TITLE : FLOW COMPUTATION FOR HIGH ALTITUDE TEST FACILITY
BY : RAFAEL, Israel - A Leitner
- Development at RAFAEL of an apogee kick motor to launch satellites
into orbit created the need for a design of high altitude test
facility with a supersonic diffuser, enabling ground level testing of
rocket motors at atmospheric conditions while maintaining full flow
expansion in the motor divergent section of the nozzle.
- Supersonic diffuser performance is sensitive to its configuration.
- Experimental work suggests an explanation of the complex phenomena
of viscous, turbulent, compressible sub trans and supersonic flow.
- PHOENICS has been used to simulate these experiments.
- After verification with te experimental tests on a sub-scale model,
PHOENICS was applied to assist in the design process of the full-size,
supersonic diffuser by up-scaling simulations.
The following assumptions were made:
- A two-dimensional axisymmetric model was used.
- Steady state.
- Single phase flow (the exhaust gases include a condensed phase but
the void fraction of the condensed phase is approximately 1%).
- The flow is assumed to be fully turbulent and the k-e model was used.
- Some computations were carried out without turbulence to study the
way in which turbulence modofies this specific flow.
Figure 1. Geometry of the diffuser.
Figure 2. Calculated and measured static pressures.
Figure 3. Calculated radial pressure profiles.
Figure 4. Velocity vectors in the diffuser entrance.
Full details of the PHOENICS simulation and the experimental
results may be obtained in:
- The results showd satisfactory agreement between the measured pressures
in the diffuser inlet cone and throat entrance and those predicted by
- This indicates that PHOENICS can be applied to predictions of flow
and thermal regimes in these regions.
- Scale-up calculations with similar geometry and boundary conditions
showed a similar flow field except in the thickness of the boundary
Flow computation for high altitude test facility
Heat and mass transfer group, RAFAEL, Haifa, Israel