局部弯曲对气举性能影响规律的试验研究

Test study on influence laws of local bend on air-lift performance

局部弯曲在实际应用中不可避免,因此有必要探讨含局部弯曲管道气举的提升特性。以气举中的核心部件提升管为研究对象,对弯曲位置和角度进行试验测试。结果表明：弯曲位置为主因,且90°弯管位于进气口上游时对气力提升性能影响最显著;在定浸没率下,不同结构提升管排水量峰值所对应的进气量在42~46 m3/h范围内略有差异;气液混合相流经局部弯管后,流型由弹状流转变为不利提升的环状流,从而影响提升能力。测试试验证实,弯曲管道压头损失和混合流体在弯曲区域的气液分层流动是气力提升效率下降的主要诱因。

Local bend is inevitable in practical application, so it is necessary to discuss the air-lift performance of local-bent pipeline. The key part of the air lift, the lifting pipe, was taken as the study object, its bending location and angle were tested. The results showed： the bending location was the main cause, while the 90° bent pipe was located at the upstream of the inlet, the air-lift performance was affected the most remarkably; at fixed immersion rate, the intake volume of various-structure lifting pipe at their drainage peak ranged from 42 to 46 m3/h; while air-liquid mixed phase flowed through the local bend, the flow pattern was transferred from slug flow to annular flow which was against lifting, thus the air-lift performance was affected. The test showed the pressure loss of bent pipe and the stratified flow of air-liquid mixed phase at bent zone were the main causes of reduction of air-lifting efficiency.