Quote:
Originally posted by winewood
Bill recommended (THIS) site to me. I think it says what joemac and I are thinking.
It is by "myv65 (Dave Smith)" and I believe this is the best article I have read on pumps and flow rates. It measures temperature as well. Look at the 3rd graphic.
Basically the pump is pulling water into itself faster that water is provided. Therefore there is a change of pressure in the loop.
|
All right, to clear this up...
Winewood meant that the pump is pulling water into itself faster (i.e. at a higher flow speed, not flow rate) than water is provided.
Of course that was a typo as well. He should have written:
The pump inlet pressure is lower than the pump outlet pressure (that's what a pump does!). Since the relative pressure at the pump inlet is low, the coolant must be flowing slower (lower flow speed, not lower flow rate) than at the outlet.
Which of course isn't necessarily true. In fact, because the pump inlet has a pressure that is lower than atmospheric, suggests a restricted inlet.
None of this has anything to do with a res... but the level of coolant explanation refers to a res where the res inlet is located below the res outlet, which of course no one would do.
The flow rate remains the same throughout each component, in a simple loop. The flow speed however will vary with the diameter of a particular point in the same loop. Since pressure is directly proportional to flow speed, it should be easy to visualize that a narrow opening will create a "pressure point", aka a flow restriction, within a loop. Hence:
Flow rate: yes
Flow speed: no