An Experimental Study on Heat-Flux Reduction by Electromagnetic Fields in Ionized Flows

Abstract

In the frame of this work an experimental study has been performed on heat-flux mitigation within high-enthalpy ionized-argon flows by application of an external magnetic-induction field. Two different axially symmetric test models, containing water-cooled magnet coils, were investigated. The models were made of a material with low thermal conductivity, in order to visualize surface-temperature distribution. The latter has been measured by infrared thermography. Heat-flux rates have been derived from measured front and rear surface temperature taking into account temperature-dependent material characteristics and considering radiative-cooling exchange to the environment. Flow-field properties have been quantitatively characterized by laser induced fluorescence, microwave interferometry, diode laser absorption spectroscopy, electrostatic probes and Pitot probes. Remarkable measured surface-temperature reductions up to 44%, and derived heat-flux mitigation up to 85%, have been observed in the presence of an externally applied magnetic-induction field. The influence of change in the polarity of the electromagnetic coils has also been measured and showed in contrast to some former studies comparable effects for both polarities.