Channamallikarjun S. Mathpati

Effect of solute transfer and interfacial instabilities on scalar and velocity field around a drop rising in quiescent liquid channel

Physics of development of flow structures around the drop rising with solute transfer is highly influenced by the interfacial behaviour and is remarkably different than a particle rising under the same conditions. We report on the use of simultaneous particle image velocimetry-planar laser induced fluorescence technique to measure scalar and velocity fields around a drop rising in a quiescent liquid channel. The selected continuous phase is glycerol, and the drop consists of a mixture of toluene, acetone, and a dye rhodamine-6G, with acetone working as a interfacial tension depressant. The drop lies in the spherical region with Eotvos number, Eo = 1.95, Morton number, M = 78.20 and the particle Reynolds number being, Rep = 0.053. With Rep approaching that of creeping flow, we analyse the effect of interfacial instabilities solely, contrary to other investigations [M. Wegener et al., “Impact of Marangoni instabilities on the fluid dynamic behaviour of organic droplets,” Int. J. Heat Mass Transfer 52, 2543-...

High Temperature Corrosion Studies in Molten Salt Using Salt Purification and Alloy Coating

Abstract Molten salt FLiNaK (LiF–NaF–KF: 29–12–59 wt%) is a promising candidate as high temperature coolant for next generation nuclear reactor. Major technical challenge in implementation is the selection of structural material which can withstand corrosive nature of FLiNaK. Purification of FLiNaK salt was carried out by preheating and vacuum drying to remove moisture content. Moisture removed by preheating and vacuum drying was found as 28.81 wt% and 45.62 wt%, respectively. The corrosion resistance was found to increase by 51% due to salt purification. The effect of coating on the corrosion characteristics of different high temperature alloys in molten FLiNaK was also investigated. Ni coating acts as a protective barrier against the dissolution of Cr content of alloys into molten salts. Corrosion of various alloys such as Hastelloy-B, Inconel-625 and Hastelloy-X was studied in molten FLiNaK salt in static condition at 650°C in graphite crucibles for 60 hours under inert atmosphere. The surface morphology of the alloy samples was analysed by Scanning Electron Microscopy. Corrosion rate of Ni (10% P) coated Hastelloy-B was reduced in comparison with non-coated Hastelloy-B by 24%. The rate of corrosion was significantly reduced due to moisture removal and Ni coating.