Title: Free volume vacancy behaviour and dynamic viscosity of diesel fuels with additives at elevated temperature and pressure: thermo-occupancy function

Authors: Fatma Sahin-Dinc; Carl Schaschke; Ugur Yahsi

Addresses: Machinery Department, Machinery and Metal Technologies, Surmene Abdullah Kanca Vocational School, Karadeniz Technical University, 61530, Camburnu, Surmene, Trabzon, Turkey ' School of Computing, Engineering and Physical Sciences, University of the West of Scotland, Paisley, PA1-2BE, UK ' Physics Department, Faculty of Arts and Sciences, Marmara University, Goztepe Campus, 34722 Kadikoy, Istanbul, Turkey

Abstract: The reported pressure-volume-temperature (PVT) data of five different diesel fuels at T = 297.95-373.06 K and P = 0.1-457.2 MPa were described by the Simha-Somcynsky (SS) equation of state (eos). From the equilibrium condition imposed on the eos, the hole fraction, h = h (P, T), a form of free volume measure, was computed. Furthermore, our physically-based correlation implicating the thermo-occupancy function, Yh = Yh(h, T), in terms of a function of h = h (P, T) and T has been extended in this study to estimate the dynamic viscosity, η, for the mixtures of commercially available fuels. The model bridges a direct relation from an equilibrium property, h, to the transport process, η, of the system and predicts the viscosity with the range from 0.15% to 0.31%. Newly designates 'viscoholibility' function defined as the derivative of logarithm of viscosity with respect to hole fraction has been discussed. It has an exponential decaying behaviour with respect to h. [Received: February 24, 2021; Accepted: May 14, 2021]

Keywords: additives; diesel fuels; dynamic viscosity; Simha-Somcynsky; free volume; thermo-occupancy function.

DOI: 10.1504/IJOGCT.2022.122624

International Journal of Oil, Gas and Coal Technology, 2022 Vol.30 No.2, pp.209 - 228

Received: 19 Jul 2020
Accepted: 14 May 2021

Published online: 04 May 2022 *

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