Characteristics and comparison of pressure-based variable spray
1.Beijing Research Center for Intelligent Agricultural Equipment,Beijing 100097,China; 2.College of Science,China Agricultural University,Beijing 100193,China; 3.College of Engineering,Nanjing Agricultural University,Nanjing,Jiangsu 210031,China）
Abstract：Spray characteristics of pressure-based variable spray,i.e. flow-rate regulating range,spray distribution,spray angle,droplet size,droplet velocity,and dynamic characteristics,are discussed and quantitatively compared with those of PWM-based continuous and intermittent variable spraies. The results showed that,for pressure-based variable spray,flow-rate regulating range is about 2.With flow-rate reducing,spray distribution concentrates greatly and spray droplet size increases significantly. Change rate of spray angle and droplet diameter are 1.08°/% and -1.562 μm/% respectively; spray droplet velocity increases obviously and consistently. Change rates of kinetic energy median diameter（KEMD） and specific energy（SE） are 1.50 μm/% and 0.228 7（J/kg）/% respectively. Energy utilization rate of pressure-based variable spray is low. Among three kinds of variable spraies,flow-rate regulating range of pressure-based spray is the narrowest,its effects on spray characteristics are the most significant; flow-rate regulating range of PWM-based continuous spray is the widest; and PWM-based intermittent spray has the minimal impact on spray characteristics.
2009, Vol. 30 
