Miscellaneous arc devices

Uhlenbusch, J.

doi:10.1016/0378-4363(76)90269-2

Cited by 8 publications

(9 citation statements)

References 43 publications

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“…A knowledge of such thermal properties is relevant to the more complicated but technically important arc forms such as those used in arc heaters (Lowke and Capriotti 1969), circuit breakers (Wermann et aZ1974b, Malghan et a1 1977), arc lamps (Lowke 1969), and space craft re-entry simulation (Hunt and Sibulkin 1967). The derivation of transport properties from lower-current arc measurements has been reviewed by Uhlenbusch (1972) and is not considered further here.…”

Section: Wall-stabilised Arcsmentioning

confidence: 99%

The physics of high-power arcs

Jones

Fang

1980

Rep. Prog. Phys.

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Recent progress in the physics of high-power arcs has been largely due to a blend of detailed experimental and theoretical investigations aimed at explaining the electrical behaviour of the discharge in terms of fundamental physical processes.I n the case of collision-dominated, high-pressure arcs the important role of radiative energy transfer, including strong self-absorption, has been established through the experimental and theoretical study of cylindrically symmetric, uncontaminated arc plasmas. As a result, an insight has been gained into the additional complications produced in naturally occurring high-pressure arcs by electrode vapour contamination and self-magnetically-propelled plasma flows. Application of the boundary layer integral method of aerodynamics in conjunction with extensive property measurements has enabled the higher-power dissipation capabilities of arcs in imposed axial flows to be related to flow acceleration and turbulent exchange processes. Integral methods have also given an insight into arc properties and behaviour in the presence of severe ablation of an arc-confining wall.The application of similarity theory based upon the conservation equations of fluid mechanics has produced good correlation of the properties of arcs in transverse flows and magnetic fields under a number of different operating conditions. Criteria defining stable arc operation have been derived using stability theory whilst axisymmetric instabilities of arcs in accelerating flows have been related to vortex production at the arc boundary.Although much detailed experimental and theoretical studies have also been made of arcs in vacuum, there remains a need for a general theoretical description. I n addition, despite agreement that cathode processes exert a strong influence upon vacuum arc properties, there is uncertainty concerning the proportion and spatial distributions of the various particle species emitted by the cathode. Nonetheless a qualitative appreciation of the processes governing the overall electrical characteristics for different current ranges has been achieved.

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Section: Wall-stabilised Arcsmentioning

confidence: 99%

The physics of high-power arcs

Jones

Fang

1980

Rep. Prog. Phys.

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“…The arc column is expected to move as a single fluid packet in a socalled 'snowplow' mode [29]. In two dimensions, this means that the arc acts as a piston so that as it is forced upwards, away from the surface of the RailPAc, a lowpressure region is formed below the arc and a highpressure region is formed above.…”

Section: Wall-stabilization Of the Arcmentioning

confidence: 99%

Study of the dynamic behavior of the rail plasma actuator arc

Gray

Choi

Sirohi

et al. 2018

J. Phys. D: Appl. Phys.

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Experimental and computational studies of a rail plasma actuator (RailPAc) magnetohydrodynamic flow actuator were performed. The actuator functions by inducing flow around a fastmoving gliding arc, with device current ∼ 1000 A, which is generated between flush mounted copper electrodes. Highspeed imaging photometry is used to analyze the composition and internal structure of the arc for flush mounted electrode spacings of 2 mm, 5 mm, and 12.5 mm, as well as freefloating electrodes with 12.5 mm spacing. Results are compared with 2D thermal plasma simulations. The dynamics of the arc movement are found to be dependent on the height of the plasma column above the RailPAc surface and on the presence of prominent anode and cathode jets. Mechanisms are proposed for wallstabilization of the arc and rootjet formation based on agreement between experimental and computational results.

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“…The current through the rails generates a magnetic field ( B) that couples with the arc current density ( j ) to impart a Lorentz force ( F B ) on the arc. The arc then accelerates along the rails and imparts momentum to the surrounding air through compression and entrainment effects similar to a moving solid body [14,15]. In previous work, RailPAc prototypes were designed and tested, establishing proof of concept and yielding quantitative measurements of electrical characteristics, impulse imparted to the flow, and induced velocity [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Static stall alleviation using a rail plasma actuator

Choi¹,

Gray²,

Sirohi³

et al. 2018

J. Phys. D: Appl. Phys.

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An experimental study was conducted to investigate the ability of a rail plasma actuator (RailPAc) to alleviate static stall on an airfoil. The RailPAc device consists of parallel rails flush mounted on the upper surface of a VR-12 airfoil, with a high-current (∼1.3 kA) arc bridging the gap between the rails. A Lorentz force (∼0.3 N lasting ∼1 ms) generated on the arc propels it along the airfoil chord and transfers momentum to the surrounding flow. Experiments were conducted in a low speed wind tunnel at two different Reynolds numbers ( and ) and various static angles of attack (up to ∼30°). Particle image velocimetry (PIV) was used to measure the flow over the passive and actuated airfoil, while the airfoil lift was measured using a force balance. The experiments showed that the RailPAc promotes flow reattachment and can suppress static stall over a wide range of angles of attack. Operation of a single RailPAc resulted in ∼40 improvement in post-stall lift and ∼4° increase in stall angle compared to a passive airfoil with an unpowered RailPAc. The results provide insight into the actuation mechanism and demonstrate, for the first time, the ability of the RailPAc to alleviate static stall on an airfoil.

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Miscellaneous arc devices

Cited by 8 publications

References 43 publications

The physics of high-power arcs

The physics of high-power arcs

Study of the dynamic behavior of the rail plasma actuator arc

Static stall alleviation using a rail plasma actuator

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