are we not actually interested in the transition between tubing sizes ?
at what point do the line friction losses indicate that performance would be improved by increasing the line size ? (all, LOL)
obviously this is a consequence of the flow rate, which is that resulting from the particular assembly of components in the system
following (more or less) the sizing from the above posts:
- for a 2m length of tubing, the flow resistance is (in mH2O):
size, mm . flow . . . 1x . . . . 2x . . . . . 4x . . where "x" is the initial flow rate for that size
6 . . . . . . . 0.6 . . 0.075 . . 0.263 . . 0.949
8 . . . . . . . 0.8 . . 0.031 . . 0.111 . . 0.389
10-3/8 . . . 1.0 . . 0.016 . . 0.056 . . 0.203
13-1/2 . . . 1.3 . . 0.007 . . 0.026 . . 0.092
now an observant reader might note that a diagonal from upper left to lower right will hold the line losses constant while the flow rate increases, which says . . . . .
simple stuff right ?
and that is quite all there is to it
the "German engineers" are making pretty wbs, and ignoring that which does not fit their conclusions
small is quite ok, if one accepts the compromises that follow
no biggie
easy friction losses:
http://www.tasonline.co.za/toolbox/pipe/velfirc.htm
and other stuff