Hydrodynamic lubrication is a term that defines a situation in which two rubbing surfaces are separated by a thin film of a lubricant. This situation is often beneficial and lubrication is used to reduce friction and/or wear of rubbing solids with the aid of liquid (or semi-solid) lubricant.
Where is hydrodynamic lubrication used?
Where can hydrodynamic lubrication be found?
1 INTRODUCTION. Elastohydrodynamic lubrication (EHL) of point contacts can be found in several machine components, such as cams and followers, bearings and gears. Even today, design work is based on the well known equations presented, for instance, by Hamrock and Dowson [1] which were developed in the 70's.
Where is hydrostatic lubrication used?
Example: the cross head pin bearing or gudgeon pin bearing in two stroke engines employs this hydrostatic lubrication mechanism. In the cross head bearing, the load is very high and the motion is not continuous as the bearing oscillation is fairly short.
Where is boundary lubrication used?
Boundary lubrication mostly occurs under high-load and low-speed conditions in bearings, gears, piston rings, pumps, transmissions, etc. It usually represents the critical regime that limits the life of components.
What is hydrodynamic lubrication in engines?
Hydrodynamic Lubrication: In this type of lubrication, the oil forms a continuous oil film of adequate thickness between the moving surfaces. The film is formed due to the motion of the moving parts and the self-generated pressure. For example, journal bearings of Main Engine have hydrodynamic lubrication.
What is a hydrodynamic film?
Hydrodynamic (full film) lubrication is obtained when two mating surfaces are completely separated by a cohesive film of lubricant. The thickness of the film thus exceeds the combined roughness of the surfaces. The coefficient of friction is lower than with boundary-layer lubrication.
Who discovered hydrodynamic lubrication?
As described above, Petrov, Tower, and Reynolds can be considered the founding fathers of the concept of hydrodynamic lubrication. The coincidence of their near simultaneous emergence on the scene marks the mid-1880s as the undisputed birthdate of this branch of science.
What is hydrostatic and hydrodynamic lubrication?
❖ Hydrostatic Lubrication :- Formed the oil film on the friction surface by the external pressure oil. Hydrodynamic lubrication means that the load carrying surfaces of the bearing. are separated by a relatively thick film of the lubricant, so as to prevent metal to. 4/12/2020.
Where are solid lubricants used?
Products containing solid lubricants are often used in applications when high specific loads are applied to sliding surfaces in the presence of boundary and mixed frictional regimes, at very low hydrodynamically effective speeds, or when the lubricant must perform over a wide temperature or under extreme temperature …