An experimental study on gas behavior and effective flow area for liquid in horizontal two-phase flow

Chaebin Song; Seongeun Kim; Museop Kim; Siwan Lyu

doi:10.3741/JKWRA.2026.59.1.51

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2026 Vol.59, Issue 1 Preview Page Next Page

Research Article

An experimental study on gas behavior and effective flow area for liquid in horizontal two-phase flow 수평 이상류 내 기체 거동 및 액체 유효흐름단면에 대한 실험 연구

31 January 2026. pp. 51-64

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Abstract

A series of experiments has been conducted to analyze the void fraction and effective flow area of two-phase flow in a horizontal pipe. Experiments were performed in a 100 mm diameter horizontal pipe under plug and slug flow conditions. The velocity field was measured using Particle Image Velocimetry (PIV) and bubble behavior was analyzed using an image processing technique. The in-pipe distribution curve of void fraction was governed by the flow regime rather than the flowrate. For plug flow, a sharp change in the cross-sectional distribution curve of void fraction can be observed due to the accumulation of air in the upper part of a pipe. While the more even distribution of air across a relatively wider area, in slug flow, results in a gradual shape for void fraction distribution profile. The upper part, which shows high void fraction and low PIV valid vector ratio, coincides with the boundary where the difference between the time-averaged and instantaneous velocity fields appears. This boundary can be defined as the edge of the region occupied by gas, this implies that the change of effective flow area contributing to actual liquid conveyance depends on the flow pattern. The effective flow area differed by up to 20 % between plug and slug flows, showing a decrease in the effective liquid flow area depending on the flow pattern. These results suggest that air entrainment should be considered in the design and operation of large-diameter conduit systems to ensure stable hydraulic performance.

Keywords

Two-phase flow

Void fraction

Effective flow area

Image processing technique

Plug flow

Slug flow

정하였다. 실험은 내경 100 mm 수평관에서 플러그 및 슬러그 흐름 조건을 대상으로 수행되었으며 PIV 기법을 이용한 유속구조 실험과 영상분석기법을 적용한 기포거동 실험을 각각 수행하였다. 실험결과를 통해 흐름 내 기체점유율 분포는 유량 조건보다 흐름양상 특성에 지배되는 것을 확인하였다. 플러그 흐름에서는 기체가 관 상부에 집중되어 관 내 기체점유율 분포에서 급격한 변화를 보였으며 슬러그 흐름에서는 기체가 단면 전반으로 확산되며 상대적으로 완만한 분포를 관찰할 수 있었다. 기체점유율이 높은 상부 영역에서는 PIV 유효 벡터비가 감소하였으며 해당 구간이 시간평균 유속장과 순간 유속장 간 차이가 발생하는 경계로 작용함을 확인하였다. 이에 따라 해당 구간을 기체 점유 영역의 경계로 정의하여 흐름양상별 유효흐름단면을 산정하였다. 그 결과 플러그 흐름과 슬러그 흐름 간 유효흐름단면에는 최대 20 % 차이를 확인하였으며 이는 흐름양상에 따라 실제 액체수송에 기여하는 유효단면적의 변화가 발생할 수 있음을 의미한다. 이러한 결과는 이상류가 발생하는 대심도 터널과 같은 대구경 관로에서 흐름양상에 따라 실제 배수능력이 설계 성능에 미치지 못할 수 있음을 의미한다. 따라서 관로시스템 설계 및 운영 시 공기 혼입에 따른 유효흐름단면 감소와 그에 따른 통수능 변화를 고려할 필요가 있다.

키워드

이상류

기체점유율

유효흐름단면

영상분석기법

플러그 흐름

슬러그 흐름

References

Baker, O. (1954). “Simultaneous flow of oil and gas.” Oil and Gas Journal, Vol. 53, pp. 185-195.

Barnea, D., Luninski, Y., and Taitel, Y. (1983). “Flow pattern in horizontal and vertical two phase flow in small diameter pipes.” The Canadian Journal of Chemical Engineering, Vol. 61, No. 5, pp. 617-620. doi: 10.1002/cjce.5450610501.

10.1002/cjce.5450610501

Bottin, M., Berlandis, J. P., Hervieu, E., Lance, M., Marchand, M., Ozturk, O.C., and Serre, G. (2014). “Experimental investigation of a developing two-phase bubbly flow in horizontal pipe.” International Journal of Multiphase Flow, Vol. 60, pp. 161-179. doi: 10.1016/j.ijmultiphaseflow.2013.12.010.

10.1016/j.ijmultiphaseflow.2013.12.010

Dang, Z., Yang, Z., Yang, X., and Ishii, M. (2018). “Experimental study of vertical and horizontal two-phase pipe flow through double 90 degree elbows.” International Journal of Heat and Mass Transfer, Vol. 120, pp. 861-869. doi: 10.1016/j.ijheatmasstransfer.2017.11.089.

10.1016/j.ijheatmasstransfer.2017.11.089

Fagundes Netto, J.R., Fabre, J., and Péresson, L. (1999). “Shape of long bubbles in horizontal slug flow.” International Journal of Multiphase Flow, Vol. 25, pp. 1129-1160. doi: 10.1016/S0301-9322(99)00041-5.

10.1016/S0301-9322(99)00041-5

Hadzovic, B.B., Æsø, E., Leinan, P.R., and Dawson, J.R. (2025). “Characterising slug flow in a horizontal pipe using bubble image velocimetry.” International Journal of Multiphase Flow, Vol. 188, 105196. doi: 10.1016/j.ijmultiphaseflow.2025.105196.

10.1016/j.ijmultiphaseflow.2025.105196

Hasan, A.R., and Kabir, C.S. (2002). Fluid flow and heat transfer in wellbores. Society of Petroleum Engineers, Richardson, TX, U.S.

Kong, R. (2018). Characterization of horizontal air-water two-phase flow in indifferent pipe sizes. Ph. D. Dissertation, Purdue University, West Lafayette, IN, U.S.

Laufer, J. (1954). The structure of turbulence in fully developed pipe flow. NACA Report 1174, National Advisory Committee for Aeronautics, Washington, D.C., U.S., pp. 1-18.

Lee, K., Cho, H., Rhee, D.S., and Lye. S. (2018). “Experimental investigation on the velocity structure and its effect on the flow patterns of air-water two-phase flow in a horizontal pipe.” KSCE Journal of Civil Engineering, Vol. 22, No. 9, pp. 3363-3372. doi: 10.1007/s12205-018-1037-z.

10.1007/s12205-018-1037-z

Lina, M., Ochoa-Phineda, J., Pico, P., Valdés, J.P., Becerra, D., Pinilla, A., Pereyra, E., and Ratkovich, N. (2020). “Comparison of 63 different void fraction correlations for different flow patterns, pipe inclinations, and liquid viscosities.” SN Applied Sciences, Vol. 2, No. 1695. doi: 10.1007/s42452-020-03464-w.

10.1007/s42452-020-03464-w

Mandhane, J.M., Gregory, G.A., and Aziz, K. (1974). “A flow pattern map for gas-liquid flow in horizontal pipes.” International Journal of Multiphase Flow, Vol. 1, No. 4, pp. 537-553. doi: 10.1016/0301-9322(74)90006-8.

10.1016/0301-9322(74)90006-8

Matamoros, L.M.C., Fabre, J., Pauchon, C., and Moujaes, S. (2014). “Length-area-volume of long bubbles in horizontal slug flow.” International Journal of Multiphase Flow, Vol. 65, pp. 24-30. doi: 10.1016/j.ijmultiphaseflow.2014.05.007.

10.1016/j.ijmultiphaseflow.2014.05.007

Rossi, L., Fayard, R., and Kassab, S. (2018). “Measurements using X-ray attenuation vertical distribution of the void fraction for different flow regimes in a horizontal pipe.” Nuclear Engineering and Design, Vol. 336, pp. 129-160. doi: 10.1016/j.nucengdes.2017.07.037.

10.1016/j.nucengdes.2017.07.037

Song, C., Ko, J.S., Choi, S.H., and Lyu, S. (2025). “Velocity structure measurement for water flow with air bubbles in a horizontal pipe.” Proceedings of the 41^st IAHR Congress, Singapore, Singapore, pp. 2296-2298.

Taitel, Y., and Dukler, A.E. (1976). “A model for predicting flow regime transitions in horizontal and near horizontal gas-liquid flow.” AlChE Journal, Vol. 22, No. 1, pp. 47-55. doi: 10.1002/aic.690220105.

10.1002/aic.690220105

Walter, H., and Epple, B. (2017). Numerical simulations of power plants and firing systems. Springer, Cham, Switzerland.

10.1007/978-3-7091-4855-6

Weisman, J., Duncan, D., Gibson, J., and Crawford, T. (1979). “Effects of fluid properties and pipe diameter on two-phase flow patterns in horizontal lines.” International Journal of Multiphase Flow, Vol. 5, No. 4, pp. 437-462. doi: 10.1016/0301-9322(79)90031-4.

10.1016/0301-9322(79)90031-4

Information

Publisher :KOREA WATER RESOURECES ASSOCIATION
Publisher(Ko) :한국수자원학회
Journal Title :Journal of Korea Water Resources Association
Journal Title(Ko) :한국수자원학회 논문집
Volume : 59
No :1
Pages :51-64
Received Date : 2025-10-17
Revised Date : 2025-11-14
Accepted Date : 2025-11-19
DOI :https://doi.org/10.3741/JKWRA.2026.59.1.51

Journal of Korea Water Resources Association ISSN:2799-8746(Print) 2799-8754(Online) 한국수자원학회 논문집

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