source: trunk/eml/pressure_changers/compressor.mso @ 760

Last change on this file since 760 was 681, checked in by gerson bicca, 14 years ago

updated compressor model

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1#*-------------------------------------------------------------------
2* EMSO Model Library (EML) Copyright (C) 2004 - 2007 ALSOC.
3*
4* This LIBRARY is free software; you can distribute it and/or modify
5* it under the therms of the ALSOC FREE LICENSE as available at
6* http://www.enq.ufrgs.br/alsoc.
7*
8* EMSO Copyright (C) 2004 - 2007 ALSOC, original code
9* from http://www.rps.eng.br Copyright (C) 2002-2004.
10* All rights reserved.
11*
12* EMSO is distributed under the therms of the ALSOC LICENSE as
13* available at http://www.enq.ufrgs.br/alsoc.
14*
15*----------------------------------------------------------------------
16* Author: Marcos L. Alencastro,  Estefane S. Horn (Revised Gerson B. Bicca)
17* $Id: compressor.mso 681 2008-11-18 14:48:24Z bicca $
18*--------------------------------------------------------------------*#
19
20using "streams";
21
22Model centrifugal_compressor
23       
24ATTRIBUTES
25        Pallete         = true;
26        Icon            = "icon/CentrifugalCompressor";
27        Brief           = "Model of a centrifugal compressor.";
28        Info            =
29"To be documented
30
31== References ==
32
33[1] GPSA, 1979, Engineering Data Book, Chapter 4, 5-9 - 5-10.
34
35[2] Bloch, Heinz P., A Practical Guide to Compressor Technology, John Wiley & Sons, Incorporate, 2006.
36
37[3] Mark R. Sandberg, Equation Of State Influences On Compressor Performance Determination,PROCEEDINGS OF THE THIRTY-FOURTH TURBOMACHINERY SYMPOSIUM, 2005.";
38       
39PARAMETERS
40
41outer PP                                        as Plugin                       (Brief = "External Physical Properties", Type="PP");
42outer NComp                     as Integer              (Brief = "Number of chemical components", Lower = 1);
43        Rgas                                            as positive             (Brief = "Constant of Gases", Unit= 'kJ/kmol/K', Default = 8.31451,Hidden=true);
44        Mw(NComp)                       as molweight    (Brief = "Molar Weight");
45        CompressorType  as Switcher             (Brief = "Compressor Model Type",Valid=["Polytropic With GPSA Method","Isentropic With GPSA Method","Isentropic With ASME Method","Polytropic With ASME Method"], Default="Isentropic With GPSA Method");
46
47VARIABLES
48
49        Pratio          as positive             (Brief = "Pressure Ratio", Lower = 1E-6, Symbol ="P_{ratio}"); 
50        Pdrop           as press_delta  (Brief = "Pressure Drop", DisplayUnit = 'kPa', Symbol ="\Delta P");
51        Pincrease       as press_delta  (Brief = "Pressure Increase",Lower = 0,  DisplayUnit = 'kPa', Symbol ="P_{incr}");
52
53        Head                                    as energy_mass  (Brief = "Actual Head");
54        HeadIsentropic  as energy_mass  (Brief = "Isentropic Head");
55        HeadPolytropic  as energy_mass  (Brief = "Polytropic Head");
56        HeadCorrection   as positive                    (Brief = "Schultz Polytropic Head Correction");
57       
58        EfficiencyOperation     as positive     (Brief = "Compressor efficiency - Polytropic or Isentropic (See Compressor Type)",Lower=1E-3,Upper=1);
59        MechanicalEff                   as positive     (Brief = "Mechanical efficiency",Lower=1E-3,Upper=1);
60       
61        FluidPower      as power        (Brief = "Fluid Power");
62        BrakePower      as power        (Brief = "Brake Power");
63        PowerLoss       as power        (Brief = "Power Losses");
64       
65        PolyCoeff                       as positive     (Brief = "Polytropic Coefficient", Lower=0.2,Protected=true);
66        IseCoeff                        as positive     (Brief = "Isentropic Coefficient", Lower=0.2,Protected=true);
67        PolytropicEff   as positive     (Brief = "Polytropic efficiency",Lower=1E-3,Upper=1,Protected=true);
68        IsentropicEff   as positive     (Brief = "Isentropic efficiency",Lower=1E-3,Upper=1,Protected=true);
69
70        Tisentropic     as temperature          (Brief = "Isentropic Temperature",Protected=true);
71        hise                    as enth_mol             (Brief = "Enthalpy at constant entropy",Hidden=true);
72        Mwm                     as molweight            (Brief = "Mixture Molar Weight",Hidden=true);
73        rho_in                  as dens_mass            (Brief = "Mass Density at inlet conditions", Lower = 1E-6, Protected=true);
74        rho_out         as dens_mass            (Brief = "Mass Density at outlet conditions", Lower = 1E-6, Protected=true);
75        rho_ise         as dens_mass            (Brief = "Mass Density at isentropic conditions", Lower = 1E-6, Hidden=true);
76        Zfac_in                 as fraction             (Brief = "Compressibility factor at inlet", Lower = 1E-3, Protected=true);
77        Zfac_out                as fraction             (Brief = "Compressibility factor at outlet", Lower = 1E-3, Protected=true);
78
79in      Inlet   as stream       (Brief = "Inlet stream", PosX=0.437, PosY=1, Symbol="_{in}");
80out     Outlet  as streamPH     (Brief = "Outlet stream", PosX=0.953, PosY=0.0, Symbol="_{out}");
81
82in      WorkIn  as work_stream  (Brief = "Work Inlet", PosX=0, PosY=0.45);
83
84SET
85
86        Mw = PP.MolecularWeight();
87
88        Rgas    = 8.31451*'kJ/kmol/K';
89
90EQUATIONS
91
92"Overall Molar Balance"
93        Outlet.F = Inlet.F;
94
95"Component Molar Balance"
96        Outlet.z = Inlet.z;
97
98"Average Molecular Weight"
99        Mwm = sum(Mw*Inlet.z);
100
101"Pressure Ratio"
102        Outlet.P = Inlet.P * Pratio;
103
104"Pressure Drop"
105        Outlet.P  = Inlet.P - Pdrop;
106
107"Pressure Increase"
108        Outlet.P  = Inlet.P + Pincrease;
109
110"Mass Density at inlet conditions"
111        rho_in = PP.VapourDensity(Inlet.T, Inlet.P, Inlet.z);
112
113"Mass Density at outlet conditions"
114        rho_out= PP.VapourDensity(Outlet.T, Outlet.P, Outlet.z);
115
116"Mass Density at isentropic conditions"
117        rho_ise= PP.VapourDensity(Tisentropic, Outlet.P, Outlet.z);
118
119"Enthalpy at isentropic conditions"
120        hise = PP.VapourEnthalpy(Tisentropic, Outlet.P, Outlet.z);
121       
122"Compressibility factor at Inlet Conditions"
123        Zfac_in = PP.VapourCompressibilityFactor(Inlet.T,Inlet.P,Inlet.z);
124
125"Compressibility factor at Outlet Conditions"
126        Zfac_out = PP.VapourCompressibilityFactor(Outlet.T,Outlet.P,Outlet.z);
127
128"Isentropic Efficiency"
129        IsentropicEff*(Outlet.h-Inlet.h) = (hise-Inlet.h);
130
131"Actual Head"
132        Head*Mwm = (Outlet.h-Inlet.h);
133
134"Isentropic Outlet Temperature"
135        PP.VapourEntropy(Tisentropic, Outlet.P, Outlet.z) = PP.VapourEntropy(Inlet.T, Inlet.P, Inlet.z);
136
137"Brake Power"
138        BrakePower = -WorkIn.Work;
139
140"Brake Power"
141        BrakePower*MechanicalEff = FluidPower;
142
143"Power Loss"
144        PowerLoss = BrakePower - FluidPower;
145
146"Polytropic-Isentropic Relation"
147        PolytropicEff*HeadIsentropic = HeadPolytropic*IsentropicEff;
148
149"Fluid Power"
150        FluidPower = Head*Mwm*Inlet.F;
151
152switch CompressorType
153
154        case "Isentropic With GPSA Method":
155
156"Efficiency"
157        EfficiencyOperation = IsentropicEff;
158
159"Polytropic Efficiency"
160        PolytropicEff*IseCoeff*(PolyCoeff-1) = PolyCoeff*(IseCoeff-1);
161
162"Isentropic Coefficient"
163        HeadIsentropic = (0.5*Zfac_in+0.5*Zfac_out)*(1/Mwm)*(IseCoeff/(IseCoeff-1.001))*Rgas*Inlet.T*((Pratio)^((IseCoeff-1.001)/IseCoeff) - 1);
164
165"Polytropic Coefficient"
166        HeadPolytropic = (0.5*Zfac_in+0.5*Zfac_out)*(1/Mwm)*(PolyCoeff/(PolyCoeff-1.001))*Rgas*Inlet.T*((Pratio)^((PolyCoeff-1.001)/PolyCoeff) - 1);
167
168"Head Correction"
169        HeadCorrection =1;
170
171"Isentropic Head"
172        HeadIsentropic = Head*IsentropicEff;
173       
174        case "Polytropic With GPSA Method":
175
176"Efficiency"
177        EfficiencyOperation = PolytropicEff;
178
179"Polytropic Efficiency"
180        PolytropicEff*IseCoeff*(PolyCoeff-1) = PolyCoeff*(IseCoeff-1);
181
182"Isentropic Coefficient"
183        HeadIsentropic = (0.5*Zfac_in+0.5*Zfac_out)*(1/Mwm)*(IseCoeff/(IseCoeff-1.001))*Rgas*Inlet.T*((Pratio)^((IseCoeff-1.001)/IseCoeff) - 1);
184
185"Polytropic Coefficient"
186        HeadPolytropic = (0.5*Zfac_in+0.5*Zfac_out)*(1/Mwm)*(PolyCoeff/(PolyCoeff-1.001))*Rgas*Inlet.T*((Pratio)^((PolyCoeff-1.001)/PolyCoeff) - 1);
187
188"Head Correction"
189        HeadCorrection =1;
190
191"Isentropic Head"
192        HeadIsentropic = Head*IsentropicEff;
193       
194        case "Isentropic With ASME Method":
195
196"Efficiency"
197        EfficiencyOperation = IsentropicEff;
198
199"Isentropic Coefficient"
200        IseCoeff*ln(rho_ise/rho_in) = ln(Outlet.P/Inlet.P);
201
202"Polytropic Coefficient"
203        PolyCoeff*ln(rho_out/rho_in) = ln(Outlet.P/Inlet.P);
204
205"Isentropic Head"
206        HeadIsentropic*rho_in = (IseCoeff/(IseCoeff-1.001))*Inlet.P*HeadCorrection*((Pratio)^((IseCoeff-1.001)/IseCoeff) - 1);
207
208"Polytropic Head"
209        HeadPolytropic*rho_in = (PolyCoeff/(PolyCoeff-1.001))*Inlet.P*HeadCorrection*((Pratio)^((PolyCoeff-1.001)/PolyCoeff) - 1);
210
211"Schultz Polytropic Head Correction"
212        HeadCorrection*Mwm*(IseCoeff/(IseCoeff-1.001))*(Outlet.P/rho_ise -Inlet.P/rho_in) = (hise-Inlet.h);
213
214        case "Polytropic With ASME Method":
215
216"Efficiency"
217        EfficiencyOperation = PolytropicEff;
218
219"Isentropic Coefficient"
220        IseCoeff*ln(rho_ise/rho_in) = ln(Outlet.P/Inlet.P);
221
222"Polytropic Coefficient"
223        PolyCoeff*ln(rho_out/rho_in) = ln(Outlet.P/Inlet.P);
224
225"Isentropic Head"
226        HeadIsentropic*rho_in = (IseCoeff/(IseCoeff-1.001))*Inlet.P*HeadCorrection*((Pratio)^((IseCoeff-1.001)/IseCoeff) - 1);
227
228"Polytropic Head"
229        HeadPolytropic*rho_in = (PolyCoeff/(PolyCoeff-1.001))*Inlet.P*HeadCorrection*((Pratio)^((PolyCoeff-1.001)/PolyCoeff) - 1);
230       
231"Schultz Polytropic Head Correction"
232        HeadCorrection*Mwm*(IseCoeff/(IseCoeff-1.001))*(Outlet.P/rho_ise -Inlet.P/rho_in) =  (hise-Inlet.h);
233
234end
235
236end
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