Friction equation for simple hydraulic plunger?

[Engineer2Alamek]

Hello, I'm trying to find an equation that models the static and dynamic friction of a reciprocating (Note: NOT rotating) lubricated plunger. I'm just interested in the friction caused by the plunger and not the back pressure from its pumping action. This would involve thin film lubrication I would imagine.

At a guess such an equation would involve the parameters;

1) plunger radius,
2) plunger length,
3) tolerance fit (between cylinder and plunger),
4) lubricant viscosity,
5) speed of plunger(?).

I've looked at numerous mechanics, hydraulics and other handbooks for this information but none have anything like this.

Any help or references appreciated.

rgs,

 

[desertfox]

Hi

Have a look at this paper on the subject:-

http://www.nt.ntnu.no/users/skoge/prost/proceedings/acc04/Papers/0791_FrA16.1.pdf

I don't think you will get a single equation on this subject as you will see its gets very complicated.

desertfox