A unified analytical model for the flight distance of flying microdroplet before solidification

Abstract

Heat dissipation and solidification of a flying microdroplet are omnipresent in nature and industrial applications. The current study lacks a model to determine the critical flight distance before the microdroplet solidification, which is crucial for powder production and microdroplet jet printing in additive manufacturing. This study investigated the transient velocity and temperature attenuation of a flying microdroplet. Both the velocity and temperature of the microdroplet were found to be decayed exponentially with the flying time. Based on energy conversion and flying velocity integration, an analytical model was proposed to determine the critical flight distances that the microdroplet begins and ends to solidify. Moreover, the parameters affecting the critical flight distance were unified into a nondimensional formula. Finally, we validated the proposed models experimentally through the deposited morphologies of copper microdroplets induced by laser pulses.