涌泉根灌灌水器外壳材料对水力性能的影响

对使用ABS、纯HDPE、HDPE+20%EVA、LDPE+20%EVA以及40%HDPE+40%LDPE+10%LLDPE+10%EVA这5种不同外壳材料制造的涌泉根灌灌水器,从外壳材料的收缩率、弹性模量、拉伸应变特点等方面研究了外壳材料对涌泉根灌灌水器出流特性的影响.结果表明,外壳材料对涌泉根灌灌水器的水力性能影响明显:外壳材料的模塑收缩率越大,灌水器外壳与内芯流道贴合越紧密,流量就越小;灌水器外壳的刚性越强,即材料的弹性模量越大,不同压力作用下灌水器的流量相差越小;相同制造工艺下,外壳材料的自然回弹率影响灌水器的制造偏差,材料的回弹性越好,得到的灌水器流量偏差越小.因此,为了得到制造偏差小、水力性能良好的涌泉根灌灌水器,对外壳材料的选配应平衡刚性及自然回弹性.推荐使用混合材料40%HDPE+40%LDPE+10%LLDPE+10%EVA用以制备涌泉根灌灌水器外壳.

Effects of shell material characteristics on hydraulic performance of bubbled-root emitter

The hydraulic performance of emitters with different shell materials should be investigated. The bubbled-root emitters made by 5 kinds of shell materials(ABS, HDPE, HDPE+20%EVA, LDPE+20%EVA, 40%HDPE+40%LDPE+10%LLDPE+10%EVA)were selected. The effects of shell material characteristics, such as shrinkage, modulus and tensile deformation on hydraulic performance were tested. The results showed that the effects of shell materials physical properties on emitter out-flow were significant. The larger the molding shrinkage of the shell material is, the closer the inner diameter of emitter shell is. Thus, the labyrinth channel fitted more closely to the shell, which led to a decrease of emitter flow rate. The shell material with better rigidity had stronger ability to resist the external deformation. Consequently, emitter flow rate was more stable as the pressure head increased. The emitter shell with better nature rebound resilience had lower manufacturing variation under the same manufacturing process. Therefore, in order to obtain a bubbled-root emitter with better hydraulic performance, the selection of emitter shell material should balance the rigidity and nature rebound resilien-ce. In this study, the most appropriate material for bubbled-root emitter shell is 40%HDPE+40%LDPE+10%LLDPE+10%EVA.