Maximum heat flux at wetting front and velocity of the front during quenching of high temperature material temperature material

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The cooling of high temperature material commonly appears in engineering field such as metal processing and safety management for loss of coolant in reactor. Heat transfer strongly depends on whether the surface is wetted or not and its values usually changes one hundred times. During quenching the high temperature material, in general, heat transfer process changes from film boiling to nucleate boiling through transition boiling. In this study, two-dimensional inverse solution is first developed using the Laplace transformation to estimate the surface temperature and heat flux. The newly developed inverse solution is numerically checked in application to the moving heat source and it is found for the solution to estimate the surface temperature and heat flux with almost the same accuracy of the measured temperature in solid and then to determine the location of the moving heat source.Experiment has been conducted to make characteristics of the wetting front velocity and heat transfer during the quench of high temperature copper, brass and steel with an impinging liquid jet. Experimental range is listed in table. By applying the inverse solution to this quench, the location at which the high temperature surface is wetted during quenching can be obtained and the maximum heat flux at this location can be obtained. The estimated location is compared with the measured position using high speed video camera, being in good agreement. The effect of liquid temperature, liquid velocity, thermal properties of material on the wetting front velocity and the maximum heat flux are made clear, experimentally.【table】