A full journal bearing operating under a steady load has the following specifications:
(1) Journal diameter : 60 mm
(2) Bearing length : 60 mm
(3) Radial load on bearing : 2.8 kN
(4) Journal speed : 1020 rpm
(5) Radial clearance : 0.05 mm
(6) Viscosity of oil : 80´10–9 N-s/mm2
(7) Density of oil : 860 kg/m3
(8) Specific heat of oil : 1.76 kJ/kg-°C
Using Raymond’s & Boyd table given at the end of the problem, determine
(i) Sommerfeld Number
(ii) Power loss in friction
(iii) Temperature rise if heat generated is entirely carried by oil
(iv) Minimum film thickness, and its location
Table – Giving Raymonds & Boyd data for journal bearing for L/D = 1.
|
Attitude
|
h0/c
|
S
|
f
|
|
|
|
|
|
0
|
1.0
|
00
|
85
|
¥
|
p
|
0
|
––
|
|
0.1
|
0.9
|
1.33
|
79.5
|
26.4
|
3.37
|
0.150
|
0.540
|
|
0.2
|
0.8
|
0.630
|
74.02
|
12.8
|
3.59
|
0.280
|
0.529
|
|
0.4
|
0.6
|
0.264
|
63.10
|
5.79
|
3.99
|
0.497
|
0.484
|
|
0.6
|
0.4
|
0.121
|
50.58
|
3.22
|
4.33
|
0.680
|
0.415
|