| Autor: |
Zhao, Qinhua, Zheng, Yanlong, Li, Jianchun, Che, Ping, Zhao, Xiaobao |
| Předmět: |
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| Zdroj: |
Rock Mechanics & Rock Engineering; Jul2024, Vol. 57 Issue 7, p4755-4770, 16p |
| Abstrakt: |
Microwave treatment has become a promising method to improve the efficiency of mechanical excavators in hard rocks. This paper conducted microwave irradiation tests on three water-bearing sandstones and analyzed the heating and water-escaping process by real-time temperature and mass measurement. Meanwhile, nuclear magnetic resonance tests were performed to investigate the water transport behavior inside the samples under microwave irradiation. The results show that the thermal behaviors are jointly governed by the water content, permeability and microwave power used. As the sample temperature increase, the contained water would firstly transport from the drying front to the surface driven by the temperature gradient. Subsequently, water began to escape from the sample with a rate determined by the permeability of the sandstone. At this stage, energy dissipation brought by water escaping would slow down the initial heating rate. Hence, the thermal cracking of the sandstones under microwave irradiation can hardly be enhanced by the existence of pore water in spite of its superior dielectric properties. Nevertheless, the vapor pressure could be large enough to burst the sample when water was heated to a high temperature. Highlights: Obtained the real-time temperature and mass change under microwave irradiation Investigated the water transport behavior in sandstones using nuclear magnetic resonance techniques Discussed the role water plays in microwave heating, fracturing and bursting of sandstones [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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