A Lagrangian sectional approach for simulating droplet size distribution of vaporizing fuel sprays in a turbulent jet

Abstract

A new Lagrangian sectional approach is used to analyze spray vaporization in a turbulent air jet flow. The fuel is considered to be in the form of discrete liquid droplets which have an arbitrary range of sizes and differ in their rates of vaporization. Assuming that the droplets follow the flow streamlines, the “residence time” of droplets as a function of the spatial coordinates is computed via the fluid Eulerian velocity field. Then, following a “group” of vaporizing droplets along a streamline, the Lagrangian approach is used. To avoid the dimensionality problem associated with the discrete form of the droplet population balance equations, “sectional conservation equations” are employed. Simulation of the downstream changes in volume distribution of fuel droplets of a vaporizing spray produced by an air-kerosene jet atomizer is presented. The theoretically predicted results of this simulation show good agreement with experimentally reported data.