Numerical modelling of a microreactor for thermocatalytic decomposition of toxic compounds

2011 ◽  
Vol 32 (3) ◽  
pp. 215-227 ◽  
Author(s):  
Paweł Jóźwik ◽  
Michał Karcz ◽  
Janusz Badur
Keyword(s):  
Numerical Modelling ◽  
Knudsen Diffusion ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Three Dimensional Model ◽  
Toxic Compounds ◽  
Slip Boundary ◽  
Standard Models ◽  
Thermocatalytic Decomposition

Numerical modelling of a microreactor for thermocatalytic decomposition of toxic compounds In this paper a three-dimensional model for determination of a microreactor's length is presented and discussed. The reaction of thermocatalytic decomposition has been implemented on the base of experimental data. Simplified Reynolds-Maxwell formula for the slip velocity boundary condition has been analysed and validated. The influence of the Knudsen diffusion on the microreactor's performance has also been verified. It was revealed that with a given operating conditions and a given geometry of the microreactor, there is no need for application of slip boundary conditions and the Knudsen diffusion in further analysis. It has also been shown that the microreactor's length could be practically estimated using standard models.

scholarly journals Astrometric Tests of Galactic Evolution

1995 ◽  
Vol 166 ◽  
pp. 251-258
Author(s):  
Gerard Gilmore
Keyword(s):  
Phase Space ◽  
Three Dimensional ◽  
Galactic Evolution ◽  
Critical Test ◽  
Current Standard ◽  
High Quality ◽  
Stellar Velocity ◽  
Formation And Evolution ◽  
Standard Models

There are many fundamental aspects of Galactic structure and evolution which can be studied best or exclusively with high quality three dimensional kinematics. Amongst these we note as examples determination of the orientation of the stellar velocity ellipsoid, and the detection of structure in velocity-position phase space. The first of these is the primary limitation at present to reliable and accurate measurement of the Galactic gravitational potential. The second is a critical test of current standard models of Galactic formation and evolution.

Strength Analysis and Optimization Methods for Four Cylinder Engine Crankshaft Based on CATIA and ANSYS

2014 ◽  
Vol 592-594 ◽  
pp. 1789-1793
Author(s):  
Amarjeet Singh ◽  
Vinod Kumar Mittal ◽  
Surjit Angra
Keyword(s):  
Static Analysis ◽  
Material Selection ◽  
Three Dimensional ◽  
Optimization Methods ◽  
Operating Conditions ◽  
Strength Analysis ◽  
Three Dimensional Model ◽  
Ic Engine ◽  
Stress Zone ◽  
Engine Crankshaft

Crankshaft is one of the most important components of an IC engine. Crankshaft should be checked carefully to ensure that its design is fully optimized. The main objective of this paper is to perform the static analysis on four cylinder engine crankshaft to find out its static strength and the maximum stress zone and analyzing the different methods for the optimization of crankshaft in terms of weight, stress and cost reduction. A three dimensional model of four cylinder engine crankshaft is prepared corresponding to actual conditions in Catia V5 software, static analysis is performed using Ansys under extreme operating conditions and the improvement methods for the optimum design are analyzed in terms of geometric improvement, appropriate material selection and methods used for manufacturing of crankshaft.

Conjugate Flow and Heat Transfer Investigation of a Turbo Charger: Part I — Numerical Results

2003 ◽  
Author(s):  
Dieter Bohn ◽  
Tom Heuer ◽  
Karsten Kusterer
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Inlet Temperature ◽  
Three Dimensional Model ◽  
Flow And Heat Transfer ◽  
Turbine Inlet ◽  
Turbo Charger ◽  
Conjugate Calculation

In this paper a three-dimensional conjugate calculation has been performed for a passenger car turbo charger. The scope of this work is to investigate the heat fluxes in the radial compressor which can be strongly influenced by the hot turbine. As a result of this, the compressor efficiency may deteriorate. Consequently, the heat fluxes have to be taken into account for the determination of the efficiency. To overcome this problem a complex three-dimensional model has been developed. It contains the compressor, the oil cooled center housing, and the turbine. 12 operating points have been numerically simulated composed of three different turbine inlet temperatures and four different mass flows. The boundary conditions for the flow and for the outer casing were derived from experimental test data (part II of the paper). Resulting from these conjugate calculations various one-dimensional calculation specifications have been developed. They describe the heat transfer phenomena inside the compressor with the help of a Nusselt number which is a function of an artificial Reynolds number and the turbine inlet temperature.

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.

scholarly journals Universal compact lower limb turning module intended for use in orthotic robots

2018 ◽  
Vol 157 ◽  
pp. 03011
Author(s):  
Mateusz Janowski ◽  
Danuta Jasińska-Choromańska ◽  
Dymitr Osiński ◽  
Marcin Zaczyk
Keyword(s):  
Lower Limb ◽  
State Of The Art ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Three Dimensional Model ◽  
Additional Degree ◽  
Rotation System ◽  
University Of Technology ◽  
Impaired Person ◽  
Turning System

In this paper, a model of an orthotic robot’s lower limb rotation system is presented. The system is intended for use in typical contemporary orthotic robots such as the ‘Veni-Prometheus’ System for Verticalization and Aiding Motion designed at the Faculty of Mechatronics, Warsaw University of Technology. In the paper, the state of the art is briefly stated, with the relatively low number of orthotic robots allowing realization of pivoting turns highlighted. The intended two-stage pivoting turning movement is analyzed in detail and the operating conditions as well as limitations of the turning module are indicated. The conception of a turning module introduces additional degree of freedom to the existing orthotic robot designs by realizing the rotation about the lengthwise axis in the thigh link. A three-dimensional model and its analysis are shown. The proposed design ensures the necessary movement of the lower limb and the torso of an impaired person during the execution of pivoting turn while remaining compact in order to ease the introduction of the turning system to different orthotic robot designs.

EFFECTS OF OPERATING CONDITIONS ON THE DEPOSITION OF GaAs IN A VERTICAL CVD REACTOR

2008 ◽  
Vol 15 (01n02) ◽  
pp. 111-116 ◽  
Author(s):  
JAE-SANG BAEK ◽  
JIN-HYO BOO ◽  
YOUN-JEA KIM
Keyword(s):  
Fluid Transport ◽  
Numerical Study ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Rotation Velocity ◽  
Operating Conditions ◽  
Deposition Condition ◽  
Three Dimensional Model ◽  
Trimethyl Gallium ◽  
Vertical Cvd Reactor

A numerical study is needed to gain insight into the growth mechanism and improve the reactor design or optimize the deposition condition in chemical vapor deposition (CVD). In this study, we have performed a numerical analysis of the deposition of gallium arsenide ( GaAs ) from trimethyl gallium (TMG) and arsine in a vertical CVD reactor. The effects of operating parameters, such as the rotation velocity of susceptor, inlet velocity, and inlet TMG fraction, are investigated and presented. The three-dimensional model which is used in this investigation includes complete coupling between the thermal-fluid transport and species transport with chemical reaction.

scholarly journals Generation of Novel-Substrate-Accepting Biphenyl Dioxygenases through Segmental Random Mutagenesis and Identification of Residues Involved in Enzyme Specificity

2006 ◽  
Vol 72 (3) ◽  
pp. 2191-2199 ◽  
Author(s):  
Marco Zielinski ◽  
Silke Kahl ◽  
Christine Standfuß-Gabisch ◽  
Beatriz Cámara ◽  
Michael Seeger ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Random Mutagenesis ◽  
Major Influence ◽  
Enzyme Specificity ◽  
Three Dimensional Model ◽  
Wild Type Enzyme ◽  
High Frequencies ◽  
Burkholderia Xenovorans ◽  
Function Relationship

ABSTRACT Aryl-hydroxylating dioxygenases are of interest for the degradation of persistant aromatic pollutants, such as polychlorobiphenyls (PCBs), or as catalysts for the functionalization of aromatic scaffolds. In order to achieve dioxygenation of technical mixtures of PCBs, enzymes with broadened or altered substrate ranges are essential. To alter the substrate specificity of the biphenyl dioxygenase (BphA) of Burkholderia xenovorans LB400, we applied a directed evolution approach that used structure-function relationship data to target random mutageneses to specific segments of the enzyme. The limitation of random amino acid (AA) substitutions to regions that are critical for substrate binding and the exclusion of AA exchanges from positions that are essential for catalytic activity yielded enzyme variants of interest at comparatively high frequencies. After only a single mutagenic cycle, 10 beneficial variants were detected in a library of fewer than 1,000 active enzymes. Compared to the parental BphA, they showed between 5- and 200-fold increased turnover of chlorinated biphenyls, with substituent patterns that rendered them largely recalcitrant to attack by BphA-LB400. Determination of their sequences identified AAs that prevent the acceptance of specific PCBs by the wild-type enzyme, such as Pro334 and Phe384. The results suggest prime targets for subsequent cycles of BphA modification. Correlations with a three-dimensional model of the enzyme indicated that most of the exchanges with major influence on substrate turnover do not involve pocket-lining residues and had not been predictable through structural modeling.

scholarly journals КОМП’ЮТЕРНА ТЕХНОЛОГІЯ АНАЛІЗУ ТА ДИЗАЙНУ ПРЕДМЕТНОГО СЕРЕДОВИЩА З ПОЗИЦІЇ ВІЗУАЛЬНОГО СПРИЙНЯТТЯ

2020 ◽  
pp. 39-48
Author(s):  
Т. В. Булгакова ◽  
О. В. Полякова ◽  
С. С. Кисіль ◽  
О. Є. Шмельова
Keyword(s):  
Visual Perception ◽  
Quantitative Determination ◽  
Three Dimensional ◽  
Geometrical Model ◽  
Human Being ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Three Dimensional Objects ◽  
Computer Technologies

The purpose of the investigation is the development of computer technology of analysis and design of built environment from the point of its visual perception in the space of its three-dimensional model without using the perspective projections. The methodology were used to achieve the purpose: analysis of the scientific publications on the topic of object environment composition; applied geometry methods, method of division of the geometrical object into simplexes (triangulation), methods of advanced algebra and analytical geometry; computer modeling for construction of the model of visual perception of the environment. Methods of analysis of the three-dimensional model on the basis of modeling of visual perception by means of computer technologies directly in the area of the model without using perspective projections are developed. It is offered to analyze the visual perception of any objects and their relations by means of using the solid angles with the vertices placed in the point of view and the surfaces that surround the visible contours of three-dimensional objects. This approach gives the opportunity to analyze the objects simultaneously regardless their position according to the observer; apart of that, the objects, which are accepted similarly in the reality, will have the same geometrical features during the modeling of visual perception and beside that, the refusal of using of the perspective projections will make possible to avoid the distortion of the images. The algorithm of determination of the solid angles to three-dimensional objects, which is the basis of computer methods of compositional analysis of the object environment from the position of visual perception without the use of perspective projections, is developed. The geometrical model of visual perception by a human being from the certain point of perception is built. It makes possible to define correctly visual features of the object environment and gives the opportunity to analyze the whole surrounding of the observer in the area of 360 degrees. Scientific novelty of the investigation means that the methods of analysis of the three-dimensional model on the basis of modeling of visual perception by means of computer technologies directly in the area of the model without using perspective projections are developed for the first time. The concept of the geometrical model of visual perception by a human being from the certain point of perception is developed. The further development of the methodology of quantitative determination of characteristics of object environment by means of computer technologies is defined. Practical significance shows that the results of the scientific investigation can be used for analysis and judgments of the aesthetic peculiarities of the object environment by means of computer technologies with quantitative determination of characteristics of object environment from the point of its visual perception. Such approach gives the opportunity to develop and create the further certain recommendations and instructions for correction of the existing environment and for the development of the new one.

scholarly journals Study of Flow Induced Noise in Vertical Inline Pump Using Lighthill Analogy

2018 ◽  
Vol 172 ◽  
pp. 01010
Author(s):  
Stephen Christopher ◽  
Shouqi Yuan ◽  
Ji Pei ◽  
G Xing Cheng ◽  
Wang Yiyun
Keyword(s):  
Power Level ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Return Flow ◽  
Sound Power ◽  
Inlet Pipe ◽  
Three Dimensional Model ◽  
Source Power ◽  
Flow Passage ◽  
Flow Induced Noise

The pump user demands for specification along with noise and vibration magnitude for extreme operating conditions apart from best efficiency flow. In order to predict the noise level in pumps, the entire unit of pump has to be considered for acoustic evaluation. Hence, the full three dimensional model of vertical inline pump which consists of inlet pipe, impeller, and volute casing is considered for detailing the flow induced noise using Lighthill analogy. The performance characteristics of pump are well matched between experimental and computational results and the overall sound power level at best efficiency flow using computation was compared with empirical relations and found to be agreed well. The streamline patterns along the inlet pipe shows the effects of recirculation and return flow at partload condition and confirm that the utilization of flow passage is not well streamlined even for nominal flow rate. Further, the detailed study of inlet pipe cross sections reveals the nature of different noise sources such as dipole and quadrupole sound levels along with Proudman source power level. The intensity of turbulence and vortices in flow passage is predicted well using quadrupole source and Proudman sound power levels.

Synthesis of Three-Dimensional Models from Drawings Based on Spectral Graph Theory

2015 ◽  
Vol 756 ◽  
pp. 598-603 ◽  
Author(s):  
Aleksey Zakharov ◽  
Arkady Zhiznyakov
Keyword(s):  
Graph Theory ◽  
Three Dimensional ◽  
Spectral Graph Theory ◽  
Boundary Representation ◽  
Three Dimensional Model ◽  
Three Dimensional Objects ◽  
Spectral Graph ◽  
Dimensional Models ◽  
Three Dimensional Models

Task of automatic reconstruction of three-dimensional objects by drawing views presented. The algorithm based on a boundary representation of three-dimensional models. The algorithm consists of the following steps: automatic separation of the drawing per the views, determination of three-dimensional coordinates of vertices, definition and marking of wire model primitives, reconstruction of model faces and model elements. The fundamental concept of the algorithm is to find the structural elements of three-dimensional model with usage of pre-specified patterns. The templates are described by means of matrices. Matching algorithm uses spectral graph theory. Reconstruction results are presented.

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