Effect of inlet velocity on the hydraulic and filtering performance of a Y-type screen filter

Abstract

Uneven sediment distribution affected by inlet velocity, particle size distribution and flow field characteristics leads to local clogging in a Y-type screen filter. This study revealed the detailed flow field characteristics and distribution of sediments on the screen via computational fluid dynamics combined with the discrete element method (CFD–DEM) simulations and experimental tests. The results showed that the distribution of the flow rate on the filter screen was extremely uneven, with the maximum flow rate being 11.72 times greater than the minimum rate. The flow rate was distributed symmetrically on the two sides along the outlet centreline, as shown by the unfolded drawing of the filter core. Numerical simulation and experimental tests using sandy water showed that the number and average particle diameter on the screen decreased, and the number and average particle diameter in the plug increased, with increasing inlet velocity. The sediments on the screen were distributed intensively, and the plugging extent coefficient and the anti-clogging performance improved. However, this process was more likely to cause local clogging and worsen the filtration performance. Therefore, low-speed filtering should be applied if the filtering effect is needed, and high-speed filtering should be applied if the filtering efficiency is favourable but the flushing frequency increases.