SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2019, Vol. 27 ›› Issue (9): 2180-2188.DOI: 10.1016/j.cjche.2019.02.034

• Special Issue on Natural Gas Hydrate • 上一篇    下一篇

Hybrid versus global thermostatting in molecular-dynamics simulation of methane-hydrate crystallisation

Niall J English, Mohammad Reza Ghaani   

  1. School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
  • 收稿日期:2018-12-01 修回日期:2019-02-01 出版日期:2019-09-28 发布日期:2019-12-04
  • 通讯作者: Niall J English

Hybrid versus global thermostatting in molecular-dynamics simulation of methane-hydrate crystallisation

Niall J English, Mohammad Reza Ghaani   

  1. School of Chemical and Bioprocess Engineering, University College Dublin, Belfield, Dublin 4, Ireland
  • Received:2018-12-01 Revised:2019-02-01 Online:2019-09-28 Published:2019-12-04
  • Contact: Niall J English

摘要: Molecular-dynamics (MD) simulations have been performed for the growth of a spherical methane-hydrate nano-crystallite, surrounded by a supersaturated water-methane liquid phase, using both a hybrid and globalsystem thermostatting approach. It was found that hybrid thermostatting led to more sluggish growth and the establishment of a radial temperature profile about the spherical hydrate crystallite, in which the growing crystal phase is at a higher temperature than the surrounding liquid phase in the interfacial region, owing to latent-heat dissipation. In addition, Onsager's-hypothesis fluctuation-dissipation analysis of fluctuations in the number of crystal-state water molecules at the interface shows slower growth.

关键词: Molecular dynamics, Clathrate hydrates, Crystallisation, Thermostatting, Radial temperature profile, Fluctuation-dissipation

Abstract: Molecular-dynamics (MD) simulations have been performed for the growth of a spherical methane-hydrate nano-crystallite, surrounded by a supersaturated water-methane liquid phase, using both a hybrid and globalsystem thermostatting approach. It was found that hybrid thermostatting led to more sluggish growth and the establishment of a radial temperature profile about the spherical hydrate crystallite, in which the growing crystal phase is at a higher temperature than the surrounding liquid phase in the interfacial region, owing to latent-heat dissipation. In addition, Onsager's-hypothesis fluctuation-dissipation analysis of fluctuations in the number of crystal-state water molecules at the interface shows slower growth.

Key words: Molecular dynamics, Clathrate hydrates, Crystallisation, Thermostatting, Radial temperature profile, Fluctuation-dissipation