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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

MOLECULAR DYNAMICS STUDY ON EVAPORATION/CONDENSATION COEFFICIENTS IN MULTI-COMPONENTS SYSTEM

Get access (open in a dialog) DOI: 10.1615/IHTC16.nmt.021498
pages 7125-7130

要約

The evaporation/condensation coefficient at liquid–vapor interface is of fundamental interest for numerous technological innovations. For the one-component system, Nagayama et al. (2003, 2015) found that the molecular evaporation/condensation behavior for simple molecules (e.g. argon, water) and long-chain molecules (e.g. butane, octane, dodecane) depend strongly on the molecular translational motion and the theoretical evaporation/condensation coefficients can be determined by a function of molecular translational length ratio based on the transition state theory. Existing molecular dynamics simulation results are consistent with the theoretical predictions. However, it is unclear how multi-components of gas affect the molecular evaporation/condensation behavior at the liquid–vapor interface in multi-components system. In this study, the effects of nitrogen gas on the molecular evaporation/condensation behavior at the liquid– vapor interface were investigated by molecular dynamics simulation. Two multi-components simulation cases, (a) water and nitrogen, (b) dodecane and nitrogen, were performed in equilibrium systems. We found that the evaporation/condensation coefficients decrease with increasing nitrogen concentration, showing a primary dependence of molecular translational length ratio. Also, the activation energy of evaporation/condensation increases as increasing nitrogen concentration. Given the accurate estimations of the free volume ratio of liquid to vapor, the theoretical prediction of evaporation/condensation coefficient proposed by Nagayama et al. (2003, 2015) is found to be valid even for the multi-components system as a general expression.