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.