Page 162 - Mechanical Engineer's Data Handbook

FLUID MECHANICS 151
Sudden exit Losses in valves

v: Globe valve wide open K= 10
Pressure loss pL=p-, (K= 1)
2 Gate valve wide open K =0.2
II Gate valve half open K = 5.6
Gate valve three-quarters open K = 1.15
Gate valve quarter open K = 24

v,_ Rounded entry
K z 0.05

Sudden contraction

v:
Pressure loss pL = Kp -
2

0 0.2 0.4 0.6 0.8 1.0
Re-entrant pipe
K 0.5 0.45 0.38 0.28 0.14 0 K = 0.8-1 .o

rl

II

Sudden entry
v: Bends
Pressure loss p,=Kp--, 2 where Kz0.5
L The factor K depends on RID, the angle of bend 0, and
-
the cross-sectional area and the Reynold's number.
Data are given for a circular pipe with 90" bend. The
loss factor takes into account the loss due to the pipe
length.
"2

K 1.0 0.4 0.2 0.18 0.2 0.27 0.33 0.4