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K_Sudden_Contraction



The K_Sudden_Contraction(d1,d2) function returns the resistance coefficient for an abrupt expansion flow process having the geometry shown in the figure.  

Note that the velocity that should be used with this resistance coefficient is the velocity in the smaller pipe, i.e., d_2.

The diameters, d_1 and d_2, are expected to be entered in m or ft, depending on the unit system setting in EES. 

Example:
$UnitSystem SI K Pa J 
$VarInfo rho units=kg/m^3
$VarInfo DELTAP units=Pa
$VarInfo h_L units=m
d_1=0.100 [m]
d_2=0.025 [m]
K=k_sudden_contraction(d_1,d_2)
V_tilde=10 [m/s]
rho=1000 [kg/m^3]
g=g#
h_L=K*V_tilde^2/(2*g)
DELTAP=h_L*rho*g

{Solution:
DELTAP=23438 [Pa]
h_L=2.39 [m]
K=0.4688 
}


Reference:
Flow of Fluids Through Valves, Fittings, and Pipe, Crane Valves North America, Technical Paper No. 410M. 1979
Pipe Friction Manual, Hydraulic Institute, New York, 1962, p. 34

Minor Losses Index