Pr. Jalil OUAZZANI

CEO of ArcoFluid and ArcoFluid Consulting LLC, Florida, USA.

Motivated by recent ground-based and microgravity experiments investigating the interfacial dynamics of a volatile liquid (FC-72, Pr = 12.34) contained in a heated cylindrical cell, we numerically study the thermocapillary-driven flow in such an evaporating liquid layer. Particular attention is given to the prediction of the transition of the axisymmetric flow to fully three-dimensional patterns when the applied temperature increases. The numerical simulations rely on an improved one-sided model of evaporation by including heat and mass transfer through the gas phase via the heat transfer Biot number and the evaporative Biot number. We present the axisymmetric flow characteristics, show the variation of the transition points with these Biot numbers, and more importantly elucidate the two fold role of the latent heat of evaporation in the stability; evaporation not only destabilizes the flow but also stabilizes it, depending upon the place where the evaporation-induced thermal gradients come into play. We also show that buoyancy in the liquid layer has a stabilizing effect, though its effect is insignificant. The present work helps to gain a better understanding of the role of a phase change in the thermocapillary instability of an evaporating liquid layer.

Pr. Jalil OUAZZANI : CEO of ArcoFluid and ArcoFluid Consulting LLC since 1992. Ouazzani got his PHD on Numerical methods for Fluid Mechanics in 1984 at University of Nice and he got his HDR in CFD (Habilitation à Diriger les recherches) at Aix-Marseille University in 1991. He has spent 6 years in Salt Lake City (Utah) and in Huntsville (Alabama) at the CMMR (Center for Microgravity and Materials Research, University of Alabama in Huntsville) as a research scientist where he performed CFD modeling in the field of microgravity and crystal growth from melt (Bridgman, Czochralski processes) and from vapor (PVT, CVD) from 1985 to 1991. In 1992, he started ArcoFluid in Bordeaux (France) and in 2012 ArcoFluid Consulting in Orlando (USA), a consultancy and software company specializing in computer simulation of fluid-flow and heat-transfer He worked in several fields of CFD (fire in tunnels, multiphase flows, atmospheric dispersion, supercritical fluids, multiphase flows). The current research topics is dew harvesting and on VOF methods for Drops Evaporation / Condensation.