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
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
<div style="text-align:justify;"> In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the applica...<div style="text-align:justify;"> In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the application of non-metallic composite continuous pipe in oil field, this paper discusses a series of new full-scale test and evaluation technologies for accurately evaluating the product quality and practical application performance of non-metallic composite continuous pipe, which effectively solves the major technical problem that the new products of non-metallic pipe cannot be accurately evaluated. Based on the characteristics of the application of non-metallic composite continuous pipe in oil field, a series of new full-scale test evaluation technologies which can accurately evaluate the product quality and practical application performance of non-metallic pipe are designed through a large number of tests. The test and evaluation technology can accurately evaluate the key performance of high and low pressure cycle, high and low temperature cycle, gas permeability resistance, minimum bending radius etc. It provides a scientific evaluation basis for the standardized application of non-metallic continuous pipe and a reliable quality control method for the selection of products in oil field. </div>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.
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.
文摘<div style="text-align:justify;"> In view of the serious lack and lag of the test and evaluation technology of non-metallic composite continuous pipe, and focusing on the characteristics of the application of non-metallic composite continuous pipe in oil field, this paper discusses a series of new full-scale test and evaluation technologies for accurately evaluating the product quality and practical application performance of non-metallic composite continuous pipe, which effectively solves the major technical problem that the new products of non-metallic pipe cannot be accurately evaluated. Based on the characteristics of the application of non-metallic composite continuous pipe in oil field, a series of new full-scale test evaluation technologies which can accurately evaluate the product quality and practical application performance of non-metallic pipe are designed through a large number of tests. The test and evaluation technology can accurately evaluate the key performance of high and low pressure cycle, high and low temperature cycle, gas permeability resistance, minimum bending radius etc. It provides a scientific evaluation basis for the standardized application of non-metallic continuous pipe and a reliable quality control method for the selection of products in oil field. </div>
