Optical Instrument to Measure Cloud Drops with Varying Concentration

75790-A cloud¿s drop size distribution has a strong influence on its radiative properties, especially in stratus clouds which cover a large portion of the earth. This project will develop technology to simultaneously measure droplet size and concentration in airborne applications characterized by a large range in both droplet size and concentration. The design will include an innovative, variable probe volume that optimizes the measurement configuration to conform to the required concentration. In previous work, measurements with calibrated glass beads and calibrated liquid sprays established an extremely high accuracy. In Phase I, analytical and experimental studies will be conducted to demonstrate the feasibility of measuring drop sizes from 3 to 200 microns in concentrations of 10 to 100 drops per cm3, as may be expected in various clouds. Commercial Applications and Other Benefits as described by the awardee: The technique should have broad commercial applications due to its large dynamic range and ability to measure either liquid or solid particles. Potential users include industries and government agencies interested in spray atomization, fire sprinklers, and powder technology. These industries include food, pulverized coal combustion, and sand blasting.