Solution 1.60
Since the problem calls for pascals, convert everything to SI units:
Find the shear stress in the oil, multiply that by the cylinder wall area to get the required force,
and divide the force by the area of the cylinder face to find the required pressure difference.
Comment: The Reynolds number of the clearance flow, Re =
VC/
, is approximately 0.8.
15
16
15
16
3
(5 )(0.0254 ) 0.1508 ; (26 )(0.0254 ) 0.6604
Clearance ( ) / 2 (6 5 )(0.0254 ) / 2 0.000794
Table A.3, glycerin: 1.49 / , 1260 / ( not needed)
cyl
pipe cyl
mm
D in m L in m
in in
m
C D D in m
in
kg m s kg m
= = = =
= = − = − =
= − =