Simultaneous determination of optical and thermodynamic properties of an evaporating aqueous solution droplet
Advances in the single-particle levitation technique have made it possible to investigate evaporation of an aqueous solution droplet under controlled humidity conditions. The technique involves the levitation of a charged micron-sized inorganic salt particle in a quadrupole cell, which can be evacuated to {approximately}10{sup {minus}7} torr and back filled with water vapor to a predetermined pressure at a fixed temperature. Water evaporation occurs as the cell is evacuated slowly through a precision leak valve. Droplet mass change is measured by the dc voltage needed to counterbalance gravity, whereas the droplet size is continuously monitored by the 90{degree}-angle laser light scattering. By fitting the light scattering data with Mie computations using appropriate refractive index and density estimates, it is possible to obtain these optical and thermodynamic properties over a wide concentration range from high dilution to high supersaturation. Such a wide concentration range can only be achieved with a suspended solution droplet. Results are presented for aqueous ammonium sulfate solution droplets. 4 refs., 4 figs.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA)
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 6750223
- Report Number(s):
- BNL-43549; CONF-9009136--1; ON: DE90010652
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540110*
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AEROSOLS
AMMONIUM COMPOUNDS
AMMONIUM SULFATES
AQUEOUS SOLUTIONS
COLLOIDS
DISPERSIONS
DROPLETS
EQUATIONS
EQUIPMENT
EVAPORATION
INORGANIC COMPOUNDS
LEVITATION
LIGHT SCATTERING
MATHEMATICAL MODELS
MIXTURES
OPTICAL PROPERTIES
OXYGEN COMPOUNDS
PARTICLES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SALTS
SCATTERING
SOLS
SOLUTIONS
SULFATES
SULFUR COMPOUNDS
THERMODYNAMIC PROPERTIES