Contents
- Index
K_gradual_expansion2
The K_gradual_expansion2(A2overA1, theta) function returns the resistance coefficient for a gradual expansion with a long discharge ducts given the ratio of the exit to inlet areas and the half angle. The correlations work for either rectangular or circular ducts. Note that the function DuctGradualExpansion_Long_CL in the component library implements the dimensional version of this function. This function differs from K_gradual_expansion in that it uses correlations from Legg (2017) rather than Crane (1979); these tend to provide larger values of the loss coefficient.
Inputs:
A2overA1 = ratio of downstream to upstream areas
theta = half angle (Degree or Radian)
Example:
$UnitSystem SI C kPa Degre
$VarInfo rho units=kg/m^3
$VarInfo DELTAP units=Pa
A2overA1=3
theta=6 [degree]
K = k_gradual_expansion2(A2overA1,theta)
vel = 15 [m/s]
P = Po#
T = 20 [C]
F$ = 'Air'
rho=density(F$,P=P,T=T)
DELTAP = rho*vel^2/2*K
{Solution:
DELTAP=20.33 [Pa]
K=0.1501
}
Reference:
Legg, R., 2017, "Chapter 14: Ducted Air Systems" in Air Conditioning System Design, Butterworth-Heinemann,
Minor Losses Index