Experimental Investigations of the Binary Interaction of Polydisperse Sprays

Abstract

Experimental investigations of the interaction of two polydisperse semi-hollow cone sprays are presented. The process, although of considerable significance for the chemical industry and applications like flue gas cleaning, has not been well-covered in the existing literature. This may be due to difficulties in getting general results from experiments involving particular geometries, like conical sprays, with fixed spray angle and geometrical arrangement of the nozzles. The present work develops a representation of the effects of the spray interaction on the spray drops in the resulting two-phase flow. The measurement technique used is phase-Doppler anemometry (PDA), which provides information about the size and two velocity components of the drops at each measurement position in the sprays. A factorial design of the experiments allows the influence of the intersection angle and the liquid flowrate of the sprays on an integral mean drop size in a spray cross section to be quantified. For varying values of these parameters, the downstream evolution of the interacting sprays is quantified in terms of the smoothness of profiles of the number-mean drop size. The collisional interaction of the spray drops is identified as the reason for the observed increase of the mean drop size caused by the spray interaction.