Experimental Investigation of Falling Liquid Film in Vertical Downward Two-Phase Pipe Flow

2012 ◽  
Author(s):  
Jose M. Lopez ◽  
Ram Mohan ◽  
Ovadia Shoham ◽  
Shoubo Wang ◽  
Gene Kouba
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Two Phase Flow ◽  
Liquid Velocity ◽  
Liquid Droplet ◽  
Mineral Oil ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Measurements ◽  
Falling Liquid Film

In this research the hydrodynamics of falling liquid film in a vertical downward two-phase flow (liquid-gas) is experimentally studied. The 4 inch clear PVC test section is 6.1 meters long, with a length to diameter ratio (L/D) of 64. The fluids utilized are compressed air, water, Conosol mineral oil (light oil) and Drake mineral oil (heavy oil). The superficial liquid velocities tested range from 12 to 72 cm/s while the superficial gas velocities range from 0.2 to 29 cm/s. The vertical facility is equipped with the state-of-the-art instrumentation for two-phase flow measurements, the capacitance Wire-Mesh Sensor (WMS), allowing two-phase flow measurements with conducting and non conducting fluids. Experimental results show that the liquid film thickness has a quasi-linear relationship with the superficial liquid velocity for the air-water case. For the air-oil cases, at superficial liquid velocities higher than 50 cm/s, the liquid film thickness trend is affected by the liquid droplet entrainment. Furthermore, it was found that the liquid droplet entrainment increases as the superficial liquid velocity increases or the surface tension decreases. Details of the liquid droplets traveling in the gas core, wave formation, wave breakup and film thickness evolution are observed in the WMS phase reconstruction.

Modeling of Falling Film in Vertical Downward Two-Phase Pipe Flow

2012 ◽  
Author(s):  
Jose M. Lopez ◽  
Ram Mohan ◽  
Ovadia Shoham ◽  
Luis Gomez ◽  
Gene Kouba
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Liquid Droplet ◽  
Mechanistic Model ◽  
Mineral Oil ◽  
Liquid Film Thickness ◽  
Falling Film ◽  
Two Phase ◽  
Droplet Entrainment ◽  
Falling Liquid Film

Falling liquid films in vertical pipes are found in a variety of different industrial applications and industrial equipment, such as downcomers, caisson separators and reactors. The hydrodynamics of the falling film in vertical two-phase pipe flow can affect droplet entrainment, gas entrainment, and pressure drop. Therefore, a mechanistic model for prediction of falling liquid film thickness, falling liquid film velocity and a correlation for liquid droplet entrainment fraction in vertical downward liquid-gas systems has been proposed. The falling film model developed is based on applying momentum balance on the liquid film. The liquid film is assumed to be in steady-state, incompressible and free of entrained gas. The mechanistic model includes both the developing and the developed regions. The shear effect between the gas core and the falling liquid film is considered. The liquid droplet entrainment fraction traveling in the gas core is considered and a new correlation for its prediction is proposed. Detailed uncertainty analysis is performed for liquid film thickness and liquid film velocity model predictions, including Monte Carlo simulation. Predicted liquid film thickness, liquid film velocity and liquid droplet entrainment fraction are validated against experimental data for different liquid fluid properties, such as water, Conosol mineral oil (light oil) and Drake mineral oil (heavy oil).

Average liquid film thickness of annular air-water two-phase flow in 8 × 8 rod bundle

2018 ◽  
Vol 73 ◽  
pp. 63-73 ◽  
Author(s):  
Peng Ju ◽  
Xiaohong Yang ◽  
Joshua P. Schlegel ◽  
Yang Liu ◽  
Takashi Hibiki ◽  
...  
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Two Phase Flow ◽  
Liquid Film Thickness ◽  
Phase Flow ◽  
Two Phase ◽  
Rod Bundle

scholarly journals Liquid Film Thickness on Fuel Rod under High Pressure and High Temperature Steam-Water Two Phase Flow

2006 ◽  
Vol 5 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Michio SATO ◽  
Shinichi MOROOKA ◽  
Kenetsu SHIRAKAWA ◽  
Yasushi YAMAMOTO ◽  
Kazumi WATANABE ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Film Thickness ◽  
Liquid Film ◽  
Two Phase Flow ◽  
Liquid Film Thickness ◽  
Phase Flow ◽  
Two Phase ◽  
Fuel Rod ◽  
High Temperature Steam

Prediction of film inversion in two-phase flow in coiled tubes

1992 ◽  
Vol 236 ◽  
pp. 497-511 ◽  
Author(s):  
G. F. Hewitt ◽  
S. Jayanti
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
Two Phase Flow ◽  
Thickness Distribution ◽  
Thin Liquid Film ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
New Criterion ◽  
Good Agreement

Depending on the flow conditions, the liquid film in annular two-phase flow in coiled tubes may be pushed towards the outer or the inner side by the centrifugal force. It is important to understand the mechanism of this ‘film inversion’ in order to develop a predictive model for the film thickness distribution. In this paper, this phenomenon is studied analytically, and a new criterion, based on the secondary flow in the thin liquid film, is proposed to predict its occurrence. The criterion shows good agreement with available experimental data. It is suggested that the analytical model can readily be extended to predict the distribution of the film thickness and film flow rate in coiled tubes.

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