水資源の高度利用に資する気液境界放電シミュレーション

Abstract

Air-water-interface discharge formation is associated with a vapor layer on the electrode surface. Understanding the water vapor plasma is crucial for their potential applications in advanced water resource utilization. This paper examines numerically the discharge dynamics and reacting chemistry of the gas-phase H2O plasmas using a time-dependent one-dimensional numerical simulation. The temporal- and spatial-evolutions of species concentrations activated by a pulsed dc voltage application (millisecond-scale duration) in a thin water vapor layer of three hundred μm are described. During a lower-density plasma is ignited, localized and shrunk in sub-microseconds, a broad range of neutral and ionic species are produced. In particular, ground-state atomic oxygen O(3P), atomic hydrogen H(1s), ground-state molecular oxygen O_2(X), molecular hydrogen H_2(X), hydroxyl radical OH(X) and cluster ions, for example H_<15>O_7^+ and H_<15>O_7^−. After the pulse termination, all excited and charged species immediately disappear, whereas the densities of hydrogen peroxide H_2O_2, hydroperoxyl HO_2, ozone O_3 and molecular singlet delta oxygen metastable O_2(a^1D) are even enhanced for sub-second time-scale.