source: branches/tests/eml/heat_exchangers/HeatExchangerSimplified.mso @ 339

Last change on this file since 339 was 339, checked in by gerson bicca, 16 years ago

testing a new streamTherm

File size: 19.0 KB
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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: Gerson Balbueno Bicca
17* $Id: HeatExchangerSimplified.mso 160 2007-02-08 18:37:44Z bicca $
18*--------------------------------------------------------------------*#
19
20using "heat_exchangers/HEX_Engine";
21
22Model HeatExchangerSimplified_Basic
23
24ATTRIBUTES
25        Pallete         = false;
26        Brief           = "Basic Models for Simplified Heat Exchangers";
27        Info            =
28        "to be documented.";
29       
30PARAMETERS
31outer PP            as Plugin   (Brief="External Physical Properties", Type="PP");
32outer NComp     as Integer  (Brief="Number of Components");
33       
34        M(NComp)  as molweight  (Brief="Component Mol Weight");
35       
36VARIABLES
37
38in  InletHot    as streamTherm          (Brief="Inlet Hot Stream", PosX=0, PosY=0.4915);
39out OutletHot   as streamPH     (Brief="Outlet Hot Stream", PosX=1, PosY=0.4915);
40in  InletCold   as streamTherm          (Brief="Inlet Cold Stream", PosX=0.5237, PosY=1);
41out OutletCold  as streamPH     (Brief="Outlet Cold Stream", PosX=0.5237, PosY=0);
42
43        Details     as Details_Main     (Brief="Heat Exchanger Details");
44        HotSide         as Main_Simplified      (Brief="Heat Exchanger Hot Side");
45        ColdSide        as Main_Simplified      (Brief="Heat Exchanger Cold Side");
46
47SET
48
49#"Component Molecular Weight"
50        M   = PP.MolecularWeight();
51
52EQUATIONS
53
54#"Flash Calculation in Hot Side"
55#       [vh, xh, yh] = PP.Flash(InletHot.T, InletHot.P, InletHot.z);
56
57#"Flash Calculation in Cold Side"
58#       [vc, xc, yc] = PP.Flash(InletCold.T, InletCold.P, InletCold.z);
59
60"Hot Stream Average Temperature"
61        HotSide.Properties.Average.T = 0.5*InletHot.T + 0.5*OutletHot.T;
62       
63"Cold Stream Average Temperature"
64        ColdSide.Properties.Average.T = 0.5*InletCold.T + 0.5*OutletCold.T;
65       
66"Hot Stream Average Pressure"
67        HotSide.Properties.Average.P = 0.5*InletHot.P+0.5*OutletHot.P;
68       
69"Cold Stream Average Pressure"
70        ColdSide.Properties.Average.P = 0.5*InletCold.P+0.5*OutletCold.P;
71
72"Cold Stream Wall Temperature"
73        ColdSide.Properties.Wall.Twall =   0.5*HotSide.Properties.Average.T + 0.5*ColdSide.Properties.Average.T;
74
75"Hot Stream Wall Temperature"
76        HotSide.Properties.Wall.Twall =   0.5*HotSide.Properties.Average.T + 0.5*ColdSide.Properties.Average.T;
77
78"Hot Stream Average Molecular Weight"
79        HotSide.Properties.Average.Mw = sum(M*InletHot.z);
80
81"Cold Stream Average Molecular Weight"
82        ColdSide.Properties.Average.Mw = sum(M*InletCold.z);
83
84"Cold Stream Average Heat Capacity"
85        ColdSide.Properties.Average.Cp  =       (1-InletCold.v)*PP.LiquidCp(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,InletCold.x) +
86                InletCold.v*PP.VapourCp(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,InletCold.y);
87
88"Cold Stream Inlet Heat Capacity"
89        ColdSide.Properties.Inlet.Cp    =       (1-InletCold.v)*PP.LiquidCp(InletCold.T,InletCold.P,InletCold.x)+
90                InletCold.v*PP.VapourCp(InletCold.T,InletCold.P,InletCold.y);
91
92"Cold Stream Outlet Heat Capacity"
93        ColdSide.Properties.Outlet.Cp   =       (1-OutletCold.v)*PP.LiquidCp(OutletCold.T,OutletCold.P,OutletCold.x)+
94                OutletCold.v*PP.VapourCp(OutletCold.T,OutletCold.P,OutletCold.y);
95
96"Cold Stream Average Mass Density"
97        ColdSide.Properties.Average.rho =       (1-InletCold.v)*PP.LiquidDensity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,InletCold.x)+
98                InletCold.v*PP.VapourDensity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,InletCold.y);
99
100"Cold Stream Inlet Mass Density"
101        ColdSide.Properties.Inlet.rho   =       (1-InletCold.v)*PP.LiquidDensity(InletCold.T,InletCold.P,InletCold.x)+
102                InletCold.v*PP.VapourDensity(InletCold.T,InletCold.P,InletCold.y);
103
104"Cold Stream Outlet Mass Density"
105        ColdSide.Properties.Outlet.rho  =       (1-OutletCold.v)*PP.LiquidDensity(OutletCold.T,OutletCold.P,OutletCold.x)+
106                OutletCold.v*PP.VapourDensity(OutletCold.T,OutletCold.P,OutletCold.y);
107
108"Cold Stream Average Viscosity"
109        ColdSide.Properties.Average.Mu  =       (1-InletCold.v)*PP.LiquidViscosity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,InletCold.x)+
110                InletCold.v*PP.VapourViscosity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,InletCold.y);
111
112"Cold Stream inlet Viscosity"
113        ColdSide.Properties.Inlet.Mu    =       (1-InletCold.v)*PP.LiquidViscosity(InletCold.T,InletCold.P,InletCold.x)+
114                InletCold.v*PP.VapourViscosity(InletCold.T,InletCold.P,InletCold.y);
115
116"Cold Stream Outlet Viscosity"
117        ColdSide.Properties.Outlet.Mu   =       (1-OutletCold.v)*PP.LiquidViscosity(OutletCold.T,OutletCold.P,OutletCold.x)+
118                OutletCold.v*PP.VapourViscosity(OutletCold.T,OutletCold.P,OutletCold.y);
119
120"Cold Stream Average Conductivity"
121        ColdSide.Properties.Average.K   =       (1-InletCold.v)*PP.LiquidThermalConductivity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,InletCold.x)+
122                InletCold.v*PP.VapourThermalConductivity(ColdSide.Properties.Average.T,ColdSide.Properties.Average.P,InletCold.y);
123
124"Cold Stream Inlet Conductivity"       
125        ColdSide.Properties.Inlet.K     =       (1-InletCold.v)*PP.LiquidThermalConductivity(InletCold.T,InletCold.P,InletCold.x)+
126                InletCold.v*PP.VapourThermalConductivity(InletCold.T,InletCold.P,InletCold.y);
127
128"Cold Stream Outlet Conductivity"
129        ColdSide.Properties.Outlet.K    =       (1-OutletCold.v)*PP.LiquidThermalConductivity(OutletCold.T,OutletCold.P,OutletCold.x)+
130                OutletCold.v*PP.VapourThermalConductivity(OutletCold.T,OutletCold.P,OutletCold.y);
131       
132"Cold Stream Viscosity at Wall Temperature"
133        ColdSide.Properties.Wall.Mu     =       (1-InletCold.v)*PP.LiquidViscosity(ColdSide.Properties.Wall.Twall,ColdSide.Properties.Average.P,InletCold.x)+
134                InletCold.v*PP.VapourViscosity(ColdSide.Properties.Wall.Twall,ColdSide.Properties.Average.P,InletCold.y);
135
136"Hot Stream Average Heat Capacity"
137        HotSide.Properties.Average.Cp   =       (1-InletHot.v)*PP.LiquidCp(HotSide.Properties.Average.T,HotSide.Properties.Average.P,InletHot.x) +
138                InletHot.v*PP.VapourCp(HotSide.Properties.Average.T,HotSide.Properties.Average.P,InletHot.y);
139
140"Hot Stream Inlet Heat Capacity"
141        HotSide.Properties.Inlet.Cp     =       (1-InletHot.v)*PP.LiquidCp(InletHot.T,InletHot.P,InletHot.x)+
142                InletHot.v*PP.VapourCp(InletHot.T,InletHot.P,InletHot.y);
143
144"Hot Stream Outlet Heat Capacity"
145        HotSide.Properties.Outlet.Cp    =       (1-OutletHot.v)*PP.LiquidCp(OutletHot.T,OutletHot.P,OutletHot.x)+
146                OutletHot.v*PP.VapourCp(OutletHot.T,OutletHot.P,OutletHot.y);
147
148"Hot Stream Average Mass Density"
149        HotSide.Properties.Average.rho =        (1-InletHot.v)*PP.LiquidDensity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,InletHot.x)+
150                InletHot.v*PP.VapourDensity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,InletHot.y);
151
152"Hot Stream Inlet Mass Density"
153        HotSide.Properties.Inlet.rho    =       (1-InletHot.v)*PP.LiquidDensity(InletHot.T,InletHot.P,InletHot.x)+
154                InletHot.v*PP.VapourDensity(InletHot.T,InletHot.P,InletHot.y);
155
156"Hot Stream Outlet Mass Density"
157        HotSide.Properties.Outlet.rho   =       (1-OutletHot.v)*PP.LiquidDensity(OutletHot.T,OutletHot.P,OutletHot.x)+
158                OutletHot.v*PP.VapourDensity(OutletHot.T,OutletHot.P,OutletHot.y);
159
160"Hot Stream Average Viscosity"
161        HotSide.Properties.Average.Mu   =       (1-InletHot.v)*PP.LiquidViscosity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,InletHot.x)+
162                InletHot.v*PP.VapourViscosity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,InletHot.y);
163
164"Hot Stream inlet Viscosity"
165        HotSide.Properties.Inlet.Mu     =       (1-InletHot.v)*PP.LiquidViscosity(InletHot.T,InletHot.P,InletHot.x)+
166                InletHot.v*PP.VapourViscosity(InletHot.T,InletHot.P,InletHot.y);
167
168"Hot Stream Outlet Viscosity"
169        HotSide.Properties.Outlet.Mu    =       (1-OutletHot.v)*PP.LiquidViscosity(OutletHot.T,OutletHot.P,OutletHot.x)+
170                OutletHot.v*PP.VapourViscosity(OutletHot.T,OutletHot.P,OutletHot.y);
171
172"Hot Stream Average Conductivity"
173        HotSide.Properties.Average.K    =       (1-InletHot.v)*PP.LiquidThermalConductivity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,InletHot.x)+
174                InletHot.v*PP.VapourThermalConductivity(HotSide.Properties.Average.T,HotSide.Properties.Average.P,InletHot.y);
175
176"Hot Stream Inlet Conductivity"
177        HotSide.Properties.Inlet.K      =       (1-InletHot.v)*PP.LiquidThermalConductivity(InletHot.T,InletHot.P,InletHot.x)+
178                InletHot.v*PP.VapourThermalConductivity(InletHot.T,InletHot.P,InletHot.y);
179
180"Hot Stream Outlet Conductivity"
181        HotSide.Properties.Outlet.K     =       (1-OutletHot.v)*PP.LiquidThermalConductivity(OutletHot.T,OutletHot.P,OutletHot.x)+
182                OutletHot.v*PP.VapourThermalConductivity(OutletHot.T,OutletHot.P,OutletHot.y);
183       
184"Hot Stream Viscosity at Wall Temperature"
185        HotSide.Properties.Wall.Mu      =       (1-InletHot.v)*PP.LiquidViscosity(HotSide.Properties.Wall.Twall,HotSide.Properties.Average.P,InletHot.x)+
186                InletHot.v*PP.VapourViscosity(HotSide.Properties.Wall.Twall,HotSide.Properties.Average.P,InletHot.y);
187
188"Energy Balance Hot Stream"
189        Details.Q = InletHot.F*(InletHot.h-OutletHot.h);
190
191"Energy Balance Cold Stream"
192        Details.Q =-InletCold.F*(InletCold.h-OutletCold.h);
193
194"Flow Mass Inlet Cold Stream"
195        ColdSide.Properties.Inlet.Fw    =  sum(M*InletCold.z)*InletCold.F;
196
197"Flow Mass Outlet Cold Stream"
198        ColdSide.Properties.Outlet.Fw   =  sum(M*OutletCold.z)*OutletCold.F;
199
200"Flow Mass Inlet Hot Stream"
201        HotSide.Properties.Inlet.Fw             =  sum(M*InletHot.z)*InletHot.F;
202
203"Flow Mass Outlet Hot Stream"   
204        HotSide.Properties.Outlet.Fw    =  sum(M*OutletHot.z)*OutletHot.F;
205
206"Molar Balance Hot Stream"
207        InletHot.F  = OutletHot.F;
208       
209"Molar Balance Cold Stream"
210        InletCold.F = OutletCold.F;
211
212"Hot Stream Molar Fraction Constraint"
213        OutletHot.z             =       InletHot.z;
214       
215"Cold Stream Molar Fraction Constraint"
216        OutletCold.z    =       InletCold.z;
217       
218"Pressure Drop Hot Stream"
219        OutletHot.P  = InletHot.P - HotSide.PressureDrop.Pdrop;
220       
221"Pressure Drop Cold Stream"
222        OutletCold.P  = InletCold.P - ColdSide.PressureDrop.Pdrop;
223       
224"Fraction of Inlet Pressure : Hot Stream"
225        HotSide.PressureDrop.Pdrop  = InletHot.P*HotSide.PressureDrop.FPdrop;
226       
227"Fraction of Inlet Pressure : Cold Stream"
228        ColdSide.PressureDrop.Pdrop  = InletCold.P*ColdSide.PressureDrop.FPdrop;
229       
230end
231
232Model HeatExchanger_LMTD                as HeatExchangerSimplified_Basic
233
234ATTRIBUTES
235        Pallete         = true;
236        Icon            = "icon/HeatExchanger_LMTD";           
237        Brief           = "Heat Exchanger Block - LMTD Method";
238        Info            =
239        "to be documented.";
240       
241PARAMETERS
242
243        FlowDirection as Switcher       (Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent");
244
245VARIABLES
246
247        Method as LMTD_Basic    (Brief="LMTD Method of Calculation");
248
249EQUATIONS
250
251"Exchange Surface Area"
252        Details.Q = Details.Ud*Details.A*Method.LMTD*Method.Fc;
253       
254switch FlowDirection
255       
256        case "cocurrent":
257
258"Temperature Difference at Inlet"
259        Method.DT0 = InletHot.T - InletCold.T;
260
261"Temperature Difference at Outlet"
262        Method.DTL = OutletHot.T - OutletCold.T;
263
264        case "counter":
265       
266"Temperature Difference at Inlet"
267        Method.DT0 = InletHot.T - OutletCold.T;
268
269"Temperature Difference at Outlet"
270        Method.DTL = OutletHot.T - InletCold.T;
271
272end
273
274end
275
276Model Shell_and_Tubes_LMTD      as HeatExchangerSimplified_Basic
277       
278ATTRIBUTES
279        Pallete         = true;
280        Icon            = "icon/Shell_and_Tubes_LMTD";
281        Brief           = "Shell and Tubes Heat Exchanger with 1 or 2 shell pass - LMTD Method";
282        Info            =
283        "to be documented.";
284       
285PARAMETERS
286
287LMTDcorrection as Switcher(Brief="LMTD Correction Factor Model",Valid=["Bowmann","Fakeri"],Default="Bowmann");
288ShellType                as Switcher(Brief="TEMA Designation for Shell Type",Valid=["Eshell","Fshell"],Default="Eshell");
289
290VARIABLES
291
292Method  as LMTD_Basic (Brief="LMTD Method of Calculation");
293R                       as positive             (Brief=" Capacity Ratio for LMTD Correction Fator",Lower=1e-6);
294P                       as positive             (Brief="Non - Dimensional Variable for LMTD Correction Fator ",Lower=1e-6);
295Pc                      as positive             (Brief="Non - Dimensional Variable for LMTD Correction Fator when 2 Pass Shell Side",Lower=1e-6);
296Rho             as positive             (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation",Lower=1e-6);
297Phi     as positive             (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation",Lower=1e-6);
298lambdaN as Real                 (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation when 2 Pass Shell Side");
299lambda1 as Real                 (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equationwhen 2 Pass Shell Side");
300
301EQUATIONS
302
303"Exchange Surface Area"
304        Details.Q = Details.Ud*Details.A*Method.LMTD*Method.Fc;
305
306"R: Capacity Ratio for LMTD Correction Fator"
307        R*(OutletCold.T - InletCold.T ) = (InletHot.T-OutletHot.T);
308
309"P: Non - Dimensional Variable for LMTD Correction Fator"
310        P*(InletHot.T- InletCold.T)= (OutletCold.T-InletCold.T);
311       
312"Temperature Difference at Inlet"
313        Method.DT0 = InletHot.T - OutletCold.T;
314
315"Temperature Difference at Outlet"
316        Method.DTL = OutletHot.T - InletCold.T;
317
318switch ShellType
319       
320        case "Fshell":
321       
322switch LMTDcorrection
323       
324        case "Bowmann":
325       
326" Variable not in use with Bowmann equation"
327        lambdaN =1;
328       
329" Variable not in use with Bowmann equation"
330        lambda1 =1;
331
332" Variable not in use with Bowmann equation"
333        Phi = 1;
334
335" Variable not in use with Bowmann equation"
336        Rho =1;
337
338if R equal 1
339       
340        then
341       
342"Non Dimensional Variable for LMTD Correction Fator when 2 Pass Shell Side"
343        Pc*(2-P)= P;
344
345"LMTD Correction Fator when 2 Pass Shell Side"
346        Method.Fc= (sqrt(2)*Pc)/((1-Pc)*ln( abs( ( 2-Pc*0.585786)/( 2-Pc*3.414214))));
347       
348        else
349       
350"Non Dimensional Variable for LMTD Correction Fator when 2 Pass Shell Side"
351        Pc = (sqrt(abs(( 1-P*R)/(1-P)))-1)/(sqrt(abs(( 1-P*R)/(1-P)))-R);
352
353"LMTD Correction Fator when 2 Pass Shell Side"
354        Method.Fc = sqrt(R*R+1)*ln(abs((1-Pc*R)/(1-Pc)))/((1-R)*ln( abs( ( 2-Pc*(R+1-sqrt(R*R+1)))/ ( 2-Pc*(R + 1 + sqrt(R*R+1))))));
355       
356end
357
358        case "Fakeri":
359       
360" Variable not in use with Fakeri equation"
361        Pc = P;
362       
363"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
364        Rho*(1-P*R) = (1-P);
365
366"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation "
367        Phi = (sqrt(((InletHot.T - OutletHot.T)*(InletHot.T- OutletHot.T))+((OutletCold.T -  InletCold.T)*(OutletCold.T -  InletCold.T))))/(2*((InletHot.T + OutletHot.T)-( InletCold.T + OutletCold.T)));
368
369if Rho equal 1
370       
371        then
372       
373" Variable not in use when Rho = 1"
374        lambdaN =       1;
375       
376" Variable not in use when Rho = 1"
377        lambda1 =       1;
378       
379"LMTD Correction Fator when 2 Pass Shell Side"
380        Method.Fc = (2*Phi )/(ln(abs((1+Phi )/(1-Phi ))));
381       
382        else
383
384"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
385        lambdaN = (1/ln(sqrt(abs(Rho))))*((2*sqrt(abs(Rho))-2)/(sqrt(abs(Rho))+1));
386       
387"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
388        lambda1 = (1/ln(abs(Rho)))*((2*Rho-2)/(Rho+1));
389
390"LMTD Correction Fator when 2 Pass Shell Side"
391        Method.Fc =     ((2*Phi *(lambdaN/lambda1))/(ln(abs((1+Phi *(lambdaN/lambda1))/(1-Phi *(lambdaN/lambda1))))))*(1/lambdaN);
392
393end
394
395
396end
397
398        case "Eshell":
399       
400" Variable not in use when 1 Pass Shell Side"
401        lambdaN =1;
402
403" Variable not in use when 1 Pass Shell Side"
404        lambda1 =1;
405       
406" Variable not in use when 1 Pass Shell Side"
407        Pc = P;
408       
409switch LMTDcorrection
410       
411        case "Bowmann":
412
413" Variable not in use with Bowmann equation"
414        Phi  = 1;
415       
416" Variable not in use with Bowmann equation"
417        Rho = 1;
418
419
420 if R equal 1
421       
422    then
423       
424"LMTD Correction Fator when 1 Pass Shell Side"
425        Method.Fc = (sqrt(2)*P)/((1-P)*ln( abs( ( 2-P*0.585786)/( 2-P*3.414214))));
426
427        else
428       
429"LMTD Correction Fator when 1 Pass Shell Side"
430        Method.Fc = sqrt(R*R+1)*ln(abs((1-P*R)/(1-P)))/((1-R)*ln( abs( ( 2-P*(R+1-sqrt(R*R+1)))/ ( 2-P*(R + 1 + sqrt(R*R+1))))));
431
432end
433
434        case "Fakeri":
435
436"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation "
437        Phi  = (sqrt(((InletHot.T- OutletHot.T)*(InletHot.T- OutletHot.T))+((OutletCold.T - InletCold.T)*(OutletCold.T - InletCold.T))))/(2*((InletHot.T+ OutletHot.T)-(InletCold.T+ OutletCold.T)));
438
439"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
440        Rho*(1-P*R) = (1-P);
441
442if Rho equal 1
443       
444        then
445       
446"LMTD Correction Fator when 1 Pass Shell Side"
447        Method.Fc = (4*Phi)/(ln(abs((1+2*Phi)/(1-2*Phi))));
448
449        else
450
451"LMTD Correction Fator when 1 Pass Shell Side"
452        Method.Fc = (2*Phi*(Rho+1)*ln(abs(Rho)))/( ln(abs((1+2*Phi)/(1-2*Phi)))*(Rho-1));
453       
454end
455
456end
457
458       
459end
460
461end
462
463Model HeatExchanger_NTU                 as      HeatExchangerSimplified_Basic
464
465ATTRIBUTES
466        Pallete         = true;
467        Icon            = "icon/HeatExchanger_NTU";     
468        Brief           = "Heat Exchanger Block - NTU Method";
469        Info            =
470        "to be documented.";
471       
472PARAMETERS
473
474        FlowDirection as Switcher       (Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent");
475
476VARIABLES
477
478Method  as NTU_Basic    (Brief="NTU Method of Calculation");
479
480EQUATIONS
481
482"Number of Units Transference"
483        Method.NTU*Method.Cmin = Details.Ud*Details.A;
484       
485"Minimum Heat Capacity"
486        Method.Cmin  = min([Method.Ch,Method.Cc]);
487
488"Maximum Heat Capacity"
489        Method.Cmax  = max([Method.Ch,Method.Cc]);
490
491"Thermal Capacity Ratio"
492        Method.Cr    = Method.Cmin/Method.Cmax;
493
494"Duty"
495        Details.Q       = Method.Eft*Method.Cmin*(InletHot.T-InletCold.T);
496
497"Hot Stream Heat Capacity"
498        Method.Ch  = InletHot.F*HotSide.Properties.Average.Cp;
499       
500"Cold Stream Heat Capacity"
501        Method.Cc = InletCold.F*ColdSide.Properties.Average.Cp;
502       
503"Effectiveness Correction"
504        Method.Eft1 = 1;
505
506if Method.Cr equal 0
507       
508        then
509       
510"Effectiveness"
511        Method.Eft = 1-exp(-Method.NTU);
512       
513        else
514
515switch  FlowDirection
516
517        case "cocurrent":
518       
519"Effectiveness in Cocurrent Flow"
520        Method.Eft = (1-exp(-Method.NTU*(1+Method.Cr)))/(1+Method.Cr);
521
522        case "counter":
523
524if Method.Cr equal 1
525       
526        then
527"Effectiveness in Counter Flow"
528        Method.Eft = Method.NTU/(1+Method.NTU);
529       
530        else
531"Effectiveness in Counter Flow"
532        Method.Eft = (1-exp(-Method.NTU*(1-Method.Cr)))/(1-Method.Cr*exp(-Method.NTU*(1-Method.Cr)));
533       
534end
535
536end
537
538
539end
540
541end
542 
543Model Shell_and_Tubes_NTU       as HeatExchangerSimplified_Basic
544
545ATTRIBUTES
546        Pallete         = true;
547        Icon            = "icon/Shell_and_Tubes_NTU";           
548        Brief           = "Shell and Tubes Heat Exchanger with 1 or 2 shell pass - NTU Method";
549        Info            =
550        "to be documented.";
551
552PARAMETERS
553
554ShellType       as Switcher (Brief="TEMA Designation",Valid=["Eshell","Fshell"],Default="Eshell");
555
556VARIABLES
557
558Method  as NTU_Basic (Brief="NTU Method of Calculation");
559
560EQUATIONS
561
562"Number of Units Transference"
563        Method.NTU*Method.Cmin = Details.Ud*Details.A;
564       
565"Minimum Heat Capacity"
566        Method.Cmin  = min([Method.Ch,Method.Cc]);
567
568"Maximum Heat Capacity"
569        Method.Cmax  = max([Method.Ch,Method.Cc]);
570
571"Thermal Capacity Ratio"
572        Method.Cr    = Method.Cmin/Method.Cmax;
573
574"Duty"
575        Details.Q       = Method.Eft*Method.Cmin*(InletHot.T-InletCold.T);
576
577"Hot Stream Heat Capacity"
578        Method.Ch  = InletHot.F*HotSide.Properties.Average.Cp;
579       
580"Cold Stream Heat Capacity"
581        Method.Cc = InletCold.F*ColdSide.Properties.Average.Cp;
582
583switch ShellType
584       
585        case "Fshell":
586       
587"Effectiveness Correction for 2 pass shell side"
588        Method.Eft1 = 2*(1+Method.Cr+sqrt(1+Method.Cr^2)*((1+exp(-Method.NTU*sqrt(1+Method.Cr^2)))/(1-exp(-Method.NTU*sqrt(1+Method.Cr^2)))) )^-1;
589
590"TEMA F Shell Effectiveness"
591        Method.Eft = ( ((1-Method.Eft1*Method.Cr)/(1-Method.Eft1))^2 -1  )*( ((1-Method.Eft1*Method.Cr)/(1-Method.Eft1))^2 - Method.Cr )^-1;
592
593        case "Eshell":
594       
595"TEMA E Shell Effectiveness"
596        Method.Eft      = 2*(1+Method.Cr+sqrt(1+Method.Cr^2)*((1+exp(-Method.NTU*sqrt(1+Method.Cr^2)))/(1-exp(-Method.NTU*sqrt(1+Method.Cr^2)))) )^-1;
597
598"Variable not in use when 1 Pass Shell Side"
599        Method.Eft1     = 1;
600       
601end
602
603end
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