Numerical Simulation and Experimental Validation of Gas-Liquid Flow Characteristics in Dual-Contact-Flow Absorption Tower

2011 ◽  
Author(s):  
Yafei Zhang ◽  
Na Li ◽  
Qulan Zhou ◽  
Shi’en Hui ◽  
Qinxin Zhao
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Liquid Flow ◽  
Liquid Velocity ◽  
Flow Characteristics ◽  
Mathematic Model ◽  
Liquid Droplets ◽  
Gas Velocity ◽  
Bed Height ◽  
Gas Liquid Flow

A mathematic model of gas-liquid flow in the dual-contact-flow absorption tower is established and some valuable theoretical and numerical simulation results are also obtained. The numerical results show that the velocity and density of liquid droplets are spatially nonuniform and the maximum density of liquid droplets appears at the top of the liquid bed. Therefore the mass and heat transfer there are significantly intense. However, once the gas or liquid velocity is so high that the liquid droplets carried away from the absorption tower can not be neglected, the heat transfer quantity will drop sharply, thus there may generate the heat transfer deterioration. Although liquid droplets consist of broken droplets of different sizes, almost all the active droplets possess the same maximum jetting height. Moreover, in most cases the theoretical analysis and numerical simulation of the actual bed height agree well with the experimental results. Besides, the gas velocity can only lead to changing of the fallback characteristic, while it has little effect on the bed height. In addition, the limit diameter of droplets increases obviously with the gas velocity, while it has little relevance with liquid jetting velocity.

CFD-DEM Numerical Simulation and Experimental Validation of Heat Transfer and Two-Component Flow in Fluidized Bed

2017 ◽  
Vol 16 (1) ◽  
Author(s):  
Feihong Guo ◽  
Zhaoping Zhong
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Fluidized Bed ◽  
Quartz Sand ◽  
Thermal Imager ◽  
Gas Velocity ◽  
Bed Height ◽  
Two Component ◽  
Superficial Gas Velocity ◽  
Infrared Thermal Imager

AbstractBased on the improved computational fluid dynamics and discrete element method (CFD-DEM), heat transfer and two-component flow of biomass and quartz sand have been studied from experiments and numerical simulation in this paper. During experiments, the particle temperature and moving images are respectively recorded by infrared thermal imager and high speed camera. With the increase of the velocity, the mixing index (MI) and the cooling rate of the particles are rising. Due to larger heat capacity and mass, the temperature of biomass drops slower than that of quartz sand. Fictitious element method is employed to solve the incompatibility of the traditional CFD-DEM where the cylindrical biomass are considered as an aggregation of numerous fictitious sphere particles arranged in certain sequence. By the comparison of data collected by infrared thermal imager and the simulated results, it can be concluded that experimental data is basically agreement with numerical simulation results. Directly affected by inflow air (25℃), the average temperature of particles in the bed height area (h>30 mm) is about 3 degrees lower than that of the other heights. When the superficial gas velocity is larger, the fluidization is good, and the gas temperature distribution is more uniform in the whole area. On the contrary, bubbles are not easy to produce and the fluidization is restricted at lower superficial gas velocity. Gas-solid heat transfer mainly exists under the bed height of 10 mm, and decreases rapidly on fluidized bed height. The mixing index (MI) is employed to quantitatively discuss the mixing effectiveness, which first rises accelerate, then rising speed decreases, finally tends to a upper limit.

Measurement of Gas/Liquid Flow Velocities in Rapidly Rotating Annular Systems

2003 ◽  
Author(s):  
Abdelwahab Aroussi ◽  
Gazala Ishaq ◽  
Mohammed Menacer
Keyword(s):  
Heat Transfer ◽  
Liquid Flow ◽  
Liquid Films ◽  
Liquid Droplets ◽  
Aerodynamic Forces ◽  
Aero Engine ◽  
Gas Liquid Flow ◽  
Liquid Flows ◽  
Oil Gas ◽  
Lubrication Mechanisms

To help understand the behaviour of oil/gas mixtures and the lubrication processes within bearing chambers of an aero-engine, a rig was developed to represent the bearing chamber at a simplified level. The velocities of gas and liquid flow prevailing around the rapidly rotating annulus were explored when exposed to various parametric conditions. The results revealed that the liquid flowrates, aerodynamic forces and shaft rotation speeds affect the phenomena of gas/liquid flows. Changes in these conditions profoundly affect the behaviour of the lubricating jet, the sizes of the liquid droplets and their velocities as well as the liquid films. These, consequently influence the heat transfer and lubrication mechanisms within annular systems.

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.

scholarly journals Heat Transmission Reinforcers Induced by MHD Hybrid Nanoparticles for Water/Water-EG Flowing over a Cylinder

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 623
Author(s):  
Firas A. Alwawi ◽  
Mohammed Z. Swalmeh ◽  
Amjad S. Qazaq ◽  
Ruwaidiah Idris
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Volume Fraction ◽  
Liquid Velocity ◽  
Flow Characteristics ◽  
Hybrid Nanoparticles ◽  
Critical Parameters ◽  
Heat Transmission ◽  
Constant Wall Temperature

The assumptions that form our focus in this study are water or water-ethylene glycol flowing around a horizontal cylinder, containing hybrid nanoparticles, affected by a magnetic force, and under a constant wall temperature, in addition to considering free convection. The Tiwari–Das model is employed to highlight the influence of the nanoparticles volume fraction on the flow characteristics. A numerical approximate technique called the Keller box method is implemented to obtain a solution to the physical model. The effects of some critical parameters related to heat transmission are also graphically examined and analyzed. The increase in the nanoparticle volume fraction increases the heat transfer rate and liquid velocity; the strength of the magnetic field has an adverse effect on liquid velocity, heat transfer, and skin friction. We find that cobalt nanoparticles provide more efficient support for the heat transfer rate of aluminum oxide than aluminum nanoparticles.

Direct numerical simulation of near‐interface turbulence in coupled gas‐liquid flow

1996 ◽  
Vol 8 (6) ◽  
pp. 1643-1665 ◽  
Author(s):  
Paolo Lombardi ◽  
Valerio De Angelis ◽  
Sanjoy Banerjee
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Liquid Flow ◽  
Gas Liquid Flow

scholarly journals Numerical simulation of the gas-liquid flow inside a horizontal static mixer

2020 ◽  
Vol 5 (2) ◽  
pp. 1-7
Author(s):  
Ryan Anugrah Putra ◽  
Akhlisa Nadiantya Aji Nugroho
Keyword(s):  
Liquid Flow ◽  
Liquid Velocity ◽  
Superficial Velocity ◽  
Static Mixer ◽  
Cfd Simulations ◽  
Mixing Behavior ◽  
Computational Fluid Dynamics Cfd ◽  
Gas Liquid Flow ◽  
Gas Layer ◽  
Superficial Liquid Velocity

The gas-liquid flow inside a horizontal static mixer was numerically investigated by using Euler-Euler Computational Fluid Dynamics (CFD) simulations. The results confirm that the liquid superficial velocity plays a significant role on the mixing behavior of the gas and liquid. The mixing behavior in this present study at a liquid superficial velocity of 0.2 m/s was the worst both axially and radially. Increasing the liquid superficial velocity significantly improve the mixing between gas and liquid. However, the unwanted gas layer still can be found at the superficial liquid velocity less than 0.8 m/s. A good mixing behavior in this study was achieved at a relatively high velocity (i.e. larger than 0.8 m/s).

CFD analysis of gas–liquid flow characteristics in a microporous tube-in-tube microchannel reactor

2018 ◽  
Vol 170 ◽  
pp. 13-23 ◽  
Author(s):  
Wen-Ling Li ◽  
Yi Ouyang ◽  
Xue-Ying Gao ◽  
Chen-Yu Wang ◽  
Lei Shao ◽  
...  
Keyword(s):  
Liquid Flow ◽  
Flow Characteristics ◽  
Cfd Analysis ◽  
Microchannel Reactor ◽  
Gas Liquid Flow
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