ISSN Online: 2377-424X
ISBN Print: 978-1-56700-474-8
ISBN Online: 978-1-56700-473-1
International Heat Transfer Conference 16
MOLECULAR DYNAMICS STUDY ON EVAPORATION/CONDENSATION COEFFICIENTS IN MULTI-COMPONENTS SYSTEM
Аннотация
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.