.AixLib.Fluid.Movers.Compressors.UsersGuide.Approaches.IsentropicEfficiency .AixLib.Fluid.Movers.Compressors.UsersGuide.Approaches.IsentropicEfficiency
Generally, two kinds of calculation approaches can be identified: A
polynomial and a power approach. A generic polynomial approach is
presented below:
ηise = corFact * sum(a[i]*P[i]^b[i] for i in
1:nT)
A generic power approach is presented below:
ηise = corFact * a * product(P[i]^b[i] for i in
1:nT)
All isentropic efficiency models presented in this library are based
on a literature review. Therefore, the variable corFact
allows a correction of the isentropic efficiency if the general
modelling approach presented in the litarature differs from
ηise = (houtIse - hinl) /
(hout - hinl).
Calculation procedures presented in the litarture have some variables
in commen and these variables are presented below:
| Type | Name | Comment |
|---|---|---|
| input |
epsRef
|
Ratio of the real and the ideal displacement volume |
| input |
VDis
|
Displacement volume |
| input |
piPre
|
Pressure ratio |
| input |
rotSpe
|
Rotational speed |
| input |
staInl
|
Thermodynamic state at compressor's inlet conditions |
| input |
staOut
|
Thermodynamic state at compressor's out conditions |
| input |
TAmb
|
Ambient temperature |
Actually, three polynomial approaches are implemented in this
package. To add further calculation procedures, just add its name
in AixLib.Fluid.Movers.Compressors.Utilities.Types
and expand the if-structure defined in
AixLib.Fluid.Movers.Compressors.Utilities.IsentropicEfficiency.PolynomialIsentropicEfficiency.
| Reference | Formula | Refrigerants |
Validity ncompressor
|
Validity Πpressure
|
|---|---|---|---|---|
| DarrAndCrawford1992 |
ηise = a1 + a2*n +
a3/ρinlet
|
R134a |
40 - 75
|
3 - 10
|
| Karlsson2007 |
ηise = a1 + a2*π + a3*π^2 + a4*n +
a5*n^2
|
R407c |
No information
|
No information
|
| Engelpracht2017 |
ηise = a1 + a2*n + a3*n^3 +
a5*π^2
|
Generic model |
0 - 120
|
1 - 10
|
Actually, one power approache is implemented in this package.
To add further calculation procedures, just add its name in
AixLib.Fluid.Movers.Compressors.Utilities.Types
and expand the if-structure defined in
AixLib.Fluid.Movers.Compressors.Utilities.IsentropicEfficiency.PowerIsentropicEfficiency.
| Reference | Formula | Refrigerants |
Validity ncompressor
|
Validity Πpressure
|
|---|---|---|---|---|
| MendozaMirandaEtAl2016 |
ηise = a1 * π^b1 *
(nref/n)^b2 *
(n^3*Vdis/dhise^1.5)^b3 *
(1/((Tinl+ToutIse)/2-Tout))^b4
|
R134a,R450a,R1324yf,R1234ze(E) |
0 - 50
|
1 - 6
|