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Analytical solution for a strong free-surface water vortex describing flow in a full-scale gravitational vortex hydropower system

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Water Science and Engineering 2021年第1期14卷 72-79页

作者： Vladimir Joel Alzamora Guzman Julie Anne Glasscock energy research group Kadagaya Research Centre for Appropriate TechnologyJunin 12866Peru

Strong free-surface water vortices are found throughout industrial hydraulic systems used for water treatment,flow regulation,and energy *** models using the volumetric flow rate as a model input have generally been semi-empirical,and have tended to have some limitations in terms of the design of practical hydropower *** this study,an analytical model of a strong free-surface water vortex was *** model only requires the water head and geometric parameters as its inputs and calculates the maximum volumetric flow rate,aircore diameter,and rotational *** experimental depthedischarge data from a full-scale gravitational vortex hydropower system,unavailable in the relevant literature,were obtained,and the simulated results showed excellent agreement with the experimental *** data could be used to verify similar models using laboratory-scale physical models in order to investigate the scaling *** contrast to previous models,this model does not assume a constant average velocity across the vortex radius and allows precise calculation of the resultant velocity ***,this model presents advantages in turbine design for energy generation systems.

关键词： Gravitational vortex Velocity measurements Scalability Analytical model Microhydropower

Reconstruction of solid oxide fuel cell electrode microstructure and analysis of its effective conductivity

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Science Bulletin 2016年第1期61卷 78-85页

作者： Keqing Zheng Meng Ni Building energy research group Department of Building and Real Estate The Hong Kong Polytechnic University Environmental energy research group Research Institute for Sustainable Urban Development (RISUD) The Hong Kong Polytechnic University

The effective conductivity （aeff） of solid oxide fuel cell （SOFC） electrode is an important parameter for predicting the ohmic loss in SOFC. This paper investigates the effective conductivity of SOFC electrodes recon- structed numerically by packing spherical particles in a computational domain, followed by a dilation process to simulate the sintering procedure. The effects of various parameters on the effective conductivity of the electrodes are investigated, including material composition, porosity, particle size and contact angle. Results show that the effective conductivity ratio （aeff/ao） of the computed con- ducting phase is mainly affected by its total volume frac- tion （VF） in electrode （including the porosity）. The effective conductivity can be improved by increasing the VF, electrode particle size or the contact angle between electrode particles. Based on the numerical results, the conventional percolation model for the calculation of O＇eft is improved by adjusting the Bruggeman factor from 1.5 to 2.7. The results are useful for understanding the microstructure properties of SOFC composite electrode and for subsequent electrode optimization.

关键词： Fuel cell Electrode Conductivity Modeling Random particle packing

Mathematical analysis of SOFC based on co-ionic conducting electrolyte

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Acta Mechanica Sinica 2013年第3期29卷 388-394页

作者： Ke-Qing Zheng Meng Ni Qiong Sun Li-Yin Shen Building energy research group Department of Building and Real Estate The Hong Kong Polytechnic University

In co-ionic conducting solid oxide fuel cell （SOFC）, both oxygen ion （O2） and proton （H＋） can transport through the electrolyte, generating steam in both the an-ode and cathode. Thus the mass transport phenomenon in the electrodes is quite different from that in conventional SOFC with oxygen ion conducting electrolyte （O-SOFC） or with proton conducting electrolyte （H-SOFC）. The generation of steam in both electrodes also affects the concentration over-potential loss and further the SOFC performance. However, no detailed modeling study on SOFCs with co-ionic electrolyte has been reported yet. In this paper, a new mathematical model for SOFC based on co-ionic electrolyte was developed to predict its actual performance considering three major kinds of overpotentials. Ohm＇s law and the Butler-Volmer formula were used to model the ion conduction and electrochemical reactions, respectively. The dusty gas model （DGM） was employed to simulate the mass transport processes in the porous electrodes. Parametric simulations were performed to investigate the effects of proton transfer number （tH） and current density （jtotal） on the cell performance. It is interesting to find that the co-ionic conducting SOFC could perform better than O-SOFC and H-SOFC by choosing an appropriate proton transfer number. In addition, the co-ionic SOFC shows smaller difference between the anode and cathode concentration overpotentials than O-SOFC and H-SOFC at certain t H values. The results could help material selection for enhancing SOFC performance.

关键词： Co-ionic electrolyte Proton transport number Concentration overpotential Mass transport Model

Modelling of finger-like channelled anode support for SOFCs application

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Science Bulletin 2016年第17期61卷 1324-1332页

作者： Bin Chen Haoran Xu Meng Ni Building energy research group Department of Building and Real EstateThe Hong Kong Polytechnic University

This paper established a numerical model for a solid oxide fuel cell （SOFC） button cell, focusing on the effects of finger-like channels on the gas transport process in the anode support. The current densities of channelled button cell and un-channelled button cell are compared at different operating temperature and voltage with H2 as the fuel. The H2 transport is discussed in detail, such as the mole fraction distribution of H2 in the porous layer, the diffusion flux and convective flux of Ha. It is found that the performance of SOFC can be improved by 2.60 % at 800 ~C, 0.5 V, com- pared with un-channelled SOFC due to the improved gas transport by the finger-like channels. Then, the model is further extended to study 2D-planar SOFC fuelled with syngas. The mole fraction gradients of H2, CO, CH4 and CO are all substantially reduced by the finger-like channels compared to un-channelled planar cell. It is found that the SOFC performance is improved by 5.93 % at 800℃, 0.5 V, when syngas fuel is used. The present study clearly demonstrated that the use of finger-like channels in the anode support is effective in improving the gas transport and the SOFC performance. The present model can be employed for subsequent optimization of the channel configuration for further performance improvement.

关键词： Phase inversion CFD modelling Finger-like channels Concentration loss

Modeling and Analysis of Global and Diffuse Solar Irradiation Components Using the Satellite Estimation Method of HELIOSAT

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Computer Modeling in Engineering & Sciences 2018年第6期115卷 327-343页

作者： Selmin Ener Rusen Department of energy Systems Engineering Academic Energy Research Group(AKEN)Karamanoglu Mehmetbey UniversityKaramanTurkey

It is very important to determine the daily horizontal global,diffuse and beam irradiations correctly in planning energy systems,in cost analysis,in the atmosphere,and in the productivity ***,the knowledge of accurate solar irradiation is the most important component of the essential climate variables according to the Global Climate Observing System(GCOS)in August *** is known that the changes of these irradiation parameters directly affect our atmosphere and cloud formation *** is one of the countries,which has high solar energy potential by reason of its climatic and regional ***,Konya and Karaman regions(in Central Anatolia Region)are seen as the most efficient area in where the solar energy systems will be *** of this reason that region has been designated as an energy Specialized Industrial Zone(ESIZ)in *** energy inputs must carefully be determined in this region where the systems will be installed with respect to the climate and energy *** this work aims to understand the components of daily solar irradiation on a horizontal surface in selected region are analyzed by using the HELIOSAT method by setting satellite *** have been determined by comparing with ground measured data and method were analyzed by using statistical *** to the seven-year data,the accuracy of the daily global and diffuse solar irradiations estimation was found acceptable ***,the estimated results reveal that this method can easily be adapted to any point in the world resembles with the Central Anatolia Region climate ***,the obtained results are significant for the simulation studies such as solar PV power plants performance,payback time,and cost of energy ***,these results can be used to increase the performance of the solar energy system and to determine long-term a road map for climate change studies.

关键词： Estimation model satellite HELIOSAT global and diffuse solar irradiation

Materials for energy conversion

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Science Bulletin 2016年第8期61卷 585-586页

作者： Ned Djilali Institute for Integrated energy Systems University of Victoria Renewable energy research group King Abdulaziz University

Advances in material science and engineering are critical to the development of economically viable technologies to address some of the grand socio-economic challenges of the twenty first *** are at the core

关键词：能量转换材料可再生能源资源太阳能电池存储技术社会经济能源转换材料科学能源需求

Anaerobic-aerobic processes for the treatment of textile dyeing wastewater containing three commercial reactive azo dyes:Effect of number of stages and bioreactor type

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Chinese Journal of Chemical Engineering 2021年第11期34卷 228-239页

作者： Banafsheh Azimi Elham Abdollahzadeh-Sharghi Babak Bonakdarpour Chemical Engineering Department Amirkabir University of TechnologyTehranIran Environmental group Energy DepartmentMaterials and Energy Research CenterAlborzIran

In this study,the effect of number of stages and bioreactor type on the removal performance of a sequential anaerobic-aerobic process employing activated sludge for the treatment of a simulated textile dyeing wastewater containing three commercial reactive azo dyes was *** stage processes performed better than one stage ones,both in terms of overall organic and color removal,as well as the higher contribution of anaerobic stage to the overall removal performance,thereby making them a more energy efficient *** employment of a moving bed sequencing batch biofilm reactor,which uses both suspended and attached biomass,for the implementation of the anaerobic stage of the process,was compared with a sequencing batch reactor that only employs suspended *** results showed that,although there was no meaningful difference in biomass concentration between the two bioreactors,the latter reactor had better performance in terms of chemical oxygen demand(COD)removal efficiency and rate and color removal *** exploratory tests revealed a difference between the roles of suspended and attached bacterial populations,with the former yielding better color removal whilst the latter had better COD removal *** sequential anaerobic–aerobic process,employing an aerobic membrane bioreactor in the aerobic stage resulted in COD and color removal of 77.1±7.9%and 79.9±1.5%,*** incomplete COD and color removal was attributed to the presence of soluble microbial products in the effluent and the autoxidation of dye reduction metabolites,***,aerobic partial mineralization of the dye reduction metabolites,was experimentally observed.

关键词： Wastewater Anaerobic Aerobic Anaerobic moving bed sequencing batch biofilm reactor Anaerobic sequencing batch reactor Aerobic membrane bioreactor

Infrastructure-based localisation of automated coal mining equipment

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International Journal of Coal Science & Technology 2017年第3期4卷 252-261页

作者： Chad O. Hargrave Craig A. James Jonathon C. Ralston Mining and Processing Technologies research group CoalMining Research Program CSIRO Energy BrisbaneAustralia

A novel radar-based system for longwall coal mine machine localisation is described. The system, based on a radar-ranging sensor and designed to localise mining equipment with respect to the mine tunnel gate road infrastructure, is developed and trialled in an underground coal mine. The challenges of reliable sensing in the mine environment are considered, and the use of a radar sensor for localisation is justified. The difficulties of achieving reliable positioning using only the radar sensor are examined. Several probabilistic data processing techniques are explored in order to estimate two key localisation parameters from a single radar signal, namely along-track position and across-track position, with respect to the gate road structures. For the case of across-track position, a conventional Kalman filter approach is sufficient to achieve a reliable estimate. However for along-track position estimation, specific infrastructure elements on the gate road rib-wall must be identified by a tracking algorithm. Due to complexities associated with this data processing problem, a novel visual analytics approach was explored in a 3D interactive display to facilitate identification of significant features for use in a classifier algorithm. Based on the classifier output, identified elements are used as location waypoints to provide a robust and accurate mining equipment localisation estimate.

关键词： Localisation · Waypoint navigation · Machine learning · Radar ·Underground · Longwall mining· Automation

Optimal placement of wind turbines within a wind farm considering multi-directional wind speed using two-stage genetic algorithm

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Frontiers in energy 2021年第1期15卷 240-255页

作者： A.S.O.OGUNJUYIGBE T.R.AYODELE O.D.BAMGBOJE Power energy Machines and Drives(PEMD)research group Department of Electrical and Electronic EngineeringUniversity of IbadanNigeria

Most wind turbines within wind farms are set up to face a pre-determined wind ***,wind directions are intermittent in nature,leading to less electricity production *** paper proposes an algorithm to solve the wind farm layout optimization problem considering multi-angular(MA)wind direction with the aim of maximizing the total power generated on wind farms and minimizing the cost of installation.A twostage genetic algorithm(GA)equipped with complementary sampling and uniform crossover is used to evolve a MA layout that will yield optimal output regardless of the wind *** the first stage,the optimal wind turbine layouts for 8 different major wind directions were determined while the second stage allows each of the previously determined layouts to compete and inter-breed so as to evolve an optimal MA wind farm *** proposed MA wind farm layout is thereafter compared to other layouts whose turbines have focused site specific wind turbine *** results reveal that the proposed wind farm layout improves wind power production capacity with minimum cost of installation compared to the layouts with site specific wind turbine *** paper will find application at the planning stage of wind farm.

关键词： optimal placement wind turbines wind direction genetic algorithm wake effect