Experimental and numerical characterisation of two-phase flow in NETmix reactors

Abstract

NETmix has been shown to be an efficient mixing technology for miscible fluids, promoting large heat and mass transfer rates. This work intends to assess NETmix for multiphase mixing, which is particularly relevant to evaluate the NETmix’s ability to couple mixing and heat transfer. The first step is to build fundamental knowledge regarding two-phase flow in these devices. A 2D CFD two-phase model was implemented based on the Euler‑Euler approach with the Volume of Fluid (VOF) method using the NETmix Unit Block (NUB). The two phases are liquids with equal density and viscosity, enabling the study of the impact of the interfacial tension and contact angle on the flow dynamics and drop formation. Mass transfer was assessed from the flow shear at the interface of the two phases. The CFD model was experimentally validated using a water-cyclohexane system. The NETmix technology promotes high flow dynamics and large interfacial area generation between the two phases. The successive split and recombining of flow contribute to an intense fluid renewal around the two phases’ interface, enhancing the mass transfer rate. NETmix shows potential for multiphase applications, particularly between two immiscible liquid phases, with a four-fold increase of the interfacial area of immiscible fluids.