Performance of high-power gas-flow spark gaps

Kuhlman, John M.; Molen, G. Marshall

doi:10.2514/3.9400

Cited by 14 publications

(6 citation statements)

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“…This venturi effect was not seen for the lowblockage nipple-wing electrodes. 4 As was seen at d -0.5 cm, the vertical profiles are again quite uniform at all three tunnel speeds until thin electrode boundary layers are entered. At this elevated gas pressure, the low-frequency relative velocity fluctuations sensed by the pitot probes are on the order of 0.2-0.8% outside of the electrode boundary layers.…”

Section: Gap Spacing Of D = 10 Cmmentioning

confidence: 72%

“…Similar, but less extensive, velocity survey data obtained using pitot probes for a second electrode configuration, termed the "nipple-wing" electrodes, are presented in Ref. 4. Previously published velocity surveys in spark gaps have been quite limited.…”

mentioning

confidence: 88%

“…A similar, but less dramatic, decrease in interelectrode velocity with decreasing gap spacing has been noted previously for the nipple-wing electrode geometry. 4 Horizontal and vertical profiles of mean velocity are presented in Figs. 6 and 7, respectively, for the electrodes at d= 1.0. cm for air at a pressure of 714kPa.…”

Section: Gap Spacing Of D = 10 Cmmentioning

confidence: 99%

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Velocity surveys in a gas-flow spark gap switch

1988

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A series of mean velocity and turbulence intensity surveys have been obtained for flow between the electrodes of a gas-flow spark gap switch over a range of gas pressures, gas species, and gap spacings for one electrode geometry consisting of two 3.81-cm-diam electrodes with domed tips placed transverse to the gas flow direction. Data include mean and fluctuating velocity profiles measured between the electrodes, both on the electrode axis and downstream of the electrodes. Pitot, total head, and one-and two-channel hot wire probes have been used. These data document flow conditions occurring in a gas-flow spark gap switch and provide insight into flow processes affecting recovery of such a switch when operated repetitively. Results have indicated that highly turbulent wakes are formed downstream of these electrodes; these wakes are believed to degrade switch electrical recovery due to trapping of heated debris from prior arcs. Also, it has been found that, for this electrode geometry, freestream turbulence levels do not have a great effect on recovery.Nomenclature d = interelectrode gap spacing / = longitudinal turbulence intensity, defined as rms x -velocity fluctuation divided by mean velocity p = gas pressure R = electrode radius U = streamwise mean velocity in x direction V = horizontal mean velocity in y direction x -horizontal coordinate, measured in direction of gas flow y = horizontal coordinate, measured transverse to direction of mean gas flow z = vertical coordinate, measured along electrode axis from midgap A = turbulence integral length scale (large, energycontaining eddy size) 1 = turbulence microscale (eddy size relating mean square strain rate fluctuation to mean square velocity fluctuation) T = switch recovery time for 70% recovery

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Section: Gap Spacing Of D = 10 Cmmentioning

confidence: 72%

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confidence: 88%

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Velocity surveys in a gas-flow spark gap switch

1988

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“…The turbulent motion may therefore significantly increase the rate of the fuel-gas mixing, which may, in turn, be used to control the mixing rate in high-speed directly fuelling combustors. Such a turbulent cooling regime is observed, for example, after the interruption of powerful spark discharges, [8][9][10][11] pulsed arcs, and laser sparks. 11,12 Another possible example is the channel decay of natural lightning, as well as that of a long artificial spark which models it, with their dynamics also defined by the formation of a turbulent flow in the channel.…”

Section: Introductionmentioning

confidence: 99%

Jet regime of the afterspark channel decay

et al. 2010

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“…Therefore, the speed with which the channel cools down and expands increases drastically. (As a result the channel's cooling and expansion rates speed up significantly) This kind of a cooling regime may be realized, for instance, after the interruption of powerful spark discharges [34][35][36][37], pulse arcs and laser sparks [37,38]. It is possible (It may be supposed) that the dynamics of the channel decay of natural lightning as well as that in a long artificial spark, which models it, is also defined by the formation of a turbulent flow in the after-discharge channel [39].…”

Section: Eoard-jiht Ras-istc May 2013mentioning

confidence: 99%

Study of Mechanisms of Filamentary Pulse Electric Discharge Interaction with Gaseous Flow of Nonuniform Composition

Leonov¹

2013

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Performance of high-power gas-flow spark gaps

Cited by 14 publications

References 0 publications

Velocity surveys in a gas-flow spark gap switch

Velocity surveys in a gas-flow spark gap switch

Jet regime of the afterspark channel decay

Study of Mechanisms of Filamentary Pulse Electric Discharge Interaction with Gaseous Flow of Nonuniform Composition

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