Accession Number:

ADA261165

Title:

Fundamental Studies of Droplet Interactions in Dense Sprays

Descriptive Note:

Final rept. 1 Nov 1989-31 Oct 1992

Corporate Author:

CALIFORNIA UNIV IRVINE DEPT OF MECHANICAL AND AEROSPACE ENGINEERING

Report Date:

1992-12-31

Pagination or Media Count:

135.0

Abstract:

The research addressed interactions amongst droplets in a dense spray. The effects of neighboring droplets, that were a few droplet diameters away, on a vaporizing droplet were examined by theoretical and computational analyses for two basic configurations 1 the axisymmetric convective situation where two or three droplets moved in tandem and 2 the fully three-dimensional convective situation where droplets moved side-by-side. Droplets in the wake of other droplets experienced a reduction in drag force, transport rates, and vaporization rate, sometimes causing collisions. Sufficiently close droplets moving side-by-side, approximately in parallel, experienced a repulsive lift force and an increased drag force. Vaporizing liquid oxygen droplets in a hydrogen gas environment were studied at both subcritical and supercritical pressures considering the variable liquid density with the associated droplet swelling during heating and the dependence of the local critical state upon local composition. Droplet surface conditions could be subcritical even if pressures were supercritical for pure oxygen due to diffusing hydrogen. The critical surface regressed towards the droplet surface as the droplet heated. Engineering correlations for the drag coefficients, Nusselt numbers, and Sherwood numbers for hydrocarbon fuel droplets in dense sprays were obtained.

Subject Categories:

  • Fluid Mechanics
  • Combustion and Ignition
  • Liquid Rocket Propellants

Distribution Statement:

APPROVED FOR PUBLIC RELEASE