報告書番号

W01021

タイトル（和文）

大気中大電流アークジェットの流速特性(その２) -鉄およびアルミニウム電極から噴出する50kA級アークジェットの流速-

タイトル（英文）

Flow Velocity Characteristics of High Current Arc Jet in Atmospheic Air (Part2)－Flow velocity in 50kA-class arc jet spouted from iron and aluminum electrode－

概要 （図表や脚注は「報告書全文」に掲載しております）

本報告では，交流実効値10-50kAで，鉄およびアルミニウム製の棒電極より噴出させた大気中大電流アークジェットの流速について述べている。流速の導出は，流れに沿った近接２地点からの放射強度波形を測定し，この波形に相互相関法を適用して実施した。電極端から100-300mmの範囲での流速について，以下のことが明らかとなった。(1)鉄電極およびアルミニウム電極での流速は，それぞれ，4000m/sおよび3000m/sに達した。(2)電極直径が60mmから20mmへ減少した場合，流速は僅かに増加する。しかし，どの電極直径でも，アーク電流値に対するばらつきは大きく，電極直径20～60mmの範囲では，流速の電極直径に対する影響は比較的小さい。(3)流速と質量密度の結果から，動圧は，80kAのケースでも1MPaを越えず，磁器がいしを想定すれば，熱歪による作用に比べ非常に小さいものであると考えられる。

概要 （英文）

This paper describes the flow velocity in high current arc jets in atmospheric air. The arc jets were spouted from the rod electrodes with an alternative current in the range of 10 to 50 kA (RMS). The rod electrodes were iron and aluminum, and were 20, 40 and 60mm in diameter. To derive the flow velocity, the radiation intensities from nearby sampling points along the jet flow were measured, and the cross-correlation method was applied to the vibration signals included in these waveforms of radiation intensity. From the results of a lot of tests, the following about the flow velocity in the range of 100 to 300mm from an electrode tip became evident:(1) The flow velocity increased with the arc current and reached 4000m/s and 3000m/s in the case of the iron electrode and the aluminum electrode, respectively. In the case of 50 to 80kA (RMS) in the arc current, it was estimated that the flow velocity would increase with the arc current proportionally with the iron electrode, whereas it would remain at the level in the case of 50kA (RMS) with the aluminum electrode. (2) The amount of scatter of the flow velocity in the arc current dependence was about 50% to the average for both the iron and the aluminum electrode.(3) The flow velocity increased slightly as the electrode diameter decreased from 60 to 20 mm. However, the amount of the flow velocity scatter in the arc current dependence was large for every electrode diameter. So the influence of the electrode diameter on the flow velocity was comparatively slight in the electrode diameter range of 20 to 60mm.(4) It was estimated from the measured results of the flow velocity and the mass density that the dynamic pressure would not exceed 1MPa in the case of 80kA (RMS) and would be very small compared with the estimated thermal strain on the ceramics insulator.

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