Experimental analysis and modeling of viscosity and thermal conductivity of GNPs/SAE 5W40 nanolubricant

Abstract

Purpose The purpose of this study is to investigate thermal conductivity and dynamic viscosity of graphene nanoplatelet-based (GNP) nanolubricant. Design/methodology/approach Nanolubricants in concentrations of 0.025, 0.05, 0.1 and 0.5 Wt% were prepared by means of two-step method. The stability of nanolubricants was monitored by visual inspection and dynamic light scattering tests. Thermal conductivity and dynamic viscosity of nanolubricants in various temperatures between 25°C–70°C were measured with KD2-Pro analyser device and a rotational viscometer MRC VIS-8, respectively. A comparison between experimentally achieved results and those obtained from existing models was performed. New correlations were proposed and artificial neural network (ANN) model was used for predicting thermal conductivity and dynamic viscosity. Findings The designed nanolubricant showed good stability after at least 21 days. Thermal conductivity and dynamic viscosity increased with particles concentration. In addition, as the temperature increased, thermal conductivity increased but dynamic viscosity decreased. Compared to the base oil, maximum enhancements were achieved at 70°C with the concentration of 0.5 Wt.% for dynamic viscosity and at 55°C with the same concentration for thermal conductivity. Besides, ANN results showed better performance than proposed correlations. Practical implications This study outcomes will contribute to enhance thermophysical properties of conventional lubricating oils. Originality/value To the best of our knowledge, there is no paper related to experimental study, new correlations and modelling with ANN of thermal conductivity and dynamic viscosity of GNPs/SAE 5W40 nanolubricant in the available literature. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0088/

Experimental study and computational intelligence on dynamic viscosity and thermal conductivity of HNTs based nanolubricant

“…A temperature rise contributes to the rise in the energy level, movement and vibration of the unfilled oil molecules, weakening the molecular bonds between the lubricant layers and increasing the speed and displacement of molecules. Therefore, an increase in thermal conductivity can occur (Wadi et al, 2020). On the other hand, despite the drop in thermal conductivity being detected at temperatures of 60°C and 70°C for the concentration of 0.025 wt%, mostly, the increase in the concentration of solid particles leads to the increase in thermal conductivity.…”

Experimental investigation of usage of POE lubricants with Al2O3, graphene or CNT nanoparticles in a refrigeration compressor

“…The results showed that the thermal conductivity and viscosity of the nanolubricant increased with the increase in volume fraction at a constant temperature. Also, Wadi et al [4] experimentally examined the thermophysical properties of the nanolubricant containing graphene nanoparticles for mass fractions of 0.025 to 0.5% in a temperature range of 25 to 70 °C. The results showed that the thermal conductivity and viscosity of the nanolubricant increased with the increase in mass fraction at a constant temperature.…”

A Review on Thermophysical Properties for Heat Transfer Enhancement of Carbon‐Based Nanolubricant

“…Wadi et al created a graphene nanoplatelet/SAE5W40 nanolubricant using a two‐step method. [ 88 ] For 30 days, no sedimentation occurred in any of the produced samples. Figure shows the results of DLS tests for the nanolubricant.…”

“…DLS analysis results for 0.025 wt% nanoparticles concentration after 7, 14, and 21 days. [ 88 ] Reproduced with permission. [ 88 ] Copyright 2020, Emerald Publishing Limited.…”