Rheological behaviour of lubrication oils used in two-stroke marine engines

Abstract

Purpose

The purpose of this study is to investigate the rheological behaviour of commercial lubrication oils used for cylinder lubrication in two-stroke marine diesel engines. Furthermore, it is of interest to investigate whether the viscosity of lubrication oils is affected by different levels of alkalinity.

Design/methodology/approach

Viscosity measurements are performed using both rotational and capillary rheometry. It was possible to measure oil viscosity in the shear rate from 0.1 to 3,000 s⁻¹ using rotational rheometry, whereas capillary rheometry allowed measurements in higher shear rates from 5 × 10⁵ to 1.3 × 10⁶ s⁻¹ at 50°C.

Findings

The viscosity measurements show that the studied lubrication oils behave as a Newtonian fluid and that the viscosities are insensitive to the level of alkalinity. Furthermore, the viscosity/temperature dependency for the lubrication oils was found to fit the Arrhenius model.

Originality/value

This study presents useful information about the rheological behaviour of lubrication oils, more precisely how the oil properties are affected by shear rate, temperature and level of alkalinity. The value of this research is considered to be important for designing two-stroke diesel engines and cylinder lubrication systems.

Citation

Ravendran, R., Jensen, P., de Claville Christiansen, J., Endelt, B. and Appel Jensen, E. (2017), "Rheological behaviour of lubrication oils used in two-stroke marine engines", Industrial Lubrication and Tribology, Vol. 69 No. 5, pp. 750-753. https://doi.org/10.1108/ILT-03-2016-0075