Effect of Y-jet nozzle geometry and operating conditions on spray characteristics and atomizer efficiency

Abstract

The investigation and optimization of the atomizer nozzle design are paramount for an efficient atomization performance. Motivated by internal mixing atomizers used in FCC-reactors in the oil industry, the present work aims to improve the gas-liquid mixing process promoted by a specific design of the Y-jet nozzle by investigating the impact of key geometric parameters. The performance assessment is conducted by investigating the internal mixing chamber pressure, high-speed images of the spray, and the analysis of droplet size and velocity spatial distributions. The investigation considers industrially representative operating conditions as opposed to the lower mass flow rates typically employed in lab-scale investigations. The geometry variation considers the length and opening angle of the internal mixing chamber, as well as the impingement angle between the gas and the liquid jets inside the atomizer nozzle. A particular geometric characteristic of the utilized nozzles is the mixing-chamber conical geometry, distinguishing them from conventional cylindrical geometries. The impact of the nozzle geometry and operation parameters on atomization efficiency and spray homogeneity are the main outcomes of this approach. Overall, nozzles with shorter mixing chambers promote more efficient atomization combined with small droplet sizes and a more homogeneous spray.