Inverse solution to the heat transfer coeffcient for the oxidized ARMCO steel plate cooling by the air nozzle from high temperature

The inverse solution tests have been performed to the experimental data obtained during the oxidised Armco steel plate cooling by the air nozzle. The three-dimensional numerical model of heat transfer during the plate cooling has been considered. Steel products cooled in the air from high temperatures are covered with the oxide layer having significantly lower conductivity and a different surface structure comparing to the non-oxidised metal surface. The Armco steel has been selected as the experimental material because it oxidised in a similar way to carbon steels but there is no microstructure evolution process in Armco steel below 900oC. It eliminates in the inverse solutions serious problems caused by a latent heat of microstructure evolutions encountered during carbon steel cooling. In the present study the steel plate has been heated to about 900℃ and cooled by the circular air jet. The plate temperature has been measured by 36 thermocouples. The test of the selected inverse solution models involving a different number of degrees of freedom have been performed. The influence of the scale layer on the results of the inverse solution to the heat flux and heat transfer coefficient has been investigated.