Modeling of Slug Velocity and Pressure Drop in Gas‐Liquid‐Liquid Slug Flow

Abstract

Gas‐liquid‐liquid slug flow in a capillary reactor is a promising new concept that allows one to incorporate gas‐liquid reaction, liquid‐liquid extraction, and facile catalyst separation in a single unit. In order to assess the performance of a gas‐liquid‐liquid slug flow reactor, it is necessary to predict the slug velocity and pressure drop to ascertain residence times and reaction rates. New empirical models for velocity and pressure drop were developed based on existing models for two‐phase gas‐liquid and liquid‐liquid slug flows, and these were validated experimentally.

Numerical and experimental studies of gas–liquid flow and pressure drop in multiphase pump valves

“…The direct reason is that the gas-liquid two-phase density and viscosity decrease obviously with the increase of the gas content. Similar to the pressure characteristics of the conventional pipelines and local fittings, 26,27 the pressure drops of the three valves increase quadratically with the increase of the inlet flow rate; that is, the sudden throttling of the narrow valve clearance and the irregular flow path of the main cavity result in a large amount of the energy loss of the twophase flow, which is more obvious as the initial flow velocity increases. The two-phase pressure drop decreases approximately exponentially during the opening process of the valves.…”

Coaxial Flow Contactors as Alternative to Double T‐Contactors for Triphasic Slug Flow Generation

“…This allows calculating the slug length of a given system in a predictive manner. This is an important feature and allows the predictive calcu-lation of the triphasic pressure drop and slug velocity [6,13]. When the disperse phase ratio is not equal to one, slug cutting can occur.…”

“…The order of slugs in the triphasic flow is determined by the slug velocities of both disperse phases. The faster phase closes up to the slower phase in the first millimeters after the second contactor and the formed double slug has the velocity of the slower disperse phase [13]. Therefore, if the first phase is cleaved the newly formed slugs stay separated.…”

Photoelectric Sensor for Fast and Low-Priced Determination of Bi- and Triphasic Segmented Slug Flow Parameters

“…Microcapillary reactors with segmented slug flow exhibit excellent behavior in such multiphase systems. Segmented slug flow has been extensively studied in circular capillaries (≤1 mm inner diameter) [2][3][4][5][6][7][8]. Each phase involved forms a regular, stable segment within a uniform alternating sequence, where a bubble is defined as a droplet and a slug as the continuous phase between two bubbles, both with an axial length greater than its diameter.…”

“…The approach of using double transmissive sensors as a sensor system for slug flows appears to be one of the most effective and economical ways to detect slug-flow characteristics. In light of recent research on three-phase slug flows, the sensor system is extended from two-phase to encompass three-phase flows in this work [2,4,27]. In this context, the influence of capillary position relative to the photodetector is also examined, since an improvement in the discrimination between the individual phases is expected as a function of the light refraction.…”