Thermal Analysis of Droplet Spray Evaporation From a Heated Solid Surface

This paper deals with the heat transfer aspects of droplet spray evaporation from a heated solid surface. The analysis is restricted to the low superheat regime, in which the impinging droplets stick onto the solid without bubble nucleations. In this limit of approximation, the heat flow is quasi-steady and conduction dominated. The difficulty arising from droplet thermal interactions is overcome with an approximate model of an evaporating droplet surrounded by a uniform surface heat flux. The size of the droplet changes with time, but the effect of the surrounding droplets, which are treated as a continuum producing the uniform surface flux, is taken into consideration in an average sense. In addition, the analysis also incorporates the effects of droplet contact angle, droplet concentration, and solid conductivity. A transcendental equation has been derived and solved by using the Newton-Raphson method to obtain the Nusselt number.