Stratified-to-annular gas-liquid flow patterns transition in a horizontal pipe
Autor: | Mikhail Cherdantsev, Andrey V. Cherdantsev, D. M. Markovich, Sergey V. Isaenkov, Semyon A. Zdornikov |
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Rok vydání: | 2022 |
Předmět: |
Fluid Flow and Transfer Processes
Coalescence (physics) geography geography.geographical_feature_category Materials science Mechanical Engineering General Chemical Engineering education Flow (psychology) Aerospace Engineering Surface finish Mechanics Inlet Secondary flow Physics::Fluid Dynamics Amplitude Nuclear Energy and Engineering Shear stress Stratified flow |
Zdroj: | Experimental Thermal and Fluid Science. 132:110552 |
ISSN: | 0894-1777 |
Popis: | Air-water flow in a 20 mm horizontal pipe is studied using side-view visualization with a background image and Brightness-Based Laser-Induced Fluorescence technique. The investigation is focused on the transition from stratified to annular flow patterns. Stratified flow is organized at the pipe inlet, and the dynamics of liquid lifting up the pipe walls is investigated. During the transition to annular flow, the liquid film is spread over the pipe walls in a stable and gradual manner; the spreading begins before the disturbance waves are formed. Two transition regimes are identified. At large gas and low liquid flow rates, the film is spread up the pipe walls reaching a stable height unaffected by the passing waves. At low gas and large liquid flow rates, the liquid can be lifted by the large-scale waves, but it promptly drains downwards between the waves. Secondary flow in the gas phase is considered the main mechanism of liquid lifting and the only mechanism able to create a stable annular film. The processes of formation and development of disturbance waves are qualitatively the same as previously observed in vertical pipes. Namely, the disturbance waves are formed due to the coalescence of high-frequency initial waves appearing near the inlet; the disturbance waves undergo coalescence and grow in amplitude and speed. Quantitatively, the disturbance wave formation occurs at larger distances from the inlet compared to the vertical flow, and the acceleration rate is much lower. An estimation of circumferential shear stress due to secondary flow is made based on the roughness of the liquid film surface at the bottom of the pipe. An increase in this shear stress increases the height of the liquid film on the pipe walls. |
Databáze: | OpenAIRE |
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