Numerical study of opposing pulsed-jet cleaning for pleated filter cartridges

Pleated filter cartridges are recently favored in industrial filtration systems because of their advantage of the large filtration area. Their use, however, places the serious concern of incomplete/patchy cleaning via reverse pulsed-jet technique. A new pulsed-jet technique, named opposing pulsed-jet cleaning (previously colliding pulse jet cleaning), had been proposed and experimentally evidenced to improve the cleaning quality of pleated filter cartridges. In the above cleaning, a second cleaning nozzle is installed at the cartridge base and its exit, facing the cartridge core, is used to launch a second pulsed-jet flow in addition to the primary one. Via the numerical Modeling, this work investigated the detail flow mechanisms in the cleaning process and the effects of delay time, Delta t, and pressure ratio, PR, on the cleaning performance. It was found that, within a certain range of Delta t, the later-initiated jet from the second nozzle would collide with the former-launched jet from the primary one, and the flow impinging location could be moved inside the pleated cartridge, resulting in wider filtration media area covered by the impinging jet flow energy (compared with that using only the primary nozzle). The cleaning performance could also be improved by the increase of PR when Delta t > 0. When Delta t = 0, the cleaning quality reduces as the PR value increases to 1.5 and remains the same when the PR value is greater than 1.5. Under the scenario of Delta t < 0, the cleaning performance improves as the PR increases and then reduces as the value of PR further increases.