Capillarity Constructed Open Siphon for Sustainable Drainage

Siphon is an effective method to transfer liquid from a higher to a lower level, which has many applications in hygienic design, clinical apparatus, and hydraulic engineering. Traditional operation requires energy to overcome gravity and establish flow in a closed system. Achieving sustainable high flux siphon drainage without energy input remains a challenge due to viscous dissipation. Here, an unexpected open siphon behavior on the South American pitcher plant Heliamphora minor consisting of trichomes covered pitcher and a wedge-shaped sheath is examined. Exploiting the concept of Digital Twin, a new biomimetic research method by transforming the biological sample to a virtual 3D model is proposed and unveiled that maintained connection of wicking on sub-millimeter long trichomes due to asymmetric pressure distribution and ascending in wedge sheath under unbalanced pressure forms continuous surface flow. Exploring this mechanism, a biomimetic siphon device achieving continuous high flux exposed to ambient air is constructed. Besides, particles floating on the meniscus in the outside wedge move under a curvature gradient as water ascends, which implies a biological nutrient capture method and new dust collection manner in the drainage system. Applying the underlying principle enhances the siphon efficiency of floor drains and has the potential for other liquid transfer device design improvements. Inspired by water drainage in the pitcher of Heliamphora minor whose lid is too small to cover the pitcher, siphon-like flow in an open system is unveiled that 2 structures, trichomes and wedge, result in spontaneous wicking under asymmetric pressure difference and guiding the overflowing water in the wedge down to the root, which can improve the design of drainage system. image