Question

A shaft inside the sleeve of a journal bearing is being rotated at 1500 rpm. The shaft is 6.00 cm in diameter and is rotating in a bearing sleeve that is 6.02 cm in diameter and 40 cm long. The clearance is filled with oil having properties of ν=0.003 m2/s and SG=0.88.

a. Find the torque required to rotate the shaft.
b. Find the power required to rotate the shaft. (Answer: 44.1 kW)
c. Discussion: How do the torque and power change when the clearance is halved? How do the torque and power change when the bearing rotates at twice the speed? Note that this discussion requires that problems should be solved using variables and numbers are substituted as a last step. Doing this allows trends to be easily observed.

Answer 1

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