Heat Transfer from Hot Metal Surface to an Impinging Water Droplet in Transitional Boiling Regime

Abstract

Transient measurements have been made of the cylindrical metal temperature upon an impingement of a single water droplet on its circular surface preheated to a specified temperature of 300 to 450°C. Results can be well explained by means of the axisymmetric three-dimensional model for conduction in metal and heat transfer coefficient between the surface and droplet has been estimated as the model parameter. Numerical values of the heat transfer coefficient obtained with stainless steel rod specimen seem to correspond with the interpolated ones of the previous results, 2) which were obtained by the stationary method with a thin circular plate of stainless steel. Heat transfer coefficient is a function of the thermal diffusivity of hot metal as well as both Weber number of the droplet and the surface temperature of metal.