Experimental and Numerical Investigation of Stratified Gas–Liquid Flow in Downward-Inclined Pipes

Faccini, José Luiz Horacio; Filho, Jurandyr S. Cunha; Sampaio, Paulo Augusto Berquó de; Su, Jian

doi:10.1080/01457632.2015.972729

Cited by 2 publications

(1 citation statement)

References 21 publications

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“…Faccini et al 19 performed an experimental and numerical analysis of stratified gas‐liquid two‐phase flow in downward‐inclined circular pipes. Experiments were conducted for three different downward‐inclined angles of a circular pipe in an air‐water two‐phase flow loop.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of effective parameters of falling film evaporation in a vertical‐tube evaporator

Haghsheno

Kouhikamali

2020

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Wastewater treatment is one of the most effective solutions to manage the problem of water scarcity. Falling film evaporators are excellent technology in wastewater treatment plants. These wastewater evaporators provide high heat transfer, short residence time in the heating zone, and high‐purity distilled water. In the present study, the mechanism of turbulent falling film evaporation in a vertical tube has been investigated. A model has been developed for symmetrical two‐dimensional pure and saline water flow in a vertical tube under constant wall heat flux. The numerical simulation has been carried out by a commercial computational fluid dynamics code. The evaporation of saturated liquid film is simulated utilizing a two‐phase volume of fluid method and Tanasawa phase‐change model. The main objective of this study is to evaluate the effects of water salinity, liquid Reynolds number, wall heat flux, and liquid film thickness on the two‐phase heat transfer coefficient and vapor volume fraction. The numerical heat transfer coefficients are compared with the obtained results by Chen's empirical correlation. With a MAPE ≤ 11%, this study proves that the numerical method is highly effective at predicting the heat transfer coefficient. Moreover, the empirical coefficient of the Tanasawa model and the minimum thickness of the falling film are determined.

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Section: Introductionmentioning

confidence: 99%

Numerical investigation of effective parameters of falling film evaporation in a vertical‐tube evaporator

Haghsheno

Kouhikamali

2020

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Comparison of 63 different void fraction correlations for different flow patterns, pipe inclinations, and liquid viscosities

et al. 2020

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Gas-liquid two-phase flow is commonly encountered in the oil industry, especially in transport pipelines. Thus, the correct prediction of operational parameters such as void fraction or pressure drop is necessary for the development of efficient processes and facility design. Nowadays, there are different studies focused on predicting the void fraction parameter with empirical correlations. This study was aimed at analyzing and comparing 63 different void fraction correlations in order to determine if there was a unique correlation capable of accurately predicting the void fraction for the different operational conditions of flow patterns, pipe inclinations, and liquid viscosity. For this reason, a database of 11,895 experimental points was used to compare the results against the different empirical correlations available in the literature and determine the best one using statistical analyses based on indicators, such as relative error, absolute average percent error, among others. It must be mentioned that the database was strictly filtered and divided depending on the flow pattern (i.e., slug, churn, bubbly, and annular), the different pipe inclinations (i.e., vertical, horizontal and inclined), and the liquid viscosities. The results showed that there was not a unique unified correlation to determine the void fraction accurately for the different operational conditions and fluid properties. However, the best correlations for each specific set of flow patterns, pipe inclinations, and intervals of liquid viscosities were determined according to the statistical indicators, the general assumptions of each correlation, and information reported in the literature. Moreover, it was possible to analyze and provide some recommendations for the patterns evaluated, taking into account that some specific cases require further study, as there was no correlation capable of providing reliable results for the prediction of void fraction. Keywords Empirical correlations • Flow pattern • Statistical indicators • Two-phase flow • Void fraction • Viscosity List of symbols D Pipe diameter (m) L Pipe length (m) Viscosity (Pa s) Density (kg/m 3) Void fraction (-) E 1 Average percent error (%) E 2 Absolute average percent error (%) E 3 Percent standard deviation (%) E 4 Average error (-) E 5 Absolute average error (-) E 6 Standard deviation (-) R 2 Determination coefficient (-) g Gravity acceleration (m/s 2) Inclination angle (°) u sG Gas superficial velocity (m/s)

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Experimental and Numerical Investigation of Stratified Gas–Liquid Flow in Downward-Inclined Pipes

Cited by 2 publications

References 21 publications

Numerical investigation of effective parameters of falling film evaporation in a vertical‐tube evaporator

Numerical investigation of effective parameters of falling film evaporation in a vertical‐tube evaporator

Comparison of 63 different void fraction correlations for different flow patterns, pipe inclinations, and liquid viscosities

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