迷宫流道齿转角与齿间距对滴头性能的影响

以齿形迷宫流道为研究对象,齿转角和齿间距分别设置4个水平,采用两因素四水平全面试验方法设计,根据流体动力学两相流理论,利用Fluent 63软件对设计滴头进行了液固两相流数值模拟,分析了齿转角和齿间距对滴头水力性能和抗堵塞性能的影响．结果表明:齿转角、齿间距与流量系数均呈正相关关系,流量系数随齿转角和齿间距的增大而增大;齿转角对流态指数的影响较为复杂,以120°为转捩角呈2种变化趋势,当齿转角大于120°时,流态指数随着齿间距的增大呈先减小后增大的趋势；当小于120°时,流态指数随着齿间距的增大呈先增大后减小的趋势．提出以颗粒浓度的某个范围分析灌水器的抗堵塞性能的方法,流道内悬浮颗粒最高浓度的高低与高浓度区域所占比例并不完全一致,但最高浓度越高,则颗粒聚集的机会越大,发生局部沉淀的可能性就越大,高浓度区域所占面积也相对较大,滴头越易发生堵塞．

Effect of tooth angle and pitch of labyrinth channel on performance of emitter

An emitter with labyrinth channel was used as the study model, the channels were designed by using a full factorial experiment for two factors with four levels, the liquid solid two phase flows in them were simulated numerically by means of Fluent 6.3. Influences of tooth angle and pitch on the hydraulic and anti clog performances of emitter were explored. The results showed that discharge coefficient can be correlated to tooth angle and pith with a positive relationship; moreover, the discharge coefficient increases with increasing tooth angle and pitch. The influences of tooth angle are more complicated; when the tooth angle is more than 120°, the flow regime index decreases initially then increases with increasing tooth pitch; when the tooth angle is less than 120°, however, the index decreases firstly, then increases with increasing tooth pitch. It was proposed that the anti clog performance can be analyzed by certain range of suspended sand particle concentration. The level of the maximum particle concentration in the channel is not completely proportional to the size of the area of high concentration, but the higher the maximum concentration, the greater chance the suspended particles to gather together and the greater the probability that a local sediment happens; at last the size of the area of high concentration gets larger and the emitter becomes clogged more easily.