HEAD LOSS COEFFICIENTS:

Major Head Loss

The major head loss considers the drop in pressure due to viscous effects, ie friction, this can either be as a result of the Darcy Weisbach equation or Poiseuille’s equation, depending on whether or not the flow is deemed to be laminar or turbulent.

Minor Head Loss

Minor head loss is due to any pressure drop caused by an elbow, tee, valve, etc. and is usually expressed as some coefficient (K) of the velocity head (M SHE).

Minor Head Loss Pipe Entrance

Minor Head Loss Pipe Exit

Minor Head Loss Conical Diffuser

Minor Head Loss 90 Degree Bend

all images and info from above are courtesy of http://sbainvent.com/fluid-mechanics/head-loss.php#.UNveGW_Za8A

TYPE OF MANHOLE	DIAGRAM	COEFFICIENT
Trunkline only with no bend at the junction		0.5
Trunkline only with 45° bend at the junction		0.6
Trunkline only with 90° bend at the junction		0.8
Trunkline with one lateral		IF SMALL 0.6 IF LARGE 0.7
Two roughly equivalent entrance lines with angle < 90° between lines		0.8
Two roughly equivalent entrance lines with angle > 90° between lines		0.9
Three or more entrance lines		1.0

The above info is courtesy of <http://docs.bentley.com/en/HMSewerCAD/SewerCAD_Help-14-117.html>

TYPE OF COMPONENT / FITTING	MINOR LOSS COEFFICIENT
Tee, Flanged, Dividing Line Flow	0.2
Tee, Threaded, Dividing Line Flow	0.9
Tee, Flanged, Dividing Branched Flow	1
Tee, Threaded , Dividing Branch Flow	2
Union, Threaded	0.08
Elbow, Flanged Regular 90	0.3
Elbow, Threaded Regular 90	1.5
Elbow, Threaded Regular 45	0.4
Elbow, Flanged Long Radius 90	0.2
Elbow, Threaded Long Radius 90	0.7
Elbow, Flanged Long Radius 45	0.2
Return Bend, Flanged 180	0.2
Return Bend, Threaded 180	1.5
Globe Valve, Fully Open	10
Angle Valve, Fully Open	2
Gate Valve, Fully Open	0.15
Gate Valve, 1/4 Closed	0.26
Gate Valve, 1/2 Closed	2.1
Gate Valve, 3/4 Closed	17
Swing Check Valve, Forward Flow	2
Ball Valve, Fully Open	0.05
Ball Valve, 1/3 Closed	5.5
Ball Valve, 2/3 Closed	200
Diaphragm Valve, Open	2.3
Diaphragm Valve, Half Open	4.3
Diaphragm Valve, 1/4 Open	21
Water meter	7

The above table is courtesy of http://www.engineeringtoolbox.com/minor-loss-coefficients-pipes-d_626.html

LOSS COEFFICIENTS FOR PIPE COMPONENTS

The above image is courtesy of http://faculty.olin.edu/~jtownsend/Transport%20Fall%202008/docs/Supplemental%20Reading%20-%20Pumps.pdf

HEAD LOSS DUE TO SUDDEN CONTRACTION / EXPANSION

this is simply (the difference between the upstream and downstream velocities) [squared] /2g, ie:

SIDE NOTE:

no copyright infringement is intended, this is for purely personal and educational purposes only, all information used is that of the original creater (referenced), I do not bare any responsibility towards the use of this information.