Progress toward a radiative and MHD driven high enthalpy, high pressure, long duration test facility
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During the past two years, the U.S. Air Force (USAF) has sponsored the Magnetohydrodynamics Accelerator Research Into Advanced Hypersonics, Radiatively Driven Hypersonic Wind Tunnel (MARIAH II/RDHWT) Program, This program represents a merger of two earlier projects, one sponsored by NASA, which had the objective of evaluating MHD technology; the other sponsored by the USAF for the purpose of evaluating beamed energy addition into supersonic flows. The objective of the current project is to evaluate the feasibility of several novel technologies as drivers for a true enthalpy hypersonic wind tunnel. As presently envisioned, the tunnel would be comprised of three stages. The first stage would consist of an ultra high pressure (UHP) driver in which air is compressed dynamically to pressures up to 2,000 MPa and released through a converging-diverging nozzle. The second stage of energy addition would consist of radiative energy beamed from downstream into the supersonic section of the nozzle. The third stage would be a nonequilibrium magnetohydrodynamic (MHD) accelerator which would rely on electron beam seeding to sustain the required electrical conductivity. The near term goal of the program is to develop credible engineering data to enable the design of a missile scale hypersonic wind tunnel (MSHWT). The ultimate goal is to design and build a Test and Evaluation wind tunnel capable of supporting near full scale engine testing at dynamic pressures up to 2000 lbf/sq. ft. (psf) and free stream Mach numbers up to 15. Test durations of tens of seconds to minutes were also specified. A substantial amount of research has been accomplished to date. Computational simulations of a conceptual facility incorporating reservoir conditions of 2,000 MPa and 900 K indicate that a test section Mach number of 12 at a dynamic pressure of 2,000 psf is attainable using only the first two stages. To achieve the Mach 15 condition at the same dynamic pressure will require MHD augmentation. This paper provides a survey of all significant computational and experimental work being conducted in support of the program. Specific areas of ongoing research which will be described in some detail in the paper include the following. • Laser energy addition tests at a scale of 10 kW conducted at the U.S. Air Force Research Laboratory (AFRL). • Electron beam energy addition tests at the 30 kW level conducted at Sandia National Labor&ories (SNL). • Planned electron beam energy addition tests at the 100 kW level to be conducted at SNL. • Computational simulations of both electron beam and laser energy addition into supersonic air flows. •Computational simulation of nonequilibrium MHD kinetic energy addition sustained by electron beam seeding. • Static cell experiments conducted at SNL for the purpose of validating the concept of electron beam seeding in air. • Design of a UHP driver, called the A-2 facility. It is planned that this facility will operate at reservoir conditions of 2,000 MPa and 900K, and will support future proof of principle tests in the area of beamed energy addition. © protection in the United States.
author list (cited authors)
Simmons, G. A., Nelson, G. L., Miles, R., Brown, G., Barker, P., Macheret, S. O., Costantino, M., & Lipinski, R.
Simmons, G., Nelson, G., Miles, R., Brown, G., Barker, P., Macheret, S., Costantino, M., & Lipinski, R.