Study on Liquid Film Formed with Liquid Column Oscillation in Vertical Pipe

2020 ◽  
Vol 2020 (0) ◽  
pp. 0114
Author(s):  
Masayoshi Miura ◽  
Yibin Zhao ◽  
Hiroyuki Ito
Keyword(s):  
Liquid Film ◽  
Liquid Column ◽  
Vertical Pipe

Hybrid Particle/Grid Method for Predicting Motion of Micro- and Macrofree Surfaces

2006 ◽  
Vol 128 (5) ◽  
pp. 921-930 ◽  
Author(s):  
Eiji Ishii ◽  
Toru Ishikawa ◽  
Yoshiyuki Tanabe
Keyword(s):  
Liquid Film ◽  
Volume Fraction ◽  
Grid Method ◽  
Particle Method ◽  
Liquid Films ◽  
Liquid Column ◽  
Computational Time ◽  
Fuel Injector ◽  
Hybrid Particle ◽  
Liquid Flows

We developed a method of hybrid particle/cubic interpolated propagation (CIP) to predict the motion of micro- and macrofree surfaces within gas-liquid flows. Microfree surfaces (smaller than the grid sizes) were simulated with the particle method, and macrofree surfaces (larger than the grid sizes) were simulated with the grid method (CIP is a kind of grid method). With the hybrid, velocities given by the advection part of the particle method were combined with those given by the advection part of CIP. Furthermore, the particles used with the particle method were assigned near the macrofree surfaces by using the volume fraction of liquid that was calculated with CIP. The method we developed was used to predict the collapse of a liquid column. Namely, it was simultaneously able to predict both large deformation in the liquid column and its fragmentation, and the predicted configurations for the liquid column agreed well with the experimentally measured ones. It was also used to predict the behavior of liquid films at the outlet of a fuel injector used for automobile engines. The particle method in the simulation was mainly used for liquid films in the air region and the grid method was used for the other regions to shorten the computational time. The predicted profile of the liquid film was very sharp in the air region where the liquid film became thinner than the grid sizes; there was no loss of liquid film with numerical diffusion.

Heat Transfer Characteristics in a Slug Unit

2010 ◽  
Author(s):  
Valery Babin ◽  
Dvora Barnea ◽  
Lev Shemer
Keyword(s):  
Heat Transfer ◽  
Liquid Film ◽  
Slug Flow ◽  
Video Camera ◽  
Transfer Mechanism ◽  
Heat Transfer Mechanism ◽  
Vertical Pipe ◽  
Two Phase ◽  
Taylor Bubble ◽  
Hydrodynamic Parameters

Heat transfer mechanism in two-phase flows and particularly in vertical slug flow is of high interest both for basic hydrodynamic research and for industrial applications. Two-phase slug flow is highly complicated and only a limited number of heat transfer studies have been carried out. The flow field around a single Taylor bubble propagating in a vertical pipe can be subdivided into three distinct hydrodynamic regions: the gas bubble surrounded by a thin liquid film, a highly turbulent liquid wake in the vicinity of the bubble bottom, and the far wake region. Experimental and theoretical works have been presented during the last decades investigating the hydrodynamic parameters in each region. Due to the complexity and intermittent nature of slug flow the existing data on the heat transfer in slug flow is limited to a narrow range of operational conditions. To improve the understanding of the heat transfer mechanism in slug flow a new experimental setup was constructed. A part of the vertical pipe wall was replaced by a thin metal foil heated by electrical current. An IR video camera was used to determine the temporal variation of the instantaneous temperature field along the foil. The video camera was synchronized with a sensor that determined the instantaneous location of the Taylor bubble. The results of the instantaneous heat transfer measurements along the liquid film and in the wake of the Taylor bubble can be correlated with the detailed velocity measurements carried out in the same facility (Shemer et al. 2007). The effect of the local hydrodynamic parameters on the heat transfer coefficient in each region is examined.

Particle/CIP Hybrid Method for Predicting Motions of Micro and Macro Free Surfaces

Volume 3 ◽  
2004 ◽  
Author(s):  
Eiji Ishii ◽  
Toru Ishikawa ◽  
Yoshiyuki Tanabe
Keyword(s):  
Liquid Film ◽  
Hybrid Method ◽  
Volume Fraction ◽  
Particle Method ◽  
Liquid Films ◽  
Liquid Column ◽  
Cip Method ◽  
Fuel Injector ◽  
Free Surfaces ◽  
Liquid Flows

To predict motions of micro and macro free surfaces simultaneously within gas-liquid flows, we have developed a particle/CIP (Cubic Interpolated Propagation) hybrid method. The micro free surfaces (smaller than grid sizes) were simulated by the particle method, and the macro free surfaces (larger than grid sizes) were simulated by the CIP method. And then the particles used in the particle method were assigned near the macro free surfaces by using volume fraction of liquid that was calculated by the CIP method. The developed method was used to predict the collapse of a liquid column. Namely, it predicted both the large deformation of the liquid column and the fragmentation of it simultaneously, and the predicted configurations of the liquid column agreed well with the experimentally measured ones. It was also used to predict breakup of liquid films in a fuel injector used for engines of automobiles, and the predicted profile of the liquid film was sharp in an air region where the thickness of the liquid film became thinner than the grid sizes.

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