Weakly Ionized Plasmas and MHD for Enhanced Performance of Hypersonic Vehicles

摘要

Aerospace Applications of Weakly Ionized Plasmas: * Power generation using MHD * Use of power to control aerodynamics and propulsion: (1) Surface plasmas for separation and turbulent transition control (virtual shapes) (2) Virtual shapes created by off-body energy addition for drag reduction, steering, shock control, flow turning (3) Plasma-assisted combustion. * Power extraction from one region and its use in another region (MHD bypass) * Dual-use MHD devices (both power generation and flow control): (1) Forces created by magnetic and electric fields acting on charged particles (transferred to neutral gas by collisions) (2) Ionization level per se is not critical if plasmas are used as a means of delivering energy to the flow (3) Ionization is critical in MHD power generation and flow control, and in cold-plasma generation of radicals (4) At high T (reentry, scramjet combustor) -- thermal ionization with alkali seed (5) At low T, artificial ionization is needed, and the ionization cost determines design and performance (6) Similar to ionization, cold plasma generation of chemically active species for combustion can have considerable energy cost (7) Both energy addition and extraction result in flow heating and losses of total pressure and (if in propulsion flowpath) thrust.