A circumferential-groove pressure-fed bearing is lubricated with SAE grade 20 oil supplied at a gauge pressure of 30 psi. The journal diameter dj is 1.750 in, with a unilateral tolerance of −0.002 in. The central circumferential bushing has a diameter db of 1.753 in, with a unilateral tolerance of+0.004 in. The l′/d ratio of the two “half-bearings” that constitute the complete pressure-fed bearing is 1/2. The journal angular speed is 3000 rev/min, or 50 rev/s, and the radial steady load is 900 lbf. The external sump is maintained at 120?F as long as the necessary heat transfer does not exceed 800 Btu/h.
(a) Find the steady-state average film temperature.
(b) Compare h0, Tmax, and Pst with the Trumpler criteria.
(c) Estimate the volumetric side flow Qs , the heat loss rate Hloss, and the parasitic friction torque.
Already registered? Login
Not Account? Sign up
Enter your email address to reset your password
Back to Login? Click here