Parametric study of electric arcs in aeronautical condition of pressure

Stability, spatial extension and extinction of an electric arc in aeronautical conditions of pressure under 540 V DC

“…-The energy dissipated in the arc may reach very important value (10 kJ or more). -As already observed for lower supply voltage (40 V DC) [1], the energy does not depend strongly on pressure values for small current intensities. -Comparing the present results to those presented in [1], the influence of the supply voltage must be mentioned: in [1], for a supply voltage of 36/42 V DC and I CC = 70 A (and v = 300 mm/s), the mean energy dissipated in the arc varies with pressure between 6 and 12 J.…”

“…The following data are automatically recorded: the current intensity is measured across the load resistance using a differential probe (bandwidth of 70 MHz), the arc voltage is measured using a similar differential probe, the electrode gap is measured using a potentiometer which allows an accuracy on the gap measurement of ±100 mm. In a previous article [1], the accuracy of the inter-electrode distance measurement was better (±13 mm) but the maximum measurable distance was much smaller than that reached during this work. Several data are determined a posteriori: the maximal electrode gap.…”

“…Under 28 V DC, the natural arc extinction occurs for an arc length near a few millimeters. For instance, in the case of 36 V DC supply voltage, it has been observed [1] that an order of magnitude of the spatial extension of an electric arc was about 6 mm at atmospheric pressure and 10 mm at 2 Â10 4 Pa.…”

“…In this case (I arc > 100 A) it was observed that the length of the arc was not necessarily an increasing function of the intensity of the current, but that it appeared for high intensities, electromagnetic instabilities which deform the arc column. More recently, academic works [1,13] have been carried out to characterize electric arcs for pressure in the range [10 4 -10 5 ] Pa for voltages of the order of 36-42 V DC and arc current of the order of a few tens of amperes. In the case of an "ideal" electric arc (axial symmetry) the arc voltage versus the arc column length is plotted and takes the following well known expression:…”

“…The arc model proposed in Figure 1 then applies (some millimeters in length for a 36 V DC supply voltage). E col values have been measured [1] in aeronautical conditions of pressure. Results are briefly summarized in Table 1.…”