Author(s)

Panagis G. Papadopoulos¹, Christopher G. Koutitas¹, Yannis N. Dimitropoulos², Elias C. Aifantis¹

¹Department of Civil Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece.
²Department of Chemistry, University of Ioannina, Ioannina, Greece.

A simplified model is proposed for an easy understanding of the coarse-grained technique and for achieving a first approximation to the behavior of gases. A mole of a gas substance, within a cubic container, is represented by six particles symmetrically moving. The impacts of particles on container walls, the inter-particle collisions, as well as the volume of particles and the inter-particle attractive forces, obeying a Lennard-Jones curve, are taken into account. Thanks to the symmetry, the problem is reduced to the nonlinear dynamic analysis of a SDOF oscillator, which is numerically solved by a step-by-step time integration algorithm. Five applications of proposed model, on Carbon Dioxide, are presented: 1) Ideal gas in STP conditions. 2) Real gas in STP conditions. 3) Condensation for small molar volume. 4) Critical point. 5) Iso-kinetic energy curves and iso-therms in the critical point region. Results of the proposed model are compared with test data and results of the Van der Waals model for real gases.

Real Gases, Coarse-Grained Molecular Dynamics, Particles Volume, Inter-Particle Attractive Forces, Lennard-Jones Curve, Step-by-Step Time Integration Algorithm, Condensation, Critical Point, Iso-Kinetic Energy Curves, Iso-Therms, Van der Waals Model

Papadopoulos, P. , Koutitas, C. , Dimitropoulos, Y. and Aifantis, E. (2017) Simplified Coarse-Grained Dynamic Model for Real Gases. Open Journal of Physical Chemistry, 7, 50-71. doi: 10.4236/ojpc.2017.72005.