Wyniki wyszukiwania - BazTech

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Electrical energy conversion characteristics based on underwater high-voltage pulse discharge

Yan Dong, Chen Songbai, Wu Qiong, Zhang Fengxiang, Lai Lipeng, Chen Inchen

Journal of Power Technologies

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2021

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Vol. 101, nr 4

190--201

EN

Underwater high-voltage (HV) pulse discharge mainly involves the process of HV discharge, breaking down water and releasing huge amounts of electrical energy, which is then rapidly converted into plasma. The plasma expands and creates shock waves and bubble pulsation effects. These effects are the main ways in which electrical energy transfers into mechanical energy. A breakdown process analysis model and an experimental method are proposed with a view to revealing the energy conversion characteristics during underwater pulse discharge and to understand the basic physical process. A plasma channel model was established in combination with the existing fundamentals of electricity and theoretical analysis. In addition, the discharge process was analyzed, along with shock wave and bubble pulsation action characteristics, on the basis of an underwater pulse discharge experiment. Meanwhile, theoretical analysis revealed the basic physical process involved in the electrical energy conversion effect. The results demonstrate the following: (1) The vaporization-ionization" breakdown model divides the breakdown process into three stages (i.e., heating effect, breakdown detonation and mechanical energy effect stages); (2) the heating effect stage is a phase prior to breakdown, which possesses significant heating characteristics and generates initial plasma; (3) a large electric current (104A) during the breakdown process heats the plasma channel to a high-temperature, where it becomes dense; this condition is followed by an instant decrease in channel resistance; the breakdown current peak depends on the residual voltage at the moment of breakdown; (4) during the breakdown detonation stage, discharge breakdown occurs, along with electric arc detonation. After the heating gasification process, when the electrical field intensity is suficient, the high-temperature HV plasma rapidly expands outward, resulting in a rapid conversion from electrical energy to mechanical energy. Thus, shock waves are formed, followed by bubble pulsation. The proposed method provides a good prospect for the application of underwater HV pulse discharge technology in the field of engineering.

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Czynniki decydujące o trwałości rurociągów poddanych oddziaływaniom mechanicznym i cieplnym

Okrajni J., Mutwil K., Cieśla M.

Dozór Techniczny

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2002

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z. 3

49--52, 62

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An Approach to quantification of the physico-chemical effect in one-dimensional consolidation test

Olchawa A.

Archives of Hydro-Engineering and Environmental Mechanics

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1999

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Vol. 46, nr 1-4

105-117

EN

The paper deals with the calculation of the quantitative contribution of both physico-chemical and mechanical effect in a one-dimensional consolidation test. The calcula-tion was performed on the basis of clay-water system behaviour in a one-dimensional consolidation test. The test was performed on fully saturated samples of montmorillonite and kaolinite with monovalent and bivalent cations in pore water. The results of calculation show that both effects are influenced by specific surface area of clays, valency of exchangeable cations in pore water and also by the magnitude of consolidation pressure.