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particle electrification in an apparatus with a draft tube operating in a fast circulating dilute spout-fluid bed regime

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particuology 2019年第1期17卷 146-153页

作者： wojciech Ludwig Wroclaw University of Science and Technology Faculty of Chemistry. Department of Chemical EngineeringNorwida 4/650-373 WroclawPoland

The intensity of the electrostatic charge accumulated during the flow of Cellets^■ particles in a modified Wurster apparatus is investigated in terms of the bed mass, and the initial moisture and velocity of the spouting gas. particle electrification is proportional to the increase in the velocity of the spouting gas, which is connected with a higher velocity of the cores and the strength of their impact on the walls of the device. The presence of moisture in the bed facilitates electrification, but does not affect circulation, since moisture simultaneously lowers the bed resistance and reduces the relaxation time of particles, leading to rapid discharging if brought into contact with the conducting elements of the apparatus. Therefore, with regard to classic dry-powder coating, the velocity of the spouting gas should be minimized to ensure good circulation, with the particle moisture held at the maximum level admissible for a given product. The investigations show that a unique construction of the apparatus, which brings about an intense natural electrification of the cores, makes it suitable for the electrostatic dry-coating process by means of a high-voltage feeder with the controlled charging of coating powder in the spray nozzle.

关键词： Electrification Electrostatic charge Spout-fluid bed Wurster apparatus

Wave propagation in A Converging Channel of Arbitrary Configuration

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China Ocean Engineering 2015年第5期29卷 771-782页

作者： wojciech SULISZ Institute of Hydroengineering Polish Academy of Sciences

A numerical solution was derived to determine wave field in a converging channel bounded by rubble-mound jetties. The solution was achieved by applying boundary element method. The model was applied to analyze the effect of channel convergence, the cross-section of the jetties and their physical and damping properties on wave field in the channel. The study reveals numerous non-intuitive results specific for jetted and convergent channels. The analysis shows that wave reflection is usually low and is of secondary practical importance. Wave transmission strongly depends on the channel geometry and transmitted waves may be higher than incident waves, despite reflection and damping processes. Moreover, wave transmission depends on physical and damping properties of rubble jetties and the results show that wave transmission may increase with the increasing damping properties of jetties, which is a non-intuitive feature of wave fields in jetted channels. The analysis reveals several novel results of practical importance. It is shown that the rubble-mound jetties should be constructed from the material of high porosity, which ensures low transmission. More attention should be devoted to hydraulic properties of porous materials. It is recommended to use the material of moderate damping properties. The material of high damping properties often increases the wave transmission. It is possible, by a selection of rubble-mound material, to obtain lower transmission level for steep waves than for waves of moderate steepness. A series of laboratory experiments were conducted in the wave flume to verify the theoretical results. The comparisons show that theoretical results are in fairly good agreement with experimental data.

关键词： jetted converging channel wave propagation wave damping numerical modeling

Numerical simulation of a dense solid particle flow inside a cyclone separator using the hybrid Euler-Lagrange approach

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particuology 2017年第2期15卷 170-180页

作者： pawel Kozolub Adam Klimanek Ryszard A. Bialecki wojciech p. Adamczyk Institute of Thermal Technology Silesian University of Technology Konarskiego 22 Gliwice Poland AMEC Foster Wheeler Energia polska Staszica 31 Sosnowiec Poland

This paper presents a numerical simulation of the flow inside a cyclone separator at high particle loads. The gas and gas–particle flows were analyzed using a commercial computational fluid dynamics code. The turbulence effects inside the separator were modeled using the Reynolds stress model. The two phase gas–solid particles flow was modeled using a hybrid Euler–Lagrange approach, which accounts for the four-way coupling between phases. The simulations were performed for three inlet velocities of the gaseous phase and several cyclone mass particle loadings. Moreover, the influences of several submodel parameters on the calculated results were investigated. The obtained results were compared against experimental data collected at the in-house experimental rig. The cyclone pressure drop evaluated numerically underpredicts the measured values. The possible reason of this discrepancies was disused.

关键词： Cyclone separator Two-phase flow Solid particle transport Computational fluid dynamics Hybrid Euler-Lagrange

Gastroenterostoma after Billroth antrectomy as a premalignant condition

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World Journal of Gastroenterology 2012年第25期18卷 3201-3206页

作者： Robert Sitarz Ryszard Maciejewski wojciech p polkowski G Johan A Offerhaus Department of pathology University Medical CentreUtrecht3584 CX UtrechtThe Netherlands Department of Human Anatomy Medical University of Lublin20-950 LublinPoland Department of Surgical Oncology Medical University of Lublin20-081 LublinPoland Department of pathology Academic Medical Centre 1105 AZ Amsterdam The Netherlands

Gastric stump carcinoma （GSC） following remote gastric surgery is widely recognized as a separate entity within the group of various types of gastric cancer. Gastrecto- my is a well established risk factor for the development of GSC at a long time after the initial surgery. Both exo- as well as endogenous factors appear to be involved in the etiopathogenesis of GSC, such as achlorhydria, hypergastrinemia and biliary reflux, Epstein-Barr virus and Helicobacter pylori infection, atrophic gastritis, and also some polymorphisms in interleukin-l~ and maybe cyclo-oxygenase-2. This review summarizes the litera- ture of GSC, with special reference to reliable early di- agnostics. In particular, dysplasia can be considered as a dependable morphological marker. Therefore, close endoscopic surveillance with multiple biopsies of the gastroenterostomy is recommended. Screening start- ing at 15 years after the initial ulcer surgery can detect tumors at a curable stage. This approach can be ofspecial interest in Eastern European countries, where surgery for benign gastroduodenal ulcers has remained a practice for a much longer time than in Western Eu- rope, and therefore GSC is found with higher frequency.

关键词： Gastric stump cancer Gastrectomy Riskfactors Endoscopic surveillance

AUGMENTED REALITY SYSTEM FOR AIDING ENGINEERING DESIGN pROCESS OF MACHINERY SYSTEMS

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Journal of Systems Science and Systems Engineering 2011年第3期20卷 294-309页

作者： Marcin JANUSZKA wojciech MOCZULSKI Department of Fundamentals of Machinery Design Silesian University of TechnologyKonarskiego 18A44-100 GliwicePoland

The paper presents the application of augmented reality for aiding product design and development of machinery systems. Augmented reality technology integrates an interactive computer-generated word with an interactive real word in such a way that they appear as one environment. AR technology can enhance a user＇s perception of the real world with information that is not actually part of the scene but is relevant to the user＇s present activity. presented in the AR system is a mode for changing views of data - especially 3D models - allowing the user to understand the prospective machinery system in a more comprehensive way, thus making the design process more efficient than the one supported by conventional present-day CAD systems. The presented prototype system contains an expert system integrated with AR system and allows the delivering of knowledge to the designer about successive steps of the design process of a mobile robot and practical solutions of realized constructional problems. An approach concerning AR enables the system user to analyze and verify solutions （represented as 3D models） relative to real scenes/objects. This approach is advantageous because the real environment around us often provides a vast amount of information that is difficult to duplicate in a computer. In some cases, the application of an AR system could be an optimal way to verify developed products.

关键词： Augmented reality human-computer interface CAD design for customer satisfaction computer-aided decision making

The Impact of Bed Temperature on Heat Transfer Characteristic between Fluidized Bed and Vertical Rifled Tubes

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Journal of Thermal Science 2016年第5期25卷 476-483页

作者： Artur Blaszczuk wojciech Nowak Czestochowa University of Technology Institute of Advanced Energy Technologies Dabrowskiego 73 AGH University Science and Technology Faculty of Energy and Fuels Czarnowiejska 30

In the present work,the heat transfer study focuses on assessment of the impact of bed temperature on the local heat transfer characteristic between a fluidized bed and vertical rifled tubes(38mm-O.D.) in a commercial circulating fluidized bed(CFB) *** transfer behavior in a 1296t/h supercritical CFB furnace has been analyzed for Geldart B particle with Sauter mean diameter of 0.219 and 0.246 *** heat transfer experiments were conducted for the active heat transfer surface in the form of membrane tube with a longitudinal fin at the tube crest under the normal operating conditions of CFB boiler.A heat transfer analysis of CFB boiler with detailed consideration of the bed-to-wall heat transfer coefficient and the contribution of heat transfer mechanisms inside furnace chamber were investigated using mechanistic heat transfer model based on cluster renewal *** predicted values of heat transfer coefficient are compared with empirical correlation for CFB units in large-scale.

关键词： Cluster renewal approach heat transfer coefficient bed temperature suspension density circulating fluidized bed

Simulation of Fluid Flow in a Channel Induced by Three Types of Fin-Like Motion

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Journal of Bionic Engineering 2007年第3期4卷 165-176页

作者： wojciech Kowalczyk Antonio Delgado Institute of Fluid Mechanics University of Erlangen-NurembergCauerstr. 4D-91058 ErlangenGermany

One of many interesting research activities in biofluidmechanics is dedicated to investigations of locomotion in water. Some of propulsion mechanisms observed in the underwater world are used in the development process of underwater autonomic vehicles （AUV）. In order to characterise several solutions according to their manoeuvrability, influence on the surrounding fluid and energetic efficiency, a detailed analysis of fin-like movement is indispensable. In the current paper an analysis of undulatory, oscillatory and combined fin-like movements by means of numerical simulation is carried out. The conservation equation of mass and the conservation equation of momentum axe solved with the Finite Volume Method （FWM） by use of the software CFX-10.0. The undulatory and oscillatory fin movements axe modelled with an equation that is implemented within an additional subroutine and joined with the main solver. N carried out in the computational domain, in which one fin is fixed in a flow-through water duct. Simulations axe carded out in the range of the Re number up to 105. The results show significant influence of applied fin motion on the velocity distribution in the surrounding fluid.

关键词： biofluid dynamics fro-like movement fish propulsion computational fluid dynamics

Modeling of propagation and Transformation of Transient Nonlinear Waves on A Current

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China Ocean Engineering 2013年第5期27卷 579-592页

作者： wojciech Sulisz Maciej paprota Institute of Hydroengineering Polish Academy of Sciencies

A novel theoretical approach is applied to predict the propagation and transformation of transient nonlinear waves on a current. The problem was solved by applying an eigenfunction expansion method and the derived semi-analytical solution was employed to study the transformation of wave profile and the evolution of wave spectrum arising from the nonlinear interactions of wave components in a wave train which may lead to the formation of very large waves. The results show that the propagation of wave trains is significantly affected by a current. A relatively small current may substantially affect wave train components and the wave train shape. This is observed for both opposing and following current. The results demonstrate that the application of the nonlinear model has a substantial effect on the shape of a wave spectrum. A train of originally linear and very narrow-banded waves changes its one-peak spectrum to a multi-peak one in a fairly short distance from an initial position. The discrepancies between the wave trains predicted by applying the linear and nonlinear models increase with the increasing wavelength and become significant in shallow water even for waves with low steepness. Laboratory experiments were conducted in a wave flume to verify theoretical results. The free-surface elevations recorded by a system of wave gauges are compared with the results provided by the nonlinear model. Additional verification was achieved by applying a Fourier analysis and comparing wave amplitude spectra obtained from theoretical results with experimental data. A reasonable agreement between theoretical results and experimental data is observed for both amplitudes and phases. The model predicts fairly well multi-peak spectra, including wave spectra with significant nonlinear wave components.

关键词： numerical modeling transient waves current boundary conditions initial conditions

Modelling of wave transmission through a pneumatic breakwater

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Journal of Hydrodynamics 2017年第2期29卷 283-292页

作者： Maciej paprota wojciech Sulisz Institute of Hydro-Engineering of polish Academy of Sciences GdafiskPoland

A theoretical approach is derived to study interaction of linear water waves with an air bubble curtain used as a pneumatic breakwater. Modelling of wave transmission through an aerial barrier is a complex task due to a need to cover processes associated with wave-current interaction, effects of two-phase flows, wave damping, etc.. An initial boundary-value problem is solved by applying an efficient eigenfunction expansion method and a time-stepping procedure. The derived semi-analytical solution is used to study the effect of basic parameters of the model on wave dissipative properties of the pneumatic breakwater. Results show that wave damping by the breakwater is mainly affected by an air flow rate. The increased air discharge results in higher velocities of ascending bubbles and increases aerial barrier width. This leads to a substantial reduction of transmitted wave heights, especially for waves of intermediate length and short waves. In order to verify the applicability of the presented theoretical approach, laboratory experiments are conducted in a wave flume for different wave regimes and pneumatic breakwater characteristics. The analysis of a wave trans- mission coefficient calculated numerically and measured in the laboratory confirms that the derived model can be used for a certain range of wave conditions.

关键词： Surface waves wave transmission wave-current interaction pneumatic breakwater numerical modelling