Bernoulli-induced self-cleaning in drainage pipes: visual micro-Venturi validation

ABSTRACT Conceptual diagram showing the self-cleaning mechanism: flow through a Venturi generates shear stress to remove deposits. Standard methods of removing sediment from drainage systems consume significant amounts of energy. This study evaluates a passive self-cleaning mechanism that is operated by the Bernoulli principle through a Venturi contraction, using little or no additional energy. A laboratory-scale micro-Venturi was utilized to quantify the relationship between hydraulically induced wall shear stress (τ) and the removal rate (R) of a surrogate kaolinite deposit. Over the flow rate range of 1–12 L·min−1, τ reached a maximum of 102.1 Pa. A strong linear correlation between τ and R was observed (r = 0.958), with a critical shear stress τ_c ≈ 5.8 Pa sufficient to achieve over 60% deposit removal. From this conclusion, a dimensionless scaling factor, Π = τ/τ_c, is presented to help with the design and application of energy-efficient cleaning technology on other pipes of larger scale and similar geometry.