I am trying to determine the force it would take to fully empty a syringe using a long nozzle, that contains a high-viscosity fluid.
Specifications I'm using:
I'm trying to determine the force through Hagen-Poiseuille equation:
However the results I am getting from physical testing show are very different. I have tested with 3 different flow rates, and difference between them is minimal, while Hagen-Poiseuille predicts it will be substantial, especially at higher flow rates:
Physical testing showed results around 1kN lower than expected. I must be missing something. Syringe and nozzle are both highly polished - is there a way to take it into account?
Any thoughts would be welcome.