Classification of configurations of two-phase vapor/liquid bubbles in an immiscible liquid in relation to direct-contact evaporation and condensation processes

An experimental setup was designed to study direct-contact evaporators using a liquid dispersed in another immiscible liquid. The study was carried out on an n-pentane–water system to determine the influence of different parameters on these systems, and consequently to construct a model for this type of evaporator. An optical probe was used to measure the local void fraction. At different column abscissas along a selected diameter, the local void fraction variations were determined. The shape of the curves can be attributed to the different processes occurring in the spray column. A one-dimensional heat transfer model in the spray column was established. Simplifying assumptions were used to establish and resolve the set of equations governing heat transfer and two-phase flow. The vaporization process induces a volumetric expansion of the two-phase mixture. A theoretical model was used, in which the coalescence between the spherical fluid particles is taken into account. Different coalescence laws dependent on particle density were introduced into the theoretical model and then tested. The numerical results are discussed and compared with the experimental data obtained for the n-pentane–water system.

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LIQUID EVAPORATION BY DIRECT CONTACT IN ANOTHER IMMISCIBLE LIQUID

Proceeding of International Heat Transfer Conference 8 ◽

10.1615/ihtc8.1060 ◽

1986 ◽

Author(s):

Lounes Tadrist ◽

Ibraheem Shehu Diso ◽

M. Larini ◽

J. Pantaloni

Keyword(s):

Direct Contact ◽

Immiscible Liquid ◽

Liquid Evaporation

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Classification of two phase flows using linear discriminant analysis and expectation maximization clustering of video footage

International Journal of Multiphase Flow ◽

10.1016/j.ijmultiphaseflow.2011.11.011 ◽

2012 ◽

Vol 40 ◽

pp. 106-112 ◽

Cited By ~ 7

Author(s):

B. Ameel ◽

K. De Kerpel ◽

H. Canière ◽

C. T’Joen ◽

H. Huisseune ◽

...

Keyword(s):

Discriminant Analysis ◽

Linear Discriminant Analysis ◽

Expectation Maximization ◽

Two Phase Flows ◽

Two Phase ◽

Linear Discriminant ◽

Video Footage

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Thermodynamics and Machine Learning Based Approaches for Vapor–Liquid–Liquid Phase Equilibria in n-Octane/Water, as a Naphtha–Water Surrogate in Water Blends

Processes ◽

10.3390/pr9030413 ◽

2021 ◽

Vol 9 (3) ◽

pp. 413

Author(s):

Sandra Lopez-Zamora ◽

Jeonghoon Kong ◽

Salvador Escobedo ◽

Hugo de Lasa

Keyword(s):

Machine Learning ◽

Liquid Phase ◽

Phase Equilibria ◽

Aspen Plus ◽

Phase Region ◽

Two Phase ◽

Technical Literature ◽

Phase Liquid ◽

Liquid Vapor ◽

Vapor Liquid

The prediction of phase equilibria for hydrocarbon/water blends in separators, is a subject of considerable importance for chemical processes. Despite its relevance, there are still pending questions. Among them, is the prediction of the correct number of phases. While a stability analysis using the Gibbs Free Energy of mixing and the NRTL model, provide a good understanding with calculation issues, when using HYSYS V9 and Aspen Plus V9 software, this shows that significant phase equilibrium uncertainties still exist. To clarify these matters, n-octane and water blends, are good surrogates of naphtha/water mixtures. Runs were developed in a CREC vapor–liquid (VL_ Cell operated with octane–water mixtures under dynamic conditions and used to establish the two-phase (liquid–vapor) and three phase (liquid–liquid–vapor) domains. Results obtained demonstrate that the two phase region (full solubility in the liquid phase) of n-octane in water at 100 °C is in the 10-4 mol fraction range, and it is larger than the 10-5 mol fraction predicted by Aspen Plus and the 10-7 mol fraction reported in the technical literature. Furthermore, and to provide an effective and accurate method for predicting the number of phases, a machine learning (ML) technique was implemented and successfully demonstrated, in the present study.

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A Physically Based, One-Dimensional Two-Fluid Model for Direct Contact Condensation of Steam Jets Submerged in Subcooled Water

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4029417 ◽

2015 ◽

Vol 1 (2) ◽

Cited By ~ 6

Author(s):

David Heinze ◽

Thomas Schulenberg ◽

Lars Behnke

Keyword(s):

Direct Contact ◽

Two Phase Flow ◽

Fluid Model ◽

Interfacial Area ◽

Phase Flow ◽

Two Phase ◽

One Dimensional ◽

Two Fluid Model ◽

Contact Condensation ◽

Two Fluid

A simulation model for the direct contact condensation of steam in subcooled water is presented that allows determination of major parameters of the process, such as the jet penetration length. Entrainment of water by the steam jet is modeled based on the Kelvin–Helmholtz and Rayleigh–Taylor instability theories. Primary atomization due to acceleration of interfacial waves and secondary atomization due to aerodynamic forces account for the initial size of entrained droplets. The resulting steam-water two-phase flow is simulated based on a one-dimensional two-fluid model. An interfacial area transport equation is used to track changes of the interfacial area density due to droplet entrainment and steam condensation. Interfacial heat and mass transfer rates during condensation are calculated using the two-resistance model. The resulting two-phase flow equations constitute a system of ordinary differential equations, which is solved by means of the explicit Runge–Kutta–Fehlberg algorithm. The simulation results are in good qualitative agreement with published experimental data over a wide range of pool temperatures and mass flow rates.

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Experiment and Numerical Simulation of Bubble Behaviors in Argon Gas Injection Into Lead-Bismuth Pool

Volume 2: Thermal Hydraulics ◽

10.1115/icone14-89431 ◽

2006 ◽

Author(s):

Yumi Yamada ◽

Toyou Akashi ◽

Minoru Takahashi

Keyword(s):

Direct Contact ◽

Two Phase Flow ◽

Experimental Result ◽

Feed Water ◽

Force Model ◽

Phase Flow ◽

Two Dimensional ◽

Two Phase ◽

Argon Gas ◽

Bubble Rising

In a lead-bismuth alloy (45%Pb-55%Bi) cooled direct contact boiling water fast reactor (PBWFR), steam can be produced by direct contact of feed water with primary Pb-Bi coolant in the upper core plenum, and Pb-Bi coolant can be circulated by buoyancy forces of steam bubbles. As a basic study to investigate the two-phase flow characteristics in the chimneys of PBWFR, a two-dimensional two-phase flow was simulated by injecting argon gas into Pb-Bi pool in a rectangular vessel (400mm in length, 1500mm in height, 50mm in width), and bubble behaviors were investigated experimentally. Bubble sizes, bubble rising velocities and void fractions were measured using void probes. Argon gas was injected through five nozzles of 4mm in diameter into Pb-Bi at two locations. The experimental conditions are the pressure of atmospheric pressure, Pb-Bi temperatures of 443K, and the flow rate of injection Ar gas is 10, 20, and 30 NL/min. The measured bubble rising velocities were distributed in the range from 1 to 3 m/s. The average velocity was about 0.6 m/s. The measured bubble chord lengths were distributed from 1mm up to 30mm. The average chord length was about 7mm. An analysis was performed by two-dimensional and two-fluid model. The experimental results were compared with the analytical results to evaluate the validity of the analytical model. Although large diameter bubbles were observed in the experiment, the drag force model for spherical bubbles performed better for simulation of the experimental result because of high surface tension force of Pb-Bi.

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