Journal Bearing Oil Flow & Temperature Rise Calculator
Determine hydrodynamic lubricant side-leakage flow (Qs), oil supply demand, and adiabatic fluid-film temperature rise (ΔT) per Raimondi-Boyd.
Bearing Geometry & Friction Load
Lube Flow & Thermal Gradient
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Frequently Asked Questions
Why is side leakage flow critical in journal bearing design?
Side leakage is the continuous axial escape of hot oil from the bearing ends. Without sufficient oil replenishing this leakage, the hydrodynamic wedge starves and oil film temperature skyrockets.
What is the maximum allowable operating temperature for Babbitt sleeve bearings?
White metal (tin-based Babbitt ASTM B23) begins losing compressive fatigue strength rapidly above 100°C–115°C. Industrial turbomachinery standards (API 670) mandate high-alarm trips at 100°C–110°C.
How does oil viscosity change across the temperature rise?
Lubricating oil viscosity drops exponentially with temperature rise. An increase from 45°C to 75°C can reduce viscosity by over 60%, reducing both oil film thickness and power loss until thermal equilibrium is established.