Accession Number:

ADA314952

Title:

A Numerical Study of Droplet-Vortex Interactions in an Evaporating Spray,

Descriptive Note:

Corporate Author:

ILLINOIS UNIV AT CHICAGO CIRCLE DEPT OF MECHANICAL ENGINEERING

Report Date:

1994-06-01

Pagination or Media Count:

10.0

Abstract:

In this paper, we present the time-dependent axisymmetric numerical simulation of an unsteady n-heptane evaporating spray, and investigate the droplet-vortex interactions which determine the structural and dynamic characteristics of a spray jet flow. The spray is formed between a droplet-laden heated nitrogen jet and a coflowing air stream. A detailed, multidimensional, two-phase algorithm is developed for the simulation. A comprehensive vaporization model is employed to calculate the instantaneous droplet size and surface temperature along the trajectory of each droplet group. Monodisperse spray in introduced into the large vortex structures that are generated due to the presence of buoyancy-induced hydrodynamic instability of the heated jet. Results focused on the two-way interactions between vortical structures and droplets, and the dynamics of both non-evaporating and evaporating sprays. The vortex structures cause droplets to disperse radially outward, and this in turn determines the fuel vapor distribution and also modifies the vortex dynamics. Thus, the dynamics and structural characteristics of the evaporating spray are strongly influenced by the two-way transient interactions. The effects of initial droplet size, injection location, and liquid-to-gas mass loading ratio on these interactions are also investigated.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE