DROPLET SIZE-VELOCITY CHARACTERISTICS OF SPRAYS GENERATED BY TWO-PHASE FEED NOZZLES

Abstract

The present study focuses on the evaluation of the droplet size-velocity characteristics of sprays generated using two-phase flow feed nozzles. Two types of nozzles were used in the study and for convenience these are designated as Nozzle-A and Nozzle-B, respectively. Liquid nitrogen is used to simulate feeds that undergo vaporization upon injection into the processing vessel and air is used as the carrier gas. For each test, the liquid flow rate and the aeration rate are varied and the droplet size-velocity measurements are conducted using a Phase-Doppler Particle Analyzer. The droplet size and velocity measurements are carried out at various axial locations along the spray. At each axial location, measurements are performed at various radial positions. The main variables of interest include the droplet velocity, droplet diameter, droplet count fraction and the droplet size-velocity correlation factor. The results indicate that the two nozzles considered in the present study generate sprays with varying characteristics. The aeration rate has a larger influence on the spray generated by Nozzle-B. The droplet size distributions are found to be sensitive to changes in the aeration rate. The droplet velocity characteristics are different from those reported in earlier studies on single-phase and droplet-laden jets.