Cutting bubbles using wire-mesh structures : direct numerical simulations

Bubble column reactors suffer from bubble coalescence resulting in a decreased mass transfer efficiency. In order to increase the mass transfer rate in bubble column reactors, a novel reactor is proposed, the Micro-Structured Bubble Column (MSBC). is novel reactor makes use of a wire-mesh serving the purpose of cuing bubbles into smaller bubbles. is increases the specific bubble surface area as well as the mass transfer coefficient, due to the enhanced surface dynamics. e first step is understanding the fluid-structure interaction in the limiting case of single-phase flow past crossing cylinders not reported in literature so far. To this end Direct Numerical Simulations (DNS) are performed, where the presence of the wire-mesh consisting of intersecting cylinders is accounted for by using an Immersed Boundary Method (IBM). e IBM is verified with existing literature data for flow past a single cylinder. Finally an extensive set of simulations has been conducted for intersecting cylinders varying in cylinder diameter and Reynolds numbers. From these simulations a new drag relation is derived describing the drag as a function of the Reynolds number and the pitch to cylinder diameter, p/D, ratio. *is chapter is based on: Segers, Kuipers, and Deen (2013)