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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

The Numerical Comparison of Heat Transfer in a Coated and Fixed Bed of an Adsorption Chiller

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Journal of Thermal Science 2018年第5期27卷 421-426页

作者： GRABOWSKA Karolina SOSNOWSKI Marcin KRZYWANSKI Jaroslaw SZTEKLER Karol KALAWA Wojciech ZYLKA Anna NOWAK Wojciech Faculty of Mathematics and Natural Science Jan Dlugosz University Faculty of energy and Fuels AGH University of Science and Technology

Ecological adsorption technology is becoming a focus of attention by industry due to the utilization of low grade thermal energy sources for cooling production. It can be a promising part of sustainable development concept of the global economy. Therefore, research aiming at improving their performance i.e. Coefficient of Performance(COP) by optimizing the construction of sorption beds with a built in heat exchanger system is crucial. The heat transfer characteristics between the bed of porous media(sorbent) and surface of the heat exchanger system determine the heating power of an adsorption chiller. The HP increase can be obtained by heat transfer intensification due to the increase in the thermal conductivity of the sorbent layer in the vicinity of the heat exchanger's surface. The novel modification of the sorbent layer structure is proposed in the paper in order to improve the heat transfer processes in the heat exchanger boundary layer. The analysis of desorption process conditions in the parametric model of a coated and fixed adsorption bed design is presented in the paper. The computational fluid dynamics(CFD) with conjugate heat transfer analysis is used to determine the crucial input parameters(temperature distribution in the sorbent bed) for further analytical calculations. The commercial code Ansys Fluent was used to perform numerical simulations. The developed computational model consisted of three subdomains representing heating water, heat exchanger material(copper) and sorbent(silica gel). The comparison of a novel coated design and a conventional fixed bed is discussed in the paper. The numerical analysis is based on experimental thermal conductivity measurements of the sorbent layer in different configurations, which were performed using Laser Flash Method.

关键词： adsorption chiller computational fluid dynamics low grade thermal energy sources coated adsorption bed silica gel thermal conductivity

High-performance oxygen permeation membranes:Cobalt-free Ba_(0.975)La_(0.025)Fe_(1-x)Cu_(x)O_(3)-δceramics

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Journal of Materiomics 2019年第2期5卷 264-272页

作者： Zilu Liu Kui Li Hailei Zhao Konrad Swierczek School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Beijing Municipal Key Lab for Advanced energy Materials and Technologies Beijing 100083China agh University of Science and Technology Faculty of Energy and Fuelsal.A.Mickiewicza 3030-059 KrakowPoland agh centre of energy AGH University of Science and Technologyul.Czarnowiejska 3630-054 KrakowPoland

A new group of cobalt-free perovskite oxides,Ba_(0.975)La_(0.025)Fe_(1-x)Cu_(x)O_(3-δ)(BLFC,x=0.05-0.15),was designed,characterized and applied as oxygen permeation *** was found that BLFC oxides with Cu doping range of 0.075-0.15 maintain cubic perovskite phase in a wide range of *** Cu introduced at the B-site results in a gradual increase of the electrical conductivity,which is attributed to the denser overlapping of electron clouds of CueO *** increasing Cu content,the oxygen vacancy concentration increases and the oxygen ion migration energy decreases,leading to the highest oxygen permeation flux of 1.59 mL cm^(-2)min^(-1)recorded for Ba_(0.975)La_(0.025)Fe_(0.9)Cu_(0.1)O_(3-δ)1mm thick membrane at 950℃.However,the oxygen permeability decreases with further Cu doping,which may be correspond to a presence of defect ***_(0.975)La_(0.025)Fe_(0.9)Cu_(0.10)O_(3-δ)membrane with 0.7mm thickness delivers stable oxygen permeation flux of 1.57 mL cm^(-2)min^(-1)for 200 h at 900℃.All of the obtained results indicate that the developed BLFC with optimized Cu content(i.e.x=0.1)is a very promising material for usage in oxygen separation applications.

关键词： Perovskite Oxygen permeability Structure stability Oxygen ion migration

Comparison of the sediment composition in relation to basic chemical,physical,and geological factors

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International Journal of Sediment Research 2020年第3期35卷 307-314页

作者： Witold Reczyński Katarzyna Szar?owicz Ma?gorzata Jakubowska Peter Bitusik Barbara Kubica agh University of Science and Technology Faculty of Materials Science and Ceramics agh University of Science and Technology Faculty of Energyand Fuels Matej Bel University Faculty of Natural Sciences

Sediment constitutes an interesting and valuable material for observation of human impact on the *** on the sediment core samples in two Tatra Mountains lakes,determination of the selected elements（including cesium 137 radionuclide activity and heavy metals' concentrations） and dating of the obtained layers by the lead 210 method,chemometric analysis of the resulting data set was *** was established,as a result of Cluster Analysis,that the variability of the determined parameters was distinct in the lakes with much higher concentrations of heavy metals in Smreczynski staw ***,the influence of human activity（long distance transport of contaminants） is notable on the north slopes of the Tatras（Smreczynski staw lake） comparing to Popradske pleso *** examined elements can be divided into two groups-natural to the site origin（iron,manganese,and magnesium）,and elements whose accumulation in the sediments can be related（at least in part） to human activity(137Cs,zinc,copper,cadmium,lead,and chromium).The results confirm the existence of the so called "screen effect",meaning that the Tatra Mountains' crest delimits to a considerable extent further transport of pollutants to the south side of the Tatra Mountains slopes.

关键词： Sediment Tatra mountains Metals Radionuclides Chemometry

Sensitivity of the area method with mono isotopic fission chambers to reactivity changes in subcritical nuclear reactors

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Nuclear Science and Techniques 2021年第10期32卷 166-176页

作者： Jerzy A.Janczyszyn Grazyna Domanska Przemysław Stanisz Faculty of energy and Fuels AGH University of Science and Technologyal.Mickiewicza 3030-0591 KrakowPoland

High-level waste is an important safety issue in the development of nuclear power.A proposed solution is the transmutation of waste in fast *** exclusion of the risk of supercriticality by using subcritical reactors is currently under *** the subcriticality level in such reactors presents difficulties.A problem is posed by the so-called space effect observed when using in reactors many neutron detectors in different locations of the core and *** obtained from measure-ments,for example,by the Sjo¨strand method,differs by nonnegligible *** corrections can partially improve this *** use of a monoisotopic fission chamber set,designed for a given reactor,when each chamber is intended for a specific position in the system,can improve the situation.A question arises about the sensitivity of the results to reactivity *** issue is analyzed by computer simulation for possible fissionable and fissile nuclides for the total range of control rod insertion,changes in reactor fuel enrichment,and fuel *** tested sensitivity was satisfactory at most levels from several dozen to several hundred pcm.A case study was conducted using the VENUS-F core model.

关键词： Subcriticality Simulation Sjostrand method Fission chambers Space effect

Simulation of mass balance behavior in a large-scale circulating fluidized bed reactor

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Particuology 2016年第2期14卷 51-58页

作者： Artur Blaszczuk Anna Zylka Jacek Leszczynski Czestochowa University of Technology Institute of Advanced Energy Technologies Dabrowskiego 73 42-200 Czestochowa Poland agh University Science and Technology Faculty of Energy and Fuels Department of Hydrogen Energy Mickiewicza 30 30-059 Cracow Poland

We determine using a compound model the influence of the mass of granular matter on the behavior of a supercritical circulating fluidized bed （CFB） reactor. Population balance enables a stationary-regime modeling of the mass flow of granular matter inside a CFB unit in a large-scale. The simulation includes some important dynamic processes of gas-particle flows in fluidized bed such as attrition, fragmenta- tion, elutriation, and fuel combustion. Numerical calculations with full boiler loading were performed of operational parameters such as furnace temperature, furnace pressure, feeding materials mass flows, and excess air ratio. Furthermore, three bed inventory masses were adopted as experimental variables in the simulation model of mass balance. This approach enables a sensitivity study of mass flows of granular matter inside a CFB facility. Some computational results from this population balance model obtained for a supercritical CFB reactor are presented that show consistency with the operational data for large-scale CFB units.

关键词： Bed inventory mass Mass flow of solids Circulating fluidized bed Population mass balance mode Sensitivity analysis

Overcoming a recent impasse in the application of artificial neural networks as solid oxide fuel cells simulator with computational topology

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energy and AI 2023年第4期14卷 451-462页

作者： Grzegorz Brus agh University of Krakow Faculty of Energy and FuelsDepartment of Fundamental Research in Energy Engineering30 Mickiewicza Ave.30059 KrakowPoland

In recent years,the solid oxide fuel cell(SOFC)scientific community has invested continuous efforts to employ artificial intelligence methods to design and develop new energy *** is crucial to gain a better understanding of the microscale phenomena that occur in the *** this review,we present a literature review of the field,discussing the limitations of including microstructural data in existing research and possible research directions to overcome *** review focuses on a particular research area that uses artificial neural networks(ANNs)to predict the performance of ***,we show that neural networks are used not only to conform to the newest trends but also for improving the design and providing a better understanding of microscale phenomena that occur in the *** review concludes by highlighting topological data analysis as a promising area of research that can incorporate detailed microstructure characterization in ANNs for performance prediction.

关键词： Solid oxide fuel cells Artificial neural networks Mathematical modeling Topological data analysis

energy Aspects of CO_2 Sorption in the Context of Sequestration in Coal Deposits

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Journal of Earth Science 2014年第4期25卷 719-726页

作者： Pawe Baran Katarzyna Zarebska Adam Nodzeński agh University of Science and Technology Faculty of Energy and Fuels Al. Mickiewicza 30 30-059 Kraków Poland

This paper summarises the results of experimental testing of carbon dioxide sorption on five coal samples. Sorption tests were done at the temperature 288, 298, 313 and 323 K, in the pressure range 0-5 MPa. The analysis of sorption isotherms and the effects of temperature on sorption capacity reveal that in the case of samples NR1, Pn, Tu, Be the temperature increase from 298 to 323 K led to 1.3-fold decrease of the sorption value. In the ease of coal Th the decrease of sorption capacity was 3-fold. It appears that the analysis of maceral content plays a major role. In the case of coals, porosity is associated with the petrographic composition. The values of the isosteric heat of sorption and the work of expansion and desorption were derived for the investigated sorption systems. Test data reveal that for hard coals the isosteric heat is inversely proportional to the ＂reserve＂ of volumetric work-a major parameter triggering the sudden release of gas from the coalbed, thus enabling us to assess the potential risk involved in rapid unsealing of the coalbed.

关键词： coal carbon dioxide sequestration sorption energy isosteric heat.

An Analysis of the Numerical Model Influence on the Ground TemperatureProfile Determination

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Journal of Thermal Science 2017年第1期26卷 82-88页

作者： Marek Jaszczur Inga Polepszyc Aneta Sapinska-Sliwa Andrzej Gonet Faculty of energy and Fuels Department of Fundamental Research in Energy Engineering Faculty of Drilling Oil and Gas ale Department of Drilling and Geoengineering AGH University of Science and Technology al. Mickiewicza 30 30-059 Krak6w Poland

The estimation of the ground temperature profile with respect to the depth and time is the key issue in many engineering applications which use the ground as a source of thermal energy. In the present work, the influence of the model components on the calculated ground temperature distribution has been analysed in order to develop an accurate and robust model for the prediction of the ground temperature profile. The presented mathematical model takes into account all the key phenomena occurring in the soil and on its top surface. The impact of individual model elements on the temperature of the soil has been analysed. It has been found that the simplest models and the most complex model result in a similar temperature variation over the simulation period, but only at a low depth. A detailed analysis shows that a larger depth requires more complex models and the calculation with the use of simple models results in an incorrect temperature and a theoretical COP estimation.

关键词： heat transfer ground heat transport ground temperature profile ground source heat pump