Validation of a General Heat Transfer Correlation for Non-Boiling Two-Phase Flow With Different Flow Patterns and Pipe Inclination Angles

Abstract

A general heat transfer correlation for non-boiling gas-liquid two-phase flow with different flow patterns and inclination angles was developed. To verify the correlation, local heat transfer coefficients and flow parameters were measured for air-water flow in a pipe for the horizontal and slightly upward inclined (2°, 5°, and 7°) positions, and all the flow patterns in the entire flow map. The test section was a 27.9 mm stainless steel pipe with a length to diameter ratio of 95. A total of 763 data points were collected for horizontal and slightly upward inclined positions by carefully coordinating the liquid and gas superficial Reynolds number combinations. The heat transfer data were collected under a uniform wall heat flux boundary condition ranging from about 1800 to 10900 W/m2. The superficial Reynolds numbers ranged from about 740 to 26000 for water and from about 560 to 48000 for air. The general heat transfer correlation was validated with the 763 data points that were experimentally collected. The validation confirmed the robustness of the general two-phase heat transfer correlation to adequately predict heat transfer data for various flow patterns and inclination angles. The accuracy of the correlation to correlate the experimental data was further explored by applying various available void fraction correlations. The performance of the correlation when applied with the different void fraction correlations were compared and appropriate recommendations are made.

Experimental Investigation and Empirical Analysis of Non-Boiling Gas-Liquid Two Phase Heat Transfer in Vertical Downward Pipe Orientation

“…For annular flow regime, the proposed correlation gave the best performance by predicting 94.4% and 100% of the data points within ±20% and ±30% error bands, respectively. The next best performance was by Shah [16] followed by Tang and Ghajar [18]. These correlations predicted 86.1% and 77.8% of data points within ±20% error bands and 100% and 94.4% of data points within ±30% error bands, respectively.…”

“…The correlation of Knott et al [14] did not meet the satisfactory performance criterion for ±20% error bands but predicted 89.5% of data points within the relaxed criterion of ±30% error bands. In addition to these the correlations of Tang and Ghajar [18] and Shah [16] showed their potential to predict the two phase heat transfer data in vertical downward flow. Both of these correlations predicted more than 75% and 90% of the data points for relaxed performance criteria of ±30% and ±40%, respectively.…”

Recent Developments in Non-Boiling Two-Phase Flow Heat Transfer and Void Fraction in Various Pipe Inclinations

“…Tang and Ghajar (2007) showed that Eq. (16) has the robustness that it can be applied with different void fraction correlations.…”

“…(16) was validated with a total of 986 experimental data points for different flow patterns in horizontal and slightly inclined air-water two-phase pipe flows Kim and Ghajar, 2006;Tang and Ghajar, 2007). Equation (16), performed relatively well by predicting over 85% of the experimental data points to within ±30% for 0°, 2°, 5°, and 7°pipe orientations.…”

“…The two-phase heat transfer correlation, Eq. (16) was validated with a total of 763 experimental data points for different flow patterns and inclination angles Kim and Ghajar, 2006;Tang and Ghajar, 2007). Overall, the correlation, Eq.…”