Determination of boiling curve of spray cooling by IR thermography

Abstract

An experimental IR thermography technique allowing the determination of the boiling curve during water spray cooling of a hot thin moving steel strip is presented. The dedicated test facility, called SprayCooling, is described. The thin thermal foil approach is combined with the strip temperature measurement obtained by IR camera. The accuracy of the method relies mainly upon the estimation of the local derivative of the temperature profile. Therefore, smooth temperature profiles are obtained by thermogramme averaging and filtering techniques. Finally, the heat transfer coefficient is obtained for strip temperature varying from 20°C to more than 400°C and at different water mass fluxes. The study deals with an experimental technique based on the use of the IR thermography to determine the heat transfer coefficient characterizing the cooling of a hot moving steel strip by water sprays.