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

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.

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

2006 ◽  
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.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

Model Experimental Study of SCR Reactor Flow Optimization in 1000MW Coal-Fired Boiler

2014 ◽  
Vol 955-959 ◽  
pp. 2177-2181
Author(s):  
Wen Yan Li ◽  
Shi Yong Wang ◽  
Xiao Ming Wang
Keyword(s):  
Flow Field ◽  
Experimental Model ◽  
Model Test ◽  
Flue Gas ◽  
Gas Flow ◽  
Similarity Theory ◽  
Cold Model ◽  
Power Plant Boiler ◽  
Design Requirements ◽  
Plant Boiler

The structure and arrangement of flue and deflector modules have significant influences on flue gas flow field and distribution of NH3 concentration in a SCR reactor. Numerical calculations about distributions of velocity, NH3 concentration and flow resistance in the deNOx reactor of a 1000MW power plant boiler with CFD have provided the optimal combination of layout scheme of guide plates. A1:15 experimental model of the reactor was constructed based on the principles of similarity theory, and cold model test was carried out with air substituting for flue gas, and CO for NH3.The consequences of model test and numerical modeling were basically similar and met the design requirements. Moreover, deposition characteristics of the experimental model was studied with fly ash from coal-fired boiler, which demonstrated that deposition was not severe under both 50% and 100% boiler full load. The model experiments indicated that the optimum program could achieve purpose of the flow field optimization.

Numerical Simulation of Gas Flow in a Square Cyclone Separator With Double Inlets

2007 ◽  
Author(s):  
Bin Xiong ◽  
Xiaofeng Lu ◽  
R. S. Amano
Keyword(s):  
Pressure Drop ◽  
Flow Field ◽  
Gas Flow ◽  
Numerical Study ◽  
Reynolds Stress Model ◽  
Cyclone Separator ◽  
Stress Model ◽  
Inlet Velocity ◽  
Vortex Finder ◽  
Flow Changes

This paper presents a numerical study of gas flow in a square cyclone separator with a double inlet. The turbulence of gas flow is computed by the use of the Reynolds stress model. The distribution of the flow field and pressure drop under different constructional details, which include changes of the shape, size and arrangement of the vortex finder are obtained. The computed results in the distributions of pressure in different sections are verified by comparison with those measured. We found that the center of the flow field is nearly on the geometric center of the cyclone. The flow fields show a feature of Rankine eddy, i.e., a strongly swirling region in the central part and a pseudo-free eddy region of weak swirling intensity near the cyclone wall. Local vortex exists at the corners where the flow changes their direction sharply, but it is less chaotic than in the general square cyclone with a single inlet. The flow field away from the outlet of the vortex finder is different from the Rankine eddy. The pressure-drop increases rapidly with the increase of the inlet velocity, and the pressure-drop increases with the decrease of the diameter of vortex finder and the increase of length of the vortex finder. The calculat ed results of this paper provide some guidance for the optimization of the square cyclone separator structure.

Numerical Study of the Pusher-Type Billet Reheating Furnace

2005 ◽  
Author(s):  
Linjiang Zou ◽  
Chaoxiang Li ◽  
Yinmei Yuan ◽  
Wei Guo ◽  
Fan Yang ◽  
...  
Keyword(s):  
Software Package ◽  
High Speed ◽  
Gas Flow ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cfd Model ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Iron And Steel ◽  
Reheating Furnace

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.

scholarly journals Numerical study on the influence of initial ambient temperature on the aerodynamic heating in the tube train system

2020 ◽  
Author(s):  
Shijie Bao ◽  
Xiao Hu ◽  
Jukun Wang ◽  
Yingyu Rao ◽  
Zigang Deng
Keyword(s):  
Low Temperature ◽  
Flow Field ◽  
Ambient Temperature ◽  
Temperature Region ◽  
High Speed ◽  
Numerical Study ◽  
Geometric Model ◽  
Flow Region ◽  
Aerodynamic Heating ◽  
Evacuated Tube Transportation

Abstract The evacuated tube transportation has great potential in the future because of its advantages of energy saving and environmental protection. The train runs in the closed tube at ultra-high speed. Because the heat quantity generated by aerodynamic heating is not easy to spread to external environment and will be accumulate in the tube, the phenomenon that the ambient temperature in the tube will gradually rise will be induced. In this paper, a three-dimensional geometric model and the Shear Stress Transport (SST) κ-ω turbulence model are used to study the influence of initial ambient temperature on the structure of the flow field in the tube. Simulation results show that when the train runs at transonic speed, the supersonic flow region with low temperature and low-pressure is produced in the wake. The structure of the flow field of the wake will change with the initial ambient temperature. And the higher the initial ambient temperature, the shorter the low temperature region in the wake. Considering that the larger temperature difference caused by the low temperature region may increase the temperature stress of the tube and affect the equipment inside the tube. Consequently, the temperature inside the tube can be maintained at a reasonable value to reduce the influence of the low temperature region in the wake on the system.

A Stochastic Immersed Model of Breakup Characteristics in Dense Air Atomization Flow Field

2020 ◽  
Author(s):  
Tian Deng ◽  
Xingming Ren ◽  
Yaxuan Li
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Large Scale ◽  
Gas Flow ◽  
Liquid Core ◽  
Average Diameter ◽  
Simulation Method ◽  
Spray Angle ◽  
Random Structure ◽  
Momentum Ratio

Abstract For the low-speed liquid injected into the high-speed strong turbulent gas flow in the same direction, the atomization is a transient-intensive spray, and there are many factors affecting and controlling the atomization. In this paper, the distribution and characteristics of the liquid breakup in the air atomized flow field are analyzed. A stochastic immersed model to simulate the liquid core is developed, in which, the liquid core is regarded as an immersed porous medium with a random structure, and the probability of existence is used to simulate the position of the liquid core. The initial fragmentation mechanism of the air blast atomization is applied as the global variables of the stochastic process. Using the above stochastic immersed model, combined with the Large Eddy Simulation method, the numerical simulation of the downstream flow field of a coaxial jet air atomizing nozzle is carried out. Additional force is added to the momentum equation in the LES model. Instantaneous air velocity at the air-liquid interface is characterized by instantaneous liquid phase velocity at the same time. The size of the initial atomized droplet satisfies a probability distribution, and once the large droplets are formed, the Lagrangian method is used to track the droplets. The comparison between the simulation results and the experimental results shows that this stochastic immersed model can quickly capture the information of length and position of the liquid nucleus. When the gas-liquid momentum ratio M is 3∼10000, the liquid core length can be predicted more accurately. When M>10, the prediction result is much better than phenomenological model. This model is capable of capturing flow field structures such as recirculation zones and large-scale vortices. The results of initial spray angle from experiment expression give slightly better agreement with this model. Increasing the momentum ratio leads to decreasing of the initial spray angle. The particle size of the droplets near the nozzle can be accurately predicted, especially when the gas velocity is large (bigger than 60 m/s), and the average diameter prediction error of the droplets is less than 10%.

Numerical Study of Performances of Vertical Axis Tidal Turbines

2012 ◽  
Vol 455-456 ◽  
pp. 296-301
Author(s):  
Yan Liu ◽  
Peng Fei Zhao ◽  
Xiao Hui Su ◽  
Guang Zhao
Keyword(s):  
Flow Field ◽  
Turbulent Flows ◽  
Stokes Equations ◽  
Numerical Study ◽  
Vertical Axis ◽  
Negative Influence ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Tidal Turbines ◽  
Central Shaft

Numerical simulations of flows over two-dimensional vertical axis tidal turbines are carried out. Unsteady Reynolds averaged Navier-Stokes Equations are applied to model turbulent flows. Influence of the central shaft and number of blades on flow field and thus performances of turbines are investigated. Performances in terms of torque and power coefficients are obtained for different types of turbines. Results demonstrates that the central shaft has a negative influence on flow field and power coefficients. Solidity and tip speed ratio are two important factors to affect turbine’s performances. This paper provides useful information for future studies.

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