Computational Predictions of the Hypersonic Material Environmental Test System Arc-Jet Facility

Area of Science:

• Aerospace Engineering
• Computational Fluid Dynamics
• Materials Science

Background:

• The NASA Langley Research Center's arc-jet facility is crucial for evaluating thermal protection systems (TPS) for hypersonic and reentry vehicles.
• Accurate simulation of the test article environment is vital for improving TPS research and development.

Purpose of the Study:

• To develop a detailed three-dimensional computational fluid dynamics (CFD) model of the arc-jet nozzle and free-jet flow field.
• To enhance the understanding and capabilities of the Hypersonic Materials Environmental Test System (HMETS).

Main Methods:

• Developed a 3D CFD model incorporating non-uniform inflow conditions and surface catalytic recombination effects.
• Simulated the arc-jet nozzle and free-jet flow field for various enthalpy test conditions.
• Validated simulation results against calibrated Pitot pressure and stagnation-point heat flux measurements.

Main Results:

• The model indicates an effectively fully-catalytic copper surface with approximately 10% recombination efficiency.
• A pressure drop of 2-3 kPa was observed from the plenum section to the nozzle inlet.
• CFD predictions aligned well with experimental data for stagnation pressure, heat flux, and nozzle exit velocity conditions.

Conclusions:

• The validated CFD model provides accurate predictions of the arc-jet test environment.
• The findings contribute to improved design and evaluation of hypersonic vehicle thermal protection systems.
• The study enhances the utility and knowledge base of the HMETS arc-jet facility.