A System of Selective Non Catalytic Reduction of NOx for Diesel Engine

2011 ◽  
Vol 201-203 ◽  
pp. 643-646 ◽  
Author(s):  
Bo Yan Xu ◽  
Hai Ying Tian ◽  
Jie Yang ◽  
De Zhi Sun ◽  
Shao Li Cai
Keyword(s):  
Catalytic Reduction ◽  
Three Dimensional ◽  
Exhaust Gas ◽  
Test Results ◽  
Practical Application ◽  
Three Dimensional Model ◽  
Reduction Efficiency ◽  
Different Temperatures ◽  
Reduction Of Nox ◽  
Good Agreement

SNCR (Selective Non Catalytic Reduction) system is proposed, with 40% methylamine aqueous solution as reducing agent to reduce NOx in diesel exhaust gas. The effect of injection position and volume on the reduction efficiency through the test bench is systematically researched. A three-dimensional model of a full-sized diesel SNCR system generated by CFD software FIRE is used to investigate the reduction efficiency under different temperatures. The simulated results have a good agreement with the test results, and it can be used to optimize SNCR system. The results can indicate the practical application of this technology.

Use of a three-dimensional model to predict heavy metal (copper) fluxes in the Oujiang estuary

2014 ◽  
Vol 69 (6) ◽  
pp. 1334-1343 ◽  
Author(s):  
Shasha Lu ◽  
Ruijie Li ◽  
Xiaoming Xia ◽  
Jun Zheng
Keyword(s):  
River Discharge ◽  
Water Surface ◽  
Three Dimensional ◽  
Measured Data ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Pollutant Concentrations ◽  
Suspended Sediment Concentrations ◽  
Adsorption Desorption ◽  
Good Agreement

Measuring pollutant concentrations in major tributaries is the standard method for establishing pollutant fluxes to the sea. However, this method is costly and difficult, and may be subject to a great deal of uncertainty due to the presence of unknown sources. This uncertainty presents challenges to managers and scientists in reducing contaminant discharges to water bodies. As one less costly method, a three-dimensional model was developed and used to predict pollutant fluxes to the sea. The sorptive contaminant model was incorporated into hydrodynamic and sediment models. Adsorption–desorption of copper by sediments in the Oujiang estuary were described using Henry's law. The model was validated using measured data for water surface elevations, flow velocity/direction, suspended sediment concentrations, and the proportion of copper sorbed to sediment. The validated model was then applied to predict fluxes of copper. Combined with the measured data, the copper concentration in the Oujiang River discharge was calculated as 13.0 μg/L and copper fluxes were calculated as 52 t in 2010. This copper flux prediction was verified using measured dissolved copper concentrations. Comparisons between the modeled and measured results showed good agreement at most stations, demonstrating that copper flux prediction in the Oujiang estuary was reasonably accurate.

An anti-crystallization design of selective catalytic reduction nozzle holder

2021 ◽  
pp. 095440702097084
Author(s):  
Dewen Liu ◽  
Kai Lu ◽  
Shusen Liu ◽  
Yan Wu ◽  
Shuzhan Bai
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Injection System ◽  
Test Results ◽  
Verification Methods ◽  
Crystallization Risk ◽  
Protective Cover ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Good Agreement

From the aspect of reducing the risk of crystallization on nozzle surface, a new design of nozzle protective cover was to solve the problem in selective catalytic reduction (SCR) urea injection system. The simulation calculation and experimental verification methods were used to compare different schemes. The results show that reducing the height of nozzle holder can reduce the vortex currents near nozzle surface and effectively reduce the risk of crystallization on the nozzle surface. It is proposed to install a protective cover in the nozzle holder under the scheme of reducing the height of nozzle holder, which can further eliminate the vortex. Simulation and test results demonstrate good agreement under the rated running condition. The scheme of adding a protective cover in the nozzle holder shows the least crystallization risk by computational fluid dynamics (CFD) method. The crystallization cycle test shows that, after the height of nozzle holder is reduced, the risk of crystallization on the nozzle surface is reduced correspondingly. The addition of a protective cover in the nozzle holder solves the problem of crystallization on the nozzle surface, which provides a new method for anti-crystallization design.

Effect of manufacturing parameters and thermal treatment on the properties of tubular braids and tubular knits

2016 ◽  
Vol 36 (4) ◽  
pp. 421-430
Author(s):  
Ching-Wen Lou ◽  
Po-Ching Lu ◽  
Jin-Jia Hu ◽  
Jia-Horng Lin
Keyword(s):  
Thermal Treatment ◽  
Three Dimensional ◽  
Textile Composites ◽  
Treatment Temperature ◽  
Test Results ◽  
Thermal Treatment Temperature ◽  
Medical Textiles ◽  
Different Temperatures ◽  
Conductive Textile ◽  
Manufacturing Parameters

Abstract Textile techniques can be applied to create two-dimensional or three-dimensional tubular fabrics. Three-dimensional tubular knits can be used in many fields, such as for medical textiles, conductive textile, composites, and tissue engineering. This study aimed to examine the effects of different yarn types on various fabrics and of different temperatures on the variations in the properties of textiles. Four types of wrapped yarn (P150, P75, S140, and S70) were made into tubular braids and knits, after which the products were thermally treated at various temperatures (120°C, 140°C, and 160°C). A shrinkage measurement, a porosity test, a braid angle test, and a tensile test were performed to evaluate the tubular braids and knits. The test results indicated that the thermal treatment temperature did not affect the porosity of the tubular braids and tubular knits. The porosity of the tubular braids was between 40.32% and 48.27%, while that of the tubular knits was between 10.15% and 35.57%. In addition, the tensile strength of both fabric types increased by 40–50%, while their displacement increased by 200–250%. In the future, the efficacy of tubular braids and tubular knits for use as vascular grafts will be examined.

The Simulation Research on Air Drag Reduction of Tail Dome on Vans

2013 ◽  
Vol 345 ◽  
pp. 48-53
Author(s):  
Li Feng Cao ◽  
Xiao Peng Xie ◽  
Jian Hao Zeng ◽  
Heng Huang
Keyword(s):  
Drag Reduction ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Test Results ◽  
Three Dimensional Model ◽  
Simulation Test ◽  
Simulation Research ◽  
Wind Resistance ◽  
Pressure Drag ◽  
Variable Speed Motor

In this paper, three different types of tail domes were designed based on the mechanism of reducing pressure drag between the front and rear of vans, and it takes the van without a dome as a comparison to discuss the drag reduction effects of three different sizes. The three-dimensional model of the van is established in PRO/E, and the pressure and velocity distribution of the van model were analyzed in Fluent; In addition, the wind resistance test of the van model is proceed in the variable speed motor wind resistance simulation test device. The results of CFD simulation have good consistency with the experimental test results, and it verifies the conclusion that the tail dome is good for drag reduction. It provides basis and reference for the optimization of drag reduction for the vans.

Numerical Simulation of a Mini-Channel Three-Way Catalytic Converter

2010 ◽  
Author(s):  
M. H. Akbari ◽  
R. Roohi ◽  
S. A. Asaee
Keyword(s):  
Conversion Efficiency ◽  
Single Channel ◽  
Heterogeneous Reaction ◽  
Catalytic Converter ◽  
Three Dimensional ◽  
Space Velocity ◽  
Kinetic Mechanism ◽  
Operating Conditions ◽  
Three Dimensional Model ◽  
Different Temperatures

A three-dimensional model is developed to simulate the behavior of a single-channel three-way catalytic converter. The flow regime is assumed to be steady and laminar, and the channel walls are considered as isothermal. A multi-step, global heterogeneous reaction mechanism with 16 reactions and 11 species is used in this investigation to enhance the accuracy of the results. The chemical reactions are assumed to occur only on the reactor walls. The developed model is validated against available experimental data for stoichiometric operating conditions. The effect of the feed temperature on the conversion efficiency of the main pollutant components is studied. The light-off temperature for the stoichiometric A/F is found to be about 530 K for CO, NO and UHC, and 425 K for H2 conversion. The model is also applied to predict the effect of reactor length and inlet mixture space velocity on the conversion efficiency at two different temperatures. By using the same kinetics a well-stirred, unsteady model is also developed to identify the sensitivity of the multi-step kinetic mechanism to the mixture composition. The effect of mole fraction variation of each species on the conversion of other mixture components is investigated.

Waves of Acoustically Induced Transparency in Bubbly Liquids: Theoretical Prediction and Experimental Validation

2013 ◽  
Author(s):  
Nail A. Gumerov ◽  
Iskander S. Akhatov ◽  
Claus-Dieter Ohl ◽  
Sergei P. Sametov ◽  
Maxim V. Khasimulin ◽  
...  
Keyword(s):  
Acoustic Field ◽  
Acoustic Waves ◽  
Three Dimensional ◽  
Self Organization ◽  
Nonlinear Phenomenon ◽  
Three Dimensional Model ◽  
Bubbly Liquids ◽  
Strongly Nonlinear ◽  
Induced Transparency ◽  
Good Agreement

Self-organization of bubbles in acoustic fields, or self-action of the acoustic waves in bubbly liquids is a strongly nonlinear phenomenon due to two-way interaction of the bubbles and the acoustic field. Theoretical model and preliminary computations predict that waves of self-induced acoustic transparency may exist. Such effect is confirmed in the experiments presented in this paper. Formation of a wave of void fraction which rapidly propagates through the bubbly medium leaving a region almost free of bubbles behind its front is observed in the experiments. Measurements of the dynamics of such a wave at different acoustic frequencies and amplitudes are carried out. A three dimensional model of self-organization of a polydisperse bubble continuum in acoustic field is developed and the results of simulations are compared with experiments. A good agreement of the theory and experiment is found.

Experimental Study of Propeller-Induced Vibratory Pressures on Simple Surfaces and Correlation With Theoretical Predictions

1964 ◽  
Vol 8 (05) ◽  
pp. 15-28
Author(s):  
J. P. Breslin ◽  
T. Kowalski
Keyword(s):  
Free Space ◽  
Three Dimensional ◽  
Theoretical Treatment ◽  
Plate Boundaries ◽  
Practical Application ◽  
Finite Area ◽  
Experimental Procedure ◽  
Theoretical Predictions ◽  
Pressure Changes ◽  
Good Agreement

Vibratory pressures exerted on cylindrical and flat-plate boundaries due to a model propeller were measured at three advance coefficients. A number of "free-space" measurements also were made. All measurements were made by driving a propeller past fixed pressure gages. This method yielded curves of pressure changes which are entirely free from background noise. The magnitudes of the free-space pressures were found to be larger than one half the corresponding magnitudes measured by gages mounted flush in a large plate at equal clearances from the propeller. By postulating that the finite area of the gage diaphragm produces a partial image of the propeller (and hence a larger pressure than that in free space) an experimental procedure was devised for correcting for this finite-area effect yielding results in good agreement with theory. A theoretical treatment of this effect of finite gage size is given in Appendix 2. The decay of maximum amplitudes of vibrating pressures is shown by means of three-dimensional plots. The pressures were found to become vanishingly small within approximately one propeller diameter fore and aft of the center of the propeller. The comparison with theoretically calculated pressures and forces gives very close agreement for free-space pressures and reasonable agreement for forces on a cylindrical surface. The agreement of both pressures and forces with theory is excellent for operation near the design advance ratio. A strong plea is made for further experiments with ship models in an effort to develop design criteria for practical application.

Ce-ZSM-5 catalysts for the selective catalytic reduction of NOx in stationary diesel exhaust gas

1999 ◽  
Vol 21 (3) ◽  
pp. 203-213 ◽  
Author(s):  
W.E.J. van Kooten ◽  
B. Liang ◽  
H.C. Krijnsen ◽  
O.L. Oudshoorn ◽  
H.P.A. Calis ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Diesel Exhaust ◽  
Catalytic Reduction ◽  
Exhaust Gas ◽  
Reduction Of Nox
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