This seems to be straightforward and simple:
I think it should also apply to a Tesla pump? - using the plate gaps to be the equivalent of "
B"?
Outside my experience, so maybe this is a stupid question? But on various types of rotary oil pumps (on cars, motorcycle engines, etc.) the clearances between rotors and housings are critical to prevent "flow-back" and loss of pressure &/or flow. E.g.
View attachment 159822View attachment 159823View attachment 159824 But I guess that is because they work towards their limit of pressure, and not so much flow. Are these "displacement pumps" rather than "inertial pumps"?
What is the corollary for leak-back on a centrifugal pump? Side rotor clearance I guess, and is there a problem with clearance around the outer diameter of the rotor? I can imagine that fluid leaking at the sides could travel from the outer "higher speed (and pressure?) zone" to the inner "lower speed zone" causing loss of performance from re-cycling of fluid, which is minimised by close fitting of parts. But does it matter if the housing around the outer diameter is close fitting or not? - Maybe not as on the outside there is only fluid at pressure and flow for the outlet, and no inlet to leak back to?
Sorry, I can't get my head around what is going on, to work it out.
Maybe it is something like:- the pump can deliver a maximum flow based on the equation above, but pressure is based on how the flow is restricted downstream - or not - at anything below a maximum pressure determined by the rotor outer diameter speed?
I have a feeling that max pressure is at zero flow, and max flow is at zero pressure. but we work somewhere between those points in real life.
Can anyone teach me what is really happening? - or point me to a website so I can learn a bit? (I have been otherwise engaged so not had time yet to study this properly). And I'm feeling a bit "thick" today... so ignore me if I am too far off track.
Thanks,
K2