Photographic observations of the boiling phenomena have played an important role in gaining insight into the boiling mechanism. This paper presents a brief historical review of the available literature on the photographic studies in pool and flow boiling. This is followed by the results of the photographic studies conducted in the author’s laboratory on liquid droplets impinging on a heated sur...

Film boiling on a horizontal elliptical tube immersed in external flowing nitrogen liquid is investigated in the present paper. The isothermal wall temperature is high enough to induce turbulent film boiling, and then a continuous vapor film runs upward over the surface. The high velocity of the flowing saturated liquid at the boundary layer is determined by potential flow theory. In addition, ...

A versatile continuous-flow synthesis of highly functionalized 1,2,4-oxadiazoles starting from carboxylic acids is reported. This process was applied to the multistep synthesis of imidazo[1,2-a]pyridin-2-yl-1,2,4-oxadiazoles, using a three reactor, multistep continuous-flow system without isolation of intermediates. This continuous-flow method was successfully combined with a single-step liquid...

Population balance equations combined with a threedimensional two-fluid model are employed to predict bubbly flows with the presence of heat and mass transfer processes. Subcooled boiling flow belongs to this specific category of bubbly flows is considered. The MUSIG (MUltiple-SIze-Group) model implemented in CFX4.4 is further developed to account for the wall nucleation and condensation in the...

Flow boiling heat transfer in parallel minichannels and microchannels is one of the solutions proposed for cooling high heat flux systems. The associated increase in the pressure drop poses a problem that needs to be studied in detail before the small diameter channels can be implemented in practical systems. The pressure drop fluctuations and the flow instability in a network of parallel chann...

Flow boiling of the perfluorinated dielectric fluid FC-77 in a silicon microchannel heat sink is investigated. The heat sink contains 60 parallel microchannels each of 100 m width and 389 m depth. Twenty-five evenly distributed temperature sensors in the substrate yield local heat transfer coefficients. The pressure drop across the channels is also measured. Experiments are conducted at five ...