M15,
Recommend you get your hands on the book, "Centrifugal Pumps Designs & Applications" by Lobanoff.
There is a pretty simple and straight forward derivation on volute design.
I agree with Bjegovic that this is a deep subject.
http://tinyurl.com/hoyk5
EnglishMuffin,
Your 07Feb 06 10:34 posting has a simple mistake;
You posted
(x1+x2)/zm = (inv(alpha)-inv(alpha'))/tan(alpha)
I think that needs to be
(x1+x2)/zm = (inv(alpha')-inv(alpha))/tan(alpha)
Otherwise everything looked good.
I've been struggling through this issue on a...
