A general heat transfer correlation for non-boiling gas-liquid flow with different flow patterns in horizontal pipes

Local heat transfer coefficients and flow parameters were measured for air-water flow in a pipe in the horizontal and slightly upward inclined (2°, 5°, and 7°) positions. The test section was a 27.9 mm stainless steel pipe with a length to diameter ratio of 100. For this systematic experimental study, a total of 758 data points were taken for horizontal and slightly upward inclined (2°, 5°, and 7°) positions by carefully coordinating the liquid and gas superficial Reynolds number combinations. These superficial Reynolds numbers were duplicated for each inclination angle. The heat transfer data points were collected under a uniform wall heat flux boundary condition ranging from about 1,800–10,900 W/m2. The superficial Reynolds numbers ranged from about 740 to 26,000 for water and about 560 to 48,000 for air. A comparison of heat transfer data and flow visualization revealed that the heat transfer results were significantly dependent on the superficial liquid and gas Reynolds numbers, inclination angle, and...

Heat Transfer Measurements, Flow Pattern Maps, and Flow Visualization for Non-Boiling Two-Phase Flow in Horizontal and Slightly Inclined Pipe

In this study a robust two-phase nonboiling heat transfer correlation for turbulent flow (Re SL > 4000) in vertical tubes with different fluid flow patterns and fluid combinations was developed using experimental data available from the literature. The correlation presented herein originates from a careful analysis of the major nondimensional parameters affecting two-phase heat transfer. This model takes into account the appropriate contributions of both the liquid and gas phases, using the respective cross-sectional areas occupied by the two phases. A total of 255 data points from three available studies (which included the four sets of data) were used to determine the curve-fitted constants in the improved correlation. The performance of the new correlation was compared with two-phase correlations from the literature, which were developed for specific fluid combinations

Robust Heat Transfer Correlation for Turbulent Gas-Liquid Flow in Vertical Pipes

In this tutorial the fundamentals of non-boiling heat transfer in two-phase two-component gas-liquid flow in pipes are presented. The techniques used for the determination of the different gas-liquid flow patterns (flow regimes) in vertical, horizontal, and inclined pipes are reviewed. The validity and limitations of the numerous heat transfer correlations that have been published in the literature over the past 50 years are discussed. The extensive results of the recent developments in the non-boiling two-phase heat transfer in air-water flow in horizontal and inclined pipes conducted at Oklahoma State University's Heat Transfer Laboratory are presented. Practical heat transfer correlations for a variety of gas-liquid flow patterns and pipe inclination angles are recommended.

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Non-boiling heat transfer in gas-liquid flow in pipes: a tutorial

Heat transfer measurements and correlations for air–water flow of different flow patterns in a horizontal pipe

In this study, the validity of 20 nonboiling heat transfer correlations obtained from a comprehensive literature review are assessed. These correlations were tested against seven extensive sets of two-phase flow experimental data available from the literature, for vertical and horizontal tubes and different flow patterns and fluids. A total of 524 data points from five available experimental studies (which included the seven sets of data) were used for these comparisons. Based on the tabulated and graphical results of the comparisons with and without considering author-specified ranges of applicability, appropriate correlations for different flow patterns and tube orientations are recommended.

Venkata K. Ryali

Papers

Comparison of 20 two-phase heat transfer correlations with seven sets of experimental data, including flow pattern and tube inclination effects