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Tribological mechanism of carbon group nanofluids on grinding interface under minimum quantity lubrication based

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0733-z

摘要： Carbon group nanofluids can further improve the friction-reducing and anti-wear properties of minimum quantity lubrication (MQL). However, the formation mechanism of lubrication films generated by carbon group nanofluids on MQL grinding interfaces is not fully revealed due to lack of sufficient evidence. Here, molecular dynamic simulations for the abrasive grain/workpiece interface were conducted under nanofluid MQL, MQL, and dry grinding conditions. Three kinds of carbon group nanoparticles, i.e., nanodiamond (ND), carbon nanotube (CNT), and graphene nanosheet (GN), were taken as representative specimens. The [BMIM]BF4 ionic liquid was used as base fluid. The materials used as workpiece and abrasive grain were the single-crystal Ni–Fe–Cr series of Ni-based alloy and single-crystal cubic boron nitride (CBN), respectively. Tangential grinding force was used to evaluate the lubrication performance under the grinding conditions. The abrasive grain/workpiece contact states under the different grinding conditions were compared to reveal the formation mechanism of the lubrication film. Investigations showed the formation of a boundary lubrication film on the abrasive grain/workpiece interface under the MQL condition, with the ionic liquid molecules absorbing in the groove-like fractures on the grain wear’s flat face. The boundary lubrication film underwent a friction-reducing effect by reducing the abrasive grain/workpiece contact area. Under the nanofluid MQL condition, the carbon group nanoparticles further enhanced the tribological performance of the MQL technique that had benefited from their corresponding tribological behaviors on the abrasive grain/workpiece interface. The behaviors involved the rolling effect of ND, the rolling and sliding effects of CNT, and the interlayer shear effect of GN. Compared with the findings under the MQL condition, the tangential grinding forces could be further reduced by 8.5%, 12.0%, and 14.1% under the diamond, CNT, and graphene nanofluid MQL conditions, respectively.

关键词： grinding     minimum quantity lubrication     carbon group nanofluid     tribological mechanism    

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横沙深水新港“全水运”的集疏运模式探索

彭德艳,秦小川

《中国工程科学》 2013年 第15卷 第6期   页码 86-90

摘要：

从世界各地港口发展的经验来看，一个合适的集疏运模式对港口物流服务效率与社会经济效益的提升至关重要。本文参考了国内外港口的成功经验，针对构想中的横沙深水新港，结合其位于长江入海口的地理位置优势，对利用长江航运开展“全水运”的集疏运模式进行了探索。

关键词： 上海港     深水港     横沙东滩     集疏运     长江航运    

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随钻提高井壁质量、保护非常规油气储层水基钻完井液新技术 Article

蒋官澄, 孙金声, 贺垠博, 崔凯潇, 董腾飞, 杨丽丽,  杨旭坤, 王星星

《工程（英文）》 2022年 第18卷 第11期   页码 129-142 doi: 10.1016/j.eng.2021.11.014

摘要：

非常规油气的高效勘探开发已成为提高我国油气自给率的重要保障，但与常规油气和国外非常规油气相比，钻井中常遭遇的“井塌、井漏、高摩阻”和诱发的储层损害不仅影响成井率，更是“高成本、低产量与低效益”的重要原因。由特殊功能材料构成、可提高井壁质量的钻井液是解决这些难题的核心。但我国非常规油气储层条件具有复杂性、多变性和不确定性，国内外现有水基钻井液无法解决这些难题，油基钻井液虽具有一定优越性，但因环境污染风险和成本高等而使应用受限。近10 余年来，国内外热点研究具油基钻井液优点的水基钻井液，但都未取得突破性进展，其成为制约经济规模开发非常规油气的“共性与关键核心”重大技术难题。为此，本文由国际前沿仅提高钻井液自身抑制性和润滑性的外因法，拓展为同时随钻提高井壁质量的内外因结合法，并将仿生学引入石油工程化学材料合成领域，模仿海洋贻贝、猪笼草、蚯蚓等生物的生命活动、生物行为、组成与结构，利用研发的固壁剂、双疏抑制剂与键合润滑剂，研制了随钻提高井壁质量型保护储层钻完井液新技术。宏观和微观研究表明，该技术能减缓甚至阻止井壁岩石强度遭受破坏、岩石毛细管对水分的吸力反转为阻力、井壁高摩阻转变为超低摩阻，使水基钻井液的井壁稳定性、润滑性和储层保护效果超过典型油基钻井液；同时，废弃钻井液环境可接受，并可成为自然界植物的养分和生态循环系统中的一环，使其由环保型钻井液升级为生态型钻井液，实现了“成井率高、储层保护效果好、成本低、环境友好”一体化目标。该技术已在我国1000 余口高难度非常规油气井得到验证与推广应用，大幅缓减了“井塌、井漏、高摩阻”诱发的储层损害难题，平均井塌率减小82.6%、井漏发生率降低80.6%、摩阻复杂率降低80%以上、提速30%以上、油气井产量较以前提高1.5 倍以上。使原来必须使用油基钻井液方可完钻的井转变为水基钻井液完钻，已成为“规模、效益、环保”开发非常规油气资源行之有效的核心技术，并为保护储层技术开辟了新的研究方向，推动了石油工业与环境保护的协调发展；同时，本文通过向自然界学习成功建立了钻井液新技术，为石油工程原创性材料、技术与理论研发和创建提供了思想与灵感的不竭源泉。

关键词： 储层保护     井壁质量     非常规油气     钻完井液     仿生学    

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A review on the application of nanofluids in enhanced oil recovery

《化学科学与工程前沿（英文）》 2022年 第16卷 第8期   页码 1165-1197 doi: 10.1007/s11705-021-2120-4

摘要： Enhanced oil recovery (EOR) has been widely used to recover residual oil after the primary or secondary oil recovery processes. Compared to conventional methods, chemical EOR has demonstrated high oil recovery and low operational costs. Nanofluids have received extensive attention owing to their advantages of low cost, high oil recovery, and wide applicability. In recent years, nanofluids have been widely used in EOR processes. Moreover, several studies have focused on the role of nanofluids in the nanofluid EOR (N-EOR) process. However, the mechanisms related to N-EOR are unclear, and several of the mechanisms established are chaotic and contradictory. This review was conducted by considering heavy oil molecules/particle/surface micromechanics; nanofluid-assisted EOR methods; multiscale, multiphase pore/core displacement experiments; and multiphase flow fluid-solid coupling simulations. Nanofluids can alter the wettability of minerals (particle/surface micromechanics), oil/water interfacial tension (heavy oil molecules/water micromechanics), and structural disjoining pressure (heavy oil molecules/particle/surface micromechanics). They can also cause viscosity reduction (micromechanics of heavy oil molecules). Nanofoam technology, nanoemulsion technology, and injected fluids were used during the EOR process. The mechanism of N-EOR is based on the nanoparticle adsorption effect. Nanoparticles can be adsorbed on mineral surfaces and alter the wettability of minerals from oil-wet to water-wet conditions. Nanoparticles can also be adsorbed on the oil/water surface, which alters the oil/water interfacial tension, resulting in the formation of emulsions. Asphaltenes are also adsorbed on the surface of nanoparticles, which reduces the asphaltene content in heavy oil, resulting in a decrease in the viscosity of oil, which helps in oil recovery. In previous studies, most researchers only focused on the results, and the nanoparticle adsorption properties have been ignored. This review presents the relationship between the adsorption properties of nanoparticles and the N-EOR mechanisms. The nanofluid behaviour during a multiphase core displacement process is also discussed, and the corresponding simulation is analysed. Finally, potential mechanisms and future directions of N-EOR are proposed. The findings of this study can further the understanding of N-EOR mechanisms from the perspective of heavy oil molecules/particle/surface micromechanics, as well as clarify the role of nanofluids in multiphase core displacement experiments and simulations. This review also presents limitations and bottlenecks, guiding researchers to develop methods to synthesise novel nanoparticles and conduct further research.

关键词： nanofluid     EOR mechanism     nanoparticle adsorption     interface property     internal property    

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Temporal dimension and water quality control in an emission trading scheme based on water environmental

Zhaoxing HAN, Zhenyao SHEN, Yongwei GONG, Qian HONG

《环境科学与工程前沿（英文）》 2011年 第5卷 第1期   页码 119-129 doi: 10.1007/s11783-011-0272-z

摘要： Emission trading is one of the most effective alternatives to controlling water pollution. Water environmental functional zone (WEFZ) is used to determine the water quality standard and identify the zone boundary for each river or reach. In this study, a new emission trading scheme was addressed based on WEFZ, accounting for both the temporal dimension and water quality control. A temporal factor of emission trading was proposed based on variations in the environmental capacity within a year by dividing the year into three periods, including high, normal, and low periods of environmental capacity. During each period, emission trading was implemented exclusively. A water quality-control scheme was suggested based on the water quality requirement in the water functional zone, in which the water quality at the downstream boundary of the zone was required to meet the water standard following auto-purification in the stream. Two methods of calculating water quality control are addressed for point-source pollution and non-point-source pollution. The calculated temporal dimension and water quality control were located in Dongxi River of the Daning Watershed in the Three Gorges Watershed. The high period was during June, July, and August, the normal period was during April, May, September, and October, and the low period was during January, February, March, November, and December. The results from the water quality calculation demonstrated that the discharge of point-source and non-point-source pollutions led to an excess of common contaminants at the downstream boundary of WEFZ. The temporal and spatial factors above should be incorporated into the emission trading scheme based on WEFZ.

关键词： emission trading     water functional zone     water quality control    

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Mechanical behavior and semiempirical force model of aerospace aluminum alloy milling using nano biological lubricant

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0720-4

摘要： Aerospace aluminum alloy is the most used structural material for rockets, aircraft, spacecraft, and space stations. The deterioration of surface integrity of dry machining and the insufficient heat transfer capacity of minimal quantity lubrication have become the bottleneck of lubrication and heat dissipation of aerospace aluminum alloy. However, the excellent thermal conductivity and tribological properties of nanofluids are expected to fill this gap. The traditional milling force models are mainly based on empirical models and finite element simulations, which are insufficient to guide industrial manufacturing. In this study, the milling force of the integral end milling cutter is deduced by force analysis of the milling cutter element and numerical simulation. The instantaneous milling force model of the integral end milling cutter is established under the condition of dry and nanofluid minimal quantity lubrication (NMQL) based on the dual mechanism of the shear effect on the rake face of the milling cutter and the plow cutting effect on the flank surface. A single factor experiment is designed to introduce NMQL and the milling feed factor into the instantaneous milling force coefficient. The average absolute errors in the prediction of milling forces for the NMQL are 13.3%, 2.3%, and 7.6% in the x-, y-, and z-direction, respectively. Compared with the milling forces obtained by dry milling, those by NMQL decrease by 21.4%, 17.7%, and 18.5% in the x-, y-, and z-direction, respectively.

关键词： milling     force     nanofluid minimum quantity lubrication     aerospace aluminum alloy     nano biological lubricant    

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Micro/nanofluidics-enabled energy conversion and its implemented devices

Yang YANG, Jing LIU

《能源前沿（英文）》 2011年 第5卷 第3期   页码 270-287 doi: 10.1007/s11708-010-0126-6

摘要： Most people were not aware of the role of energy as a basic force that drives the development and economic growth of the world until the two great oil crises occurred. According to the conservation law, energy not only exists in various forms but is also capable of being converted from one form to another. The common forms of energy are mechanical energy, chemical energy, internal energy, electrical energy, atomic energy, and electromagnetic energy, among others. The fluids in nature serve as the most common carriers and media in the energy conversion process. Following the rapid development of microelectromechanical systems (MEMS) technology, the energy supply and conversion issue in micro/nano scale has also been introduced in research laboratories worldwide. With unremitting efforts, great quantities of micro/nano scale energy devices have been investigated. Micro/nanofluid shows distinct features in transporting and converting energy similar to their counterpart macroscale tasks. In this paper, a series of micro/nanofluid-enabled energy conversion devices is reviewed based on the transformation between different forms of energy. The evaluation and contradistinction of their performances are also examined. The role of micro/nanofluid as media in micro/nano energy devices is summarized. This contributes to the establishment of a comprehensive and systematic structure in the relationship between energy conversion and fluid in the micro/nano scale. Some fundamental and practical issues are outlined, and the prospects in this challenging area are explored.

关键词： micro/nanofluid     different energy forms     energy conversion     medium role    

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PV based water pumping system for agricultural irrigation

T A BINSHAD,K VIJAYAKUMAR,M KALEESWARI

《能源前沿（英文）》 2016年 第10卷 第3期   页码 319-328 doi: 10.1007/s11708-016-0409-7

摘要： This paper investigates the operation and analysis of the photovoltaic water pumping system in detail. Power electronic controllers were designed and developed for the water pumping system using a boost converter along with an inverter followed by an induction motor pump set. The proposed system could be employed in agricultural irrigation under any operating condition of varying natures of solar irradiances and temperatures. The configuration and implementation of the system were described in detail. Further, the detailed method of analysis and simulation characteristics of such PV water pumping system was also presented. With the concern of shortage of fossil fuel, global warming and energy security, the proposed PV based water pumping system can meet the significant demand of electricity and serve for the agricultural sector.

关键词： photovoltaic water pumping system     power electronic controller     solar irradiances and temperature    

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A novel hybrid model for water quality prediction based on VMD and IGOA optimized for LSTM

《环境科学与工程前沿（英文）》 2023年 第17卷 第7期 doi: 10.1007/s11783-023-1688-y

摘要：

● A novel VMD-IGOA-LSTM model has proposed for the prediction of water quality.

关键词： Water quality prediction     Grasshopper optimization algorithm     Variational mode decomposition     Long short-term memory neural network    

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State-of-the-art progress in overall water splitting of carbon nitride based photocatalysts

Bing LUO, Yuxin ZHAO, Dengwei JING

《能源前沿（英文）》 2021年 第15卷 第1期   页码 600-620 doi: 10.1007/s11708-021-0737-0

摘要： Converting solar energy into hydrogen (H ) by photocatalytic water splitting is a promising approach to simultaneously address the increasing energy demand and environmental issues. Half decade has passed since the discovery of photo-induced water splitting phenomenon on TiO photoanode, while the solar to H efficiency is still around 1%, far below the least industrial requirement. Therefore, developing efficient photocatalyst with a high energy conversion efficiency is still one of the main tasks to be overcome. Graphitic carbon nitride (g-C N ) is just such an emerging and potential semiconductor. Therefore, in this review, the state-of-the-art advances in g-C N based photocatalysts for overall water splitting were summarized in three sections according to the strategies used, and future challenges and new directions were discussed.

关键词： photocatalysis     overall water splitting     carbon nitride     hydrogen    

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A cellphone-based colorimetric multi-channel sensor for water environmental monitoring

《环境科学与工程前沿（英文）》 2022年 第16卷 第12期 doi: 10.1007/s11783-022-1590-z

摘要：

● A cellphone-based colorimetric multi-channel sensor for in-field detection.

关键词： Colorimetric analysis     Multi-channel sensor     Cellphone     Water quality indexes     Environmental monitoring    

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Structural engineering of transition metal-based nanostructured electrocatalysts for efficient water

Yueqing Wang, Jintao Zhang

《化学科学与工程前沿（英文）》 2018年 第12卷 第4期   页码 838-854 doi: 10.1007/s11705-018-1746-3

摘要： Water splitting is a highly promising approach for the generation of sustainable, clean hydrogen energy. Tremendous efforts have been devoted to exploring highly efficient and abundant metal oxide electrocatalysts for oxygen evolution and hydrogen evolution reactions to lower the energy consumption in water splitting. In this review, we summarize the recent advances on the development of metal oxide electrocatalysts with special emphasis on the structural engineering of nanostructures from particle size, composition, crystalline facet, hybrid structure as well as the conductive supports. The special strategies relay on the transformation from the metal organic framework and ion exchange reactions for the preparation of novel metal oxide nanostructures with boosting the catalytic activities are also discussed. The fascinating methods would pave the way for rational design of advanced electrocatalysts for efficient water splitting.

关键词： water splitting     structure engineering     metal organic framework     ion exchange     synergistic effect     hybrid structure     conductive supports    

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Efficient Identification of water conveyance tunnels siltation based on ensemble deep learning

Xinbin WU; Junjie LI; Linlin WANG

《结构与土木工程前沿（英文）》 2022年 第16卷 第5期   页码 564-575 doi: 10.1007/s11709-022-0829-x

摘要： The inspection of water conveyance tunnels plays an important role in water diversion projects. Siltation is an essential factor threatening the safety of water conveyance tunnels. Accurate and efficient identification of such siltation can reduce risks and enhance safety and reliability of these projects. The remotely operated vehicle (ROV) can detect such siltation. However, it needs to improve its intelligent recognition of image data it obtains. This paper introduces the idea of ensemble deep learning. Based on the VGG16 network, a compact convolutional neural network (CNN) is designed as a primary learner, called Silt-net, which is used to identify the siltation images. At the same time, the fully-connected network is applied as the meta-learner, and stacking ensemble learning is combined with the outputs of the primary classifiers to obtain satisfactory classification results. Finally, several evaluation metrics are used to measure the performance of the proposed method. The experimental results on the siltation dataset show that the classification accuracy of the proposed method reaches 97.2%, which is far better than the accuracy of other classifiers. Furthermore, the proposed method can weigh the accuracy and model complexity on a platform with limited computing resources.

关键词： water conveyance tunnels     siltation images     remotely operated vehicles     deep learning     ensemble learning     computer vision    

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Ecological compensation based on willingness to accept for conservation of drinking water sources

Linyu XU,Bing YU,Yang LI

《环境科学与工程前沿（英文）》 2015年 第9卷 第1期   页码 58-65 doi: 10.1007/s11783-014-0688-3

摘要： Ecological compensation is a powerful environmental economic tool for environmental protection in areas where drinking water sources are located. We established an ecological compensation accounting system based on respondents’ willingness to accept (WTA). In this system, stakeholder preferences and the factors that influence them can be gauged effectively using logit and tobit models. We applied this accounting system to ecological compensation for the Miyun Reservoir, Beijing, China. The average WTA value for Miyun Reservoir residents was approximately 1186 CNY per family in 2012, which could be set as a suitable compensation standard, since it is slightly higher than the local protection cost. Thus, the annual total ecological compensation could be 58.73 million CNY. Distance from the reservoir, job types, and attitude to environmental protection were variables with significant effects on WTA. In addition, trends for individual preferences were identified via an analysis of key influential factors. The results suggest some useful information for establishing ecological compensation mechanisms for conservation of drinking water sources. Suggestions include popularizing the concept and meaning of ecological compensation among residents, setting different compensation levels based on distance from the reservoir, considering the requirements of farmers, and taking various in-kind and out-of-kind compensation approaches.

关键词： contingent valuation method     questionnaire survey     Miyun Reservoir    

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Application of different CFD multiphase models to investigate effects of baffles and nanoparticles on heat transfer enhancement

Ali SHAHMOHAMMADI,Arezou JAFARI

《化学科学与工程前沿（英文）》 2014年 第8卷 第3期   页码 320-329 doi: 10.1007/s11705-014-1437-7

摘要： In this work, the effect of baffles in a pipe on heat transfer enhancement was studied using computational fluid dynamics (CFD) in the presence of Al O nanoparticles which are dispersed into water. Fluid flow through the horizontal tube with uniform heat flux was simulated numerically and three dimensional governing partial differential equations were solved. To find an accurate model for CFD simulations, the results obtained by the single phase were compared with those obtained by three different multiphase models including Eulerian, mixture and volume of fluid (VOF) at Reynolds numbers in range of 600 to 3000, and two different nanoparticle concentrations (1% and 1.6%). It was found that multiphase models could better predict the heat transfer in nanofluids. The effect of baffles on heat transfer of nanofluid flow was also investigated through a baffled geometry. The numerical results show that at Reynolds numbers in the range of 600 to 2100, the heat transfer of nanofluid flowing in the geometry without baffle is greater than that of water flowing through a tube with baffle, whereas the difference between these effects (nanofluid and baffle) decreases with increasing the Reynolds number. At higher Reynolds numbers (2100–3000) the baffle has a greater effect on heat transfer enhancement than the nanofluid.

关键词： CFD simulation     heat transfer     nanofluid     baffle     single phase model     multiphase model    

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标题 作者 时间 类型 操作

Tribological mechanism of carbon group nanofluids on grinding interface under minimum quantity lubrication based

期刊论文

横沙深水新港“全水运”的集疏运模式探索

彭德艳,秦小川

期刊论文

随钻提高井壁质量、保护非常规油气储层水基钻完井液新技术

蒋官澄, 孙金声, 贺垠博, 崔凯潇, 董腾飞, 杨丽丽,  杨旭坤, 王星星

期刊论文

A review on the application of nanofluids in enhanced oil recovery

期刊论文

Temporal dimension and water quality control in an emission trading scheme based on water environmental

Zhaoxing HAN, Zhenyao SHEN, Yongwei GONG, Qian HONG

期刊论文

Mechanical behavior and semiempirical force model of aerospace aluminum alloy milling using nano biological lubricant

期刊论文

Micro/nanofluidics-enabled energy conversion and its implemented devices

Yang YANG, Jing LIU

期刊论文

PV based water pumping system for agricultural irrigation

T A BINSHAD,K VIJAYAKUMAR,M KALEESWARI

期刊论文

A novel hybrid model for water quality prediction based on VMD and IGOA optimized for LSTM

期刊论文

State-of-the-art progress in overall water splitting of carbon nitride based photocatalysts

Bing LUO, Yuxin ZHAO, Dengwei JING

期刊论文

A cellphone-based colorimetric multi-channel sensor for water environmental monitoring

期刊论文

Structural engineering of transition metal-based nanostructured electrocatalysts for efficient water

Yueqing Wang, Jintao Zhang

期刊论文

Efficient Identification of water conveyance tunnels siltation based on ensemble deep learning

Xinbin WU; Junjie LI; Linlin WANG

期刊论文

Ecological compensation based on willingness to accept for conservation of drinking water sources

Linyu XU,Bing YU,Yang LI

期刊论文

Application of different CFD multiphase models to investigate effects of baffles and nanoparticles on heat transfer enhancement

Ali SHAHMOHAMMADI,Arezou JAFARI

期刊论文