New Heat Transfer Data for Two-Phase, Gas-Liquid Flows under Microgravity Conditions

1995 ◽  
pp. 521-528 ◽  
Author(s):  
R.W. Rite ◽  
K. Rezkallah
Keyword(s):  
Heat Transfer ◽  
Two Phase ◽  
Transfer Data ◽  
Microgravity Conditions ◽  
Liquid Flows

Two-Phase Convective Heat Transfer in Miniature Pipes Under Normal and Microgravity Conditions

2008 ◽  
Vol 130 (7) ◽  
Author(s):  
Chidambaram Narayanan ◽  
Djamel Lakehal
Keyword(s):  
Heat Transfer ◽  
Pure Water ◽  
Small Diameter ◽  
Transfer Model ◽  
Mean Flow ◽  
Two Phase ◽  
Nusselt Numbers ◽  
Nusselt Number Distribution ◽  
Microgravity Conditions ◽  
Flow Heat

Detailed numerical simulations have been performed to study the effect of flow orientation with respect to gravity on two-phase flow heat transfer (without phase change) in small diameter pipes. The Nusselt number distribution shows that the bubbly, slug, and slug-train regimes transport as much as three to four times more heat from the tube wall to the bulk flow than pure water flow. The flow blockage effect of the inclusions results in a circulating liquid flow superimposed on the mean flow. For upflow, the breakup into bubbles/slugs occurs earlier and at a higher frequency. The average Nusselt numbers are not significantly affected by the flow orientation with respect to gravity. A mechanistic heat transfer model based on frequency and length scale of inclusions is also presented.

Two-Phase Heat Transfer for Flow in Tubes and Over Rod Bundles With Blockages

1984 ◽  
Vol 106 (4) ◽  
pp. 856-864 ◽  
Author(s):  
M. I. Drucker ◽  
V. K. Dhir ◽  
R. B. Duffey
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Transfer Coefficient ◽  
Rod Bundles ◽  
Two Phase ◽  
Number Range ◽  
Transfer Data ◽  
Void Fractions ◽  
Two Phase Heat Transfer ◽  
The Heat Transfer Coefficient

A study of single- and two-component, two-phase heat transfer mechanisms for vertical flow inside of tubes and over rod bundles with blockages has been made. Existing heat transfer data for air–water flow in tubes with a liquid Reynolds number range of 2000 to 150,000 and void fractions up to 0.40 have been correlated as a function of αGr/Re2. The correlation has also been found to compare well with limited high Prandtl number data obtained with liquids other than water and for flow over rod bundles when an empirical constant is modified. Correlations have also been developed for the heat transfer coefficient in the vicinity of flow blockages in rod bundles. The heat transfer data have been obtained on a four rod bundle with sleeve-type blockages for a Reynolds number range of 230 to 6900 and void fractions up to 0.15. Significant enhancement of the heat transfer coefficient has been observed downstream of the blockages.

A Mechanistic Heat Transfer Correlation for Non-Boiling Two-Phase Flow in Horizontal, Inclined and Vertical Pipes

2011 ◽  
Author(s):  
Clement C. Tang ◽  
Afshin J. Ghajar
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Two Phase Flow ◽  
Mechanistic Model ◽  
Local Heat Transfer ◽  
Phase Flow ◽  
Heat Transfer Correlation ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Transfer Data

A mechanistic heat transfer correlation is proposed to estimate heat transfer coefficient for non-boiling two-phase flow in horizontal, slightly inclined, and vertical pipes using the analogy between friction factor and heat transfer. Local heat transfer coefficients, pressure drops and flow parameters were measured for air-water flow in a 27.9 mm stainless steel pipe. The heat transfer and pressure drop data were collected by carefully coordinating the gas and liquid superficial Reynolds numbers. The proposed mechanistic correlation is validated by using experimentally measured heat transfer data. Evaluation of the mechanistic correlation with the measured heat transfer data indicated that the analogy between friction factor and heat transfer can be used with reasonable accuracy for heat transfer predictions in non-boiling two-phase pipe flow. Comparison with experimental results showed that the bulk of the data points were predicted within ±30% by the mechanistic model.

Estimation of Two-Phase Flow Heat Transfer in Pipes

1999 ◽  
Vol 121 (2) ◽  
pp. 75-80 ◽  
Author(s):  
R. D. Kaminsky
Keyword(s):  
Heat Transfer ◽  
Two Phase Flow ◽  
Small Diameter ◽  
Estimation Methods ◽  
Prediction Methods ◽  
Phase Flow ◽  
Liquid Holdup ◽  
Two Phase ◽  
Flow Models ◽  
Liquid Flows

Heat transfer can be of importance in the design of multiphase petroleum flowlines. However, heat transfer data for gas-liquid flows are available only for small-diameter pipes at low pressures. Moreover, existing prediction methods are largely not suited to petroleum pipeline conditions due to implicit use of simplistic two-phase flow models. In this work heat transfer estimation methods are derived for nonboiling gas-liquid flow in pipes of high Prandtl number liquids, such as crude oil. The methods are readily evaluated for engineering applications and are applicable to all flow regimes, except those with low liquid holdup. Comparison is made with literature data. Accuracies of ±33 percent are obtained in general. The methods explicitly couple with arbitrary prediction methods for two-phase flow pressure drop and liquid holdup. This explicit coupling makes plausible the hypothesis that predictions will be robust at conditions well beyond the range of the existing experimental data.

Heat Transfer Measurements and Correlations for Air-Water Two-Phase Slug Flow in a Horizontal Pipe

Volume 3 ◽  
2004 ◽  
Author(s):  
Afshin J. Ghajar ◽  
Kapil Malhotra ◽  
Jae-Yong Kim ◽  
Steve A. Trimble
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Slug Flow ◽  
Reynolds Numbers ◽  
Mean Deviation ◽  
Heat Transfer Correlation ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Transfer Data ◽  
Heat Transfer Coefficients

Local heat transfer coefficients and flow parameters were measured for air-water slug flow in a horizontal 25.4 mm stainless steel schedule 10S pipe with a length to diameter ratio of 100. For this systematic study, a total of 83 data points were taken by carefully coordinating the liquid and gas superficial Reynolds number combinations. The heat transfer data were measured under a uniform wall heat flux boundary condition ranging from about 3800 to 16000 W/m2. The superficial Reynolds numbers ranged from about 3160 to 30290 for water and from about 1480 to 5840 for air. Comparison of heat transfer data for slug flow revealed that the heat transfer results were significantly dependent on the liquid and gas superficial Reynolds numbers. Overall, the experimental heat transfer data showed that the liquid phase dominated the heat transfer. However, it was found that the heat transfer data having a fixed liquid superficial Reynolds number showed that the heat transfer coefficients decreased as the gas superficial Reynolds number increased. A general heat transfer correlation for two-phase gas-liquid flow was fitted to our experimental horizontal slug flow heat transfer data with a mean deviation of −2.77% and an RMS deviation of 9.92%. Furthermore, a simplified heat transfer correlation for slug flow was developed based on the trends of heat transfer coefficient over the superficial liquid and gas Reynolds numbers. The proposed correlation predicted the experimental data with a mean deviation of −1.44% and an RMS deviation of 5.15%.

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

2007 ◽  
Author(s):  
Clement C. Tang ◽  
Afshin J. Ghajar
Keyword(s):  
Heat Transfer ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Heat Transfer Correlation ◽  
Two Phase ◽  
Transfer Data ◽  
Inclination Angles ◽  
Data Points

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.

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