Characterization of the gas-liquid interfacial waves in vertical upward co-current annular flows

Computational and Experimental Methods in Multiphase and Complex Flow X

Berna

et al. 2019

A flow pattern, which appears in many industrial applications, is annular two-phase flow. Its main characteristic is that the main portion of the liquid mass is located at the walls of the tube forming an annulus, while the gas phase flows through the annulus core dragging small liquid drops. These drops are largely produced by the interactions of the gas-phase flowing through the gas core with the peaks of the disturbance waves, which are produced in the liquid/gas interface. This paper describes a set of experiments performed at the Vertical Annular Film Flow facility, in the annular flow regime, with upward liquid and gas flows, at different flow conditions varying the liquid surface tension by adding small amounts of 1-butanol to the water. The main property of 1-butanol is that small amounts of this substance significantly change the surface tension while the viscosity remains practically unchanged. The set of experiments were carried out inside a vertical tube 44 mm inner diameter, and 4.5 m high, the annular flow was created by means of a porous material with known porosity coefficient. The experimental conditions range from 2000 to 3500 l/min for the gas volumetric flow rate, and from 4 to 10 l/min for the liquid volumetric flow rate at atmospheric conditions. Several experiments have been carried out on 1-butanol varying the water surface tension from 72 10 Nm , to 45 10 Nm , at intermediate surface tensions. To measure the height of the disturbance waves and the thickness of the film we use a conductance probe -the electrical signal collected in the receiver sensor depends on the thickness of the liquid film layer. Correlations for the amplitude of the disturbance waves, the film base thickness and other physical magnitudes have been obtained with a good value for the coefficient of determination and the root mean square error.

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Section: Introductionmentioning

confidence: 94%

Experimental Study of the Interfacial Waves Produced in Upward Vertical Annular Flows When Varying the Liquid-Phase Surface Tension

Computational and Experimental Methods in Multiphase and Complex Flow X

Berna

et al. 2019

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“…Therefore, the test section receives an annular flow that develops through the pipe of the test component. Two differential pressure sensors, located in the upper part of the test section, measure the pressure drop of the annular flow at different points to know if the annular flow is fully developed or not (Cuadros et al 2019). In the upper part of the test section, it is also located the conductance probe that measures the film thickness evolution with time.…”

Section: The Vertical Annular Flow Facility (Vaff) Instrumentation Da...mentioning

confidence: 99%

“…Because, according to Darcy formula (Cuadros et al 2019), the volumetric flow rate depends on the pressure difference between the inner and outer sides of the porous sintered material, then the local pressure measurements are made at two different points, one in the water injection tank and the other one near the inner side of the porous sintered pipe, see figure 1 for more details. These local measurements are performed with Burkert 8314 relative pressure transducers (difference in pressure between the inner part of the facility and the surrounding atmosphere).…”

Section: Main Facility Instrumentationmentioning

confidence: 99%

Experimental study of the effects produced by the changes of the liquid and gas superficial velocities and the surface tension on the interfacial waves and the film thickness in annular concurrent upward vertical flows

Experimental Thermal and Fluid Science

Cuadros

et al. 2021

“…The most important element to accomplish the measurements in the GEPELON facility is the conductance probes represented in Fig. 2(a) and detailed in Muñoz-Cobo et al [6] and Cuadros et al [7]. These devices take advantage of the conductive properties of water to detect the film thickness near the wall.…”

Section: Liquid Sensormentioning

confidence: 99%

Study of Liquid Film Behaviour in Vertical Downward Air–water Annular Flow

WIT Transactions on Engineering Sciences

Berna

et al. 2020