Analysis of squeeze characteristics of thin films of Sisko fluids between a sphere and a plate

The demand for squeeze film bearings has risen significantly with the advancement of modern industries and engineering systems, as these bearings effectively support heavy loads and ensure smooth operation of machine components through lubrication. To enhance the durability and performance of lubricants in such systems, commercial additives like polyisobutylene and ethylene propylene are commonly incorporated. While these additives improve the lubricants' stability under varying temperatures, pressures, and strain rates, they also alter the lubricants’ fundamental properties, leading to shear thinning or shear thickening behaviour based on the type and amount of additives used. Such lubricants can be modelled as Sisko fluid and their influence on different performance parameters of film lubricated bearings can be studied. This study investigates the squeeze film performance of a sphere-plane bearing systems lubricated with Sisko fluid. A modified form of the Reynolds equation is derived and solved to evaluate performance parameters such as film pressure, load-carrying capacity, and squeeze time. Numerical results are presented and compared with previous results. It has been observed that in comparison to base lubricant, the dilatant lubricants increase the film pressure and load capacity of the system with longer response time, while the pseudoplastic lubricants produce lower film pressure and load capacity with a shorter response time. However, in both the cases, the additives increase the stability and life of the system by avoid cavitation. Overall, the additives enhance film pressure, load capacity, and bearing response time.