Sommerfeld Number of Bearing Formula

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Sommerfeld Number of Journal Bearing is a dimensionless number that is used in designing a hydrodynamic bearing. Check FAQs
S=((rc)2)μlnsp2π
S - Sommerfeld Number of Journal Bearing?r - Radius of Journal?c - Radial clearance for bearing?μl - Dynamic Viscosity of Lubricant?ns - Journal Speed?p - Unit bearing pressure for bearing?π - Archimedes' constant?

Sommerfeld Number of Bearing Example

With values
With units
Only example

Here is how the Sommerfeld Number of Bearing equation looks like with Values.

Here is how the Sommerfeld Number of Bearing equation looks like with Units.

Here is how the Sommerfeld Number of Bearing equation looks like.

2.5871Edit=((25.5Edit0.024Edit)2)220Edit10Edit0.96Edit23.1416
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Sommerfeld Number of Bearing Solution

Follow our step by step solution on how to calculate Sommerfeld Number of Bearing?

FIRST Step Consider the formula
S=((rc)2)μlnsp2π
Next Step Substitute values of Variables
S=((25.5mm0.024mm)2)220cP10rev/s0.96MPa2π
Next Step Substitute values of Constants
S=((25.5mm0.024mm)2)220cP10rev/s0.96MPa23.1416
Next Step Convert Units
S=((0.0255m2.4E-5m)2)0.22Pa*s62.8319rad/s960000Pa23.1416
Next Step Prepare to Evaluate
S=((0.02552.4E-5)2)0.2262.831996000023.1416
Next Step Evaluate
S=2.58707682278493
LAST Step Rounding Answer
S=2.5871

Sommerfeld Number of Bearing Formula Elements

Variables
Constants
Sommerfeld Number of Journal Bearing
Sommerfeld Number of Journal Bearing is a dimensionless number that is used in designing a hydrodynamic bearing.
Symbol: S
Measurement: NAUnit: Unitless
Note: Value should be greater than 0.
Radius of Journal
The Radius of Journal is the radius of the journal (which rotates freely in a supporting metal sleeve or shell).
Symbol: r
Measurement: LengthUnit: mm
Note: Value should be greater than 0.
Radial clearance for bearing
Radial clearance for bearing is a measured value of the total movement of one ring relative to the other in a plane perpendicular to the bearing axis.
Symbol: c
Measurement: LengthUnit: mm
Note: Value should be greater than 0.
Dynamic Viscosity of Lubricant
The Dynamic Viscosity of Lubricant is the resistance to movement of one layer of fluid over another.
Symbol: μl
Measurement: Dynamic ViscosityUnit: cP
Note: Value should be greater than 0.
Journal Speed
The Journal Speed Value is defined as the speed of the journal of a bearing.
Symbol: ns
Measurement: Angular VelocityUnit: rev/s
Note: Value should be greater than 0.
Unit bearing pressure for bearing
Unit bearing pressure for bearing is the average pressure acting on the contact surface of the bearing.
Symbol: p
Measurement: PressureUnit: MPa
Note: Value should be greater than 0.
Archimedes' constant
Archimedes' constant is a mathematical constant that represents the ratio of the circumference of a circle to its diameter.
Symbol: π
Value: 3.14159265358979323846264338327950288

Other formulas in Dimensionless Performance Parameters category

​Go Coefficient of Friction Variable of Bearing in Terms of Coefficient of Friction
CFV=rμjbc
​Go Radius of Journal in Terms of Coefficient of Friction Variable
r=CFVcμjb
​Go Radial Clearance in Terms of Coefficient of Friction Variable of Bearing
c=rμjbCFV
​Go Coefficient of Friction in Terms of Coefficient of friction Variable
μjb=CFVcr

How to Evaluate Sommerfeld Number of Bearing?

Sommerfeld Number of Bearing evaluator uses Sommerfeld Number of Journal Bearing = (((Radius of Journal/Radial clearance for bearing)^2)*Dynamic Viscosity of Lubricant*Journal Speed)/(Unit bearing pressure for bearing*2*pi) to evaluate the Sommerfeld Number of Journal Bearing, The Sommerfeld Number of Bearing formula is defined as the product of the square of the ratio of the radius of the journal to the radial clearance, and the ratio of the product of viscosity of lubricant and journal speed to unit bearing pressure. Sommerfeld Number of Journal Bearing is denoted by S symbol.

How to evaluate Sommerfeld Number of Bearing using this online evaluator? To use this online evaluator for Sommerfeld Number of Bearing, enter Radius of Journal (r), Radial clearance for bearing (c), Dynamic Viscosity of Lubricant l), Journal Speed (ns) & Unit bearing pressure for bearing (p) and hit the calculate button.

FAQs on Sommerfeld Number of Bearing

What is the formula to find Sommerfeld Number of Bearing?
The formula of Sommerfeld Number of Bearing is expressed as Sommerfeld Number of Journal Bearing = (((Radius of Journal/Radial clearance for bearing)^2)*Dynamic Viscosity of Lubricant*Journal Speed)/(Unit bearing pressure for bearing*2*pi). Here is an example- 2.587077 = (((0.0255/2.4E-05)^2)*0.22*62.8318530685963)/(960000*2*pi).
How to calculate Sommerfeld Number of Bearing?
With Radius of Journal (r), Radial clearance for bearing (c), Dynamic Viscosity of Lubricant l), Journal Speed (ns) & Unit bearing pressure for bearing (p) we can find Sommerfeld Number of Bearing using the formula - Sommerfeld Number of Journal Bearing = (((Radius of Journal/Radial clearance for bearing)^2)*Dynamic Viscosity of Lubricant*Journal Speed)/(Unit bearing pressure for bearing*2*pi). This formula also uses Archimedes' constant .
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