A journal bearing with a diameter of 200 mm and length 150 mm carries a load of 20 kN, when the journal speed is 150 r.p.m. The diametral clearance ratio is 0.0015. If possible, the bearing is to operate at 35°C ambient temperature without external cooling with a maximum oil temperature of 70°C. If external cooling is required, it is to be as little as possible to minimize the required oil flow rate and heat exchanger size. 

i. What type of oil do you recommend?

 ii. Will the bearing operate without external cooling?

 iii. If the bearing operates without external cooling, determine the operating oil temperature?

 iv. If the bearing operates with external cooling, determine the amount of oil in kg/min required to carry away the excess heat generated overheat dissipated, when the oil temperature rises from 85°C to 90°C, when passing through the bearing.