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Friction 2024年第4期12卷 745-779页

作者： Haoyuan LUO Siyu CHEN Leyi ZHU Xiyin LIU Yangzezhi ZHENG Runming ZHAO Xiaoming HUANG School of Transportation Southeast UniversityNanjing 211189China National Demonstration Center for Experimental Education of Road and Traffic Engineering Southeast UniversityNanjing 211189China

Many rubber friction theories or some method combined theories and field-experiments are employed to evaluate the pavement skid-resistance deterioration due to the evolution of surface textures.However,these methods are difficult to be implemented in the analysis of situations with multi-factor coupling and some extreme conditions.This study developed a framework to evaluate the skid-resistance deterioration of asphalt pavements.In this framework,the portable laser scanning was used to create the digital worn pavement model,and a hydroplaning finite element(FE)model for these digital worn pavements was constructed to evaluate coupling effects of the texture evolution and factors of slip ratio,slip angle,velocity and water film on braking-cornering characteristics of tire.In this study,the deterioration of skid-resistance of five typical asphalt pavements due the surface texture wear was systematically investigated by this framework.Compared with previous works,this study established the rubber friction models for each digital worn pavement considering the energy hysteresis of rubber and the power spectrum density of surface texture.And the rubber friction model was used to define the interaction behaviors between the tire and corresponding wore pavements in the FE hydroplaning model,rather than using an empirical friction model or a fixed friction coefficient.

关键词： worn pavement skid-resistance friction coefficient textures evolution water film computer numerical simulation

Removal of NO and SO2 in Corona Discharge Plasma Reactor with water film

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Plasma Science and Technology 2004年第2期6卷 2250-2254页

作者：贺元吉董丽敏杨嘉祥 The Fourth Institute of the Second Artillery Beijing 100085 China Harbin University of Science and Technology Harbin 150040 China

In this paper, a novel type of a corona discharge plasma reactor was designed, which consists of needle-plate-combined electrodes, in which a series of needle electrodes are placed in a glass container filled with flue gas, and a plate electrode is immersed in the water. Based on this model, the removal of NO and SO2 was tested experimentally. In addition, the effect of streamer polarity on the reduction of SO2 and NO was investigated in detail. The experimental results show that the corona wind formed between the high-voltage needle electrode and the water by corona discharge enhances the cleaning efficiency of the flue gas because of the presence of water, and the cleaning efficiency will increase with the increase of applied dc voltage within a definite range. The removal efficiency of SO2 up to 98%, and about 85% of NOx removal under suitable conditions is obtained in our experiments.

关键词： corona discharge plasma reactor water film

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A study on water film in saturated sand

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International Journal of Sediment Research 2010年第3期25卷 221-232页

作者： LU X. B.1 and CUI P.2 1 Dr., Laboratory for Hydraulic and Ocean Engineering, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China, 2 Prof., Key Laboratory for Mountain Hazard and Earth Surface Process, Institute of Mountain Hazard and Environment, Chinese Academy of Sciences, Chengdu 610041, China, Dr. Laboratory for Hydraulic and Ocean Engineering Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China Prof. Key Laboratory for Mountain Hazard and Earth Surface Process Institute of Mountain Hazard and Environment Chinese Academy of Sciences Chengdu 610041 China

water film can serve as a sliding surface and cause landslides on gentle slopes. The development of "water film" in saturated sand is analyzed numerically and theoretically based on a quasi-three-phase model. It is shown that stable water films initiate and grow if the choking state (where the fluid velocity decreases to near zero) remains steady in a liquefied sand column. Discontinuity can occur in pore water velocity, grain velocity and pore pressure after the initiation of a water film. However, the discontinuity and water film can disappear once the choking state is changed. The key to the formation of water film is the choking in the sand column caused by eroded fine grains.

关键词： Saturated sand water film Liquefaction

Permeability evolution and gas flow in wet coal under non-equilibrium state:Considering both water swelling and process-based gas swelling

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International Journal of Mining Science and Technology 2023年第5期33卷 585-599页

作者： Zhiyong Xiao Gang Wang Changsheng Wang Yujing Jiang Feng Jiang Chengcheng Zheng Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Shandong University of Science and TechnologyQingdao 266590China College of Civil Engineering Fujian University of TechnologyFuzhou 350118China c State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology Shandong University of Science and TechnologyQingdao 266590China

Accurate knowledge of gas flow within the reservoir and related controlling factors will be important for enhancing the production of coal bed methane.At present,most studies focused on the permeability evolution of dry coal under gas adsorption equilibrium,gas flow and gas diffusion within wet coal under the generally non-equilibrium state are often ignored in the process of gas recovery.In this study,an improved apparent permeability model is proposed which accommodates the water and gas adsorption,stress dependence,water film thickness and gas flow regimes.In the process of modeling,the water adsorption is only affected by water content while the gas adsorption is time and water content dependent;based on poroelastic mechanics,the effective fracture aperture and effective pore radius are derived;and then the variation in water film thickness for different pore types under the effect of water content,stress and adsorption swelling are modeled;the flow regimes are considered based on Beskok’s model.Further,after validation with experimental data,the proposed model was applied to numerical simulations to investigate the evolution of permeability-related factors under the effect of different water contents.The gas flow in wet coal under the non-equilibrium state is explicitly revealed.

关键词： Gas flow Apparent permeability water film Adsorption Non-equilibrium state

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Shale gas transport in nanopores with mobile water films and water bridge

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Petroleum Science 2023年第2期20卷 1068-1076页

作者： Ran Li Zhangxin Chen Keliu Wu Jinze Xu Department of Chemical and Petroleum Engineering University of CalgaryCalgaryAlbertaT2N 1N4Canada State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China

Gas flow properties in nanopores are significantly determined by the flow patterns. Slug flow pattern is a potential water–gas two phase flow pattern, in which gas molecules flow in form of gas slugs and water molecules separate gas slugs. Considering water slippage, a portion of water molecules accumulates at the wall with lower mobility, while the remaining water molecules take the shape of a water bridge. Adopting foam apparent viscosity model to represent slug rheological behavior, how water bridge disturbs on gas flow capacity is estimated. The results are compared with the water–gas two phase flow model that assumes annular flow pattern as well as the single gas flow model without the consideration of water. The comparison illustrates that gas molecular movement is significantly hindered by flow space reduction and loss of gas slippage. The impact from water phase of slug flow pattern is more significant than that of annular flow pattern on gas flow capacity. It is discovered that larger nanopores improve gas flow capacity while maintaining bulk water layer thickness and increasing water bridge thickness tend to reduce gas transport ability. A better understanding of the structure and transport of water and gas molecules is conducive to figure out the specific gas–water flow behavior and predict shale gas production.

关键词： Shale gas water bridge water film Nanopore

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Bionic Design to Reduce Jacking Force for Trenchless Installations in Clay Soil

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Journal of Bionic Engineering 2020年第4期17卷 686-694页

作者： Donghui Chen Xiao Yang Taidong Dai Youhong Sun Zhiyong Chang College of Biological and Agricultural Engineering Jilin UniversityChangchun 130022China Key Laboratory of Bionic Engineering Ministry of EducationChangchun 130022China School of Engineering and Technology China University of GeosciencesBeijing 100083China National-Local Joint Engineering Laboratory of In-situ Conversion Drilling and Exploitation Technology for Oil ShaleChangchun 130021China

The application of trenchless technology is the trend of underground public facilities'installation,replacement and repairing.As the soil-engaging component during penetrating bore,the working resistance of penetration head has remarkable effect on energy consumption of the whole working process.Some typical soil-digging animals,like pangolin and earthworm,they own special micro structures on their surface.It has been widely proved that some micro geometrical structures can effectively reduce adhesion resistance.Four kinds of bionic penetration heads were designed by imitating micro geometrical structures inspired by the soil animals.In this work,the real time jacking forces of the bionic penetration heads were measured and compared with a smooth penetration head(control group)without micro geometrical structures.The result indicated that the jacking forces of the bionic penetration heads were smaller than that of the smooth penetration head.This proved that the bionic penetration heads have the ability of reducing adhesion resistance.The vertical concave penetration head got the smallest jacking force,of which the average jacking force was 18.7%lower than that of the smooth penetration head.The interaction between soil and bionic surface of penetration head was discussed on the condition of wet friction.The bionic surface reduced the adhesion resistance by disturbing the soil and braking the continuous water film between soil and the surface of the penetration head.

关键词： trenchless technology soil bionic adhesion reduction water film wet friction