抄録
The laser Rayleigh scattering technique has been applied for the time and space resolved measurements of vapor concentration in the boundary layer formed around a droplet evaporating in a uniform field of air stream. The droplet evaporation is simulated by a porous sphere method to remedy the inaccuracy arising from the distortion and the fluctuation of droplets in a conventional suspended droplet method. The results show that the optical system provided in the present study is successful in identifying the Rayleigh scattering light unaffected by the background noise due to the reflection of the incident laser beam. The time averaged concentration is observed to be fairly uniform, except in the vicinity of the surface. A low concentration region exists in the central portion of the wake. It is also indicated that an increase in Reynolds number causes a decrease in the boundary layer thickness, while the concentration profile remains similar.
