Abstract
Though there are many other forms of multiphase flow and a wide range of flow geometries, this seminar focuses on two-phase gas-liquid upwards flow in vertical tubes. Even with this restriction, the field is a vast one and is possible only to deal with a few of the highlights. The seminar begins with a definition of flow regimes (bubble flow, slug flow, churn flow, annular flow and wispy annular flow). The following main topics are then addressed:
- The bubble flow to slug flow transition, with particular emphasis on void waves.
- Slug flow behaviour and in particular the variation of shear stress in slug flow.
- The slug flow to churn flow transition and the nature of churn flow and the components of pressure gradient in this regime.
- Annular flow and the calculation of critical heat flux.
- Heat transfer in annular flow and the significance of disturbance waves.
- A possible link between bubble nucleation and turbulence in disturbance waves.
Biography
Geoffrey F. Hewitt is Professor Emeritus of Chemical Engineering at Imperial College London. He graduated in chemical engineering at UMIST Manchester in 1954 and completed a PhD at UMIST in 1957 on flow in packed beds. He was formerly Head of the Thermal Hydraulics Division and founder of the Heat Transfer and Fluid Flow Service (HTFS) at the UKAEA Harwell Laboratory. He has authored and edited many books and has published over 500 papers and reports, mainly on gas-liquid flow and evaporative heat transfer. He was a Founding Editor of Multiphase Science and Technology and Executive Editor for the 2008 Edition of the Heat Exchanger Design Handbook. He is the recipient of the AIChE Donald Q. Kern Award, the ASME Max Jakob Award, the Nusselt Reynolds Prize, the Luikov Medal, the IChemE Council and Armstrong medals, the Global Energy Prize and the Senior Award of the ICMF. He has received Honorary Doctorates at Louvain, UMIST and Heriot Watt. He is a Fellow of the Royal Academy of Engineering, a Fellow of the Royal Society and a Foreign Associate of the US National Academy of Engineering.