Experimental research on flow regime and transitional criterion of slug to churn-turbulent and churn-turbulent to annular flow in rectangular channels
1
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
As for two-phase flow in rectangular channels, the flow regimes especially like churn-turbulent and annular flow are significant for the physical problem like Countercurrent Flow Limitation (CCFL). In this study, the rectangular channels with cross-sections of 4 × 66 mm, 6 × 66 mm, 8 × 66 mm are adopted to investigate the flow regimes of air-water vertical upward two phase flow under adiabatic condition. The gas and liquid superficial velocities are 0 ≤ jg ≤ 20m/s and 0.25 ≤ jf ≤ 3m/s respectively which covering bubbly to annular flow. The flow regimes are identified by random forest algorithm and the flow regime maps are obtained. As the results, the transitional void fraction from slug to churn turbulent flow fluctuate from 0.47 to 0.58 which is significantly affected by the dimensional size of channel and flow rate. Besides, the void fraction at transitional points from churn-turbulent (slug) to annular flow are 0.66–0.67, which are independent with the gap size. Furthermore, a new criteria of slug to churn-turbulent flow is established in this study. In addition, by introducing the interfacial force model, the criteria of churn-turbulent (slug) flow to annular flow is verified.
Abstract
As for two-phase flow in rectangular channels, the flow regimes especially like churn-turbulent and annular flow are significant for the physical problem like Countercurrent Flow Limitation (CCFL). In this study, the rectangular channels with cross-sections of 4 × 66 mm, 6 × 66 mm, 8 × 66 mm are adopted to investigate the flow regimes of air-water vertical upward two phase flow under adiabatic condition. The gas and liquid superficial velocities are 0 ≤ jg ≤ 20m/s and 0.25 ≤ jf ≤ 3m/s respectively which covering bubbly to annular flow. The flow regimes are identified by random forest algorithm and the flow regime maps are obtained. As the results, the transitional void fraction from slug to churn turbulent flow fluctuate from 0.47 to 0.58 which is significantly affected by the dimensional size of channel and flow rate. Besides, the void fraction at transitional points from churn-turbulent (slug) to annular flow are 0.66–0.67, which are independent with the gap size. Furthermore, a new criteria of slug to churn-turbulent flow is established in this study. In addition, by introducing the interfacial force model, the criteria of churn-turbulent (slug) flow to annular flow is verified.
참고문헌 (26)
- Q. He, "Research on bubbly to slug flow regime transition of air-water co-current upward flow in vertical rectangular channels with different gap sizes", Prog. Nucl. Energy, 151, pp.104332~ (2022)
- K. Liu, "Numerical investigation of flow and heat transfer characteristics in plate-type fuel channels of IAEA MTR based on", Open, 141, pp.103963~ (2021)
- M. Wang, "Development of Subcooled Wall Boiling Model Considering Bubble Sliding in Narrow Rectangular Channel", 181, pp.107787~ (2022)
- M. Wang, "Recent progress of CFD applications in PWR thermal hydraulics study and", Future Direct, 150, pp.107836~ (2021)
- K. Mishima, "Some characteristics of gas-liquid flow in narrow rectangular ducts", Int. J. Multiphas. Flow, 19(1), pp.115~124 (1993)
- T. Wilmarth, "Two-phase flow regimes in narrow rectangular vertical and horizontal channels", Int. J. Heat Mass Tran, 37(12), pp.1749~1758 (1994)
- K. Mishima, "Flow regime transition criteria for upward two-phase flow in vertical tubes", Int. J. Heat Mass Tran, 27(5), pp.723~737 (1984)
- J. L. Xu, "Gas–liquid two-phase flow regimes in rectangular channels with mini", micro gaps, 1999, pp.25(3), 411~432
- D. Xing, "Effects of void fraction correlations on pressure gradient separation of air–water two-phase flow in vertical mini rectangular ducts", Prog. Nucl. Energy, 70, pp.84~90 (2014)
- V. S. Chalgeri, "Flow regime identification and classification based on void fraction and differential pressure of vertical two-phase flow in rectangular channel", Int. J. Heat Mass Tran, 132, pp.802~816 (2019)
- P. Yuan, "Air-water twophase flow regime and transition criteria in vertical upward narrow rectangular channels", Prog. Nucl. Energy, 136, pp.103750~ (2021)
- M. Sadatomi, "Two-phase flow in vertical noncircular channels", Int. J. Multiphas. Flow, 8(6), pp.641~655 (1982)
- Y. Taitel, "Modeling flow pattern transitions for steady upward gas-liquid flow in vertical tubes", AIChE J, 26(3), pp.345~354 (1980)
- M. Zhang, "Experimental study of vertical cocurrent slug flow in terms of flow regime transition in relatively small diameter tubes", Int. J. Multiphas. Flow, 108, pp.140~155 (2018)
- T. Hibiki, "Flow regime transition criteria for upward two-phase flow in vertical narrow rectangular channels", Nucl. Eng. Des, 203(2), pp.117~131 (2001)
- K. McQuillan, "Flooding in vertical two-phase flow", Int. J. Multiphas. Flow, 11(6), pp.741~760 (1985)
- M. Kaichiro, "Flow regime transition criteria for upward two-phase flow in vertical tubes", Int. J. Heat Mass Tran, 27(5), pp.723~737 (1984)
- RELAP5, "MOD3 Code Manual: Code Structure, System Models, and Solution Methods, vol. 1", L.I.T. Co, 1995
- TRACE V5.0 THEORY MANUAL Field Equations, Solution Methods, and Physical Models, "U.S.N.R. Commission", ~ (2012)
- Q. He, "Research on frictional pressure drop of air-water Co-current upward flow in vertical rectangular channels with different sizes", Prog. Nucl. Energy, 152 (2022)
- Q. -y. Ren, "Sub-channel flow regime maps in vertical rod bundles with spacer grids", Int. J. Heat Mass Tran, 122, pp.1138~1152 (2018)
- N. Brauner, "Slug", Churn transition in upward gas-liquid flow, 1986, pp.41(1), 159~163
- A. Dukler, "Flow regime transitions for vertical upward gas liquid flow: a preliminary approach through physical modelling", Workshop Held in Houston (1977)
- I. Khan, "Two-phase bubbly flow simulation using CFD method", Rev. Mod. Interf. forces, 125, pp.103360~ (2020)
- G. B. Wallis, "One-dimensional Two-phase Flow" (2020), Courier Dover Publications
- Q. He, "The research on the interfacial area transport equation in rectangular channels : interfacial characteristics distribution and bubbles interaction mechanism", Prog. Nucl. Energy, 160, pp.104698~ (2023)