Abstract: The fluid pivot tilting pad journal bearing has been widely used in hydraulic turbine units because of its good vibration damping performance and large bearing capacity. To examine its bearing capacity, this paper first discusses its basic dynamic lubrication mechanism, and constructs a new method of oil film pressure distribution for the bearing, using the Reynolds equation, flow balance equation between the inner and the outer oil film, and the Walther equation. The calculation results show that the hydrodynamic pressure oil film follows a bimodal distribution, while the hydrostatic film is steady in the pressure tap; the bottom pad is in a one-sided floating state under the test conditions. Then, we design and build a bearing test stand of inverted type, test the three-tilting pad bearing with an inner diameter of 125mm, and measure the oil film pressure under different rotational speeds and load conditions. The results show that rotational speed is the first factor of bearing capacity to consider in bearing design. Under higher rotational speeds, the oil film shows higher stiffness and better bearing capacity.Therefore, it can be widely applied to hydraulic turbine units.

Key words: hydraulic turbine, fluid pivot, tilting pad journal bearing, bearing capacity, experimental research, oil film pressure distribution