Enhancement of journal bearings characteristics using novel elliptical grooves

Abstract

Most studies in the past employed straight-line herringbone-grooved journal bearings (HGJB) to improve their performance. However, no study has analysed numerically or experimentally the improved effects of curved grooves. This work utilizes novel elliptical grooves on a journal bearing and analyses the characteristics of the elliptical-grooved journal bearings (EGJB) numerically. Spectral element method is employed to analyse the curved geometries on a journal bearing. Load capacity, stability parameter, and total side leakage of the EGJB are compared with those of the HGJB. The comparison shows that the introduced EGJB have higher radial force, higher load capacity, and lower side leakage than the conventional HGJB. The optimum geometrical parameters of the groove of EGJB are investigated based on the maximum radial force. Finally, the load distributions of several grooved journal bearings are compared to elucidate how elliptical grooves enhance load characteristics. The load distribution along the axial direction in EGJB is more uniform than that in the HGJB. The low load near the bearing centre for the EGJB may be offset by the load away from the bearing centre; thus, a higher total load capacity than that of HGJB is achieved. On the other hand, the investigation, which increases the number of groove sides of the HGJB to resemble the elliptical grooves asymptotically, shows that the load capacities and side leakages of a grooved journal bearing with four sides and eight sides are close to those of the EGJB. Hence if manufacturing elliptical grooves is difficult, an alternative is to use multi-sided grooves with four sides. However, resembling an elliptical shape with grooves with more than four sides to increase load is unnecessary.