GearPump3

GearPump3_CL

This procedure provides a simple model of a gear pump. The volumetric flow rate is determined from displacement rate less leakage flow. Power is determined from overall efficiency applied to displacement flow rate. The model is presented here and in addition to the displacement (V_disp) it requires the parameters K_leak, K_f, and eta_o. All four of these parameters can be obtained from manufacturer's performance data using the companion model GearPump4_CL. If the parameters K_leak, K_f, and eta_o are not provided (i.e., if negative values are passed to the procedure for any of these arguments) then typical values are used.

Call GearPump3_CL(F$, C, T_in, P_in, N, V_disp, m_dot, K_leak, K_f, eta_o: DELTAP, W_dot, eta_p, eta_v)

Inputs:

F$: fluid string identifier

C: concentration (%) {applicable when F$ is a brine. Otherwise set C=0.}

T_in: inlet temperature (K, C, F, or R)

P_in: inlet pressure (bar, atm, Pa, kPa, MPa)

N: rotational speed (1/s)

V_disp: displacement of pump per cycle (in^3 or m^3)

m_dot: mass flow rate (kg/s or lbm/s)

K_leak: leakage constant (-); if K_leak<0 then a typical value will be used

K_f: friction constant (W-s/m^3 or Btu/in^3); if K_f<0 then a typical value will be used

eta_o: overall efficiency of pump (-); if eta_o<0 then a typical value will be used

Outputs:

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

W_dot: power (W, kW or Btu/hr)

eta_p: actual efficiency relative to power

eta_v: volumetric efficiency

Example 1:

$Load Component Library

$UnitSystem SI Mass C kPa J

$VarInfo DELTAP Units='kPa'

$VarInfo W_dot Units = 'W'

F$ = 'Water'

T_in = 20 [C]

P_in = 200 [kPa]

N = 10 [1/s]

V_disp = 12 [cm^3]*Convert(cm^3,m^3)

m_dot = 0.08 [kg/s]

CALL GearPump3_CL(F$, 0 [%], T_in, P_in, N, V_disp, m_dot, -1, -1 [W-s/m^3], -1: DELTAP, W_dot, eta_p, eta_v)

{Solution:

DELTAP = 377.2 [kPa]

W_dot = 127.6 [W]

eta_p = 0.237

eta_v = 0.6678

}

Example 2:

$Load Component Library

$UnitSystem SI Mass C kPa J

$VarInfo DELTAP Units='kPa'

$VarInfo W_dot Units = 'W'

F$ = 'EG'

T_in = 20 [C]

P_in = 200 [kPa]

C = 20 [%]

N = 30 [1/s]

V_disp = 40 [cm^3]*Convert(cm^3,m^3)

m_dot = 0.5 [kg/s]

CALL GearPump3_CL(F$, C, T_in, P_in, N, V_disp, m_dot, -1, -1 [W-s/m^3], -1: DELTAP, W_dot, eta_p, eta_v)

{Solution:

DELTAP = 6891 [kPa]

W_dot = 10600 [W]

eta_p = 0.3172

eta_v = 0.4069

}