直冲洗网式过滤器的流场模拟及结构优化

Numerical Simulation and Structural Optimization of Direct-Washing Screen Filter

针对直冲洗网式过滤器在实际应用中无法将黏附在滤网内表面泥沙冲洗干净的问题,提出结构优化方案,即在保持滤网面积不变的前提下,将滤网形状做成渐缩式。采用Fluent软件,分别对圆筒式和渐缩式网式过滤器在过滤和冲洗条件时的清水流场进行模拟。结果显示,数值模拟和现场测试的水头损失和排污压强的相对误差分别为6.04%、4.03%,采用的多孔阶跃模型和Realizableκ-ε模型,具有较高的准确性;圆筒式和渐缩式网式过滤器在过滤时流场分布相似,但渐缩式网式过滤器在直冲洗时能明显提高滤网内部及滤网内表面的流速,从而将滤网内表面冲刷得更干净,缩短了冲洗时间,降低了冲洗频率,减小了耗水量。该结果为过滤器后续的研发奠定了基础。

In practical application,direct-washing screen filter can not rinse off the sediment which is adhere to the internal surface of screen filter.Therefore,we put forward structure optimization program that the screen is made in the tapered shape under the condition of the screen area unchanged.The flow field of clear water was respectively simulated in cylindrical and tapered screen filter using Fluent software when screen filter was run.By comparing the results of numerical simulation and field test,we can get the relative errors of head loss and discharge pressure which is 6.04%and 4.03%respectively.So,porous jump and Realizableκ-εmodel have higher accuracy.Flow field distribution of the tapered screen filter is similar to cylindrical screen filter during filtration.But the tapered screen filter significantly increases the flow rate inside the screen and the inner surface of the screen during direct-washing.Thus,the inner surface of screen is washed cleaner.Meanwhile,the tapered screen filter shortens the washing time,reduces the frequency of washing and water consumption.The results lay the foundation for the subsequent research and development of the screen filter.