introduction: there are several methods for evaluating microleakage in dentistry, for example dye or bacterial leakage, electro-chemical methods, radioisotope labeling and fluid filtration. the purpose of this study was to assemble the fluid filtration system for quantitative evaluation of microleakage in dental materials. materials and methods: the roots were connected to a tube filled with an...

In this paper, a CFD model of syngas flow in slurry bubble column was developed. The model is based on an Eulerian-Eulerian approach and includes three phases: slurry of solid particles suspended in paraffin oil and syngas bubbles. Numerical calculations carried out for catalyst particles, bubble coalescence and breakup included bubble-fluid drag force and interfacial area effects. Also, the ef...

Although CO2 injection is one of the most common methods in enhanced oil recovery, it could alter fluid properties of oil and cause some problems such as asphaltene precipitation. The maximum amount of asphaltene precipitation occurs near the fluid pressure and concentration saturation. According to the description of asphaltene deposition onset, the bubble point pressure has a very special imp...

if an air flow is injected into a liquid fluid, many ambulant air bubbles are formed inside the fluid. air bubbles move inside the liquid fluid because of the buoyancy force, and the mobility of these air bubbles makes sizable commixture and turbulence inside the fluid. this mechanism was employed to enhance the heat transfer rate of a horizontal double pipe heat exchanger in this paper. howeve...

Gas holdup and bubble size are important parameters for simulation and designing in bubble column reactors. Because based on these parameters, the available gas-liquid interfacial area is defined for mass transfer. In this paper, the results of applying magnetic fields on the velocity field and volume fraction of gas holdup are reported. Hydrodynamics of the bubble column in the reactors is inv...

Effect of interparticle force on the hydrodynamics of gas-solid fluidized beds was investigated using the combined method of computational fluid dynamics and discrete element method (CFD-DEM). The cohesive force between particles was considered to follow the van der Waals equation form. The model was validated by experimental results from literature in terms of bed voidage distribution and Eule...

in this paper, a cfd model of syngas flow in slurry bubble column was developed. the model is based on an eulerian-eulerian approach and includes three phases: slurry of solid particles suspended in paraffin oil and syngas bubbles. numerical calculations carried out for catalyst particles, bubble coalescence and breakup included bubble-fluid drag force and interfacial area effects. also, the ef...

bubble columns are gas- liquid contactors that are widely used in chemical and bio- chemical industries. high mixing that result in high heat and mass transfer rates are amongst their advantages. heat transfer in a bubble column having a bundle of heaters investigated and the variation of heat transfer coefficient with variation in heaters pitch to diameter ratios in a bundle of heaters reporte...

In this work, rising of a single bubble in a quiescent liquid under microgravity condition was simulated. The related unsteady incompressible full Navier-Stokes equations were solved using a conventional finite difference method with a structured staggered grid. The interface was tracked explicitly by connected marker points via hybrid front capturing and tracking method. One field approximatio...