What is the minimum current required to drive a magnet plunger in a micro pump?

[muxtih]

I have to design a micro pump which uses a magnet as a plunger. the magnet is pushed and pulled by and electromagnet whose current can be controlled. I wanted to know that how do I relate the current in the electromagnet to the amount and flow rate of the fluid expelled by the pump.
The dimensions of the pump are all variable but should be very small (micropump). I need to basically prove that it can work mathematically but my fluid mechanics is very weak.
Please help

 

[Delphi51]

The flow rate will be related to the volume displaced by the plunger and the number of plunges per unit time. About all you can say about the current is that it must adequate to drive the plunger.

 

[muxtih]

Yes. But is there a way I can quantify this minimum current required to drive the plunger>