Janghoon Han, Taesuk Hong, Byoungjae Kim, Youngjoong Ko, Jungyun Seo. Proceedings of the 2021 Conference North American Chapter Association for Computational Linguistics: Human Language Technologies. 2021.

Offshore nuclear power plants are characterized by a potential oscillatory motion depending on ocean waves. Investigating the local flow behavior in system undergoing oscillating is necessary. In particular, because void fraction near heating element surface significantly affects nucleating boiling heat transfer and critical flux, understanding dynamic of very important. Therefore, this study, as an essential first step predicting departure from nucleate offshore reactors, air–water bubbly...

Micro particle image velocimetry (PIV) characterization of two-fluid flow in a microchannel was analysed focusing on the effect differences refractive indices two fluids accuracy PIV data. In present study, we first objective-imaging system used for measurement, and then derived precondition measurement valid velocity profile across interface. A micro experimental set up to measure inside Y-shaped microchannel. Using this system, glycerol–water mixtures with different glycerol mass...

A two-fluid model is widely employed to predict gas–liquid two-phase flows. Conventional equations, derived by assuming that all phases are interpenetrating continua, occasionally yield impractical results. For example, the bubble velocity predicted be higher than water for a horizontal fully developed bubbly flow. One solution this irrational result momentum equations based on motion of fluid particles. This study revisits particle-motion-based equations. Previously, it was validated only...

Film boiling on a horizontal surface is typical example of the Rayleigh-Taylor instability. During film boiling, phase changes take place at interface, and thus heat mass transfer must be taken into consideration in stability analysis. Moreover, since vapor layer not quite thick, viscous flow analyzed. Existing studies assumed equal kinematic viscosities two fluids, and/or considered thin fluids. The purpose this study to derive analytical dispersion relation instability for more general...

When fluid particles such as bubbles and droplets are not in contact with the wall, one probably neglects wall drag term one-dimensional momentum equation for dispersed phase. This treatment however leads to an unphysical prediction of motion In framework conventional two-fluid model, how apply phase is disputable. The interface force acting on a particle results from interaction between surrounding continuous fluid. To clarify contributions forces phase, volume-averaged equations formulated...

The spacer grids within a fuel assembly of nuclear reactor core disrupt and re-establish the momentum thermal boundary layers so that they enhance local heat transfer downstream grids. An experimental study in 6×6 rod bundle has been performed to investigate effects on single-phase convective enhancement. data showed Reynolds number significant impact enhancement only when numbers are lower than about 10,000. conventional correlations poor predictions by at low numbers; particular, maximum...

We investigate the flow physics of non-equilibrium gases in interaction with solid particles a microscale shock tube and collection efficiency jet impingement on permeable surface. One interesting application flows tubes at low pressures or micro-shock is needle-free injection technology where drug are delivered by waves. To such problems, new two-fluid model system coupled second-order Boltzmann–Curtiss-based constitutive relationships for modeling gas was developed. were specifically...

This study involved a numerical investigation of the homogeneous nucleation CO2 from CO2–Ar gas mixture in supersonic nozzle with throat size 2.11 mm, total pressure 61.15 kPa, and temperature 293.15 K. The flow conditions covered cryogenic range (∼75 K). Therefore, surface tension clusters was calculated using Tolman–Tanaka correction, growth evaluated considering both free molecular continuum regimes. Numerical simulations were conducted for wide mole fractions (3%–39%). In particular,...

This study proposes ideas for simultaneous mixing and pumping using asymmetric microelectrode arrays. The driving force of the was based on electroosmotic flows induced by alternating current (ac) electric fields microelectrodes. key idea to bend/incline microelectrodes like diagonal/herringbone shapes. Four patterns electrode arrays were considered depending shape For diagonal shape, repeated staggered studied. herringbone diverging converging examined. These forced fluid in lateral...

Models for the rate of atomization and deposition droplets stratified annular flow in horizontal pipes are presented. The entrained fraction is result a balance between liquid layer that contact with air droplets. strongly affected by gravity pipes. gravitational settling influenced droplet size: heavier deposit more rapidly. Model calculation simulation results compared experimental data from various diameter Validation suggested models was performed comparing Safety Performance Analysis...

It had been disputed how to apply wall drag the dispersed phase in framework of conventional two-fluid model for two-phase flows. Recently, Kim et al. [1] introduced volume-averaged momentum equation based on a solid/fluid particle motion. They showed theoretically that flows, overall pressure drop by friction must be apportioned each phase, proportion fraction. In this study, validity proposed is demonstrated though one-dimensional (1D) simulations. addition, it shown existing form loss...

Lately, ocean nuclear power plants have attracted attention as one of diverse uses plants. Because are movable or transportable, it is necessary to analyze the thermal hydraulics in a moving frame reference, and computer codes been developed predict large systems. The purpose this study incorporate three dimensional dynamic motion model into SPACE code (Safety Performance Analysis CodE) so that able an plant. A rotation system describes three-dimensional rotations about arbitrary axis was...