Programme

P.12 -- Poster, VCTP-44

Date: Tuesday, 30 July 2019

Time: 08:30 - 10:00

Effect of Rigidity on Thermophysical Properties of Lennard-Jones Chains: A Molecular Simulation Study

Phuc Nguyen (1), Vinh Nguyen Thanh Pham (2), Stéphanie Delage Santacreu(3), Hai Hoang (4), Guillaume Galliero (5).

(1) Ho Chi Minh University of science, 227 Nguyen Van Cu, District 5, Ho Chi Minh City 700000, Vietnam (2) Ho Chi Minh University of Education, 280 An Duong Vuong, District 5, Ho Chi Minh City 700000, Vietnam. (3) Laboratoire de Mathematiques et De Leurs Applications de PAU−IPRA, UMR5142, CNRS/Univ Pau et Pays Adour, 64000, PAU, France (4) Institute of Fundamental and Applied Sciences, Duy Tan University, 10C Tran Nhat Duat Street, District 1, Ho Chi Minh City 700000, Viet Nam (5) Laboratoire des Fluides Complexes et leurs Réservoirs (UMR-5150 with CNRS, and TOTAL), Université de Pau et des Pays de l’Adour, BP 1155, F-64013 Pau Cedex, France

A simple coarse-grained (CG) molecular model able to simultaneously accurately predict the thermophysical (Thermodynamic + Transport) properties of fluids would be interesting in many fields including chemical and petroleum engineering. There have been a non-negligible number of such GC models proposed in the literature. Among them, it seems that a fully flexible Lennard-Jones (LJ) chain (FF-LJC) model is one of the best options. This model needs only three parameters but able to yield good predictions simultaneously for the thermophysical properties over wide range of thermodynamic condition for various fluids. However, when dealing with fluids containing large molecules at low temperature and high pressure, the FF-LJC model provides good results only for the thermodynamic properties, but not for the transport properties (particularly for shear viscosity). To improve this model, Galliero [Chem. Eng. Res. Des. 92, 3031-3037 (2014)] additionally introduced a bending potential between bonds, leading to the so-called partially Rigid LJC (RLJC) model. It has shown that the RLJC model can provide simultaneously accurate thermophysical properties including the transport properties at low temperatures. Hence, it would be useful to investigate effects of rigidity on thermophysical properties. In this work, we have performed the molecular simulations to compute various thermophysical properties of RLJC fluids over a wide range of values of rigidity. Monte-Carlo molecular method has been used to estimate the thermodynamic properties including liquid-vapor phase equilibrium, direct thermodynamic properties (e.g. density), static structure (e.g. radial distribution function), thermodynamic response functions (e.g. heat capacity) and entropic properties (e.g. chemical potential). In addition, we have employed molecular dynamics method to calculate the transport properties: shear viscosity, thermal conductivity and self-diffusion coefficients. It has been found that the rigidity has a stronger effect on the transport properties, particularly on shear viscosity, than on the thermodynamic properties. Keywords : Thermodynamic properties, Transport properties, Lennard-Jones Chain model, Monte-Carlo molecular method, Molecular dynamics method

Presenter: Nguyễn Phúc