作　　者： ; ; ; ; ;

机构地区： 教育部

出　　处： 《农业工程学报》 2013年第18期34-42,F0004,共10页

摘　　要： 风送式喷雾机喷筒结构的不同,影响其流场的分布及喷幅的大小,该文提出在原有的圆形喷筒喷雾机的基础上附加扩幅段的方法,使同一台风送式喷雾机具有不同的喷雾特性。利用数值计算方法,采用RNG k-ε模型,对附加3种不同类型扩幅段的喷筒进行了数值计算与分析。仿真分析发现,喷筒中气流运动分为3个阶段：靠近风扇区域中,气流呈紊流状态,在柱形喷筒与收缩喷筒区域中,层流与紊流并存,而在扩幅喷筒中,气流存在紊流并发生了流速的重新分布。其中,3种类型的喷筒中,在柱形喷筒及收缩喷筒内,I型和III型喷筒内气流速度的突变区域较多,II型喷筒中气流速度的突变区域较少;在扩幅喷筒中,I型和III型喷筒内的紊流区域较多,使得I型和III型喷筒效率较低。以喷筒效率高为优化目标,获得了宽喷幅风送式喷雾机扩幅段喷筒的优化结构,并试制了试验样机;利用试验样机,对宽喷幅风送式喷雾机的出风口风速及喷幅进行了实际测试。试验结果表明,采用优化后的扩幅喷筒,在出风口处实测的流场数据与仿真结果之间的误差在-1.49%~1.91%内;宽喷幅风送式喷雾机喷幅与送风距离间成二次多项式变化规律,在喷筒轴线方向上距出风口4.5 m处出现的喷幅最宽为3.56 m,与同功率下的未加扩幅喷筒的风送式喷雾机最大喷幅2.29 m相比,喷幅扩大了55.46%。 The distribution of flow field, efficiency and spraying swath of an air-blast sprayer were influenced by its structure and its shape of the duct outlet. In this paper, an additional expansion swath duct was subjoined to the original circular duct in order to make the same air-blast sprayer have different spray characteristics. Aiming at the high duct efficiency, three different types of wide-swath air-blast sprayer＇s segment of expanding duct structure were optimized via numerical calculation and analysis of the internal flow field by using the RNG k-ε model. The simulating results indicated that the wind flowed in the duct was divide into three stages. The air flow was turbulent near the fan area. Inside the cylindrical duct and contraction duct, the air flow was not only layered but also turbulent. Moreover, in the expanding duct, the air flow was turbulent and the wind speed distributed renewed. Furthermore, the areas where air flow velocity change suddenly in type Ⅰ and type Ⅲ ducts were larger than that of type Ⅱ duct. In the expanding duct, the turbulent area were also larger in type Ⅰ and type Ⅲ ducts, and that leaded this two types duct efficiency was more less than that of type Ⅱ duct. The air flow total pressure at inlet and outlet, the air flow average speed and the duct efficiency were simulated. The optimized structure of expansion swath duct was obtained and the testing prototype was manufactured based on the numerical calculation results. The wind speed at the outlet and the swath of wide-swath air-blast sprayer were tested and measured via prototype test. The test results showed that the error between measuring and simulating of the flow field was within -1.49% to 1.91%. The relationship between spraying swath and blast distance of wide-swath air-blast sprayer appears to be quadratic polynomial. The widest spraying swath measured away from the outlet 4.5m along the duct axial direction was 3.56 m. Compared with the same power air-blast sprayer without segment of expanding duct, the

关 键 词： 数值计算 优化 试验 风送式喷雾机 喷幅 喷筒

领　　域： [农业科学] [农业科学]