Semnan University Press Journal of Heat and Mass Transfer Research 2345-508X 8 1 2021 06 01 Thermodynamic Properties of Monatomic, Diatomic, and Polyatomic Gaseous Natural Refrigerants: A Molecular Dynamics Simulation خواص ترمودینامیکی مبردهای طبیعی گازی تک اتمی، دو اتمی و چند اتمی: مطالعه شبیه سازی دینامیک مولکولی 61 69 4740 10.22075/jhmtr.2020.21350.1305 EN Ali Rajabpour Faculty of Engineering and Technology, Department of Mechanical Engineering , Imam Khomeini International University Milad Abbasi Faculty of Engineering and Technology, Department of Mechanical Engineering , Imam Khomeini International University Journal Article 2020 09 11 Owing to their lower adverse environmental impacts, natural refrigerants have recently attracted a huge deal of attention. In this regard, the present study is aimed to evaluate the thermodynamic properties of different gaseous natural refrigerants at the molecular level using molecular dynamics (MD) simulations. In this context, the density (as a representative of structural features), enthalpy, and specific heat capacity (as representatives of energy properties) of several natural gaseous refrigerants including helium, nitrogen, methane, and ethane were assessed. Lennard-Jones potential was used for simulation of helium and nitrogen while AIREBO potential and OPLS-AA force-fields were employed for simulation of methane and ethane as polyatomic hydrocarbon refrigerants. Simulations are carried out at various temperatures above the boiling point and pressures of 1, 2, and 5 bar. MD results were in good agreement with the experimental data. Among the applied potentials, AIREBO potential offered results closer to the experimental data as compared with OPLS-AA force-field. The methane-ethane mixture was also addressed at different pressures and compared with the Peng-Robinson equation of state. The results of this study indicated that molecular dynamics can be employed as a reliable tool for predicting the thermodynamic properties of natural refrigerants. The results can be used in the refrigeration cycles. https://jhmtr.semnan.ac.ir/article_4740_0f304eddb4ad6007a3093fd6d963a1d2.pdf