Mechanism analysis of Magnetohydrodynamic heat shield system and optimization of externally applied magnetic field

Proceedings of the Institution of Mechanical Engineers, Part G:

et al. 2021

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The effects of external magnetic fields on the shock-wave configuration at hypersonic plasma flow field are investigated in this paper. A series of numerical simulations over various geometry configurations, namely, a blunt body and a fixed-geometry inlet forebody, have been conducted by varying the applied magnetic field under different freestream conditions. Results show that magnetohydrodynamic shock control capabilities under three types of magnetic field are ranked from weak to strong as dipole magnet, solenoid magnet, and uniform magnet field. Under the same applied magnetic field, it is easier to deflect the shock at a relatively high altitude condition, compared with the low altitude case. The bow shock standoff distance is dependent on the distribution of counter-flow Lorentz force right after shock in the stagnation region. For the oblique shock control, the function of two components of Lorentz force is different that the counter-flow one decelerates the flow and increases the shock-wave angle, while the normal one squeezes the oblique shock and deflects the streamlines.

Section: Mechanism Analysis Of Mhd Bow Shock Controlmentioning

confidence: 97%

Section: Governing Equations and Numerical Proceduresmentioning

confidence: 99%

Section: Governing Equations and Numerical Proceduresmentioning

confidence: 99%

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Mechanism analysis of magnetohydrodynamic shock control in hypersonic flow

Proceedings of the Institution of Mechanical Engineers, Part G:

et al. 2021

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“…Amongst these plasma techniques, magnetohydrodynamic (MHD) has potential within the high-speed flow control field because the coupling of both a magnetic field and plasma provides a volume force (Lorentz force) that is several times larger than that of ion wind. It is noteworthy that the air encountered in hypersonic flight is highly ionized subsequent to bowl shock in front of the blunt body and no artificial ionization is required for MHD control for flow fields with Ma>12 (Li et al, 2017a). In contrast, MHD effects in a relatively cold hypersonic flow under a flight Ma of approximately 12 can only be significant using artificial ionization such as electric discharges to amplify air conductivity and provide directional current.…”

Section: Introductionmentioning

confidence: 99%

Hypersonic flow control of shock wave/turbulent boundary layer interactions using magnetohydrodynamic plasma actuators

J. Zhejiang Univ. Sci. A

et al. 2020

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The effect of magnetohydrodynamic (MHD) plasma actuators on the control of hypersonic shock wave/turbulent boundary layer interactions is investigated here using Reynolds-averaged Navier-Stokes calculations with low magnetic Reynolds number approximation. A Mach 5 oblique shock/turbulent boundary layer interaction was adopted as the basic configuration in this numerical study in order to assess the effects of flow control using different combinations of magnetic field and plasma. Results show that just the thermal effect of plasma under experimental actuator parameters has no significant impact on the flow field and can therefore be neglected. On the basis of the relative position of control area and separation point, MHD control can be divided into four types and so effects and mechanisms might be different. Amongst these, D-type control leads to the largest reduction in separation length using magnetically-accelerated plasma inside an isobaric dead-air region. A novel parameter for predicting the shock wave/turbulent boundary layer interaction control based on Lorentz force acceleration is then proposed and the controllability of MHD plasma actuators under different MHD interaction parameters is studied. The results of this study will be insightful for the further design of MHD control in hypersonic vehicle inlets.

“…The conservation of momentum equation and the total energy equation are modified with the inclusion of a Lorentz force (J × B) and Joule heating (J ⋅ E), respectively, which appear on the right side of the above equations. The current density can be evaluated from Ohm's law [21,22].…”

mentioning

confidence: 99%

Magnetohydrodynamic Control of Hypersonic Separation Flows

International Journal of Aerospace Engineering

et al. 2021

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Magnetohydrodynamic (MHD) control of hypersonic laminar separation flows is investigated in this paper. A series of numerical simulations over various geometry configurations, namely, a compression corner and a double wedge ramp hypersonic inlet, have been conducted by application of an external electromagnetic field. Results show that the performance of MHD separation flow control is mainly determined by flow acceleration of the Lorentz force directed in the streamwise direction. The Joule heating term always brings negative effects on the MHD separation flow control and increased the static pressure locally, where the electromagnetic field is applied. With an external electromagnetic field applied, the low velocity fluid in the boundary layer can be accelerated. Moreover, there exists a best location for the MHD zone to be applied and completely eliminate the separation of the flow from the surface.