I Calculate Pressure Needed to Move Grease

[Tritkoss]

Good day. My question is as follows, I have a column of white lithium grease 1/4” diameter 24’ long. I want to figure out the pressure needed to move this column of grease. I am having a hard time to find the right formula to calculate this so any help will be greatly appreciated. Thank you.

 

[phinds]

Good day. My question is as follows, I have a column of white lithium grease 1/4” diameter 24’ long. I want to figure out the pressure needed to move this column of grease. I am having a hard time to find the right formula to calculate this so any help will be greatly appreciated. Thank you.

What factors have you identified that will have an effect on the answer?

 

[Tritkoss]

What factors have you identified that will have an effect on the answer?

I’m not sure what you mean? I’m guessing the friction along the walls of the column and sticky ness of the grease would come into play.

 

[phinds]

I’m not sure what you mean? I’m guessing the friction along the walls of the column and sticky ness of the grease would come into play.

So you figure the mass of it is irrelevant?

 

[Nik_2213]

Is the stuff thixotropic ? ie, when it starts to move, will the core blow out, leaving a significant layer stuck to the tube wall ?

Also, temperature / viscosity variations. Ambient temperature is one factor. Another may be frictional heating...

 

[phinds]

@Tritkoss we have touched on, but not completed, the list of things you will need to know. Do you begin to get the idea that it's not going to be a simple formula? It may well be that many of the possible factors are negligible, but you have to figure that out after you have a complete list.

 

[Tritkoss]

@Tritkoss we have touched on, but not completed, the list of things you will need to know. Do you begin to get the idea that it's not going to be a simple formula? It may well be that many of the possible factors are negligible, but you have to figure that out after you have a complete list.

Yes I know it’s not a simple formula if you take into account all the possible variables, I was just looking for some help in the right direction. The column of grease is pushed on by fluid ranging in temp from 2degC to 25degC. It does not flow through but pushes up against a sensor that reads pressure. I am wondering how much pressure it would take to overcome the friction holding the grease stationary. It is most likely negligible but it would help me explain certain pressure readings to people I work for.