.AixLib.Fluid.Movers.Compressors.UsersGuide.Approaches.IsentropicEfficiency .AixLib.Fluid.Movers.Compressors.UsersGuide.Approaches.IsentropicEfficiencyGenerally, 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 |