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


Personal Author(s) : Sirignano, W A ; Elghobashi, S E ; Kim, I ; Chiang, C H


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a261165.pdf


Report Date : 31 Dec 1992


Pagination or Media Count : 135


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.


Descriptors :   *COMBUSTION , *DROPS , *FUEL SPRAYS , *LIQUID ROCKET FUELS , VELOCITY , HEAT TRANSFER , DENSITY , DIAMETERS , INTERACTIONS , FUELS , HYDROCARBONS , SPRAYS , NAVIER STOKES EQUATIONS , LIFT , DRAG , FLUID DYNAMICS , AXISYMMETRIC , WAKE , PRESSURE , TRANSPORT , THREE DIMENSIONAL FLOW , LIQUID OXYGEN , VAPORIZATION , FLUID FLOW , COLLISIONS , RADIUS(MEASURE) , REYNOLDS NUMBER , HEATING , SURFACE PROPERTIES , COMBUSTORS , VORTICES , SPHERES , HYDROGEN , OXYGEN


Subject Categories : Fluid Mechanics
      Combustion and Ignition
      Liquid Rocket Propellants


Distribution Statement : APPROVED FOR PUBLIC RELEASE