A journal bearing of D = 1 in. and L = 1 in. is to be used to support a turbine rotor that rotates at 12,000 rpm. SAE 10 oil is to be used, and the average lubricant temperature in the bearings is estimated to be about 148°F. Excellent oil filtration is provided, and the journal roughness is less than 32 min. rms. Because of these factors, the minimum oil film thickness can be as little as 0.0003 in.
(a) What diametral clearance will give the bearing its greatest load-carrying capacity?
(b) Using this clearance, what maximum load can be carried?
(c) With this clearance and load, what would be the friction power lost in the bearing?