Oil flow for bearing cooling calculator
Enter the heat to remove in watts and the oil temperature rise you will allow. You get the flow in litres per minute.
Worked example
Inputs: 1,500 W of heat to remove, 15 °C allowed oil temperature rise.
This is the live calculator output for the default values above.
The rule behind it
Litres per minute ≈ heat in watts ÷ (29 × temperature rise in °C). It assumes a mineral oil density of about 870 kg/m³ and a specific heat of about 2,000 J/kg·K. The heat includes bearing friction and any heat coming in from the shaft or housing. Add a margin for the cooler and a lower return temperature, and make sure the return line drains freely.
Related tools and guides
Questions
How much oil flow do I need to cool a bearing?
Flow in litres per minute is about the heat in watts divided by 29 times the allowed oil temperature rise in °C.
How hot should circulating bearing oil run?
It depends on the oil and bearing, but running temperature drives viscosity, so use the oil grade selector to check the film at your temperature.
Results are starting points from standard engineering practice. Confirm critical selections with the bearing or lubricant maker.