Experimental and Computational Studies of Low-Temperature M=4 Flow Deceleration by Lorentz Force

Abstract

The paper presents results of cold MHD flow deceleration experiments using repetitively pulsed, short pulse duration, high voltage discharge to produce ionization in a M=4 nitrogen flow in the presence of transverse DC electric field and transverse magnetic field. Effective flow conductivity is significantly higher than was previously achieved, σ eff =0.1 S/m. MHD effect on the flow is detected from the flow static pressure measurements. Retarding Lorentz force applied to the flow produces a static pressure increase of 19%, while accelerating force of the same magnitude applied to the same flow results in static pressure increase of 11%. The effect is produced for two possible combinations of the magnetic field and transverse current directions producing the same Lorentz force direction (both for accelerating and retarding force). The results of static pressure measurements are compared with predictions of a 3-D Navier-Stokes / MHD flow code. The static pressure rise predicted by the code, 18% for the retarding force and 8% for the accelerating force, agrees well with the experimental measurements.

Magnetic Field Effects on Axis-Switching and Instabilities in Rectangular Plasma Jets

“…Nishihara et al [16] detected low temperature supersonic air flow deceleration by Lorentz force from the static pressure measurements. Rawat et al [17] performed 3D compressible Navier-Stokes MHD simulations and showed results of flow deceleration consistent with Nishihara et al [18,19].…”

“…Hunt and Leibovich [13] focused on high magnetic interaction parameters and Hartmann numbers but low magnetic Reynolds-number effects on variable cross-section channel flows, which are decelerated by transverse magnetic fields. More recent work focused on flow control prospects of transverse magnetic fields on channel flows [14][15][16][17][18]. Macheret et al [14] studied the scramjet inlet flow control by applying an MHD system upstream of the inlet and showed that, with reasonable parameters, shocks could be brought back to the cowl lip when flying at off-design Mach numbers.…”

A Critical Review of Electric and Electromagnetic Flow Control Research Applied to Aerodynamics

“…One current channel flow system has been configured to place an accelerating or retarding force on a high-speed flow (Mach 3.0-4.0) of air or another mixture of gases. 12,23,[27][28][29][30][31][32][33][34][35][36][37] The test section pressure is limited to 7-20 torr. 27 The gas is transformed into a weakly ionized gas (WIG) by means of a high voltage, high frequency electric field pulse circuit.…”

“…With slightly different test section conditions, a current oscillogram appears in Ref. 37 for an ionization frequency of 100 kHz, which results in a steadier Lorentz force because the WIG decays less. As one can see from Fig.…”