An assessment of pressure drop and void fraction correlations with data from two-phase natural circulation loops

Vijayan, P.K.; Patil, Aniket; Pilkhwal, D. S.; Saha, Dilip; Raj, V. Venkat

doi:10.1007/s002310000108

Cited by 42 publications

(12 citation statements)

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“…In presenting the correlations, different categorizing criteria were sought into which the developed correlations might conveniently fall. Rather than going after physical parameters which most of the time are too narrow, we have followed the work of Vijayan et al (2000) to classify the correlations into four categories as shown in Table 1. These are:…”

Section: Correlationsmentioning

confidence: 99%

Comparison of void fraction correlations for different flow patterns in horizontal and upward inclined pipes

Woldesemayat

Ghajar

2007

International Journal of Multiphase Flow

419

229

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Section: Correlationsmentioning

confidence: 99%

Comparison of void fraction correlations for different flow patterns in horizontal and upward inclined pipes

Woldesemayat

Ghajar

2007

International Journal of Multiphase Flow

419

229

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“…In general, the correlations used in this study have been classified in four different categories: slip ratio, K H , drift flux, and general correlations, according to the work of Vijayan et al [7]. The categories and the equations of each correlation studied are depicted in Annex A.…”

Section: Correlationsmentioning

confidence: 99%

“…K H correlations are calculated by multiplying a constant or factor by the homogeneous void fraction H . Consequently, the slip ratio is considered equal to one, and this type of correlation is considered as a homogeneous model [7].…”

Section: Correlationsmentioning

confidence: 99%

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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“…In general, the void fraction correlations can be classified into four categories according to Vijayan et al [7] which are: a) slip ratio correlations in which the void fraction is calculated as a function of a constant term, mixture quality, gas and liquid densities, and gas and liquid viscosities, b) k·a H correlations in which the void fraction is calculated based on the homogeneous void fraction, a H , multiplied by a constant term that has either a fixed value or is a function of fluid flow parameters depending on the applied correlation, c) drift flux correlations in which the void fraction is calculated based on a distribution parameter and the drift velocity, and finally d) miscellaneous empirical correlations which does not meet the criteria to be classified into previous categories and they are empirical in nature.…”

Section: Void Fraction Correlationsmentioning

confidence: 99%

Assessment of Premoli et al. Correlation Predictions in Horizontal Stratified-Wavy Two-Phase Flow Encountered at Small Diameter T-Junction

Makrygiannis¹,

Margaris²

2020

International Journal of New Technology and Research

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An assessment of pressure drop and void fraction correlations with data from two-phase natural circulation loops

Cited by 42 publications

References 0 publications

Comparison of void fraction correlations for different flow patterns in horizontal and upward inclined pipes

Comparison of void fraction correlations for different flow patterns in horizontal and upward inclined pipes

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

Assessment of Premoli et al. Correlation Predictions in Horizontal Stratified-Wavy Two-Phase Flow Encountered at Small Diameter T-Junction

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