Investigation of Structure-Induced Cavitation at the Oil-Groove–Oil-Hole Intersection of a Diesel Engine Main Bearing

Structure-induced cavitation occurs at the oil groove–oil hole intersection of main bearings in high-performance diesel engines. Large eddy simulation combined with a multiphase cavitation model was used to investigate the effects of oil-hole fillet radius, chamfer angle, oil-groove depth, and groove-end profile. Cavitation volume fraction, cavitation extent ratio, and their time integrals were evaluated separately on the bearing-shell and journal sides. Compared with the 3 mm fillet baseline, a 5 mm fillet reduced the integrated cavitation volume fraction by 66.26% on the bearing-shell side and 22.62% on the journal side. A 30° chamfer also reduced both integrated indices relative to the baseline, whereas increasing the chamfer angle shifted cavitation clouds toward the bearing-shell wall. Increasing groove depth intensified cavitation on both sides. Tangent Bézier profiles reduced peak velocity and weakened incipient cavitation, but promoted wall-attached jets and prolonged cavitation, increasing the time-integrated indices. These results show that local geometry affects the responses on the two sides through changes in jet direction, cavitation migration, and duration, providing design guidance for controlling cavitation in diesel-engine main bearings.