scholarly journals Numerical and Experimental Investigations on Reducing Particle Accumulation for SCR-deNOx Facilities

2019 ◽  
Vol 9 (19) ◽  
pp. 4158
Author(s):  
Zeng ◽  
Yuan ◽  
Wang
Keyword(s):  
High Speed ◽  
Power Plants ◽  
Catalyst Deactivation ◽  
Catalytic Reduction ◽  
Experimental Investigations ◽  
Duct Flow ◽  
Cfd Simulations ◽  
Particle Accumulation ◽  
Computational Fluid Dynamics Cfd ◽  
Vertical Duct

Selective catalytic reduction (SCR) is widely used to remove nitrogen oxides (NOx) in the flue gas of coal-fired power plants. The accumulation of ash particles inside the SCR-deNOx facility will increase the risk of catalyst deactivation or even damage. This paper presents the numerical and experimental investigations on the particle dispersal approach for the SCR-deNOx facility of a 1000 MW coal-fired power plant. The accumulation of different-sized particles is evaluated based on computational fluid dynamics (CFD) simulations. To prevent particles from accumulation, an optimized triangular deflector is proposed and attempts are made to find out the optimal installing position of the deflector. For the π-type SCR-deNOx facilities, the particle accumulation predominantly occurred on one side of the catalysts’ entrance, which corresponds to the inner side of the wedge-shaped turning. It is indicated that particles larger than 8.8 × 10−2 mm are responsible for the significant accumulation. The triangular deflector is proved to be an effective way to reduce particle accumulation and is found most efficient when it is installed at the high-speed area of the vertical duct. Flow model test (FMT) is carried out to validate the dispersal effect for the particle with relatively large sizes and the optimal installing position of the triangular deflector.

Transient CFD Visualization of Fossil Fuel Combustion Simulations

2003 ◽  
Author(s):  
Brian Dotson ◽  
Kent Eshenberg ◽  
Chris Guenther ◽  
Thomas O’Brien
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Cfd Simulation ◽  
Low Cost ◽  
Three Dimensional ◽  
Cfd Simulations ◽  
Projection System ◽  
Computational Fluid Dynamics Cfd ◽  
High Level ◽  
Wall System

The design of high-efficiency lower-emission coal-fed power plants is facilitated by the extensive use of computational fluid dynamics (CFD) simulations. This paper describes work conducted at the National Energy Technology Laboratory (NETL) and Pittsburgh Supercomputing Center (PSC) to provide an environment for the immersive three-dimensional visualization of CFD simulation results. A low-cost high-resolution projection system has been developed in the visualization lab at NETL. This multi-wall system consists of four projection screens, three of which are tiled into four quadrants. The graphics for the multi-wall system are rendered using a cluster of eight personal computers. A high-level visualization interface named Mavis has also been developed to combine the powerful 3D modules of OpenDX with methods developed at NETL for studying multiphase CFD data. With Python, a completely new OpenDX user interface was built that extends and simplifies the features of a basic graphics library.

Measurement of the Aerodynamic Pressures Produced by Passing Trains

Joint Rail ◽  
2002 ◽  
Author(s):  
Robert A. MacNeill ◽  
Samuel Holmes ◽  
Harvey S. Lee
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Electric Locomotive ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Freight Car

This paper describes measurement of the aerodynamic pressures produced by a Bombardier High-Speed Non-Electric Locomotive (HSNEL) on an adjacent stationary double-stack freight car. Static pressures are measured on the near and far-side faces of the freight containers over a range of locomotive speeds from 60 to 130 mph. This data is also compared with the pressures predicted by computational fluid dynamics (CFD) simulations.

Investigation of the System Coupling Regenerative Heat Exchange and Selective Catalytic Reduction for Heat Exchange and NOx Removal

2014 ◽  
Vol 955-959 ◽  
pp. 2087-2092
Author(s):  
Zhong Jun Tian ◽  
Shi Ping Jin ◽  
Yu Ming Liang
Keyword(s):  
Heat Exchange ◽  
Selective Catalytic Reduction ◽  
Power Plants ◽  
Switching Time ◽  
Catalytic Reduction ◽  
Coupled System ◽  
Experimental Investigations ◽  
Regenerative Heat ◽  
System Coupling ◽  
Peak Value

In conjunction with theoretical heat exchange model, experimental investigations have been conducted for a coupled system of Selective Catalytic Reduction (SCR) and Regenerative Heat Exchange (RHE), to reduce nitrogen oxides (NOx) from coal-fired boilers and High Temperature Air Combustion (HiTAC) furnaces. Results indicate there is no effect of catalysis reactions on heat transfer; catalysts serve the function of heating elements. The outlet NO concentration periodically decreased in an almost linear fashion. NO conversion: i) rose slowly with a longer switching time; and ii) reached the peak value of temperature with a delay compared with the steady state. The coupled system requires less space and hence is a suitable option for SCR renovations in coal-fired power plants.

Experimental Investigation of Steam Bubble Condensation in Flowing Subcooled Water With Two Different Injection Nozzle Geometries

2013 ◽  
Author(s):  
Suleiman Al Issa ◽  
Patricia B. Weisensee
Keyword(s):  
Test Section ◽  
High Speed ◽  
Nuclear Power ◽  
Power Plants ◽  
Bubble Diameter ◽  
Large Diameter ◽  
Low Pressure ◽  
Test Facility ◽  
Experimental Investigations ◽  
Subcooled Water

A multiphase flow test facility was built at the Department of Nuclear Engineering at the Technical University Munich. The main goal of this facility is to investigate the condensation of steam bubbles injected into a vertical large diameter pipe (104 mm) with flowing subcooled water (6–15 K) at low pressure conditions (1.1–1.45 bar). Current experimental investigations will contribute to a better understanding of subcooled boiling at low pressures, accidental conditions in nuclear power plants and low-pressure research reactors and correlations for the validation of CFD codes. The test section is a 1 m long transparent pipe that is surrounded by an 18×18 cm rectangular “aquarium” filled with distilled water for refraction correction. High-speed camera (HSC) recording was used to gather data about condensing bubbles including bubble diameter, shape and rising velocity. Steam was injected via two different vertical injection nozzles with an inner diameter of 4 and 6 mm, respectively, directly into the center of the test section. The present experiments were carried out at three different steam superficial velocities, water superficial velocities and water temperatures leading to bubble diameters up to 50 mm and bubble relative velocities around 1 m/s. The measurements enabled the calculation of bubble Reynolds and Nusselt numbers and comparison with correlations given in literature. Even though significant differences could be observed between the two injection nozzles with respect to the bubble’s diameter and velocity, the Nusselt and Reynolds numbers are in the same range of values. The bigger bubbles of the 6 mm with respect to the 4 mm nozzle are almost neutralized by the lower rising velocities.

Comparison of the CFD Results to PIV Measurements in Kinematics of Spilling and Plunging Breakers

2020 ◽  
Author(s):  
Bülent Düz ◽  
Jule Scharnke ◽  
Rink Hallmann ◽  
Jan Tukker ◽  
Siddhant Khurana ◽  
...  
Keyword(s):  
High Speed ◽  
Piecewise Linear ◽  
Sampling Rate ◽  
Navier Stokes ◽  
Computational Domain ◽  
Cfd Simulations ◽  
High Sampling Rate ◽  
Interface Reconstruction ◽  
Image Velocimetry ◽  
Computational Fluid Dynamics Cfd

Abstract The kinematics under spilling and plunging breakers are investigated using both experimental and numerical methods. In a modular laboratory flume, the breakers were generated using dispersive focusing, and the kinematics underneath them were measured utilizing the Particle Image Velocimetry (PIV) technique. Using the state-of-art high-speed video cameras and lasers, the kinematics were measured at a high sampling rate without needing phase-locked averaging. Afterwards, Computational Fluid Dynamics (CFD) simulations were carried out for comparison purposes. These simulations were run in single-phase using a finite-volume based Navier-Stokes solver with a piecewise-linear interface reconstruction scheme. The spilling and plunging breakers from the measurements were reconstructed in the computational domain using an iterative scheme. As a result a good match with the measured waves was obtained in the simulations. Results indicate that even though measured kinematics are somewhat higher than the simulated ones especially in the spilling and overturning regions, the CFD simulations can accurately capture the relevant details of the flow and produce reasonably accurate kinematics in comparison with the PIV results.

Study on the Porpoising Phenomenon of High-Speed Trimaran Planing Craft

2018 ◽  
Author(s):  
Yuming Yuan ◽  
Chao Wang
Keyword(s):  
Fluid Dynamics ◽  
High Speed ◽  
Center Of Gravity ◽  
Rolling Motion ◽  
Upward Movement ◽  
Cfd Simulations ◽  
Flow Lines ◽  
Planing Craft ◽  
Computational Fluid Dynamics Cfd ◽  
Aerodynamic Lift

This paper presents the application of Computational Fluid Dynamics (CFD) simulations to the heaving and rolling motion of the planing craft under different speeds and centers of gravity. Comparing the flow lines, the pressure distribution at the bottom of the boat, the heave and the trim angle before instability with those elements after instability, a critical trim angle results in the early separation of the air in the bow. Meanwhile, due to effect of aerodynamic lift, the bow is lifted, which eventually leads to instability of the hull. Forward or upward movement of the center of gravity may eliminate or postpone the porpoising, the backward center of gravity may result in the unstablity of the ship. Serious porpoising is random and irregular. It will damage the structure of the hull, affect the maneuverability of the ship and threaten the safety of the crew.

Numerical and Experimental Studies of Collapsing Cavitation Bubbles for Ballast Water Treatment

2018 ◽  
Author(s):  
Chang-Wei Kang ◽  
Tandiono Tandiono ◽  
Xin Lu ◽  
Cary K. Turangan ◽  
Hafiiz Osman ◽  
...  
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Hydrodynamic Cavitation ◽  
High Speed Photography ◽  
Gas Bubble ◽  
Liquid Pressure ◽  
Cfd Simulations ◽  
Bubble Cloud ◽  
Computational Fluid Dynamics Cfd ◽  
Sudden Jump

In this paper, we report both experimental and computational studies of hydrodynamic cavitation generated by accelerating liquid through a series of constrictions. The detailed process of cavitation generation is visualized using a high-speed photography. The cavitation is initiated when a gas bubble moves towards the constrictions. The gas bubble initially accelerates, expands and then splits into smaller bubbles when it moves along the constriction. As these bubbles migrate into a large liquid compartment, they collapse violently to form a bubble cloud, owing to a sudden jump in liquid pressure in the compartment. The experimental observation is further confirmed using computational fluid dynamics (CFD) simulations. We also present experimental evidence showing a significant reduction in gram-negative Escherichia coli concentration after it passes through the constrictions.

scholarly journals Deactivation of V2O5−WO3/TiO2 DeNOx Catalyst under Commercial Conditions in Power Production Plant

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6200
Author(s):  
Maciej Zyrkowski ◽  
Monika Motak ◽  
Bogdan Samojeden ◽  
Krzysztof Szczepanek
Keyword(s):  
Power Plants ◽  
Catalyst Deactivation ◽  
Catalytic Reduction ◽  
Production Plant ◽  
Health It ◽  
High Concentration ◽  
Ammonia Slip ◽  
Different Types ◽  
The Impact ◽  
Denox Catalyst

Nitrogen dioxide is one of the most dangerous air pollutants, because its high concentration in air can be directly harmful to human health. It is also responsible for photochemical smog and acid rains. One of the most commonly used techniques to tackle this problem in large combustion plants is selective catalytic reduction (SCR). Commercial SCR installations are often equipped with a V2O5−WO3/TiO2 catalyst. In power plants which utilize a solid fuel boiler, catalysts are exposed to unfavorable conditions. In the paper, factors responsible for deactivation of such a catalyst are comprehensively reviewed where different types of deactivation mechanism, like mechanical, chemical or thermal mechanisms, are separately described. The paper presents the impact of sulfur trioxide and ammonia slip on the catalyst deactivation as well as the problem of ammonium bisulfate formation. The latter is one of the crucial factors influencing the loss of catalytic activity. The majority of issues with fast catalyst deactivation occur when the catalyst work in off-design conditions, in particular in too high or too low temperatures.

Using Experimental Fluid Dynamics and Computational Fluid Dynamics for Evaluating Periodic Mixing

2018 ◽  
Author(s):  
Judith Ann Bamberger ◽  
Leonard F. Pease ◽  
Kurtis P. Recknagle ◽  
Carl W. Enderlin ◽  
Michael J. Minette
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
System Performance ◽  
Experimental Investigations ◽  
Cfd Simulations ◽  
Mixing Processes ◽  
Experimental Fluid Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Fluid ◽  
Pulse Jet

Periodic mixing using pulse jet mixers is being developed and applied for processing unique slurries of radioactive waste that depending upon the slurry properties may possess either Newtonian or non-Newtonian characteristics. To investigate the performance of these mixing systems, scaled experimental fluid dynamics (EFD) experiments have been conducted and in addition, for certain investigations, computational fluid dynamics (CFD) simulations have been applied. The purpose of this paper is to describe the periodic mixing processes, elaborate regarding the types of scaled experiments that were conducted, and present examples of computational investigations conducted to further define the mixing system performance. The experimental investigations showed the ability to track visual metrics such as cloud height and cavern size. The computational investigations demonstrated the ability to model full-scale experiments with Newtonian slurries.

scholarly journals Simulation of the Filling Capability in Vane Pumps

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 283 ◽  
Author(s):  
Massimo Rundo ◽  
Giorgio Altare ◽  
Paolo Casoli
Keyword(s):  
High Speed ◽  
Maximum Flow ◽  
Vane Pump ◽  
Cfd Simulations ◽  
Flow Area ◽  
Positive Displacement ◽  
Incomplete Filling ◽  
Computational Fluid Dynamics Cfd ◽  
Suction Flow ◽  
Dissolved Air

In positive displacement pumps, the main volumetric loss at high speed is due to the incomplete filling of the variable volume chambers. The prediction of the limit speed and of the maximum flow rate delivered by a pump can be obtained only through Computational Fluid Dynamics (CFD) simulations, since the shape, the orientation, and the movement of the chambers with respect to the inlet volume must be considered, along with the non-uniform distribution of the gaseous phase, due to the dissolved air release. In this paper, the influence of different geometric parameters on the filling of a vane pump has been investigated through the commercial software PumpLinx®. At first, a model of a reference pump has been created and validated with different configurations of the suction flow area, then a simplified model has been used for assessing the influence of the geometry of the rotating assembly. It was found that a pump with a low ratio between the axial thickness and the diameter has a higher volumetric efficiency if the chambers are fed from one side only. Opposite behaviors were found in the case of pumps with small diameters and high thicknesses. Moreover, the filling could be improved by increasing the number of chambers, and by reducing the diameter of the rotor, even only locally.

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