Prediction of Rheological Properties of Some Linear Hydrocarbons Using Molecular Dynamics Simulation

Document Type : Research Paper

Abstract

Present work aims at investigating rheological behavior of linear hydrocarbons by means of non-equilibrium molecular dynamics (NEMD) simulation. Simulation set up was a flow of hydrocarbon molecules confined between two molecular parallel plates. Through moving the top wall at constant velocity and investigation of relation of viscosity to shear stress, rheological behavior of hydrocarbons could be found out. Viscosity of hydrocarbons has been calculated by means of integration of Newtonian equations of motion and then shear stress tensor calculation and division of calculated shear stress by exerted shear rate. Our code verified with experimental data for light hydrocarbons (methane, ethane, propane and n-butane), reported results for a long chain hydrocarbon (C100H202), and results presented for some other hydrocarbons. According to the obtained results, it was found that with increasing hydrocarbon chain length, fluid viscosity will increase. Furthermore, the simulation results reveal that long chain hydrocarbons have a shear thinning non-Newtonian behavior with a power law relation.

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منابع
[1] Jabbarzadeh A., Atkinson J.D. & Tanner R.I. “A parallel algorithm for molecular dynamics simulation of branched molecules”, Journal of Computer Physics Communications, Vol. 150, pp. 65–84, 2003.
[2] Wang L., Liu X., Yang H., Chen Y., & Bian X. “The molecular dynamics simulation of structure and transport properties of sheared super-cooled liquid metal”, Journal of Physics Letters, Vol. 319 A, pp. 518–522, 2003.
[3] Cui S.T. & Gupta S.A., “Molecular dynamics simulations of the rheology of normal decane”, hexadecane, and tetracosane, J. Chem. Phys, Vol 105, No 3, pp. 1214-1220, 1996.
[4] Khare R. & de Pablo J., “Rheological, thermodynamic, and structural studies of linear and branched alkanes under shear”, J. Chem. Phys. Vol. 107, No 17, pp. 6956-6964, 1997.
[5] Jabbarzadeh A., Atkinson J.D. & Tanner R.I., “Nanorheology of molecularly thin films of n-hexadecane in couette shear flow by molecular dynamics simulation”, J. Non-Newtonian Fluid Mech., Vol. 77, pp. 53–78, 1998.
[6] Jabbarzadeh A., Atkinson J.D. & Tanner R.I., “Wall slip in the molecular dynamics simulation of thin films of hexadecane”, J. Chem. Phys., Vol. 110, No. 5, pp. 2612-2620, 1999.
[7] Jabbarzadeh A., Atkinson J.D. & Tanner R.I., “Effect of molecular shape on rheological properties in molecular dynamics simulation of star”, H, Comb, and Linear Polymer Melts, J. of Macromolecules, Vol. 36, No 13, pp. 5020-5031, 2003.
[8] Kim J.M., Keffer D.J., ¨ogerM. Kr. & B.J. Edwards, “Rheological and entanglement characteristics of linear-chain polyethylene liquids in planar couette and planar elongational flows”, J. Non-Newtonian Fluid Mech. Vol. 152, pp. 168–183, 2008.
[9] Irving J.H. & Kirkwood J.G., “The statistical mechanical theory of transport processes”, Journal of Chem. Phys, Vol. pp. 18, 817–829, 1950.
[10] Jabbarzadeh A., Atkinson J.D. & Tanner R.I., “The Effect of branching on slip and rheological properties of lubricants in molecular dynamics simulation of couette shear flow”, Journal of Tribology International, Vol. 35, pp. 35–46, 2002.
[11] Prausnitz J.M., Lichtenthaler R.N. & Azevedo E.G., Molecular Thermodynamics of fluid-phase equilibria, prentice hall PTR, Upper Saddle River, New Jersey, 1999.
[12] Robert H., Perry D. & Green W., Perry’s chemical engineer’s handbook, 7th Ed., McGraw Hill, 1997.
[13] Moore J.D., Cui S.T., Cochran H.D. & Cummings P.T., “A Molecular dynamics study of a short-chain polyethylene melt”, Journal of Non-Newtonian Fluid Mechanics, Vol. 93, pp. 83–99, 2000.
Journal of Petroleum Research
Volume 20, Issue 64 - Serial Number 64
January and February 2011
Pages 3-11

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