灌水器流道结构对水力性能影响的数值分析

采用计算软件Fluent,通过将壁面粗糙元抽象为多孔介质的微尺度效应处理方法进行建模,选用realizable k-ε模型,对3种齿形流道的灌水器内流进行数值研究。利用Micro-PIV试验测量结果验证了该模拟方法的可靠性,在多种流动条件下对3种齿形结构灌水器进行数值计算,并进行抗堵性能和水力性能分析。抗堵性分析表明,3种齿形流道在转角内侧都存在回流区,由于其侧均为高速主流而使颗粒沉积缓慢;尖角齿形流道的尖角部位,大部分区域由于具有一定的紊流强度也不易沉积杂质,只有其齿尖和平角齿形流道的左顶角部位易产生颗粒沉积。在水力性能分析中,通过对压力降和流态指数的比较表明,尖角齿形的灌水器在控制和稳定出流方面具有优势。

Numerical investigation on effect of channel structure to hydraulic performance of emitter

Employing realizable k-ε turbulence model,emitters of three different jagged channels were numerically investigated,in which the wall roughness elements were simulated by adopting porous medium model so as to describe geometric model of micro-channels based on Fluent.The testing result of Micro-PIV proves the reliability of the approach,which also can be applied to numerical computations of emitters of three different structure jags.According to the numerical simulation,anti-clogging and hydraulic property were analyzed.In the analysis of anti-clogging,it was found that impurity sediment was seldom to happen because of the high speed mainstream,next to which there were recirculation zones at the swerving inside of all the three channels;it was also not liable to happen at the cusp of the jags because of the turbulence;while it only exited s at the jag cusp and the left side of the flat-jagged channel.By comparing the pressure drops and flow pattern index in emitters of three different jagged channels,the hydraulic property is analyzed,which proves the advantage of cusp jag emitters to control steady outflow.