Author Topic: IC Engine Water Pumps  (Read 2197 times)

Online Roger B

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Re: IC Engine Water Pumps
« Reply #15 on: October 25, 2023, 11:31:50 AM »
That's some very interesting research  :ThumbsUp:  :ThumbsUp: Thank you for posting it  :)  :wine1:
Best regards

Roger

Offline Charles Lamont

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Re: IC Engine Water Pumps
« Reply #16 on: October 26, 2023, 10:09:06 AM »
MJM460, you raise several interesting points.

I agree the pressure produced by the regenerative pump is impressive, especially as I think I am running these little pumps at speeds way below their optimum. However it does not match the reqirements of the cooling curcuit. This is something I have not said much about yet. From the tests I have done, the circuit needs greater flow at lower pressure than this particular pump offers. The centrifugal pumps appear to be better matched.

Friction is an important consideration in pumps this small, and I think that the problem with the curved blade impeller may be that the flow is too restricted near the eye. Observe also that, except at zero flow, the brown curves for the six bladed radial impeller are slightly worse that for either of the four bladed ones, when one would otherwise expect the progression of the rake angles to give it a performance intermediate between the two. I ought really to make an impeller with shorter curved blades, and one with just three or four radial blades. (I could easily remachine the existing ones, but then I would not have the originals for any further testing)

In view of the close clearance requirements and friction, I do want to try some time an impeller with a front shroud (though probably not a wear ring!).

I think the inlet manometer problem is one of too much resistance in the inlet tube. Probably the easiest way to get more suction head is to raise the inlet tank, but a bigger bore hose fitting at the tank outlet might be more practical.

On the matter of the gear pump as a fallback option; not long before things got nasty, I acquired on Ebay from a Russian, a full set of 0.6 module gear cutters. They were cheap enough to buy against an idea of building a clock, if I ever get the time (pun intended). Aaanyway, 0.6mod, 12T, and a 3mm face width would give the output I think I need.

 

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