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ASME 2024 power Conference, power 2024

作者： Li, Mengjie Li, Maoliang Yin, Chaoqiang Liu, Ming Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China Clean Combustion and Flue Gas Purification Key Laboratory of Sichuan Chengdu China Dongfang Electric group Dongfang Boiler Co. LTD Sichuan Zigong China

ISBN: (纸本)9780791888186

Lignite is a kind of low rank coals with abundant reserves, and it is cost-effective for power plants. However, the moisture content is about 30% to 60% for the lignite, and the water carried by the raw lignite is dried in the pulverization system, which will consume much energy. Therefore, high temperature should be maintained for the primary air of the lignite-fired power plants, especially when the power plant operates under low power ratio or with low temperature feed air. In this study, a 1000 MW lignite-fired power system integrated with a primary air heater is proposed and analyzed. In the primary air heater, the low temperature reheated steam is extracted from the boiler to heat the primary air after the air preheater. The integration of primary air heater makes the lignite-fired power system be more complex, which will influence the operational flexibility of the power plant. Therefore, dynamic models of steam turbines and the boiler with waste heat recovery system were developed in this study. The transient characteristics of the unit under load cycling conditions and primary frequency modulation processes were analyzed. Then, control strategy of the primary air heater of turbine and boiler were enhanced based on the simulation results. The results show that the temperature of primary air can be increased by 51-69 °C by the additional air preheater, and the primary frequency modulation capacity can be improved by 8 MW at 50% power load ratio during primary frequency modulation process. Copyright © 2024 by ASME.

关键词： Steam turbines

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Application-oriented hydrolysis reaction system of solid-state hydrogen storage materials for high energy density target:A review

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Journal of Energy Chemistry 2022年第11期31卷 218-238,I0007页

作者： Jing Yao Zhen Wu Huan Wang Fusheng Yang Jianwei Ren Zaoxiao Zhang School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina Department of Mechanical Engineering Science University of JohannesburgJohannesburg 2092South Africa State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina

Hydrogen storage and delivery technology is still a bottleneck in the hydrogen industry *** all kinds of hydrogen storage methods,light-weight solid-state hydrogen storage(LSHS)materials could become promising due to its intrinsic high hydrogen *** reaction of LSHS materials occurs at moderate conditions,indicating the potential for portable *** present,most of review work focuses on the improvement of material performance,especially the catalysts *** part is important,but the others,such as operation modes,are also vital to to make full use of material potential in the practical *** operation modes of hydrolysis reaction have an impact on hydrogen capacity to various *** example,hydrolysis in solution would decrease the hydrogen capacity of hydrogen generator to a low value due to the excessive water participating in the ***,application-oriented operation modes could become a key problem for hydrolysis reaction of LSHS *** this paper,the operation modes of hydrolysis reaction and their practical applications are mainly *** implements of each operation mode are discussed and compared in detail to determine the suitable one for practical applications with the requirement of high energy *** current challenges and future directions are also discussed.

关键词： Solid-state hydrogen storage High energy density Hydrogen generator Hydrolysis reaction Portable applications

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Experimental and Numerical Investigations on Heat Transfer Characteristics of Supercritical Water in a Vertical Tube

SSRN

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SSRN 2024年

作者： Du, Xiaocheng An, Ning Wei, Ziyu Yang, Dong State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University China

Heat transfer performance of working medium is important for supercritical units. In this work, heat transfer experiments and simulations were carried out at 25 to 29.8 MPa. The impacts and influence mechanisms of operation parameters on heat transfer characteristics were analyzed. To describe the fluid heat storage capacity, a metric called cdv is proposed. The findings indicate that thermal conductivity, cdv, and flow turbulence intensity are the three types of factors influencing heat transfer characteristics. As mass flux rises, the radial flow turbulence intensity increases, leading to an improvement in heat transfer performance. The impact of heat flux is mainly showed in high enthalpy zone. Due to the reduction in radial thermal conductivity, heat transfer enhances as heat flux decreases. Large specific heat zone, where the thermophysical parameters vary quickly, are where the influence of pressure is most evident. Because of the high thermal conductivity and cdv, the heat transfer characteristics get better as pressure drops. Finally, typical heat transfer correlations were evaluated using experiment results. The Bishop, Mokry and Miropoiskii-Shitsman correlations exhibited relatively large errors, and the correlations proposed by Swenson and Jackson have a low error and are highly consistent with the experiment results. © 2024, The Authors. All rights reserved.

关键词： Heat flux

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Development of a filtered drag model considering effect of the solid shear rate

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Particuology 2022年第12期71卷 63-74页

作者： Lingxue Wang Ming Jiang Qiang Zhou School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an710049China Engineering Research Center of New Energy System Engineering and Equipment University of Shaanxi ProvinceXi'an710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710049China

This study investigates a 2D gas-solid fast fluidized bed of typical Geldart A particles using highly resolved simulations with two-fluid *** results show that the solid shear rate has a considerable impact on the orientation of the meso-scale structures and hence on the filtered drag *** the basis of the correlation for the filtered drag force established in the literature using the traditional markers(such as filtered solid volume fraction,filtered slip velocity and filter scale),a correction correlated with the solid shear rate in the direction of gravity is proposed for better prediction of the filtered drag *** corrected model is shown to produce improved results in posterior tests of flows in different fluidization regimes including bubbling,turbulent and fast fluidization.

关键词： Gas-solid flows Fluidization Two-fluid model Dimensionless solid shear rate Filtered drag force

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Dynamic simulation of a space gas-cooled reactor power system with a closed Brayton cycle

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Frontiers in Energy 2021年第4期15卷 916-929页

作者： Chenglong WANG Ran ZHANG Kailun GUO Dalin ZHANG Wenxi TIAN Suizheng QIU Guanghui SU Department of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power EngineeringShaanxi Key Laboratory of Advanced Nuclear Energy and TechnologyXi’an Jiaotong UniversityXi’an 710049China

Space nuclear reactor power(SNRP)using a gas-cooled reactor(GCR)and a closed Brayton cycle(CBC)is the ideal choice for future high-power space *** investigate the safety characteristics and develop the control strategies for gas-cooled SNRP,transient models for GCR,energy conversion unit,pipes,heat exchangers,pump and heat pipe radiator are established and a system analysis code is developed in this ***,analyses of several operation conditions are performed using this *** full-power steady-state operation,the core hot spot of 1293 K occurs near the upper part of the *** 0.4$reactivity is introduced into the core,the maximum temperature that the fuel can reach is 2059 K,which is 914 K lower than the fuel melting *** system finally has the ability to achieve a new steady-state with a higher reactor *** the GCR is shut down in an emergency,the residual heat of the reactor can be removed through the conduction of the core and radiation heat *** results indicate that the designed GCR is inherently safe owing to its negative reactivity feedback and passive decay heat *** paper may provide valuable references for safety design and analysis of the gas-cooled SNRP coupled with CBC.

关键词： gas-cooled space nuclear reactor power closed Brayton cycle system startup and shutdown positive reactivity insertion accident

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Rotor dynamic analysis of supercritical carbon dioxide Bryton cycle coaxial integrated unit 14

Rotor dynamic analysis of supercritical carbon dioxide Bryto...

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14th IEEE Global Reliability and Prognostics and Health Management Conference, PHM-Hangzhou 2023

作者： Xu, Xiaokang Yang, Yi Wang, Jiangfeng Lou, Juwei Chen, Liangqi State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an China Laboratory of Science and Technology on Integrated Logistics Support College of Intelligence Science and Technology National University of Defense Technology Changsha China

ISBN: (纸本)9798350301359

The rotor system plays a very important role in supercritical carbon dioxide Brayton cycle system, and its dynamic problem will directly affect the motion stability and safety of the whole unit. In this paper, the rotor dynamic model of supercritical CO2 coaxial unit is established by finite element method, and the critical speed, modal shape and unbalance response of the rotor are studied. The first seven critical speed of the rotor and the first seven natural frequency of the rotor at the working speed are calculated. The bending modal of the rotor and the position where the rotor amplitude is the largest are analyzed, which can provide reference for the optimization design of the rotor stability. The influences of mass unbalances at the operational speed of rotor are analyzed. The research can provide some suggestions for the optimal design and actual operation of the supercritical CO2 coaxial integrated unit. © 2023 IEEE.

关键词： critical speed unbalance response vibration analysis

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Comparative analysis on gas–solid drag models in MFIX-DEM simulations of bubbling fluidized bed

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Chinese Journal of Chemical engineering 2023年第12期64卷 64-75页

作者： Ruiyu Li Xiaole Huang Yuhao Wu Lingxiao Dong Srdjan Beloševic Aleksandar Milicevic Ivan Tomanovic Lei Deng Defu Che State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China Shunde Institute of Inspection Guangdong Institute of Special Equipment Inspection and ResearchFoshan 528300China Department of Thermal Engineering and Energy "VINCA" Institute of Nuclear Sciences–National Institute of the Republic of SerbiaUniversity of BelgradeMike Petrovica Alasa 12-1411351 VincaPO Box 52211001 BelgradeSerbia

In this study,the open-source software MFIX-DEM simulations of a bubbling fluidized bed(BFB)are applied to assess nine drag models according to experimental and direct numerical simulation(DNS)*** influence of superficial gas velocity on gas–solid flow is also *** results show that according to the distribution of time-averaged particle axial velocity in y direction,except for Wen–Yu and Tenneti–Garg–Subramaniam(TGS),other drag models are consistent with the experimental and DNS *** the TGS drag model,the layer-by-layer movement of particles is observed,which indicates the particle velocity is not correctly *** time domain and frequency domain analysis results of pressure drop of each drag model are *** is recommended to use the drag model derived from DNS or fine grid computational fluid dynamics–discrete element method(CFD-DEM)data first for CFD-DEM *** the investigated BFB,the superficial gas velocity less than 0.9 m·s^(-1) should be adopted to obtain normal hydrodynamics.

关键词： MFIX-DEM Simulation Dense flow Gas-solid Bubbling fluidized bed Drag model

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Research on the THMC Coupling Model for Enhanced Geothermal Systems Based on the Framework of EDFM 29th

Research on the THMC Coupling Model for Enhanced Geothermal ...

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29th International Conference on Computational and Experimental engineering and Sciences, ICCES 2023

作者： Zhang, Weitao Han, Dongxu Jiao, Kaituo Chen, Yujie Yuan, Qing Gong, Liang Yu, Bo Qingdao266580 China Beijing Key Laboratory of Pipeline Critical Technology and Equipment for Deepwater Oil and Gas Development School of Mechanical Engineering Beijing Institute of Petrochemical Technology Beijing102617 China State Key Laboratory of Multiphase Flow in Power Engineering School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an710049 China

ISBN: (纸本)9783031429866

The Enhanced Geothermal System (EGS) involves a complex thermo-hydro-mechanical-chemical (THMC) coupling process during long-term heat extraction. However, many models used to solve fractured reservoir problems are computationally time-consuming, especially when dealing with reservoir-scale engineering problems. To address this challenge, this paper proposes a novel THMC coupling model that solves the governing equations using a unified FVM framework based on the embedded discrete fracture model (EDFM). The accuracy of the model is confirmed by comparing the THC coupling and displacement (M) results with the Fully Resolved Solution Method (FRSM) from MRST software and COMSOL, respectively. Moreover, the model developed is utilized to simulate and analyze the spatiotemporal behavior of pressure, temperature, concentration, and mechanical deformation in EGS. The results suggest that the model is appropriate for effectively assessing the long-term production performance of EGS. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Finite volume method

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Evaporation and drying characteristics of the sessile ferrofluid droplet under a horizontal magnetic field

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Fundamental Research 2022年第2期2卷 222-229页

作者： Zhaonan Liu Jiandong Zhou Yang Li Xin Zhuo Xiujuan Shi Dengwei Jing State Key Laboratory of Multiphase Flow in Power Engineering and International Research Center for Renewable Energy X^an Jiaotong UniversityXi'an 710049China

In this study,the evaporation characteristics and drying patterns of various sessile ferrofluid droplets on certain substrate under horizontal magnetic fields of controlled intensities are *** effects of droplet concentration and magnetic field intensity on the duration of each evaporation stage and drying patterns of droplets have been systematically *** turned out that a plateau appears at the initial stage of evaporation in the absence of magnetic field and it was found that the plateau value is positively correlated with the concentration of ferrofluid *** the external magnetic field,the evaporation time of droplets decreases,the stage of contact line retreat extends,the stage of late pinning mode shortens,and the deposition area of ferrofluid droplet decreases compared to that of without magnetics *** deposition area increases gradually and becomes more uniform with the increase of magnetic *** decrease of friction force which is due to the decrease of the number of nanoparticles at the contact line under external magnetic field is the main reason for the observed *** found that the coffee ring and the uniform deposition inside the droplet will be destroyed when the magnetic field intensity is higher than a critical *** work has a significant reference value for the evaporation of sessile magnetic fluid droplets under the applied magnetic field,especially when the drying pattern needs to be precisely controlled,such as in spray or biomedicine.

关键词： Ferrofluid Droplet Drying pattern Evaporation characteristics Magnetic field

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Synergy of porous structure and cation doping in Ta3N5 photoanode towards improved photoelectrochemical water oxidation

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Journal of Energy Chemistry 2021年第1期30卷 343-350,I0011页

作者： Yubin Chen Hongyu Xia Xiaoyang Feng Ya Liu Wenyu Zheng Lijing Ma Rui Li International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina

Herein,a cross-linked porous Ta3N5 film was prepared via a simple solution combustion route followed by a high-temperature nitridation process for photoelectrochemical(PEC) water ***,the metal cations(Mg2+ and Zr4+) were incorporated into the porous Ta3N5 to enhance the PEC *** porous Mg/Zr co-doped Ta3N5 photoanode yielded a photocurrent density of 1.40 mA cm^(-2) at 1.23 V vs RHE,which is 5.6 times higher than that of the dense Ta3N5 *** enhanced performance should be ascribed to the synergistic effect of porous structure and cation doping,which can enlarge the electrochemical active surface area and accelerate the charge transfer by introducing ON substitution ***,Co(OH)2 cocatalyst was loaded on the Mg/Zr-Ta3N5 photoanode to negatively shift the onset potential to 0.45 V vs RHE and further improve the photocurrent density to 3.5 mA cm^(-2)at 1.23 V ***,with a maximum half-cell solar to hydrogen efficiency of 0.45%.The present study provides a new strategy to design efficient Ta3N5 photoelectrodes via the simultaneous control of the morphology and composition.

关键词： Photoelectrochemical water oxidation Ta3N5 Porous structure Doping Solution combustion

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