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ValveCoef_Inc_ISA75_CL

 

 

The procedure ValveCoef_Inc_ISA75_CL uses the detailed sizing relations laid out in ANSI/ISA-75.01.01 (IEC 60534-2-1 Mod)-2007, "Flow Equations for Sizing Control Valves" to determine the valve coefficients (C_v and K_v) for a valve with incompressible flow given the flow conditions, geometry, valve type, pressure drop and required flow rate.  A simpler method is programmed in ValveCoef_Inc_CL.  The values of the liquid pressure recovery factor (F_L), valve style modifier (F_d), and pressure differential ratio factor (x_T) depend on the valve style and trim and can be found in Table 2 of the standard.

 

ValveCoef_Inc_ISA75_CL(F$,T_1,P_1,P_2, Q, D, D_1, D_2, F_L, F_d, x_T, Conc: K_v, C_v)

 

Inputs:

 F$   fluid

 T_1  inlet temperature (C, K, F, or R)

 P_1,P_2 inlet and outlet pressures (kPa, Pa, bar, MPa, atm, or psi)

  Q flow rate (m^3/s or ft^3/min)

  D valve diameters (m or ft)

  D_1, D_2 inlet and outlet tube diameters (m or ft)

  F_L liquid pressure recovery factor (-), depends on valve style

  F_d valve style modifier (-), depends on valve style

  x_T pressure differential ratio factor (-), depends on valve style

  Conc concentration (%), only required if fluid is a solution (brine)

 

Output:

  K_v  SI valve coefficient (-), returned as dimensionless but technically this is measured as m^3/hr of water passing through a valve with a pressure drop of 1 bar

  C_v English valve coefficient (-), returned as dimensionless but technically this is measured as gpm of water passing through a valve with a pressure drop of 1 psi

 

Example:

$Load Component Library

$UnitSystem SI Mass J Pa K

 

F$ = 'Acetone'

T_1 = 320 [K]

P_1 = 500e3 [Pa]

P_2 = 300e3 [Pa]

Q = 0.05 [m^3/s]

D_1 = 0.05 [m]

D_2 = 0.05 [m]

D = 0.04 [m]

F_L = 0.9 [-]

x_T = 0.7 [-]

F_d = 0.48 [-]

 

CALL ValveCoef_Inc_ISA75_CL(F$,T_1,P_1,P_2, Q, D, D_1, D_2, F_L, F_d, x_T, 0 [%]: K_v, C_v)

 

{Solution:

K_v = 36.6 [-]

C_v = 42.31 [-]

}

 

Index