How do you measure the friction coefficient between two surfaces?

Question

I'm faced with a situation where I need to calculate the force that will be exerted on a pipe due to the passage of a certain fluid through it, as well as the clamping force required to hold the pipe in place, so I thought that knowing how to calculate the friction between the material of the piping and the fluid on the one hand, as well as the clamping material on the other, would allow me to grasp the specifics of the situation.

Answer 1

Flow resistance depends on the viscosity of the fluid and the roughness of the pipe. Additional resistances are caused by irregularities at joints. Direction changes also add resistance. In high flow situations, the momentum loading from bends can be considerable.

Most of these situations have been encountered many times before, so it is common practice to use tables, spreadsheets, or pipe flow programs with predetermined values of fluid resistance.

If you really need to take measurements, pressure drop versus flow will usually tell you what you need to know.Standard practices are often adequate to design joints. If not, finite element analysis is very useful.

Answer 2

Take a speciman of a simple geoamtry like a block.
Place this block on a a plate of the other material.
Lift plate one end to create a slope:

At the point where just before the block slides down the slope measure this angle. This is the angle of static friction. the "tan" of that angle is your staitic coefficent of friction

At the point where the block slides down the slope measure this angle. This is the angle of kinetic friction. the "tan" of that angle is your kinetic coefficent of friction

As far as pipe friction this is difficult without knowing material properties and suface topography . Have you ever used e-funda
they may help link is here:

http://www.efunda.com/formulae/fluids/calc_pipe_friction.cfm

Answer 3

You either look it up, or you develop an experiment to measure it.

Answer 4

you can measure the coefficient of friction by heat the more heat on two rubbing material the more heat it produce