Returns the pressure drop associated with a gradual expansion with a long discharge duct length given the fluid, its flow rate and state, the upstream and downstream areas, and the half angle.  Valid for both rectangular and circular duct cross-sections.  This function calls the K_gradual_expansion2 function from the minor loss library.  Note that a sudden contraction can be simulated by using a half-angle greater than 45 degree.


DELTAP = DuctGradualExpansion_Long_CL(F$, m_dot, T, P, A_2, A_1, theta)



F$:  fluid string identifier

m_dot:  mass flow rate (kg/s, lbm/hr)

T:  inlet temperature (K, C, F, or R)

P:  inlet pressure (bar, atm, Pa, kPa, or MPa)

A_2:  downstream duct area (m^2 or ft^2)

A_1:  upstream duct area (m^2 or ft^2)

theta:  half angle (radian or degree)



DELTAP:  pressure drop (bar, atm, Pa kPa, or MPa)



$UnitSystem SI Mass J K Pa Degree

$Load Component Library

$VarInfo DP_Duct units=Pa


m_dot = 0.25 [kg/s]

T = 300 [K]

P = 100e3 [Pa]

A_1 = 0.05 [m^2]

A_2 = 0.2 [m^2]

theta=15 [degree]

F$ = 'Air'

DP_Duct = ductgradualexpansion_long_cl(F$, m_dot, T, P, A_2, A_1, theta)



DP_Duct = 5.791 [Pa]}