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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 921-930页

作者：刘文洁 WANG Yang LI Jingtao 李宝让 School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China

Industrial wastes such as steel slag and coal gangue *** chosen as raw materials for preparing ceramic via the conventional solid-state reaction *** steel slag and coal gangue mixed in various mass ratios,from 100%steel slag to 100%coal gangue at 10%intervals,microstructure and possible phase evolution of the coal gangue-steel slag ceramics were investigated using X-ray powder diffraction,scanning electron microscopy,mercury intrusion porosimetry and Archimedes boiling *** experimental results suggest that the phase compositions of the as-prepared ceramics could be altered with the increased amount of coal gangue in the *** anorthite-diopside eutectic can be formed in the ceramics with the mass ratios of steel slag to coal gangue arranged from 8:2 to 2:8,which was responsible for the melting of the steel slag-coal gangue ceramics at relatively high *** investigations on the microstructure suggested that the addition of the proper amount of steel slag in ceramic compositions was conducive to the pore formation and further contributed to an increment in porosity.

关键词： steel slag-coal gangue ceramics synthesis phase evolution microstructure characteristics

Utlra-fast hydrolysis performance of MgH_(2) catalyzed by Ti-Zr-Fe-Mn-Cr-V high-entropy alloys

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Journal of Energy Chemistry 2024年第11期98卷 77-86页

作者： Jinting Chen Tingting Xu Zeyu Zhang Jinghan Zhang Haixiang Huang Bogu Liu Yawei Li Jianguang Yuan Bao Zhang Ying Wu School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China Institute of Energy power Innovation North China Electric Power UniversityBeijing 102206China

Hydrogen energy is one of the ideal energy alternatives and the upstream of the hydrogen industry chain is hydrogen production,which can be achieved via the reaction of inorganic materials with water,known as *** inorganic materials,the high hydrogen capacity for hydrolysis of MgH_(2)(15.2 wt%)makes it a promising material for hydrogen production via ***,the dense Mg(OH)_(2) passivation layer will block the reaction between MgH_(2) and the solution,resulting in low hydrogen yield and sluggish hydrolysis *** this work,the hydrogenyield and hydrogen generation rate of MgH_(2) are considerably enhanced by adding Ti-Zr-Fe-Mn-Cr-V high-entropy alloys(HEAs) for the first *** *** MgH_(2)-3 wt% TiZrFe_(1.5)MnCrV_(0.5)(labelled as MgH_(2)-3 wt% Fe_(1.5)) composite releases 1526.70 mL/g H_(2) within 5 min at 40℃,and the final hydrolysis conversion rate reaches 95.62% within 10 *** mean hydrogen generation rate of the MgH_(2)-3 wt% Fe_(1.5) composite is 289.16 mL/g/min,which is 2.38 times faster than that of pure MgH_(2).Meanwhile,the activation energy of the MgH_(2)-3 wt% Fe_(1.5) composite is calculated to be 12.53 kJ/mol. The density functional theory(DFT) calculation reveals that the addition of HEAs weakens the Mg-H bonds and accelerates the electron transfer between MgH_(2) and HEAs,Combined with the cocktail effect of HEAs as well as the formation of more interfaces and micro protocells,the hydrolysis performance of MgH_(2) is considerably *** work provides an appealing prospect for real-time hydrogen supply and offers a new effective strategy for improving the hydrolysis performance of MgH_(2).

关键词： Mg-based materials High-entropy alloys Hydrolysis Hydrogen generation Cocktail effect Catalysis

Structure and magnetic properties of RAlSi(R=light rare earth)

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Chinese Physics B 2021年第7期30卷 332-338页

作者： Tai Wang Yongquan Guo Cong Wang School of Energy power and Mechanical engineering North China Electric Power UniversityBeijing 102206China

We prepared the semimetals RAl Si(R=light rare earth),and systematically study their crystal structures and magnetic properties.X-ray diffractions confirm the coexistence of the site-disordered phase with group space of I41/amd and the noncentrosymmetrically ordered phase with space group of I41 md in RAl Si *** ordered phase is the main phase in RAl Si *** Si alloys show nonmagnetic character for R=La,low temperature ferromagnetic order for R=Ce,Pr,and paramagnetic character for R=Nd,*** Al Si shows metamagnetic transition at 10 K and ferromagnetic order at 143 K,*** Al Si follows the van Vleck paramagnetic model in its paramagnetic *** magnetization curves of RAl Si(R=Ce,Pr,Sm)follow the mixed model of ferromagnetism and paramagnetism,and the fitted saturation moment MSdepends on the moment of trivalent rare *** paramagnetic susceptibilityχof RAl Si is going up with increasing the atomic order numbers of rare earth *** reveals that the magnetic property of RAl Si originates from the rare earth.

关键词： RAlSi crystal structure magnetic properties

NUMERICAL AND EXPERIMENTAL STUDY OF FLOW AROUND TWO PLATES HAVING ASYMMETRIC BEVELED TRAILING EDGE

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Journal of Hydrodynamics 2008年第5期20卷 624-628页

作者： MOSALLEM M. M. Department of Mechanical power engineering and Energy Faculty of Engineering Minia University Minia

The flow around two plates having asymmetric beveled trailing edge placed side-by-side in a uniform stream were investigated both numerically and experimentally. Two plates with spacing ratio of 1.0 and beveled trailing edge of angle 20° were tested at Reynolds numbers equal to 3.97×10^4. The numerical simulation results displayed that the flow separates on one plate beveled trailing edge surface. The vortex formation and shedding from this plate led to deflecting the flow toward the other plate and consequently the wake behind the plates showed an asymmetric development. The photographs obtained from the flow visualization confirmed the numerical results concerning the flow separation and vortex formation. It was also found that the computed pressure distribution on the two plate surfaces was different, particularly on the beveled trailing edge surfaces and on the fiat sides.

关键词： Flow wake two plates vortex shedding beveled trailing edge

Enhancement of Thermo-Flow Performances by Windbreakers for Two-Tower Indirect Dry Cooling System

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Journal of Thermal Science 2020年第3期29卷 676-686页

作者： YAN Jingbo WANG Weijia CHEN Lei YANG Lijun DU Xiaoze School of Energy power and Mechanical engineering North China Electric Power UniversityBejjing 102206China

The winds will greatly weaken the cooling performance of indirect dry cooling system with twin *** exterior windbreakers are recommended to restrain the wind adverse effects in this *** macro heat exchanger model was adopted to simulate the heat exchange between circulating water and ambient *** performances of natural draft dry cooling system(NDDCS)with and without exterior windbreakers were numerically *** pressure,velocity and temperature distribution of cooling air in wind angles of 0°,45°and 90°was obtained and *** results show that in all wind directions,the performances for lateral sector of towers with windbreakers are significantly improved,but the low-pressure zone appears unexpectedly for the rear sectors,which reduces the air flow *** cooling performances of the twin towers with or without windbreakers decrease at first but then recover with the wind velocity ***,the optimal flow and heat transfer performances appear in the wind angle of 0°.The cooling performances can be significantly improved in all three wind directions due to windbreaker configuration.

关键词： indirect dry cooling system twin towers windbreakers wind directions flow and heat transfer performances

Assessment and Enhancement of FRC of power Systems Considering Thermal power Dynamic Conditions

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CSEE Journal of power and Energy Systems 2024年第4期10卷 1371-1383页

作者： Feng Hong Yalei Pang Weiming Ji Lu Liang Fang Fang Junhong Hao Jizhen Liu State Key Laboratory of Alternate electric power System with Renewable Energy Sources and School of Control and Computer engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Alternate electric power System with Renewable Energy Sources School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China

Frequency stability and security have been a vital challenge as large-scale renewable energy is integrated into power *** contrast,the proportion of traditional thermal power units decreases during the decarbonization transformation process,resulting in poor frequency *** paper aims to explore the potential of frequency regulation support,dynamic assessment,and capacity promotion of thermal power plants in the transition *** the dynamic characteristics of the main steam working fluid under different working conditions,a nonlinear observer is constructed by extracting the main steam pressure and valve opening degree *** real-time frequency modulation capacity of thermal power units can provide a dynamic state for the power grid.A dynamic adaptive modification for primary frequency control(PFC)of power systems,including wind power and thermal power,is proposed and *** power dynamic allocation factor is adaptively optimized by predicting the speed droop ratio,and the frequency modulation capability of the system is improved by more than 11%under extreme ***,through the Monte Carlo simulation of unit states of the system under various working conditions,the promotion of the frequency regulation capacity with high wind power penetration(WPP)is verified.

关键词： Dynamic evaluation frequency regulation power system predictive modeling wind penetration

Natural Frequency of Oscillating Gaseous Bubbles in Ventilated Cavitation

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Chinese Physics Letters 2017年第7期34卷 134-137页

作者：张宇宁 School of Energy Power and Mechanical Engineering North China Electric Power University Beijing 102206

An improved formula is proposed for the prediction of natural frequency of oscillating gaseous bubbles in the ventilated cavitation by considering the liquid compressibility and the thermal effects. The differences between the previous formula and ours are quantitatively discussed in terms of both dimensional parameters （e.g., frequency and bubble radius） and non-dimensional parameters （e.g., the Feclet number）. Our analysis reveals that our formula is superior to the existing formula in the low-frequency excitation regions.

关键词： CAVITATION BUBBLE measurement GAS compressibility EQUATIONS of motion OSCILLATIONS

NUMERICAL STUDY ON EFFECT OF WAVING BED ON THE SURFACE WAVE

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Journal of Hydrodynamics 2006年第4期18卷 464-468页

作者： WU Zheng-ren CHENG You-liang WANG Song-ling School of Energy and power engineering North China Electric Power University Baoding 071003 China

The effect of the waving bed on the surface wave was investigated. The wave equation was reduced from the potential flow theory with the perturbation technique, and then was solved by using the pseudo-spectral method. The waterfall of the surface wave was simulated with the Matlab. It is shown that for the waving bed, an additional harmonic wave appears on the surface together with the solitary wave existing for the non-waving bed, and two kinds of waves do not interfere with each other. With the development of time, the waveform for the waving bed is kept invariable, and just the amplitude is reduced gradually. Wave-breaking phenomenon for the non-waving bed does not appear, so the waving bed seems useful to prevent the breaking of the wave.

关键词： waving bed pseudo-spectral method solitary wave wave breaking waterfall

Theoretical prediction of wear of disc cutters in tunnel boring machine and its application

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Journal of Rock Mechanics and Geotechnical engineering 2019年第1期11卷 111-120页

作者： Zhaohuang Zhang Muhammad Aqeel Cong Li Fei Sun School of Energy power and Mechanical engineering North China Electric Power University School of Foreign Languages North China Electric Power University

Predicting the cutter consumption and the exact time to replace the worn-out cutters in tunneling projects constructed with tunnel boring machine(TBM) is always a challenging issue. In this paper, we focus on the analyses of cutter motion in the rock breaking process and trajectory of rock breaking point on the cutter edge in rocks. The analytical expressions of the length of face along which the breaking point moves and the length of spiral trajectory of the maximum penetration point are derived. Through observation of rock breaking process of disc cutters as well as analysis of disc rock interaction, the following concepts are proposed: the arc length theory of predicting wear extent of inner and center cutters, and the spiral theory of predicting wear extent of gage and transition cutters. Data obtained from5621 m-long Qinling tunnel reveal that among 39 disc cutters, the relative errors between cumulatively predicted and measured wear values for nine cutters are larger than 20%, while approximately 76.9% of total cutters have the relative errors less than 20%. The proposed method could offer a new attempt to predict the disc cutter's wear extent and changing time.

关键词： Full-face rock tunnel boring machine(TBM) Disc cutter Wear prediction

Crystal structure and electromagnetic responses of tetragonal GdAlGe

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Chinese Physics B 2020年第12期29卷 469-474页

作者： Cong Wang Yong-Quan Guo Tai Wang Shuo-Wang Yang School of Energy power and Mechanical engineering North China Electric Power UniversityBeijing 102206China

The ternary rare-earth aluminum germanide GdAlGe with tetragonal structure is systematically studied by x-ray diffraction,magnetic and electric *** magnetic and electric properties of GdAlGe are strongly related to its special magnetic structure formed by magnetic Gd3 isosceles triangles△*** GdAlGe orders ferromagnetically at 21 K due to the exchanging interaction of Gd3△↑-△↑*** mechanism of magnetic transport originates from the slip scattering induced by Stoner spin fluctuation in the magnetic ordering region and the spin wave scattering induced by the thermal photon excitation and phonon scattering in the paramagnetic *** positive magnetoresistance is observed in GdAlGe,which might be due to the disordered magnetic scatter induced by magnetic anisotropy in GdAlGe.

关键词： GdAlGe Weyl semimetal magnetic isosceles triangle electromagnetic response