Study of the Performance of a Thrust Sliding Bearing in Startup and Rundown Regimes

This article describes the experimental bench simulating the operation of thrust bearings of the main circulation pump (MCP) of powerful power plants. The coolant moves in them at high speeds (5–10 m/s), at high pressure (up to 150 × 10⁵ Pa) and temperatures up to 300°C. This entails the requirements for increased reliability of this unit. The bench was adapted for testing both when the bearing is lubricated with oil and when lubricated with water. The substitution of mineral oils with water became possible thanks to a comprehensive improvement of the bearing through the introduction of new antifriction materials and design solutions. The bench was also equipped with measuring systems for recording the moment of resistance to the rotation of the disk, the rotational speed of the disk, the angular velocity of the disk, and the temperature field near the working surfaces of the thrust bearings. The startup–rundown operating regime was programmed with a special software function. As a result of the studies, it was shown that simulating the main rundown stage on a test bench when a thrust bearing is operating in a water-filled volume cannot provide a comprehensive assessment of the performance of the main thrust bearing, since under operating conditions the lubrication process may be disrupted due to partial drainage of the bearing, leading to lubrication starvation, a sharp deterioration in heat dissipation, and damage. These phenomena must be carefully studied on real objects.