PIPE SYSTEM HYDRAULICS - Environmentally Conscious Materials Handling - page 242

Tab l e 9 . 2 Minor Loss Coefficients
Minor Loss Element K

Pipe Inlets
Projecting pipe

0.5 to 0.9

Sharp corner-flush 0.50

Slightly rounded 0.04 to 0.5

Bell mouth 0.03 to 0.1

Sudden expansions a (based on inlet velocity, V 1 ) A p 1 / A p 2 ) 2 (1 −

Sudden contractions b (based on outlet velocity, V 2 ) − 1) 2 (1/ C c

A p 2 / A p 1 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

C c 0.624 0.632 0.643 0.659 0.681 0.712 0.755 0.813 0.892

Steel Bell Reducers c (Welded, D 1 /D 2 = 1.2 to 1.33) 0.053 to 0.23

Steel Bell Expanders c

(Welded, D 2 /D 1 = 1.2 to 1.33) 0.02 to 0.11

PVC Fabricated Reducers c ( D 1 /D 2 = 1.33 to 1.5) 0.12 to 0.68

PVC Fabricated Expanders c

( D 2 /D 1 = 1.2 to 1.33) 0.07 to 1.19

Bends d
Short radius, curve radius/pipe diameter = 1

90 ◦ 0.3 to 0.6

45 ◦ 0.10

30 ◦ 0.06

Long radius, curve radius/pipe diameter = 1.5
90 ◦ 0.07 to 0.33

45 ◦ 0.09

30 ◦ 0.06

Mitered (one miter)
90 ◦ 1.10

60 ◦

0.40 to 0.59

45 ◦ 0.35 to 0.44

30 ◦ 0.11 to 0.19

Valves (full-open) Average K Values Range

Check valves e
Swing check 1.0 0.29 to 2.2

Tilt disc 1.2 0.27 to 2.62

Lift 4.6 0.85 to 9.1

Double-door 1.32 1.0 to 1.8

Gate 0.15 0.1 to 0.3

Butterfly 0.56 0.2 to 0.6

Globe 4.0 3 to 10

a See Streeter and Wylie (1975)
b See Streeter and Wylie (1975)
c See Rahmeyer (2002)
d See Miller (1990)
e See Kalsi and Tullis (1993)