Hydrodynamic journal bearing.

Hydrodynamic journal bearings

Problem 1	Problem 2
L/D	L/D		R	10^-3 m
ε	ε		n	rpm
	dR/R		η	Pa.s

S^G	F	N
�	�	deg.
c�	�
cq	q	l/h


Symbols
L	Bearing length	[m]
D	Shaft diameter	[m]
ε	eccentricity ratio (e/ΔR)	[-]
e	eccentricity	[m]
dR	radial clearance	[m]
R	bearing diameter D=2R	[m]
n	rotations per minute (ω=2πn/60)	[1/s]
η	lubricant viscosity	[Pas]
F	Bearing load	[N]
�	attitude angle	[deg.]
�	Friction coefficient	[-]
c�	friction number c� = �(R/ΔR)	[-]
q	side leakage, expressed in liter/hour	[l/h]
cq	flow number	[-]
S^G	Sommerfeld number	[-]

The calculation method is based on interpolation functions (Andres,1989) between
so called short bearings (Ocvirk) and infinite long bearings (Sommerfeld).

An alternative solution method to find the Sommerfeld number is using the widely
known design chart of Sassenfeld and Walther. Note that in this chart along the
y-axis the number h_min/dR=1-ε is used along the x-axis the bearing number
with D in the denominator.