.AixLib.Fluid.Actuators.Valves.ExpansionValves.UsersGuide.Approaches.PowerApproach .AixLib.Fluid.Actuators.Valves.ExpansionValves.UsersGuide.Approaches.PowerApproachA generic power approach is presented below:
C = corFact * a * product(P[i]^b[i] for i in
1:nT)
All flow coefficient models presented in this library are based on
a literature review. Therefore, the variable corFact
allows a correction of the flow coefficient if the general
modelling approach presented in the litarature differs from
ṁ =
C*Avalve*sqrt(2*ρinlet*dp).
Calculation procedures presented in the litarture have some
variables in commen and these variables are presented
below:
| Variable | Comment |
|---|---|
A |
Cross-sectional flow area |
dinlet |
Diameter of the pipe at valve's inlet |
pinlet |
Pressure at valve's inlet |
poutlet |
Pressure at valve's outlet |
ρinlet |
Density at valve's inlet |
ρoutlet |
Density at valve's outlet |
Tinlet |
Temperature at valve's inlet |
μinlet |
Dynamic viscosity at valve's inlet |
σinlet |
Surface tension at valve's inlet |
Coutlet |
Specific heat capacity at valve's outlet |
hfg |
Heat of vaparisation |
Actually, three power approaches are implemented in this
package. To add further calculation procedures, just add its name
in
AixLib.Fluid.Actuators.Valves.ExpansionValves.Utilities.Choices
and expand the if-structure defined in
AixLib.Fluid.Actuators.Valves.ExpansionValves.Utilities.FlowCoefficient.PolynomialFlowCoefficient.
| Reference | Formula | Refrigerants | Validity Tcondensing |
Validity Tevaporating |
Validity Tsubcooling |
|---|---|---|---|---|---|
| ShanweiEtAl2005 | C = a * a * (A/dclearance^2)^b1 *
((pinlet-poutlet)/pcrit)^b2 *
(Tcrit/Tsubcooling)^b3 *
(rhoinlet/rhooutlet)^b4 *
(quality)^b5 |
R22, R407C, R410A |
40 - 50 °C |
0 - 10 °C |
1.5 - 10 °C |
| ZhifangAndOu2008 | C = a * ((pinlet-poutlet) *
sqrt(A)/σinlet)^b1 *
(dinlet*sqrt(ρinlet *
pinlet)/μinlet)^b2 |
R134a |
31 - 67.17 °C |
no information |
0 - 20 °C |
| Li2013 | C = a * (opening)^b1 *
(Tsubcooling/Tcrit)^b2 |
R22, R407C, R410A |
30 - 50 °C |
0 - 30 °C |
1.5 - 15 °C |