Description: 2D Axisymmetric transient compressible supersonic simulation of a rd107 nozzle exhaust
Model
The model consists of the actual provided dimensions of rd107 nozzle in literature.
Meshing
Meshing was performed using blockMesh.
A blockMeshDict generator framework called classy_blocks was used for the parametric structured mesh generation. The parametric design can easily be varied and extended for surrogate modelling.
The resulting mesh had 47200 structured cells. Out of these, 46040 were hexahedral cells and 1160 were prisms
Physics
The model solves 2D-axisymmetric compressible Navier-Stokes equations. This is a higher order solver that is capable of accurately capturing shocks and simulating high-speed physics. The solver has the capability of higher order central differencing schemes that are more stable than the conventional upwind schemes.
RAS models were used to compute the turbulence in both phases.
The $k-\epsilon$ model was used for closure of the turbulence stress.
Simulation
The case was simulated using the rhoCentralFoam solver in OpenFOAM. Kurganov flux scheme was used along with valAlbada interpolations. These are higher order methods that tend to be more suitable for high-speed physics since they are capable of resolving shock physics with a higher accuracy compared to the conventional schemes.
Boundary Conditions
| Parameter | Internal Field | Inlet | Outlet | Walls |
|---|---|---|---|---|
| U | uniform (140 0 0) |
zeroGradient |
zeroGradient |
noSlip |
| p | uniform 5.85e6 |
5.85e6 |
waveTransmissive; p_inf=1e5 |
zeroGradient |
Appropriate conditions for $k$, $\epsilon$ are provided.
Other Settings
A custom mixture thermophysical properties were provided. The properties were calculated for the combustion products. JANAF tables were provided for the mixture.
The transient simulation was run for 0.02 s with an adaptive time step of $\Delta T = 1e-5$.
Results
The results accurately capture the shock diamonds as well as the exhaust plume length and temperatures.