Abstract
In this paper, theoretical investigation of hypersonic aerodynamic control with cold-air MHD devices was conducted. Arrays of MHD devices can be positioned at the bottom of the vehicle aft of the combustor, where the density is close to that in the freestream, and/or on the top of the vehicle. The cold hypersonic flow is ionized by electron beams injected along the magnetic field lines. The j→×B→ accelerating or decelerating forces together with the Joule heating of the flow can ensure both angle-of-attack and steering control. The tangential forces were shown to vary dramatically with the ratio Χ of the applied electric field to the product of freestream velocity and the magnetic field at the surface. Computations for Mach 8 demonstrated how the profile of j→×B→ forces changes with Χ, from predominantly decelerating forces (drag) at low Χ to a combination of deceleration near the surface and acceleration of the outer flow at Χ≈0.5, to only acceleration (thrust) at Χ=1. Varying the tilt angle of the magnetic field was shown to increase the flexibility of MHD control. The normal (lift) force created by the MHD region turned out to be substantially stronger than the drag/thrust force, with the lift-to-drag (for MHD generators) or lift-to-thrust (for accelerators) ratios increasing from about 2 with magnetic field tilted against the flow or normal to the surface to more than 3 with aft-tilted magnetic field. Computations performed for representative generator and accelerator cases in the range of Mach numbers from Mach 6 to Mach 10 revealed that, while both tangential (drag - for generators, and thrust - for accelerators) and normal (lift) forces tend to increase with Mach number, the lift-to-drag (for MHD generators) or lift-to-thrust (for accelerators) ratios monotonically decrease with Mach number.
Original language | English (US) |
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Pages | 9553-9568 |
Number of pages | 16 |
State | Published - 2005 |
Event | 43rd AIAA Aerospace Sciences Meeting and Exhibit - Reno, NV, United States Duration: Jan 10 2005 → Jan 13 2005 |
Other
Other | 43rd AIAA Aerospace Sciences Meeting and Exhibit |
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Country/Territory | United States |
City | Reno, NV |
Period | 1/10/05 → 1/13/05 |
All Science Journal Classification (ASJC) codes
- General Engineering