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An experimental study is presented on the evaporation of diluted droplet-laden two-phase jet flows within a heated air channel co-flow. In this study, n-heptane is pre-atomized by an ultrasonic nozzle to produce droplet cluster with a median diameter of about15μm, and a continuous cold air flow is applied to carry the fuel droplet cluster to emerge from a nozzle tube, producing a free turbulent jet of droplet stream. The droplet stream is then introduced as a central jet into a square-shaped channel with heated air co-flow for evaporation investigations. With flexibilities of the initial properties of droplet stream and surrounding conditions of channel flow, the axial evolution of droplet size is determined to characterize the evaporation behavior of n-heptane droplet stream under various boundary conditions. The equivalence ratios of droplet streams are varied by changing both the carrier-air flow rate and the fuel flow rate.

The objective of this work was to investigate the potential of the electrostatic atomization for its application in internal combustion engines. In this paper, a theoretical model for secondary breakup of charged droplets was established. The electric force reduces the surface tension of liquid, whereby atomization is promoted. To improve the diesel droplet atomization remarkably by means of electrostatic charge, the charge-mass ratio should be at least at the order of 10-6C/g. In the interest of the practical application conditions in internal combustion engines, the high-pressure injected electrospray was generated and investigated under various injection pressures and electric conditions. By means of the Photron high-speed camera, the special features of electrospray were observed. The micro-characters including the drop size distribution and the variance of the drop diameter in the spray front area were investigated.