PIPE FLOW 



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79. FLOW THROUGH PIPES COUPLED UP IN PARALLEL 

 (FiG. 117). 



Here pipes d ly <h, etc., of length 1 1} Z 2 , etc, couple up two vessels whose 

 pressures at tbe points of exit and inlet are pi and p% Ibs. per square foot. 

 We now have 



neglecting all losses except those due to friction. 



If Q= total flow through pipes in cubic feet per second, we have 



Q = I [n d? + v* d? + v 



+ etc. 



FIG. 117. 



.'. Writing v d* = / - ~ - ~i we get 



And since = . L, this becomes 



w ' 



(i 



EXAMPLE. 



Determine the diameter of a pipe of length I, to give the same 

 discharge as two parallel pipes of the same length and of diameter d. 



