Cooling of High-Temperature Cylindrical Surfaces Using a Water–Air Spray

Abstract

In materials processing such as heat treating, metal extrusion, forging, etc., control of the surface heat flux rate contributes to better products. Spray cooling using a mixture of water and air is studied for these applications. It is shown that the heat transfer rate depends on the mass fraction of liquid and that it can be adjusted to a desired value. Experimental heat flux data are presented for different liquid mass fractions, and at surface temperatures up to 1000°C. Two distinct heat transfer regions above the dry wall temperature are recognized: radiation-dominated and convection-dominated, where droplets evaporate in the boundary layer. In between these two regions is a transition region. The inverse thermal conduction technique based on the Monte Carlo simulation is used to provide surface temperature and subsequently to compute heat flux.