Pressure Drop and Liquid Film Thickness of Two-Phase Annular and Annular-Mist Flows

1964 ◽  
Vol 86 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Sze-Foo Chien ◽  
W. Ibele
Keyword(s):  
Pressure Drop ◽  
Film Thickness ◽  
Liquid Film ◽  
Liquid Film Thickness ◽  
Two Phase

scholarly journals Dynamics and effective distance of gas–liquid two-phase swirling flow induced by vortex tools

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879961 ◽  
Author(s):  
Zhao Zhang ◽  
Ruiquan Liao ◽  
Jie Liu
Keyword(s):  
Pressure Drop ◽  
Film Thickness ◽  
Liquid Film ◽  
Swirling Flow ◽  
Flow Behavior ◽  
Helix Angle ◽  
Liquid Film Thickness ◽  
Liquid Ratio ◽  
Effective Distance ◽  
Two Phase

Based on the mechanistic model of the two-phase swirling annular flow behavior, a calculation method for the effective distance of vortex tool is obtained by taking Kelvin–Helmholtz instability into account. The rationality of the proposed method is validated by comparing the predicted liquid film thickness and pressure under non-swirling flow with the commonly used correlations. Then, the influences of gas–liquid ratio, helix angle, and hub diameter of vortex tool on the liquid film thickness, pressure drop, and effective distance have been analyzed. Results show that the presence of the vortex tool causes the decrease in the liquid film thickness and increase in the pressure drop. The liquid film thickness increases gradually as the helix angle and the hub diameter increase, and the larger helix angle results in smaller pressure drop. The effective distance increases with an increase in the gas–liquid ratio and decreases with an increase in helix angle and hub diameter. A sudden decrease occurs when the helix angle exceeds 60°. The gas–liquid ratio and helix angle are more dominant factors than the hub diameter on the liquid film thickness, pressure drop, and effective distance.

Characteristics of the Liquid Film and Pressure Drop in Horizontal, Annular, Two-phase Flow Through Round, Square and Triangular Tubes

2004 ◽  
Vol 126 (5) ◽  
pp. 807-817 ◽  
Author(s):  
Timothy A. Shedd ◽  
Ty A. Newell
Keyword(s):  
Pressure Drop ◽  
Film Thickness ◽  
Liquid Film ◽  
Friction Velocity ◽  
Thickness Measurement ◽  
Secondary Flows ◽  
Liquid Film Thickness ◽  
Two Phase ◽  
Flow Through ◽  
Film Thickness Measurement

A unique set of liquid film thickness and pressure drop data has been obtained for horizontal, annular flow of air and water through round, square and triangular tube using a noninvasive, optical liquid film thickness measurement system. In the square and triangular tubes, the liquid film was thinned in the corners, indicating an effect of turbulent secondary flows in these geometries. In addition, when the film thickness is nondimensionalized using a friction velocity based on the total pressure drop, it is found that virtually all the data lie below h+=35 and that dryout occurs at approximately h+=5. The two-phase friction factor for the annular flows examined in all the tubes can be correlated using the Lockhart–Martinelli parameter, Xtt, when adjustments are made for the hydraulic diameters of the nonround tubes.

Measurement of Liquid Film Thickness in Micro Tube Annular Flow

2010 ◽  
Author(s):  
Hiroshi Kanno ◽  
Youngbae Han ◽  
Yusuke Saito ◽  
Naoki Shikazono
Keyword(s):  
Heat Transfer ◽  
Film Thickness ◽  
Liquid Film ◽  
Annular Flow ◽  
Liquid Film Thickness ◽  
Phase Flow ◽  
Two Phase ◽  
Micro Scale ◽  
Film Model ◽  
Annular Film

Heat transfer in micro scale two-phase flow attracts large attention since it can achieve large heat transfer area per density. At high quality, annular flow becomes one of the major flow regimes in micro two-phase flow. Heat is transferred by evaporation or condensation of the liquid film, which are the dominant mechanisms of micro scale heat transfer. Therefore, liquid film thickness is one of the most important parameters in modeling the phenomena. In macro tubes, large numbers of researches have been conducted to investigate the liquid film thickness. However, in micro tubes, quantitative information for the annular liquid film thickness is still limited. In the present study, annular liquid film thickness is measured using a confocal method, which is used in the previous study [1, 2]. Glass tubes with inner diameters of 0.3, 0.5 and 1.0 mm are used. Degassed water and FC40 are used as working fluids, and the total mass flux is varied from G = 100 to 500 kg/m2s. Liquid film thickness is measured by laser confocal displacement meter (LCDM), and the liquid-gas interface profile is observed by a high-speed camera. Mean liquid film thickness is then plotted against quality for different flow rates and tube diameters. Mean thickness data is compared with the smooth annular film model of Revellin et al. [3]. Annular film model predictions overestimated the experimental values especially at low quality. It is considered that this overestimation is attributed to the disturbances caused by the interface ripples.

Measurement of Liquid Film Thickness for Annular Two-Phase HFC134a Gas-Liquid Ethanol Flow in the Vertical Tube

2021 ◽  
Author(s):  
Huacheng Zhang ◽  
Tutomo Hisano ◽  
Shoji Mori ◽  
Hiroyuki Yoshida
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Thin Liquid Film ◽  
Atmospheric Condition ◽  
Heating Surface ◽  
Operating Conditions ◽  
Liquid Film Thickness ◽  
Two Phase ◽  
Disturbance Waves ◽  
Analytical Approaches

Abstract Annular gas-liquid two-phase flows, such as the flows attached to the fuel rods of boiling water reactors (BWR), are a prevalent occurrence in industrial processes. At the gas-liquid interface of such flows, disturbance waves with diverse velocity and amplitude commonly arise. Since the thin liquid film between two successive disturbance waves leads to the dryout on the heating surface and limits the performance of the BWRs, complete knowledge of the disturbance waves is of great importance for the characterized properties of disturbance waves. The properties of disturbance waves have been studied by numerous researchers through extensive experimental and analytical approaches. However, most of the experimental data and analyses available in the literature are limited to the near atmospheric condition. In consideration of the properties of liquids and gases under atmospheric pressure which are distinct from those under BWR operating conditions (7 MPa, 285 °C), we employed the HFC134a gas and liquid ethanol whose properties at relatively low pressure and temperature (0.7 MPa, 40 °C) are similar to those of steam and water under BWR operating conditions as working fluids in a tubular test section having an inside diameter 5.0mm. Meanwhile, the liquid film thickness is measured by conductance probes. In this study, we report the liquid film thickness characteristics in a two-phase HFC134a gas-liquid ethanol flow. A simple model of the height of a disturbance wave was also proposed.

scholarly journals ANALYSIS OF INTERFACIAL AND MASS TRANSFER EFFECTS ON FORCED CONVECTION IN GAS-LIQUID ANNULAR TWO-PHASE FLOW

2004 ◽  
Vol 3 (1) ◽  
pp. 45
Author(s):  
E. Nogueira ◽  
B. D. Dantas ◽  
R. M. Cotta
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Film Thickness ◽  
Liquid Film ◽  
Liquid Film Thickness ◽  
Phase Flow ◽  
Transfer Effects ◽  
Two Phase ◽  
Transfer Rates ◽  
Interface Waves

In a gas-liquid annular two-phase flow one of the main factors influencing the determination of heat transfer rates is the average thickness of the liquid film. A model to accurately represent the heat transfer in such situations has to be able of determining the average liquid film thickness to within a reasonable accuracy. A typical physical aspect in gas-liquid annular flows is the appearance of interface waves, which affect heat, mass and momentum transfers. Existing models implicitly consider the wave effects in the momentum transfer by an empirical correlation for the interfacial friction factor. However, this procedure does not point out the difference between interface waves and the natural turbulent effects of the system. In the present work, the wave and mass transfer effects in the theoretical estimation of average liquid film thickness are analyzed, in comparison to a model that does not explicitly include these effects, as applied to the prediction of heat transfer rates in a thermally developing flow situation.

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