Study on imaging method for measuring droplet size in large sprays  

作　　者：Wu Zhou Jiarui Hu Mingliang Feng Bin Yang Xiaoshu Cai 

机构地区：[1]School of Energy and Power Engineering,University of Shanghai for Science and Technology

出　　处：《Particuology》2015年第5期100-106,共7页颗粒学报（英文版）

基　　金：support from the National Natural Science Foundation of China(Grant nos.51206112, 51327803,51176128);the Natural Science Foundation of Shanghai (Grant no.12ZR1446900);Innovation Project of Scientific Research of Shanghai Municipal Education Commission(Grant no. 12YZ110)

摘　　要：Information of droplet size and size distribution lays the basis for investigations of atomization mechanisms and performance optimization, However, the laser diffraction and phase Doppler particle analyzers have difficulty in accurately characterizing sprays with a wide range of droplet sizes and very large droplets, especially ira large number of droplets are aspherical. A method to measure size in such large- droplet sprays based on digital imaging with backward illumination was developed, including an image acquisition system and image process programs. Calibration of the measurement system was performed using a dot calibration target with different dot sizes. An experimental setup was designed and established to characterize spray nozzles under different operation loads, as well as different nozzle arrangements. Results show that the droplet size of sprays ranges from dozens of microns to several millimeters. The superiority of wide load range for such nozzles was indicated by the size-measurement results under half-load to full-load operations. The present study revealed that the image processing technique can be effectively implemented for in-line size measurements of sprays with a wide distribution of droplet size and aspherical droplets, which would be difficult to characterize bv other methods.Information of droplet size and size distribution lays the basis for investigations of atomization mechanisms and performance optimization, However, the laser diffraction and phase Doppler particle analyzers have difficulty in accurately characterizing sprays with a wide range of droplet sizes and very large droplets, especially ira large number of droplets are aspherical. A method to measure size in such large- droplet sprays based on digital imaging with backward illumination was developed, including an image acquisition system and image process programs. Calibration of the measurement system was performed using a dot calibration target with different dot sizes. An experimental setup was designed and established to characterize spray nozzles under different operation loads, as well as different nozzle arrangements. Results show that the droplet size of sprays ranges from dozens of microns to several millimeters. The superiority of wide load range for such nozzles was indicated by the size-measurement results under half-load to full-load operations. The present study revealed that the image processing technique can be effectively implemented for in-line size measurements of sprays with a wide distribution of droplet size and aspherical droplets, which would be difficult to characterize bv other methods.

关 键 词：Digital image Spray size Wide size distribution Large droplets 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]