内镶式滴灌带绕流流道水力性能研究

该文运用水力学公式、数值模拟和快速原型试验研究了绕流流道滴灌带的水力性能，并建立了设计流量与流道结构参数之间的计算模型。数值模拟得到的流场水力结构显示水流的水头损失主要集中在流道的拐角，分支和交汇处。在数值模拟的基础上，利用快速成形技术制造出16种结构形式的绕流流道，并进行压力与流量特性试验。试验结果表明：绕流流道的流态指数为0.5左右，且受流道的截面积和单元数的影响较小；而流量系数则随截面积的增加而增加，随单元数的增加而减小。144组试验数据的回归结果显示：流量随流道的截面积和工作压力的增加而增大，随单元数的增加而减小；其中，截面积影响最大，单元数次之，最后是工作压力。

Hydraulic performances of the round-flow channel inan in-line drip-tape

Through hydraulic formulas, numerical simulations and rapid prototyping experiments, the hydraulic performances of the round-flow channel inan in-line drip-tape were analyzed, and a computational model for the relationship between the designed discharge and structural parameters of the channel was established. The hydraulic structure of the micro flow field was obtained fromthe numerical simulations, which showed that the pressure loss of water mainlyoccurred at the corner, offset and meet parts of channel. On the basis of the simulations, 16 types of round-flow channels were fabricated by using the technique of rapid prototyping, and then the pressure and discharge were analyzed with these prototype emitters. Results show that the flow exponent of the round-flow channel is about 0.5, which does not vary with the change of the cross-sectional area and cell number of the channel. The discharge coefficient increases with the increase of the cross-sectional area. But it decreases with the increase of the cell number. The regression results for 144 groups of experimentaldata show that the discharge increases with the increase of cross-sectional area and inlet water pressure, but decreases with the increase of the cell number.The impact on the emitter discharge caused by the cross-sectional area is thelargest, the cell number takes second place, and the last is the operational pressure at the channel inlet.