中文摘要：

设计了一套试验装置，并在面接触润滑状态下，进行凹坑表面形貌的润滑试验．结果表明，在一定的试验条件下，由于摩擦副接触面上凹坑形貌的存在，可观察到有气泡稳定存在于油膜中．气泡的存在取决于凹坑的深度和润滑油量，凹坑深度越深，润滑油量越少，稳定存在的气泡比例越高．分析可知，由于接触面中气油界面的弯月面力作用，气泡被封存于凹坑中，从而能稳定存在，因此，在乏油润滑时，在润滑油和气泡的共同承载作用下，较其他试样，摩擦力明显减小．在面接触润滑时，从乏油润滑到全膜润滑的过程中，存在着一个最优凹坑深度，在此深度时，摩擦阻力最小．通过计算分析可知，凹坑的最优深度和摩擦副间距大小相当，且理论分析结果和试验结果吻合．

英文摘要：

An experimental system was designed to evaluate the drag reduction by dimples on surfaces in plane - plane contact lubrication. Because of the dimples on the surfaces, in some of the experiments, it was observed that gas bubbles existed stably in the lubricant film. The results of the experiments show that the existence of gas was decided by the depth of dimples and the supply volume of lubricant; the deeper the dimples were and the less lubricant there was, the higher the probability of gas existence was. The reason for the existence of gas, based on a model analysis, is the meniscus force of the gas - liquid interface, which caused the gas enclosed in the dimples. In low- oil lubrication, the friction force was reduced obviously because a mixed lubrication film of oil and gas existed, in which lubricant film and gas carried the load together. From the low - oil lubrication to the full film lubrication in plane - plane contact lubrication, an optimal depth of dimples existed, which obviously reduce the friction force. The theoretical analysis result shows that the optimal dimple depth is approximately proportional to the distance between the two surfaces, and it agrees with the experiments.