ELECTRIC ARCS IN TURBULENT FLOWS, II
GENERAL ELECTRIC CO PHILADELPHIA PA PHILADELPHIA United States
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Turbulent heat transfer in axial flow electrical arcs was experimentally studied. The arcs were operated with argon in the current range of 10 to 100 amps, with pressures of 1 to 10 atm., and with flow rates of 0.02 to 35 gramssec. The flow tubes employed were 75 cm long and had inner diameters of 0.5 and 1.0 cm. It was found that the arc potential increased linearly along most of the tube length for all flow rates. Also, calorimetric measurements at the end of a flow tube with 0.5 cm diameter showed close agreement between wall heat flux and electrical input per cm for all flow rates. This, together with a careful estimate of the remaining flow terms, showed that a fully developed temperature profile was achieved. The arcs at high flow rates showed considerably larger electrical gradients than the arcs at low flow rates. In addition to this, high speed photographs revealed that increased electrical gradients were accompanied by the onset of disturbances of the plasma column. At conditions of the highest flow rates and electrical gradients achieved, the arcs appeared to be strongly turbulent, with the arc column broken up into plasma globules of irregular shapes and sizes.
- Electricity and Magnetism