流道结构对低压旋转式喷头水力性能影响试验研究

以低压旋转式喷头为研究对象,选择喷盘空间流道的结构参数:出口截面形状、流道偏转角、流道型线弧长、出口仰角作为试验因素,采用L₄³(9)的正交设计,测量了工作压力为250 kPa时,不同因素水平下各试验喷头的水量分布和流量,并利用线性插值法计算了单喷头的射程,选用Matlab软件模拟了正方形布置下喷头的组合均匀系数,分析了空间流道各结构参数值对喷头水力性能的影响规律.结果表明:低压喷头空间流道的出口截面为圆形和倒U形时,其喷洒均匀性优于出口截面为异形的喷头;空间流道结构参数的改变对流量基本无影响,波动范围在±0.1 m³/h.运用综合评分法分析得到各空间流道结构参数因素对组合均匀系数和射程的综合评价指标影响的主次顺序为流道偏转角、出口截面形状、出口仰角、流道型线弧长、最终得出低压旋转式喷头空间流道结构参数的最佳组合为出口截面圆形,流道偏转角4.5°,流道型线半径29 mm,出口仰角25°.

Experimental study on influence of flow channel structure on hydraulic performance of low-pressure rotary sprinkler

A low-pressure rotary sprinkler was taken as the study object and the geometrical parameters of channel in the sprinkler head were chosen as the experimental factors,including the shape of outlet section,deflection angle of flow channel,are length of passage shape and elevation angle of outlet.An orthogonal array of four factors and three levels was selected to carry out the experiment,measuring the water distribution and flow rate of each sprinkler under the working pressure of 250 kPa,and the range of sprinkler was calculated by the linear interpolation method,the uniformity coefficient was simulated by Matlab under the square arrangement,the influence of geometrical parameters on the hydraulic performance of sprinkler was analyzed.The results show that the spraying uniformity of low-pressure rotary sprinkler which the shape of outlet is circular or inverted U is superior to that of irregular outlet.There is little water of irregular outlet near the sprinkler,mostly concentrating in the center,resulting more water accumulation in the overlapping region of combined sprinkler irrigation.The change of the geometrical parameters change in the flow channel has little effect on the flow rate,and its fluctuation ranges between-0.1 and 0.1 m3/h.The graduations of geometrical parameters which affect the range and spraying uniformity of low-pressure rotary sprinkler are achieved after the orthogonal experiment,which are deflection angle of flow channel,shape of outlet section,elevation angle of outlet and arc length of passage shape.The best geometrical parameters of low-pressure rotary sprinkler are summarized,that is the shape of outlet is circular,deflection angle of flow channel is 4.5°,arc length of passage shape is 29 mm and elevation angle of outlet is 25°.