Bio-inspired particle separator design based on the food retention mechanism by suspension-feeding fish.

A new particle separator is designed using a crossflow filtration mechanism inspired by suspension-feeding fish in this study. To construct the model of the bio-inspired particle separator, computational fluid dynamics techniques are used, and parameters related to separator shape, fluid flow and particle properties that might affect the performance in removing particles from the flow, are varied and tested. The goal is to induce a flow rotation which enhances the separation of particles from the flow, reduce the particle-laden flow that exits via a collection zone at the lower/posterior end of the separator, while at the same time increase the concentration of particles in that flow. Based on preliminary particle removal efficiency tests, an exiting flow through the collection zone of about 8% of the influent flow rate is selected for all the performance tests of the separator including trials with particles carried by air flow instead of water. Under this condition, the simulation results yield similar particle removal efficiencies in water and air but with different particle properties. Particle removal efficiencies (percentage of influent particles that exit through the collection zone) were determined for particles ranging in size from 1 to 1500 µm with a density between 1000 and 1150 kg m(-3) in water and 2 and 19 mm and 68 and 2150 kg m(-3) in air. As an example, removal efficiencies are 66% and 64% for 707 µm diameter particles with a density of 1040 kg m(-3) in water and for 2 mm particles with a density of 68 kg m(-3) in air, respectively. No significant performance difference is found by geometrically scaling the inlet diameter of the separator up or down in the range from 2.5 to 10 cm.