Numerical modeling of the influence of bubbles on flow and heat transfer in the descending gas-liquid flow in a pipe

2012 ◽  
Vol 9 (1) ◽  
pp. 131-135
Author(s):  
M.A. Pakhomov
Keyword(s):  
Heat Transfer ◽  
Gas Phase ◽  
Liquid Flow ◽  
Bubble Diameter ◽  
Gas Content ◽  
Two Phase ◽  
Eulerian Description ◽  
Flow And Heat Transfer ◽  
Gas Liquid Flow ◽  
The Mathematical Model

The paper presents the results of modeling the dynamics of flow, friction and heat transfer in a descending gas-liquid flow in the pipe. The mathematical model is based on the use of the Eulerian description for both phases. The effect of a change in the degree of dispersion of the gas phase at the input, flow rate, initial liquid temperature and its friction and heat transfer rate in a two-phase flow. Addition of the gas phase causes an increase in heat transfer and friction on the wall, and these effects become more noticeable with increasing gas content and bubble diameter.

Heat Transfer in Gas-Liquid Flow in a Triangular Arrranged Rod Bundle

2014 ◽  
Author(s):  
O. N. Kashinsky ◽  
P. D. Lobanov ◽  
A. S. Kurdyumov ◽  
N. A. Pribaturin ◽  
S. E. Volkov
Keyword(s):  
Heat Transfer ◽  
Gas Phase ◽  
Void Fraction ◽  
Liquid Flow ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Spacer Grid ◽  
Two Phase ◽  
High Heat Transfer ◽  
Gas Liquid Flow

An experimental study of gas-liquid flow in a vertical bundle of rods in a hexagonal arrangement with spacer grids was performed. The test section was a bundle consisted of 37 rods. Experiments were performed in system water – air at room temperature. New information about characteristics of two-phase flow near a spacer grid is presented. A comparison of distribution of local heat transfer from the central rod surface and distribution of local void fraction around this rod for two ways of gas phase addition was performed. A non uniform void profile around the central rod of the bundle was obtained for both cases. Just downstream the spacer grid an increase of void fraction was obtained Gas addition to the flow results in heat transfer enhancement. This is especially clear for the case of gas supply by a single nozzle. In this case high void fraction and high heat transfer coefficient were observed in one of the subchannels. The data obtained allow to estimate the transfer of gas bubbles in rod bundles and heat transfer augmentation by the addition of gas phase into the coolant flow.

Analysis of Runback Water Flow on Anti-Icing Surface Using Volume-of-Fluid Method

2017 ◽  
Author(s):  
Mei Zheng ◽  
Wei Dong ◽  
Zhiqiang Guo ◽  
Guilin Lei
Keyword(s):  
Heat Transfer ◽  
Water Flow ◽  
Thin Liquid Film ◽  
Flow Characteristics ◽  
Volume Of Fluid ◽  
Complex Model ◽  
Two Phase ◽  
Flow And Heat Transfer ◽  
Liquid Film Flow ◽  
The Mathematical Model

The runback water flow and heat transfer on the surface of aircraft components has an important influence on the design of anti-icing system. The aim of this paper is to investigate the water flow characteristics on anti-icing surface using numerical method. The runback water flow on the anti-icing surface, which is caused by the impinging supercooled droplets from the clouds, is driven by the aerodynamic shear forces and the pressure gradient around the components. This is a complex model of flow and heat transfer that considers flow field, super-cooled droplets impingement and runback water flow simultaneously. In this case of gas-liquid two phase flow, the Volume-of-Fluid (VOF) method is very suitable for the solution of thin liquid film flow so that it is applied to simulate the runback water flow on anti-icing surfaces in this paper. Meanwhile, the heat and mass transfer of the runback water flow are considered in the calculation using the User-Defined Functions (UDFs) in ANASYS FLUENT. The verification is conducted by the comparison with the results of the experimental measurement and the mathematical model calculation. The effect of the airflow velocity and contact angle on the water flow are also considered in the numerical simulation.

Numerical Investigation on Bubbly Flow and Heat Transfer Characters in a Liquid-Reactor

2008 ◽  
Author(s):  
Lixin Yang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Liquid Flow ◽  
Nuclear Reactor ◽  
Research Work ◽  
Diameter Distribution ◽  
Flow And Heat Transfer ◽  
Cooling Coils ◽  
Gas Liquid Flow

Gas-liquid flow and heat transfer in a nuclear reactor were investigated by the CFD simulation. The MUSIG model and the mono-disperse model are applied to model the multiphase flow and heat transfer. The comparison with experimental data indicates that the gas-liquid flow and heat transfer in the nuclear reactor could be well captured by the suggested numerical model. The temperature distribution, velocity distribution, bubble diameter distribution in the nuclear reactor and heat transfer coefficient of the cooling coils were analyzed. In addition, the effect of gas generation rate on heat transfer coefficient of the cooling coils was discussed. This research work has provided fundamental understanding of gas-liquid flow and heat transfer in the nuclear reactor as well as the design guidance of the cooling coils.

scholarly journals Countercurrent Gas-Liquid Flow and Heat Transfer Charicteristics in Narrow Gap with Closed Bottom

2005 ◽  
Vol 71 (702) ◽  
pp. 610-616 ◽  
Author(s):  
Yukimitsu OKANO ◽  
Takashi NAGAE ◽  
Michio MURASE ◽  
Yasuo KOIZUMI ◽  
Hiroyasu OHTAKE ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Liquid Flow ◽  
Narrow Gap ◽  
Flow And Heat Transfer ◽  
Gas Liquid Flow

Study on Gas-Liquid Two-Phase Flow Distribution Inside a Flute Header

2020 ◽  
Author(s):  
Liping Pang ◽  
Shangmin Li ◽  
Hu Yuan ◽  
Liqiang Duan
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Liquid Flow ◽  
Two Phase Flow ◽  
Phase Distribution ◽  
Flow Distribution ◽  
Phase Flow ◽  
Two Phase ◽  
Parallel Channels ◽  
Gas Liquid Flow

Abstract When the supercritical boiler is working at low load during flexible operation, the uneven distribution of the gas-liquid flow at the intermediate header may affect the safety of the water-cooled wall at the vertical parallel panels. In order to improve the uniformity of gas-liquid flow distribution in the water-cooled wall of intermediate header and study the internal flow mechanism, a flute inside the header is applied with parallel vertical parallel channels and experiments under different operating conditions are conducted to verify the effectiveness of this geometrical structure. The flow pattern in the experiment belongs to stratified and wavy flow. Computational fluid dynamic (CFD) simulation is conducted in order to investigate two-phase flow distribution behavior inside a flute header. It was found that the radial gas phase distribution in the flute tube shows a symmetrical relationship, and there are two vortexes in opposite directions. With the increasing distance from the inlet, the uniformity of the gas phase distribution becomes even. The gravity is greater than the drag force, which has effect on the two-phase flow distribution. The gas phase velocity has been improved inside flute section and liquid phase flow has more even flow distribution along annular section. It makes liquid phase sent to far end of flute header. That benefits two-phase flow distribution along 10 parallel channels equally.

Numerical modeling for stratified gas–liquid flow and heat transfer in pipeline

2014 ◽  
Vol 115 ◽  
pp. 83-94 ◽  
Author(s):  
Jimiao Duan ◽  
Jing Gong ◽  
Haiyuan Yao ◽  
Tao Deng ◽  
Jun Zhou
Keyword(s):  
Heat Transfer ◽  
Numerical Modeling ◽  
Liquid Flow ◽  
Flow And Heat Transfer ◽  
Gas Liquid Flow
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