Structural parameters regulate valley flow diversion and filtration-area scaling during particle loading in pleated cylindrical oil filters

Pleated cylindrical oil filters exhibit coupled hydraulic and particle-loading behavior because structural parameters influence filtration area, flow redistribution, valley accessibility, and regional particle accumulation. However, the mechanisms linking pleated geometry to pressure-drop growth and service life over a complete loading cycle remain insufficiently understood. A baseline-calibrated dynamic CFD model was used to simulate filters from the clean state to a common terminal pressure-drop criterion. The effects of pleat count N , media thickness Δ n , filter height H , inner diameter D in , and outer diameter D out were examined across 33 unique configurations using one-parameter-at-a-time analysis. For the baseline filter, the model reproduced the measured dynamic pressure-drop and filtration-efficiency histories with R 2 > 0.99. Pleat count, inner diameter, and media thickness primarily altered valley accessibility, whereas filter height and outer diameter primarily acted through filtration-area scaling. Reducing N from 85 to 55 and increasing H from 90 to 150 mm extended service life by 56% and 86%, respectively; thinner media further extended service life but reduced initial filtration efficiency. A consistent valley/lateral/tip decomposition organized the regional trends into two interpretive pathways: valley-diversion-related regulation and area-scaling regulation. Under the investigated filter medium, structural ranges, rated flow condition, contaminant distribution, and loading protocol, the results indicate that pleated-filter design should account for regional flow accessibility and load distribution in addition to nominal filtration area.