A liquid phase viscosity–temperature model for long-chain n-alkanes up to C64H130 based on the Free Volume Theory

Predicting physical properties of alkanes with neural networks

“…Next, we compare the values for kinematic viscosity at 20 • C and atmospheric pressure obtained by our ANN to values obtained by a model based on free volume theory [34] (Table 5). The neural network model is more accurate than the free volume theory model, reproducing experimental data with R 2 = 0.998 and an average absolute deviation of 0.05 cSt, compared to R 2 = 0.899 and an average absolute deviation of 0.31 cSt predicted by the free volume theory model [34]. Furthermore, the neural network model shows greater consistency for the molecules analysed than the free volume theory model.…”

“…However, eicosane is a solid below 36 • C so could only be present in a base oil lubricant in relatively small amounts, as lubricants are usually expected to operate between -15 • C and 100 • C. Therefore, it is likely that linear alkanes are present in base oil lubricants only in relatively small amounts. Free Volume Theory Model [34] Prediction (cSt) Table 5: Experimental values and prediction of the kinematic viscosity at 20 • C and atmospheric pressure for indicated molecules. The table compares the accuracy of our neural network model with the accuracy of a model based on the free volume theory.…”

“…Mathieu developed a group contribution based method to calculate the flash point of various alkanes [31], while Ruzicka and Domalski estimated the heat capacity of various liquid alkanes using a second order group additivity method [32]. De La Porte and Kossack have developed a model based on free volume theory to study long chain linear alkane viscosity as a function of temperature and pressure [34], Riesco and Vesovic have expanded a hard sphere model to study similar systems [35], and Novak has established a corresponding-states model to study viscosity of linear alkanes for the entire fluid region [36].…”

“…Parity plot for kinematic viscosity of linear alkanes. Our neural network model is compared to a model based on free volume theory[34]. (cSt)…”

Nonempirical Free Volume Viscosity Model for Alkane Lubricants under Severe Pressures

“…In particular, the strength of nonbonded interactions has little influence, but a scaling of the atomic radii σ LJ results in strong variations of the diffusivity caused by the exponential term in Eq. (5). Moreover, the prefactor D 0 is sensitive to variations of the energy barrier for bond rotation, which influences intramolecular relaxations.…”