Numerical Study of Evaporation and Motion Characteristics of Liquid Nitrogen Droplet in High-Speed Gas Flow

In the present work, a commercial CFD software package, FLUENT, was used to develop a three-dimensional model of pusher-type billet reheating furnace for the second high speed wire rod plant of XiangTan Iron and steel Co. Ltd. The purpose of the study was to gain a better understanding of the gas flow and velocity and pressure distribution in the furnace. The results show that the numerical results are in agreement with the practice and the characteristics of the furnace configuration. The CFD model can be used to improve the performance and structure by analyzing and studying the behavior of the reheating furnace.

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Numerical Study on Flow Field Distribution Regularities in Wet Gas Desulfurization Tower Changing Inlet Gas/Liquid Feature Parameters

Journal of Energy Resources Technology ◽

10.1115/1.4047590 ◽

2020 ◽

Vol 143 (2) ◽

Author(s):

Qingbo Deng ◽

Jingyu Ran ◽

Juntian Niu ◽

Zhongqing Yang ◽

Ge Pu ◽

...

Keyword(s):

Flow Field ◽

Field Distribution ◽

Flue Gas ◽

High Speed ◽

Gas Flow ◽

Negative Impact ◽

Numerical Study ◽

Negative Influence ◽

Wet Gas ◽

Integration Effect

Abstract In the wet gas desulphurization tower, the uneven distribution of flue gas will have a negative impact on the desulphurization process. The effect should be counterbalanced by increasing the amount of slurry spray, which will increase the operating costs. Adding deflectors will also bring negative effects and increase the expenses. In order to avoid the negative influence, this paper studied the flow field distribution regularities of flue gas in desulfurization tower at different inlet velocities and liquid–gas ratios. Velocity field distribution character was evaluated by uniformity index. The results showed that the flue gas forms a vortex in the tower and a local high-speed gas-flow appears in the empty tower, which led to a poor flow field uniformity. After adding the spray, the flow field is integrated into uniformity. The slurry has obvious integration effect on flue gas. The lower the inlet flue gas velocity is, the higher the velocity uniform index in the desulfurization tower will be, and the heat exchange between the two phases more sufficient. To achieve the same uniformity, the less amount of slurry is required while the inlet velocity is slower. The energy consumption and material consumption of the desulfurization system can be effectively reduced by reducing the import speed reasonably.

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Hydrodynamic Study of Bubbles in a Bubble Column Reactor Part II – Numerical Study

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.813-814.1023 ◽

2015 ◽

Vol 813-814 ◽

pp. 1023-1027

Author(s):

S. Arunkumar ◽

V. Harshavardhan Reddy ◽

T.M. Sreevathsav ◽

M. Venkatesan

Keyword(s):

High Speed ◽

Gas Flow ◽

Bubble Column ◽

Numerical Study ◽

Image Processing Technique ◽

Bubble Velocity ◽

Bubble Column Reactor ◽

Hydrodynamic Characteristics ◽

Flow Rates ◽

Column Reactor

The present work deals with the use of CFD analysis and the validation of the experimental work carried out on the artificial splitting of an air bubble in a bubble column reactor. In Part I of this work, artificial splitting of bubble in a bubble column rector is experimentally studied by using a high speed camera. Image processing technique was used to identify bubble size and bubble velocity. In present work CFD simulations are carried out using ANSYS FLUENT software using Volume of Fluids (VOF) method. VOF is based on a surface tracking technique applied to a fixed Eulerian space. The phase fraction in physical quantities that can be used to distinguish the distribution of gas hold up in a bubble Column reactor. The numerical study of splitting of bubble into two bubbles of nearly equal size is considered. In the bubble column reactor, the liquid phase is stationary and gas flow rate in it is varied. The superficial gas flow rates are 10 lph, 15 lph, 20 lph and 25 lph. The characteristics of bubble after splitting which include its shape, size and velocity for various gas flow rates mentioned above are studied numerically and are compared with experimental results. These hydrodynamic characteristics play a pivotal role in the reactions occurring between the liquid and gas phases in the bubble column reactor.

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Mono-Disperse Spray Generation by a Flow Focusing Atomizer: A Numerical Study

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2012-72088 ◽

2012 ◽

Author(s):

Babak Samareh ◽

Arash Kashani ◽

Javad Mostaghimi

Keyword(s):

High Speed ◽

Gas Flow ◽

Numerical Study ◽

Theoretical Models ◽

Flow Focusing ◽

Flow Solver ◽

Jet Breakup ◽

Compressible Turbulent Flow ◽

Controlled Flow ◽

Good Agreement

Pneumatic flow focusing technology is a relatively new atomizing process first introduced in 1998. A liquid microjet is formed by a high speed co-flowing gas stream when a pressure drop is applied across an orifice. The microjet eventually disintegrates into fine droplets by the perturbing gas downstream of the atomizer exit. Under certain controlled flow regimes the resulting spray demonstrates strong monodispersity. In the present study, the gas flow is numerically modeled by a compressible turbulent flow solver and the liquid jet evolution is captured using Volume of Fluid (VOF) interface tracking method. Jet breakup parameters and drop size distribution are studied for different liquids and flow rates. Results are in good agreement with experiments and theoretical models.

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Experimental and Numerical Study of Real-Gas Flow in a Supersonic ORC Turbine Nozzle

Volume 6: Turbomachinery, Parts A and B ◽

10.1115/gt2006-91118 ◽

2006 ◽

Cited By ~ 1

Author(s):

Teemu Turunen-Saaresti ◽

Jin Tang ◽

Jos van Buijtenen ◽

Jaakko Larjola

Keyword(s):

Flow Field ◽

High Speed ◽

Power Plants ◽

Gas Flow ◽

Numerical Study ◽

Rankine Cycle ◽

Nozzle Geometry ◽

Working Fluid ◽

Cfd Simulations ◽

Real Gas

Using organic matter as the working fluid in small Rankine cycle power plants is beneficial. However, high molecular weight of the fluid and the single-stage design of the turbine lead to a supersonic flow in the turbine. An Organic Rankine Cycle (ORC) plant was designed and tested. Toluene was used as the working fluid and as lubricant. The turbine and the feed pump were placed on the same shaft as the high-speed generator in the designed 175 kW unit. CFD simulations were used in the design process. Toluene is behaving as a real gas in the nozzle. To ensure an accurate simulation, a real gas model of toluene was implemented in an existing Navier-Stokes flow solver. Polynomial and rational regression were used to achieve the functions for the gas properties. The pressure and temperature were measured at the nozzle inlet and outlet. In the CFD simulations the nozzle ring was modelled with and without a temperature probe in order to model the effect of the probe to the flow field and compare the simulated pressure and temperature values against the measurements. The nozzle geometry was also modelled in 2D and 3D in order to see the effect of the 3D in the flow field. There was quite a good agreement between the measured and simulated data. The agreement in the temperature was better than in the pressure. The effect of 3D on the simulation results was minor, which was expected. The simulated flow field revealed that the shock waves developing in the trailing edge of the nozzle were seen in the turbine rotor inlet.

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Numerical Study on Powder Stream Characteristics of Coaxial Laser Metal Deposition Nozzle

Crystals ◽

10.3390/cryst11030282 ◽

2021 ◽

Vol 11 (3) ◽

pp. 282

Author(s):

Liqun Li ◽

Yichen Huang ◽

Chunyu Zou ◽

Wang Tao

Keyword(s):

High Speed ◽

Gas Flow ◽

Numerical Study ◽

Metal Deposition ◽

Laser Metal Deposition ◽

Discrete Phase Model ◽

Stream Morphology ◽

Flow Phase ◽

Discrete Phase ◽

Stream Characteristics

A 3D model was established to accurately simulate the internal and external powder stream characteristics of the coaxial discrete three-beam nozzle for laser metal deposition. A k-ε turbulence model was applied in the gas flow phase, and powder flow was coupled to the gas flow by a Euler-Lagrange approach as a discrete phase model. The simulated powder stream morphology was in good agreement with the experimental results of CCD and high-speed camera imaging. The simulation results showed that the length, diameter and shrinkage angle of the powder passage in the nozzle have different effects on the velocity and convergence characteristics of the powder stream. The influence of different particle size distribution and the inner laser shielding gas on the powder stream were also discussed in this study. By analyzing the powder stream caused by different incident directions of powder passage, and the collision process between powder and the inner wall, the basic principle of controlling powder stream convergence was obtained.

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