Flow structure inside a thin film lubricating bearing is analyzed using computational approach. Computation Fluid Dynamics is used for detailed analysis of fluid flow and heat transfer through bearing land for different flow rates to investigate load carrying characteristics.
Results from different turbulence models are compared to ensure accurate modeling of transitional flow through the pad. Custom program is added to commercial CFD code to capture temperature dependent viscosity and its impact on load carrying capacity. Temperature, pressure, viscosity and their variations across the pad are captured for loads at different surface speeds. Effect of change in gap size on load carrying capacity of the bearing is examined. Computational results are compared with the experimental measurements.
CFD results are in close agreement with the experimental measurements. Temperature rise due to viscous sheer reduces the load carrying capacity by up to 25 %. Viscous and thermal resistance increases with increase in the flow rate. Additional reduction in load carrying capacity of up to 10 % is observed due to viscous resistance when load is moving. Most of the temperature rise happens in the region of narrow gap outside the recess depth. Pressure, temperature and viscosity variations across the bearing surface are presented.
Effect of motion creates localized thermal gradient due to reverse flow. Nature of temperature variations and locations of localized heating offer greater insight in designing a more efficient hydrostatic bearing for machines at higher speed.
