$ $k-omega$ model for turbulence.
Materials
Set Density as Perfect Gas, Viscosity as Sutherland.
Boundary Conditions
Set the boundary type and values as shown below.
- inlet
- Pressure Inlet
- Total Pressure : 400000
- Temperature : 3000
- Turbulence : intensity and viscosity ratio(0.1 and 1)
- inletAir
- Pressure Inlet
- Total Pressure : 10000
- Temperature : 300 K
- Turbulence : intensity and viscosity ratio(0.1 and 1)
- outlet
- Pressure Outlet
- Pressure : 10000
- nozzle
- Wall – no slip, adiabatic
- top
- symmetry
- bottomEmptyFaces, topEmptyFaces
- Wedge
farfield Riemann condition
Numerical Conditions
Set [Formulation] as [Implicit], [Flux Type] as [Roe-FDS] and [Entropy Fix Coefficient] as 0.5.
Numerical Conditions
Monitor
Monitor flowrate at nozzle inlet. Select [Add]-[Surface] and set values as follows
- Report Type : Mas Flow Rate
- Surface : inlet
Initialization
Set values as follows
- Velocity : (0, 0, 0)
- Pressure : 10000
- Temperature : 300
- Turbulence
- Scale of Velocity : 100
- Turbulent Intensity : 0.1
- Turbulent Viscosity Ratio : 1
The solver is unstable at the beginning of the calculation because of the large difference between the flow variables in the region through which the nozzle flow passes and the outer region. To solve this problem, set the initialization values for the nozzle flow section separately.
Click [Initialization]-[Advanced]-[Section]-[Create] and set the following settings.
- region1 – Hex
- Min. point : (-0.15, -0.1, -0.1)
- Max. point : (0.12, 0.065 0.1)
- Select Velocity and set value (100, 0, 0)
- Select Pressure and set value 400000
Section initialize
Run
Change the values as shown below, and click [Start Calculation] button.
- Number of Iterations : 100000
- Courant Number : 1000
- Save Interval : 500
Post-processing
Click the parview button in [External tools] to open the paraview.
Change [Coloring] to Mach.
>
Mach number