Effect of Sunflower, Almond, and Rapeseed Oils as Additives on Thermal Properties of a Machinery Oil

Carlos Omar González Morán,Gemima Lara Hernandez,Citlalli Jessica Trujillo Romero,José Pastor Rodríguez Jarquin,José De Jesús Agustín Flores Cuautle,Oscar Osvaldo Sandoval González

doi:10.3390/app11167441

Abstract

Vegetable oils are considered to be eco-friendly and to offer good lubricant properties; however, their low thermo-oxidative stability makes their use as a lubricant base challenging. In this research, sunflower, almond, and rapeseed vegetable oils were added in volumes of 5, 10, 15, and 20% to a machinery oil, and the thermal properties of the resulting fluids were studied. Sunflower, almond, and rapeseed oils were chosen considering their fatty acid composition and the tocopherol content. During this investigation, thermal diffusivity was measured by using the thermal wave resonance cavity technique, while thermal effusivity was determined by the inverse photopyroelectric method, and the obtained values ranged from 4.63 to 5.75 Ws1/2m−2K−1 × 102. The thermal conductivity was calculated by obtaining a complete thermal characterization. The results showed a linear relationship between the percentage of vegetable oil and the thermal diffusivity. It was also noted that the thermal properties of diffusivity and effusivity could be tuned when using almond, sunflower, and rapeseed oils in the appropriate percentages. Hence, the influence of vegetable oils on the thermal properties of lubricating oil were closely related to the number of fatty acids.

Highlights

Since scientists have become aware of how harmful and irreparable carbon footprints can be, as well as the fact that about half of the lubricating oil used in an engine is released into the environment through engine exhaust vapors, leaks, and spills, many researchers have started to make use of technological advances such as renewable resources, biofuels, and synthetic oils obtained from vegetable sources to reduce the damage of carbon footprints
Photothermal techniques provide enough precision to measure thermal properties with errors lower than 2%; this precision makes it possible to obtain the variation of thermal properties when vegetable oils are added to motor oil
Vegetable oils as additives in motor oil can modify thermal diffusivity values for the obtained mixtures; this can be useful depending on the application

Summary

Introduction

Since scientists have become aware of how harmful and irreparable carbon footprints can be, as well as the fact that about half of the lubricating oil used in an engine is released into the environment through engine exhaust vapors, leaks, and spills, many researchers have started to make use of technological advances such as renewable resources, biofuels, and synthetic oils obtained from vegetable sources to reduce the damage of carbon footprints. Even though its thermo-oxidative stability can be improved by using chemical additives or even by using herbal extracts [25,26], the chemical compositions of vegetable oils vary according to the weather, harvest region, and processing method. For these reasons, it is not recommended to use pure oils when lubricating an engine [8]. The effect of adding different vegetable oils with high tocopherol contents and different fatty acid compositions over a mineral-based oil is studied in this research, in which vegetable oils with a concentration within a 5% to 20% range are used as additives mixed with fossil oils

Samples

Thermal Effusivity

Thermal Diffusivity

Results

Discussion and Conclusions