DIVAS 一种液滴成像法粒径和速度测量技术
This paper discusses the measurement of transparent particles and droplets from a few microns to mm in diameter with the Droplet Imaging Velocimeter and Sizer (DIVAS), a two-dimensional technique to measure particle size and velocity. Unlike Interferometric Laser Imaging for Droplet Sizing (ILIDS), DIVAS can measure sprays with realistic concentrations, size distributions from microns to millimeters, and non-spherical spray features. The measurement of particles with a broad range of diameters is discussed to illustrate the capability of DIVAS and signal analysis strategies are suggested to expand the measurement envelop and accuracy of the technique. DIVAS uses a Particle Imaging Velocimetry (PIV) configuration that is, pulsed lasers illuminate the droplets in the measurement plane and CCD cameras collect the off-axis scattered light, thus yielding a small measurement volume and correspondingly a high number density measurement capability. Particle sizing is based on measuring the separation of cross-polarized glare points captured by two separate cameras.