Study on the bubbly lubrication of journal bearings at various shear rates and temperatures

The rheological properties of bubbly oil are measured under relatively low to high shear rates using a rheometer. A constitutive equation including shear rate and temperature is constructed and used to develop the bubbly lubrication model of journal bearings, in which cavitation algorithm is applied. The effects of air volume fraction and shear rate on bearing performance are analyzed. The results show that as volume fraction increases, maximum pressure, load capacity, friction force and leak flow increase slightly at lower shear rates, decline obviously at higher shear rates, but increase to a peak and then decrease at intermediate shear rates.