Brown high viscosity liquids examples manual#

Mao and Dukler explained that in a situation whereby the liquid is flowing, the rise velocity of a Taylor bubble must depend on the velocity of the liquid flowing upstream as well as the rise due to buoyancy. A number of parameters affect the rise velocity of Taylor bubbles through a stagnant liquid such parameters include density of liquid, surface tension of liquid, liquid viscosity, acceleration due to gravity, diameter of bubbles etc. The rise velocity of a single isolated Taylor bubble is dependent on inertia and drag forces. and Mandal and Das described the Taylor bubble length to exceed 1.5 times of the tube diameter or its diameter is greater than 60% of the tube diameter. The Taylor bubble is surrounded by a thin film of liquid, and below, it is the liquid slugs, which are agglomerate of small bubbles. Slug flow is characterized by Taylor bubbles, which has large pockets of bullet shaped bubbles occupying almost the entire cross-section of the column. It was concluded that the rise velocity of Taylor bubbles decreases with an increase in liquid viscosity and, on the other hand, increases with an increase in superficial gas velocity. Hence, the drag force increases as viscosity increases (5 < 100 < 1000 < 5000 mPa s), leading to a decrease in the rise velocity of Taylor bubbles. A dominant effect of viscous and gravitational forces over inertia forces was obtained, which showed an agreement with Stokes law, where drag force is directly proportional to viscosity.

It was found that the Froude number decreases with an increase in viscosity with a variation in flow as superficial gas velocity increases with reduction in rise velocity. Fluid flow analysis was carried out using slug Reynolds number, Froude number and inverse dimensionless viscosity, which are important dimensionless parameters influencing the rise velocity of Taylor bubbles in different liquid viscosities, with the parameters being functions of the fluid properties and column diameter. The inertia, viscous and gravitational forces were identified as forces, which could influence the rise velocity.

Brown high viscosity liquids examples manual#

This was subsequently compared with the rise velocity obtained from the high-speed camera, manual time series analysis and likewise empirical models. The rise velocity of Taylor bubbles in small diameter bubble column was measured via cross-correlation between two planes of time-averaged void fraction data obtained from the electrical capacitance tomography (ECT).