Papers by Author: Yan Wu

Abstract: An experimental device capable of producing uniform metal droplet stream and electric charging and deflecting has been developed. Uniform spherical powder of 180μm in diameter was obtained after cooling and solidification. Numerical models of heat transfer and solidification of droplets were established. The thermal history including solid fraction of droplets in uniform droplet spray process were calculated. Under the common processing conditions, the cooling rate of a droplet of 180μm diameter is of the order of 103−104°C/s. To obtain homogeneous and dense preforms, the substrate should be positioned at a distance of 1.1-1.3m from the nozzle.

Abstract: In this study an experimental device capable of producing uniform metal droplet stream with image gathering was set up. A periodic vibration was applied to a compound liquid jet for an experimental study on its breakup. The breakup processes of the compound jet were discussed from the image taken from the experiment. The aim is to study the relationship of the factors which determine the jet breakup into a series of uniform droplets.

Abstract: The generation of uniform droplets in the size of hundred microns was described in this paper. An experimental device capable of producing uniform droplet has been developed. For the purpose of adjusting the signal generator for both continuous droplets spray and drop-on-demand, the piezoelectric driving signal was set up with a PC and software of Labview. With the signal generation system, Flexible signal adjustment appears to be more suitable than simple signal generator to generate uniform droplets.