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Flow Electrification of Insulated Liquid in Metal Pipes

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Chinese Journal of Mechanical Engineering 2012年第6期25卷 1115-1120页

作者： ZHU Shouxin LIU Lin TAKAHASHI Satoshi School of Information and Engineering Huzhou Teachers College Huzhou 313000 China Graduate School of Natural Science and Technology Okayama University Okayama Japan

When relative motion occurs between a liquid and a solid, the two phases carry electric charge with opposite signs. The created charge easily accumulates in the liquid, and the amount of the charge carried in an insulated liquid refers to many factors, such as contact area with the solid surface, the contact time, and so forth. However, current theories agree that the amount of charge created during flow electrification is proportional to the contact surface. In this paper, the classical wall current theory is applied to establish an interfacial electrical double-layer model of flow electrification phenomena when an insulated liquid passes over metal pipe surface. Meanwhile, in conjunction with charge relaxation function, the relation between the charge density and flow velocity, the contact time and the contact area is obtained during the liquid flowing process. The experimental result demonstrates that the flowing charge carried in the insulated liquid is not simply proportional to the contact area, but has a non-linear dependence on the contact area and the contact time. Moreover, down flow experimental equipment pipes of different length and diameter, and dielectric hydraulic oil VG46 are used in an experimental study of laminar flow, in order to understand electrification phenomena in dielectric liquid flowing over metal pipes of different length and aperture. If they both increase linearly, charge relaxation will increase exponentially. As a result, the test result verifies related theoretical analysis, and the method given provides a theoretical basis to analyze interracial electrical phenomena.

关键词： flow electrification metal pipes contact time relaxation

Effect of active species in crude oil on the interfacial tension behavior of alkali/synthetic surfactants/crude oil systems

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Petroleum Science 2008年第4期5卷 353-358页

作者： Liu Liwei Hou Jirui Yue Xiang＇an Zhao Ji Key Laboratory of Petroleum Engineering Ministry of Education China University of Petroleum Beijing 102249 China China Petrochemical Corporation Beijing 100029 China

The effect of active species present in crude oil on the interfacial tension （IFT） behavior of alkali/synthetic surfactants/crude oil systems was studied. The system consisted of heavy alkyl benzene sulfonate, sodium chloride, sodium hydrate and Daqing crude oil. Experimental results indicated that active species would diffuse from oil/aqueous interface to aqueous phase and finally an equilibrium could be reached in the system with increasing contact time. Moreover, the minimum IFT and equilibrium IFT values increased with increasing contact time and a linear relationship existed between dynamic IFT and f^-1/2 when IFT value approaching the minimum and after the minimum IFT was reached. This indicated that the dynamic IFT-time behavior was diffusion controlled. The oil and aqueous phases were analyzed by infrared （IR） spectroscopy. IR spectra of oil and aqueous phases illustrated that the content of active species in the oil phase decreased, but the content of active species in the aqueous phase increased after alkali reacted with crude oil. This indicated that the active species present in oil played an important role in reducing IFT.

关键词： contact time diffusion alkali interfacial tension

Kinetic Study for Adsorption of Heavy Metals on Zeolite

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Journal of Harbin Institute of Technology(New Series) 2022年第1期29卷 70-76页

作者： Kow Jing Yang Lim Lee Fong Chan Mieow Kee Aseel Ali Saeed Centre for Water Research Faculty of EngineeringBuilt Environment and Information TechnologySEGi UniversityPetaling JayaSelangor 47810Malaysia

Heavy metals⁃polluted water has negative impact on the ecosystem.In Malaysia,minimum discharge limit for Cu^(2+)and Zn^(2+)are 1 mg/L and 2 mg/L,respectively.Zeolite is a highly porous adsorbent and its performance is affected by various factors,including contact time and pH.Thus,the objective of this study is to identify an ideal operating condition to treat Cu^(2+)and Zn^(2+)solutions up to the allowable discharge limit,by considering the pH and contact time factors.Six kinetic models were studied to identify the adsorption mechanism of the heavy metal removal process.Single solute batch adsorption experiment was conducted within pH 3-11 from 30 to 150 min.Results showed that hydration enthalpy(ΔHhyd)governed the selectivity of heavy metals,where a maximum of 90.87%Zn^(2+)(ΔH_(hyd)=-1955 kJ/mol)and 82.15%Cu^(2+)(ΔH_(hyd)=-2010 kJ/mol)removals were found at pH≥7.Without pH adjustment,selectivity towards Cu^(2+)was higher compared with Zn^(2+)due to the size of hydration radii,where Cu^(2+)is 0.11Åsmaller than Zn^(2+).By considering both pH and contact time factors,this study shows that by adjusting the pH of Zn^(2+)solutions to a minimum pH value of 7,the contact time required to achieve maximum Zn^(2+)removal rate was 90%,which can be achieved within 60 min.Meanwhile,zeolite performed better in Cu^(2+)removal without any pH adjustment where a maximum of 94%was achieved at 120 min.Final concentration of 0.523 mg/L Cu^(2+)and 0.981 mg/L Zn^(2+)were obtained in this study.Kinetic study showed that Ritchie’s equation predicted Cu^(2+)adsorption the best,while Zn^(2+)adsorption could be represented by Elovich model.This suggested that the adsorption on the activate site governed Cu^(2+)and Zn^(2+)removal process.Hence,future work should focus on modifying zeolite surface to improve the adsorptive performance.

关键词： zeolite heavy metal removal pH contact time

Mechanical Behaviors of TiNi Alloy under Dynamic Impact Loading Conditions

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Petroleum Science 2005年第3期2卷 40-43页

作者： Xu Renbo Cui Lishan Zheng Yanjun Chen Hongling Faculty of Mechanical and Electronic Engineering China University of Petroleum ChinaBeijing 102249

The mechanical behaviors of Ti-50.7%Ni shape memory alloy under a dynamic impact loading condition were investigated by a home-built impact testing system. Both the contact force and the contact time during the impact process were measured with a piezoelectric force sensor and a digital signal processing system in real time. The predicted instantaneous velocity and the displacement formulae are presented. Results show that the maximum contact force increased, while the contact time decreased with the increase of the temperature when the TiNi alloy was in a martensitic state. When the compressive stress during the impact process was higher than the critical stress of the stress-induced martensitic transformation, the TiNi alloy specimen in the parent phase left no permanent deformation but could dissipate the impact energy.

关键词： TiNi shape memory alloy contact force contact time impact energy