EHL

[MolaKule]

Before the new Semester shifts into high gear, here is a new QOTD:

EHL, or ElastoHydrodynamic Lubrication films, less than 1 micron thick, are the main lubricant regimes in non-conformal contacts common in Wind Turbines.

EHL films are less effective under transient loading, start-stop operations, and slow speed.

Define EHL:

This Question of the Day is open only to non-scientific disciplines so regular membership will have a chance to research it and respond.

 

[blingo]

EHL is where the MOFT ideas are more precarious than usual, the metal crusts creak and the PIB as always shines.

 

[MolaKule]

Hint.

A potential response might include the effect of mechanical deformation on materials such as bearings.

 

[bruce381]

As the name suggests EHL is lubrication regime that occurs only in very high contact areas such as roller bearings or gear teeth.
With loads so high that deformation of the metal elements can occur.

Under this condition an oil film that is trapped in such contact zones will increase in viscosity to perhaps almost a solid, keeping surfaces from touching.

This was drilled into me 30-40 years ago By Douglas Godfrey STLE Fellow and Chevron researcher.

 

[bruce381]

EHL I thought was conterintuitive is that you would think a oil would squish out under high loads but EHL regime the oil could impart the load enough to dent roller bearing races