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Investigations of Water Flow Behaviors Induced by Local Temperature Variations through a Single Rough Fracture for the Enhanced Geothermal Systems

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Journal of Thermal Science 2024年第3期33卷 1055-1064页

作者： li jiawei YE lin Department of Energy and Power Engineering Tsinghua UniversityBeijing100084China School of Power and Energy Northwestern Polytechnical UniversityXi’an710072China

In recent years,Enhanced Geothermal System(EGS)technologies have been applied to the geothermal resources production in the Hot Dry Rock(HDR).The core of EGS technologies is to adopt hydraulic fracturing in the reservoir to create a connected network of discrete fractures with the consideration of water as a working fluid for hydraulic fracturing and heat *** paper investigates the characteristics of water flow behaviors through a single rough fracture under different temperature and pressure conditions.A single fracture model with rough fracture surfaces is constructed and then characterized,and influences of the anisotropic factor on the average tortuosity and frictional resistance coefficient of water flow through a single fracture with rough surfaces have been compared and *** consideration of other impacting factors(temperature,pressure,fracture roughness),the impact of mass flow rate has also been *** simulation results present that changes of average tortuosity for water flow through a single rough facture are mainly affected by *** can be observed that higher temperature leads to larger average tortuosity but the frictional resistance coefficient shows an opposite *** for pressure conditions,it is found that effects of pressure on average tortuosity and frictional resistance coefficient is very small,which can be neglected under high pressure ***,the average tortuosity shows a progressively linear relationship with the mass flow *** the contrary,the frictional resistance coefficient has a negative relationship with the mass flow *** is revealed that when the mass flow rate reaches a critical point,the influences of temperature on the frictional resistance coefficient will be *** of single rough fractures with different anisotropic factors show that values of average tortuosity and frictional resistance coefficient have positive relationships with the increase

关键词： single rough fracture tortuosity frictional resistance enhanced geothermal system

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A modeling study of the impact of heterogeneous reactions on mineral aerosol surfaces on tropospheric chemistry over East Asia

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Particuology 2010年第5期8卷 433-441页

作者： jiawei li Zhiwei Han Key Laboratory of Regional Climate-Environment Research for Temperate East-Asia (RCE-TEA) Institute of Atmospheric Physics Chinese Academy of Sdences Beijing China

Nine heterogeneous reactions （uptake of H2O2, HNO3, HO2, N2O5, NO2, NO3, O3, OH and SO2 on mineral aerosol surfaces） are incorporated into a Regional Air Quality Model System （RAQMS） to investigate their impacts on tropospheric chemistry in East Asia during the dust storm period in March 2006. Comparison with observations shows the model system well represents the behaviors of the gaseous and aerosol species. Most of the reaction probability γvalues used for this study are the best estimation specifically for dust samples from deserts of China, derived from analysis of a number of recent laboratory studies. There are large variations in gas and aerosol concentrations while taking heterogeneous reactions on mineral aerosol surface into account, especially during dust storm events. The domain-averaged monthly mean percentage changes in SO2, NO2, O3, HNO3, NH3, total sulfate, total nitrate and total ammonium concentrations are -4.4%, -3.8%, -2.1%, -22.0%, 12.7%, 6.6%, 26.1%, and -9.5%, respectively below 3 km. These changes indicate the considerable perturbation of heterogeneous reactions on mineral aerosol surface to tropospheric chemical system and components. The strength of heterogeneous reactions is determined by both reaction probability and gas precursor concentration. Among the nine reactions, dust uptakes of HNO3, SO2, and N2O5 exert relatively large influences on the other chemical components, whereas the reactions regarding H2O2, HO2, and OH have little impacts.

关键词： Heterogeneous reactionMineral aerosolTropospheric chemistryNumerical simulationDust storm

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Molecular Dynamics Study on the Mechanism of Nanoparticle Phase Change Caused by Collision with Wall Surface

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Journal of Thermal Science 2022年第4期31卷 1145-1154页

作者： li jiawei WANG Guanbang ZHANG Xinrong Department of Energy and Resources Engineering College of Engineering Peking University Beijing 100871China Beijing Engineering Research Center of City Heat Peking University Beijing 100871China

The collision between the nanoparticle and wall surface is supposed to cause the escape of nanoparticle molecules which indicates the potential phase change of the *** is significant to understand the mechanism of the collision process involved with phase change for applications of nanoparticles in energy and mass *** this study,the collision process between nanoparticle made of monatomic argon molecule and wall surface made of nickel metal crystal is simulated by molecular dynamics *** travelling behavior and energy transformation of escaped molecules are respectively *** effects of the intermolecular force and initial temperature on the collision process are further *** results show that the nanoparticle can be accelerated by the wall surface with the intermolecular force and finally collide with *** molecules escape from the nanoparticle either by bouncing off the wall surface or the intermolecular energy exchange with the energy transformation between the potential energy and kinetic *** molecules far from the nanoparticle center are more likely to escape,while the velocity distributions of the escaped molecules follow the Maxwell *** escaped molecules,namely higher phase change potential,are observed with lower intermolecular force and higher initial *** a fundamental study on nanoparticle phase change in the vicinity of wall surface,the present investigation will be helpful for further study on the heat transfer characteristics and phase change mechanisms of nanoparticles.

关键词： collision molecule escape nanoparticle phase change wall surface

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A hybrid lattice Boltzmann flux solver for integrated hypersonic fluid-thermal-structural analysis

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Chinese Journal of Aeronautics 2020年第9期33卷 2295-2312页

作者： jiawei li Jiangfeng WANG liming YANG Chang SHU College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Mechanical Engineering National University of SingaporeSingapore 119260Singapore

In this paper,a hybrid Lattice Boltzmann Flux Solver(LBFS)with an improved switch function is proposed for simulation of integrated hypersonic fluid-thermal-structural *** the solver,the macroscopic Navier–Stokes equations and structural heat transfer equation are discretized by the finite volume method,and the numerical fluxes at the cell interface are reconstructed by the local solution of the Boltzmann *** compute the numerical fluxes,two equilibrium distribution functions are *** is the D1Q4 discrete velocity model for calculating the inviscid flux across the cell interface of Navier–Stokes equations,and the other is the D2Q4 model for evaluating the flux of structural energy *** this work,a new dual thermal resistance model is proposed to calculate the thermal properties at the fluid–solid *** accuracy and stability of the present hybrid solver are validated by simulating several numerical examples,including the fluid-thermal-structural problem of cylindrical leading *** results show that the present solver can accurately predict the thermal properties of hypersonic fluid-thermalstructural problems and has the great potential for solving fluid-thermal-structural problems of long-endurance high-speed vehicles.

关键词： Finite volume method Fluid-structural-thermal Hybrid lattice Boltzmann flux solver Hypersonic Improved switch function

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A Modeling Study of Seasonal Variation of Atmospheric Aerosols over East Asia

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Advances in Atmospheric Sciences 2012年第1期29卷 101-117页

作者： li jiawei HAN Zhiwei Key Laboratory of Regional Climate-Environment Research for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029

In this study, a regional air quality model system （RAQMS） was applied to investigate the spatial distributions and seasonal variations of atmospheric aerosols in 2006 over East Asia. Model validations demonstrated that RAQMS was able to reproduce the evolution processes of aerosol components reasonably well. Ground-level PM10 （particles with aerodynamic diameter ≤10 μm） concentrations were highest in spring and lowest in summer and were characterized by three maximum centers： the Taklimakan Desert （-1000 μg m^-3）, the Gobi Desert （-400 μg m^-3）, and the Huabei Plain （- 300 μg m^-3） of China. Vertically, high PM10 concentrations ranging from 100 μg m-3 to 250 μg m-3 occurred from the surface to an altitude of 6000 m at 30°-45°N in spring. In winter, the vertical gradient was so large that most aerosols were restricted in the boundary layer. Both sulfate and ammonium reached their highest concentrations in autumn, while nitrate reached its maximum level in winter. Black carbon and organic carbon aerosol concentrations reached maximums in winter. Soil dust were strongest in spring, whereas sea salt exerted the strongest influence on the coastal regions of eastern China in summer. The estimated burden of anthropogenic aerosols was largest in winter （1621 Gg） and smallest in summer （1040 Gg）. The sulfate burden accounted for -42% of the total anthropogenic aerosol burden. The dust burden was about twice the anthropogenic aerosol burden, implying the potentially important impacts of the natural aerosols on air quality and climate over East Asia.

关键词： East Asia aerosol components model simulation spatial distribution seasonal variation,column burden

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Biological function of resveratrol and its application in animal production:a review

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Journal of Animal Science and Biotechnology 2023年第3期14卷 864-886页

作者： Qingwei Meng jiawei li Chunsheng Wang Anshan Shan College of Animal Science and Technology Northeast Agricultural UniversityHarbin150030China

With the prohibition of antibiotics in feed,plant functional substances have been widely studied as feed ***,a natural stilbene,and a non-flavonoid polyphenol found in plants,possesses antioxidant,anti-inflammatory,and metabolic regulatory *** generated intense scientific and public interest,primarily due to its widely reported ability to prevent cancer,delay aging and alleviate related metabolic ***,resveratrol has been studied and applied as a feed additive in animal *** review focuses on the outline of the absorption and metabolism and biological functions of resveratrol and summarizes the application of dietary resveratrol in animal production up to the present,including pigs,poultry,and *** pigs,dietary resveratrol improved intestinal health,mitochondrial function,meat quality,and *** poultry,studies have shown that dietary resveratrol improves growth performance and meat and egg quality and alleviates heat stress induced adverse *** are few studies on dietary resveratrol in ruminants;however previous studies have indicated that dietary resveratrol increases nutrient digestibility and reduces methane emissions in *** is hoped that this review could provide a specific theoretical basis and research ideas for the research and application of resveratrol.

关键词： Animal production Biological function Health Pigs Poultry Resveratrol Ruminants

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Resistance to salt stresses by aerobic granular sludge:sludge property and microbial community

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Frontiers of Environmental Science & Engineering 2024年第8期18卷 107-116页

作者： Xiao Wu Hui li Meili Wang Tianying Zhang jiawei li Yongdi liu Key Laboratory of Pollution Control Chemistry and Environmental Functional Materials for Qinghai-Tibet Plateau of the National Ethnic Affairs Commission School of Chemistry and EnvironmentSouthwest Minzu UniversityChengdu 610041China Institute for Environmental Pollution and Health School of Environmental and Chemical EngineeringShanghai UniversityShanghai 200444China School of life Sciences Southwest UniversityChongqing 400715China State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process School of Resources and Environmental EngineeringEast China University of Science and TechnologyShanghai 200237China Institute of Qinghai-Tibetan Plateau Southwest Minzu UniversityChengdu 610041China

Saline wastewater is regarded as a challenge for wastewater treatment plants because high-salinity conditions negatively affect on traditional biological *** granular sludge(AGS)has gained attention as a promising technology for saline wastewater treatment because of its compact structure and the ability to withstand toxic ***,this study investigated the saltresistance performance,sludge properties and microbial community of AGS under low-salinity and high-salinity conditions,with the saline concentrations ranging from 0 to 50 g/*** results showed that AGS could withstand long-term saline stresses,and the maximum salinity reached 50 g/L within 113 *** salinities of 10,30,and 50 g/L,the chemical oxygen demand(COD)removal efficiencies were 90.3%,88.0%and 78.0%,*** also its maintained strength and aggregation at salinities of 10 and 30 g/*** of extracellular polymeric substances(EPS)by non-halophilic bacteria that enhanced sludge *** compact structure that ensured the microorganisms bioactivity helped to remove organic matters under salinities of 10 and 30 g/*** a salinity of 50 g/L,moderately halophilic bacteria,including Salinicola,Thioclava,Idiomarina and Albirhodobacter,prevailed in the *** dominant microbial communities shifted to moderately halophilic bacteria,which could maintain aerobic granular stabilization and remove organic matters under 50 g/L *** results in this study provide a further explanation for the long-term operation of AGS for treating saline wastewater at different *** is hoped that this work could bring some clues for the mystery of salt-resistance mechanisms.

关键词： Aerobic granular sludge Long-term saline stresses Performance Sludge property Microbial community

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High corrosion and wear resistant electroless Ni–P gradient coatings on aviation aluminum alloy parts

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 155-164页

作者： Bo Wang jiawei li Zhihui Xie Gengjie Wang Gang Yu College of Chemistry and Chemical Engineering Hunan UniversityChangsha 410012China Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province/College of Chemistry and Chemical Engineering China West Normal UniversityNanchong 637002China Zhongchuan Machinery Ltd.Co. Aero Engine Corporation of ChinaChangsha 410200China

A Ni–P alloy gradient coating consisting of multiple electroless Ni–P layers with various phosphorus contents was prepared on the aviation aluminum alloy. Several characterization and electrochemical techniques were used to characterize the different Ni–P coatings’ morphologies, phase structures, elemental compositions, and corrosion protection. The gradient coating showed good adhesion and high corrosion and wear resistance, enabling the application of aluminum alloy in harsh environments. The results showed that the double zinc immersion was vital in obtaining excellent adhesion (81.2 N). The optimal coating was not peeled and shredded even after bending tests with angles higher than 90°and was not corroded visually after 500 h of neutral salt spray test at 35℃. The high corrosion resistance was attributed to the misaligning of these micro defects in the three different nickel alloy layers and the amorphous structure of the high P content in the outer layer. These findings guide the exploration of functional gradient coatings that meet the high application requirement of aluminum alloy parts in complicated and harsh aviation environments.

关键词： aluminum alloy electroless nickel coating corrosion adhesion

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A method for weighing broiler chickens using improved amplitude-limiting filtering algorithm and BP neural networks

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Information Processing in Agriculture 2021年第2期8卷 299-309页

作者： Weihong Ma Qifeng li jiawei li Luyu Ding Qinyang Yu Beijing Research Center for Information Technology in Agriculture Beijing 100097China National Engineering Research Center for Information Technology in Agriculture Beijing 100097China Key Laboratory of Agri-informatics Ministry of AgricultureBeijing 100097China Beijing Engineering Research Center of Agriculture Internet of Things Beijing 100097China

Broiler chickens are traditionally weighed by steelyard or platform scale,which is timeconsuming and *** chickens usually exhibit stress-related behavior during *** 3D camera-based weighing system for broiler chickens can only weigh the broiler chicken in the monitoring ***,it makes poor weight prediction due to poor segmentation especially when the broiler chicken is flapping its *** solve these issues,we developed one simple and low-cost weighing system with high stability and accuracy.A validity value extraction method from dynamic weighing was ***,an improved amplitude-limiting filtering algorithm and a BP neural networks model were developed to avoid accidental *** BP neural networks model used daily weight gain,day-age,average velocity,and the weight data after filtering algorithm as the input *** weighing system was tested in a commercial Beijing Fatty Chickens house with Beijing Fatty *** tested thirteen groups of Beijing Fatty Chickens of different weights,from 500 g to 1800 g in intervals of 100 g,using the three different methods:no filtering algorithm or BP neural networks,only the improved amplitude-limiting filtering algorithm and a hybrid of the improved amplitude-limiting filtering algorithm and BP neural *** results showed that the hybrid algorithm had a better performance in minimizing the error,lowering from the original 6%down to 3%.The accurate weight data was transmitted to the remote service platform for further decision-making,such as activity analysis,feeding management,and health alerts.

关键词： Weighing of broiler chickens Improved amplitude-limiting filtering algorithm BP neural networks Dynamic weighing

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Field-line-Circuit Coupling Based Method for Predicting Radiated Electromagnetic Emission of IGBT-PMSM Drive System

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Chinese Journal of Electronics 2021年第3期30卷 561-569页

作者： XIAO Pei HE Jiagang PENG Zishun li jiawei QIU Yongfeng liU Zhu li Gaosheng College of Electrical and Information Engineering Hunan University School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China

Electric drive system with Insulated gate bipolar transistor(IGBT) power device is widely used in Electric vehicle(EV), which consists of inverter, cables and Permanent magnet synchronous motor(PMSM). Due to the fast switching in di/dt and dv/dt of IGBT device,the system produces serious radiated Electromagnetic interference(EMI) through the interconnection ***, modeling of EMI source, propagation path and load PMSM is the key to accurately evaluate the system’s radiation level. In addition, the system’s radiated EMI involves the integrated calculation of circuit, cable and electromagnetic field, which cannot be solved by using a single circuit or electromagnetic calculation method. Therefore, this paper develops an effective fieldlinecircuit coupling based method to investigate the radiated EMI problems for IGBT-PMSM drive system,which is validated by experimental measurement. Besides,the impact of power cable parameters on radiated EMI is discussed. The proposed approach has guiding significance for electromagnetic compatibility design of EV.

关键词： field-line-circuit coupling electromagnetic calculation method power cable parameters permanent magnet motors electromagnetic interference electromagnetic field electromagnetic compatibility design Electric vehicle electromagnetic compatibility radiated EMI problems Permanent magnet synchronous motor predicting radiated Electromagnetic emission IGBT-PMSM drive system interconnection cables load PMSM effective field-linecircuit coupling power cables synchronous motors EMI source synchronous motor drives machine control Insulated gate bipolar transistor power device electric drives electromagnetic fields Electric drive system insulated gate bipolar transistors serious radiated Electromagnetic interference IGBT device

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