An analysis of quantum effects on the thermodynamic properties of cryogenic hydrogen using the path integral method.
In this paper, we describe the analysis of the thermodynamic properties of cryogenic hydrogen using classical molecular dynamics (MD) and path integral MD (PIMD) method to understand the effects of the quantum nature of hydrogen molecules. We performed constant NVE MD simulations across a wide density-temperature region to establish an equation of state (EOS). Moreover, the quantum effect on the difference of molecular mechanism of pressure-volume-temperature relationship was addressed. The EOS was derived based on the classical mechanism idea only using the MD simulation results. Simulation results were compared with each MD method and experimental data. As a result, it was confirmed that although the EOS on the basis of classical MD cannot reproduce the experimental data of saturation property of hydrogen in the high-density region, the EOS on the basis of PIMD well reproduces those thermodynamic properties of hydrogen. Moreover, it was clarified that taking quantum effects into account makes the repulsion force larger and the potential well shallower. Because of this mechanism, the intermolecular interaction of hydrogen molecules diminishes and the virial pressure increases.
School of Engineering, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
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H
Nagashima
Department of Mechanical Systems Engineering, Shinshu University, Nagano 380-8553, Japan.
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S
Tsuda
Department of Mechanical and Control Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550, Japan.
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N
Tsuboi
Graduate School of Environment and Information Science, Yokohama National University, Yokohama 240-8501, Japan.
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M
Koshi
Department of Mechanical Engineering, Aoyama Gakuin University, Sagamihara 229-8558, Japan.
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KA
Hayashi
Institute of Fluid Science, Tohoku University, Sendai 980-8577, Japan.
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Tokumasu