摘要
射流式混药装置是实现药水分离、农药在线混合的关键部件,在大型植保机械上具有较好的应用前景。理论分析了射流式混药装置最佳面积比、工作喷嘴截面面积和喷嘴与混合室的距离等关键结构参数;采用标准的k-ε双方程湍流模型数值研究混药装置内部流场,并结合试验数据研究混药装置结构参数对其性能影响及其特性曲线。研究结果表明,最佳面积比与工作压力、出口压力、引射压力有关,喷嘴与混合室的距离应等于最佳自由流束长度;不同面积比下可达相对压力降模拟值与试验值的最大相对误差和平均误差分别为0.125和0.051,验证了本文所选数值模型与模拟方案可以满足工程需求;当相对压力降大于0.3后,吸入流量急剧减小。不同可用压力降下所达到最大相对压力降介于0.5~0.6之间;射流式混药装置的最佳面积比在1.6~2.0之间,喷嘴与混合室的最佳距离为2.6~4.6 mm之间。
The jet mixing apparatus( JMA) is an important part for mixing the water with the pesticide,which has good prospect in large plant protection machinery.The parameter of area ratio,area of nozzle and distance between nozzle and mixing chamber were discussed by theoretical analysis.The standard k-εtwo-equation model was adopted to simulate the interior flow field.Combined with experiment data,the performance characteristics,the effects of structural parameters on the JMA property were discussed.Results showed that the optimum area ratio was related to working pressure,outlet pressure and jet pressure.The distance between nozzle and mixing chamber should be equal to optimum extent of free stream.The maximum relative error and average error of relative pressure at different area ratio were0.125 and 0.051,respectively.The numerical model and simulation method were validated validate to meet the requirements of engineering.The jet flow decreased when the relative pressure greater than 0.3.The maximum relative pressure was between 0.5 and 0.6 under different available pressures.The optimum area ratio of JMA was between 1.6 and 2.0.The optimum distance between nozzle and mixing chamber was between 2.6 mm and 4.6 mm.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2013年第S1期107-112,共6页
Transactions of the Chinese Society for Agricultural Machinery
基金
公益性行业(农业)科研专项经费资助项目(201220025)
关键词
植保机械
在线混药装置
数值模拟
Plant protection machine Online mixing apparatus Numerical simulation
