Generation of pressurized underwater plasma and evaluation of physical properties for on-site elemental survey in marine resource exploration

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06123
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Thermal engineering
• Research Institution: Ehime University
• Principal Investigator: Mukasa Shinobu 愛媛大学, 理工学研究科(工学系), 准教授 (20284391)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 液中放電 / 高電圧パルス / 純水 / 海水 / 加圧 / 海底資源探査 / 発光スペクトル / 電気分解

Outline of Final Research Achievements

For the purpose of developing a device for on-site identification of substances contained in the marine sediments in exploration of marine resources, experiments on high-voltage pulse discharge in pure water and 3wt% NaCl aqueous solution simulating seawater pressurized to 1MPa was conducted. The emission spectrum was measured using a spectrometer. Two continuous spectra were measured for the emission spectrum in pure water. In addition, the luminescence of metal in the powder was observed in the emission spectrum when the metal oxide powder simulating the bottom sediment was exposed to electric discharge, and the effectiveness of this method could be shown. When using NaCl aqueous solution, the discharge was made possible by covering the electrode for the discharge with hydrogen generated by electrolysis of the solution. Discharge occurred between the tip of one electrode and the liquid surface.

Free Research Field

伝熱工学

Academic Significance and Societal Importance of the Research Achievements

本研究は，加圧した純水およびNaCl水溶液中で放電を起こす実験を行ったものである．これまで海水のような導電率の高い液体中で低消費エネルギーの放電を起こすことは困難とされてきたが，放電領域を気体で覆うことにより可能となった．技術的には単純であるが，海底資源の現地探査の実用化における意義，そして実用化された際の社会にもたらす影響は大きいと考える．また，加圧水中下での放電現象における物理的背景について学術的に興味深く，今後の学術的な発展が期待される．