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 insul...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.展开更多
A particular kind of triboelectrification occurs during the flow of liquids through tubes.Here,we used Faraday cups and Kelvin probes to investigate the charge of aqueous solutions and alcohols flowing through a polyt...A particular kind of triboelectrification occurs during the flow of liquids through tubes.Here,we used Faraday cups and Kelvin probes to investigate the charge of aqueous solutions and alcohols flowing through a polytetrafluorethylene tube.An excess of positive charges was observed in all liquids collected by the Faraday cup after the flow.While the tube displays a small potential during the flow,likely due to electrokinetic effects,a very high negative potential was observed after the completion of the flow.Aqueous solutions with varying pH showed significant differences in charge accumulation only at pH 2.93 and 4.99,while most of the charge accumulation can be suppressed using common surfactants.Alcohols displayed an inverse relationship between charge accumulation and carbon chain length,except for methanol.Thus,we used graphite-based nanocomposites as noncontact induction electrodes near the tube for flow sensing.A proof of concept was conducted using these induction electrodes to differentiate between water and ethanol flowing inside the tube,which was repeated thousands of times.Finally,the output voltage signal from the induction electrode was processed through an input signal filter and a microcontroller,where four lightemitting diodes(LEDs)were incorporated to indicate the flow and type of liquid.展开更多
The interfacial electrification properties play an important role in the electrochemical corrosion reaction which leads the electrostatic charge to generate and accumulate on the metal surface when the insulating oil ...The interfacial electrification properties play an important role in the electrochemical corrosion reaction which leads the electrostatic charge to generate and accumulate on the metal surface when the insulating oil flows through a metal pipe. In this paper, the interfacial electrification properties resulted by the oil flow rate and the action of electric charge trapper are investigated by measuring the current and potential on the surface of the test metal pipe. The measured results showed that the current and potential between the metal pipe and the earth increased with the rise of flow rate; and as the flow rate increased, the growth trends of the current and potential difference between two close flow rates increased and decreased, respectively, while there was an electric charge trapper set in the radial direction of the pipe, the measured current and potential decreased compared with that of without electric charge trapper, which was because it captured and caught part of charge in the oil flow bulk to neutralize the opposite charge on the surface of the metal pipe.展开更多
基金supported by Qianjiang Talent Project Foundation of China(Grant No. 2010R10013)
文摘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.
基金supported by the Brazilian agencies MCTIC/CNPq(465452/2014-0),FAPESP(2014/50906-9),and CAPES-Finance Code 001 through INCT/INOMAT(National Institute for Complex Functional Materials)and MCT/Finep/CT-Infra 02/2010.Yan Araujo Santos da Campo acknowledges CAPES(88887.674802/2022-00)for receiving a master’s degree fellowship.Authors have used large language models(ChatGTP)to improve readability and language.
文摘A particular kind of triboelectrification occurs during the flow of liquids through tubes.Here,we used Faraday cups and Kelvin probes to investigate the charge of aqueous solutions and alcohols flowing through a polytetrafluorethylene tube.An excess of positive charges was observed in all liquids collected by the Faraday cup after the flow.While the tube displays a small potential during the flow,likely due to electrokinetic effects,a very high negative potential was observed after the completion of the flow.Aqueous solutions with varying pH showed significant differences in charge accumulation only at pH 2.93 and 4.99,while most of the charge accumulation can be suppressed using common surfactants.Alcohols displayed an inverse relationship between charge accumulation and carbon chain length,except for methanol.Thus,we used graphite-based nanocomposites as noncontact induction electrodes near the tube for flow sensing.A proof of concept was conducted using these induction electrodes to differentiate between water and ethanol flowing inside the tube,which was repeated thousands of times.Finally,the output voltage signal from the induction electrode was processed through an input signal filter and a microcontroller,where four lightemitting diodes(LEDs)were incorporated to indicate the flow and type of liquid.
文摘The interfacial electrification properties play an important role in the electrochemical corrosion reaction which leads the electrostatic charge to generate and accumulate on the metal surface when the insulating oil flows through a metal pipe. In this paper, the interfacial electrification properties resulted by the oil flow rate and the action of electric charge trapper are investigated by measuring the current and potential on the surface of the test metal pipe. The measured results showed that the current and potential between the metal pipe and the earth increased with the rise of flow rate; and as the flow rate increased, the growth trends of the current and potential difference between two close flow rates increased and decreased, respectively, while there was an electric charge trapper set in the radial direction of the pipe, the measured current and potential decreased compared with that of without electric charge trapper, which was because it captured and caught part of charge in the oil flow bulk to neutralize the opposite charge on the surface of the metal pipe.
