Gas density effect on dropsize of simulated fuel sprays
Two-phase flow in pneumatic two-fluid fuel nozzles was investigated experimentally to determine the effect of atomizing-gas density and gas mass-flux on liquid-jet breakup in sonic-velocity gas-flow. Dropsize data were obtained for the following atomizing-gases: nitrogen; argon; carbon dioxide; and helium. They were selected to cover a gas molecular-weight range of 4 to 44. Atomizing-gas mass-flux ranged from 6 to 50 g/sq cm-sec and four differently sized two-fluid fuel nozzles were used having orifice diameters that varied from 0.32 to 0.56 cm. The ratio of liquid-jet diameter to SMD, D sub o/D sub 32, was correlated with aerodynamic and liquid-surface forces based on the product of the Weber and Reynolds number, and gas-to-liquid density ratio, rho sub g/rho sub 1. To correlate spray dropsize with breakup forces produced by using different atomizing-gases, a new molecular-scale dimensionless group was derived. The derived dimensionless group was used to obtain an expression for the ratio of liquid-jet diameter to SMD, D sub o/D sub 32. The mathematical expression of this phenomenon incorporates the product of the Weber and Reynolds number, liquid viscosity, surface tension, acoustic gas velocity, the RMS velocity of gas molecules, the acceleration of gas molecules due to gravity, and gas viscosity. The mathematical expression encompassing these parameters agrees well with the atomization theory for liquid-jet breakup in high velocity gas flow. Also, it was found that at the same gas mass-flux, helium was considerably more effective than nitrogen in producing small droplet sprays with SMD's in the order of 5 micrometers. 13 refs.
- OSTI ID:
- 5526275
- Report Number(s):
- AIAA-Paper-89-2322; CONF-8907118-
- Resource Relation:
- Conference: 25. American Society of Mechanical Engineers joint propulsion conference, Monterey, CA (USA), 10-13 Jul 1989
- Country of Publication:
- United States
- Language:
- English
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42 ENGINEERING
GAS TURBINES
FUEL INJECTION SYSTEMS
LIQUID FUELS
SPRAYS
TWO-PHASE FLOW
ARGON
ATOMIZATION
CARBON DIOXIDE
DENSITY
DROPLETS
EFFICIENCY
GAS FLOW
HELIUM
MATHEMATICAL MODELS
NITROGEN
NOZZLES
REYNOLDS NUMBER
VISCOSITY
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
FLUID FLOW
FLUIDS
FUEL SYSTEMS
FUELS
GASES
MACHINERY
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PARTICLES
PHYSICAL PROPERTIES
RARE GASES
TURBINES
TURBOMACHINERY
330603* - Vehicle Design Factors- Engine System
420400 - Engineering- Heat Transfer & Fluid Flow