Influence of orifice type and wetting properties on bubble formation at bubble column reactors. (2nd October 2016) - Huber, M.
Abstract: We show a direct numerical simulation (DNS), which is capable of describing immiscible two-phase flow including surface tension and the dynamics of partial wetting. Our investigation focuses on the initial bubble formation process at the inlet and analyzes the dynamics of the bubble detachment. It is shown, how orifice geometry and wetting properties influence size and surface of the bubble. This approach has a high potential for liquid–liquid reactions and high pressure gas–liquid reactions. The use of different materials for an orifice like stainless steel or ptfe is considered by taking their distinct wetting properties into account. The investigated orifice types range from an injector nozzle over a regular capillary to a diffuser. Furthermore the influence of different volume fluxes in the feed is analyzed and a systematic comparison with respect to a desired bubble volume is given. The physical model is implemented in the Lagrangian smoothed particle hydrodynamics (SPH) method, which is, due to its mesh-free nature, particularly suitable for moving interfaces. Abstract : Highlights: A complete description for surface tension and wetting dynamics is utilized. The influence thereof on bubble detachment and bubble size is shown. Investigations are made based on different wetting conditions and orifice geometries. The significance on gas–liquid and liquid–liquid reactions is stated.