source: branches/newlanguage/eml/heat_exchangers/HeatExchangerSimplified.mso @ 145

Last change on this file since 145 was 145, checked in by Rafael de Pelegrini Soares, 17 years ago

Updated switcher sample again
  • Property svn:eol-style set to native
  • Property svn:keywords set to Id
File size: 18.2 KB
Line 
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 145 2007-01-30 18:20:00Z rafael $
18*--------------------------------------------------------------------*#
19
20using "HEX_Engine";
21
22Model HeatExchangerSimplified_Basic
23       
24ATTRIBUTES
25        Pallete         = false;
26        Brief           = "Basic Models for Simplified Heat Exchangers";
27        Info            =
28        "write some information";
29       
30PARAMETERS
31outer PP                as Plugin               (Brief="External Physical Properties");
32                HE              as Plugin               (Brief="STHE Calculations",File="heatex");
33outer NComp     as Integer      (Brief="Number of Components");
34                M(NComp)  as molweight  (Brief="Component Mol Weight");
35       
36VARIABLES
37
38in      Inlet                   as Inlet_Main_Stream    (Brief="Hot and Cold Inlets");
39out     Outlet                  as Outlet_Main_Stream (Brief="Hot and Cold Outlets");
40                Properties              as Main_Properties              (Brief="Hot and Cold Properties");
41                Details                 as Details_Main                         (Brief="Heat Exchanger Details");
42                PressureDrop    as Main_Pdrop                   (Brief="Heat Exchanger Pressure Drop");
43
44SET
45
46M   = PP.MolecularWeight();
47
48EQUATIONS
49
50"Hot Stream Average Temperature"
51        Properties.Hot.Average.T = 0.5*Inlet.Hot.T + 0.5*Outlet.Hot.T;
52       
53"Cold Stream Average Temperature"
54        Properties.Cold.Average.T = 0.5*Inlet.Cold.T + 0.5*Outlet.Cold.T;
55       
56"Hot Stream Average Pressure"
57        Properties.Hot.Average.P = 0.5*Inlet.Hot.P+0.5*Outlet.Hot.P;
58       
59"Cold Stream Average Pressure"
60        Properties.Cold.Average.P = 0.5*Inlet.Cold.P+0.5*Outlet.Cold.P;
61
62"Cold Stream Wall Temperature"
63        Properties.Cold.Wall.Twall =   0.5*Properties.Hot.Average.T + 0.5*Properties.Cold.Average.T;
64
65"Hot Stream Wall Temperature"
66        Properties.Hot.Wall.Twall =   0.5*Properties.Hot.Average.T + 0.5*Properties.Cold.Average.T;
67
68"Hot Stream Average Molecular Weight"
69        Properties.Hot.Average.Mw = sum(M*Inlet.Hot.z);
70
71"Cold Stream Average Molecular Weight"
72        Properties.Cold.Average.Mw = sum(M*Inlet.Cold.z);
73
74
75if Inlet.Cold.v equal 0
76       
77        then   
78       
79"Cold Stream Average Heat Capacity"
80        Properties.Cold.Average.Cp      =       PP.LiquidCp(Properties.Cold.Average.T,Properties.Cold.Average.P,Inlet.Cold.z);
81
82"Cold Stream Inlet Heat Capacity"
83        Properties.Cold.Inlet.Cp        =       PP.LiquidCp(Inlet.Cold.T,Inlet.Cold.P,Inlet.Cold.z);
84
85"Cold Stream Outlet Heat Capacity"
86        Properties.Cold.Outlet.Cp       =       PP.LiquidCp(Outlet.Cold.T,Outlet.Cold.P,Outlet.Cold.z);
87
88"Cold Stream Average Mass Density"
89        Properties.Cold.Average.rho =   PP.LiquidDensity(Properties.Cold.Average.T,Properties.Cold.Average.P,Inlet.Cold.z);
90
91"Cold Stream Inlet Mass Density"
92        Properties.Cold.Inlet.rho       =       PP.LiquidDensity(Inlet.Cold.T,Inlet.Cold.P,Inlet.Cold.z);
93
94"Cold Stream Outlet Mass Density"
95        Properties.Cold.Outlet.rho      =       PP.LiquidDensity(Outlet.Cold.T,Outlet.Cold.P,Outlet.Cold.z);
96
97"Cold Stream Average Viscosity"
98        Properties.Cold.Average.Mu      =       PP.LiquidViscosity(Properties.Cold.Average.T,Properties.Cold.Average.P,Inlet.Cold.z);
99
100"Cold Stream inlet Viscosity"
101        Properties.Cold.Inlet.Mu        =       PP.LiquidViscosity(Inlet.Cold.T,Inlet.Cold.P,Inlet.Cold.z);
102       
103"Cold Stream Outlet Viscosity"
104        Properties.Cold.Outlet.Mu       =       PP.LiquidViscosity(Outlet.Cold.T,Outlet.Cold.P,Outlet.Cold.z);
105
106"Cold Stream Average Conductivity"
107        Properties.Cold.Average.K       =       PP.LiquidThermalConductivity(Properties.Cold.Average.T,Properties.Cold.Average.P,Inlet.Cold.z);
108
109"Cold Stream Inlet Conductivity"       
110        Properties.Cold.Inlet.K         =       PP.LiquidThermalConductivity(Inlet.Cold.T,Inlet.Cold.P,Inlet.Cold.z);
111
112"Cold Stream Outlet Conductivity"
113        Properties.Cold.Outlet.K        =       PP.LiquidThermalConductivity(Outlet.Cold.T,Outlet.Cold.P,Outlet.Cold.z);
114
115"Cold Stream Heat Capacity at Wall Temperature"
116        Properties.Cold.Wall.Cp         =       PP.LiquidCp(Properties.Cold.Wall.Twall,Properties.Cold.Average.P,Inlet.Cold.z);
117       
118"Cold Stream Viscosity at Wall Temperature"
119        Properties.Cold.Wall.Mu         =       PP.LiquidViscosity(Properties.Cold.Wall.Twall,Properties.Cold.Average.P,Inlet.Cold.z);
120
121"Cold Stream Conductivity at Wall Temperature"
122        Properties.Cold.Wall.K          =       PP.LiquidThermalConductivity(Properties.Cold.Wall.Twall,Properties.Cold.Average.P,Inlet.Cold.z);
123
124
125        else
126
127"Cold Stream Average Heat Capacity"
128        Properties.Cold.Average.Cp      =       PP.VapourCp(Properties.Cold.Average.T,Properties.Cold.Average.P,Inlet.Cold.z);
129
130"Cold Stream Inlet Heat Capacity"       
131        Properties.Cold.Inlet.Cp        =       PP.VapourCp(Inlet.Cold.T,Inlet.Cold.P,Inlet.Cold.z);
132
133"Cold Stream Outlet Heat Capacity"     
134        Properties.Cold.Outlet.Cp       =       PP.VapourCp(Outlet.Cold.T,Outlet.Cold.P,Outlet.Cold.z);
135
136"Cold Stream Average Mass Density"
137        Properties.Cold.Average.rho =   PP.VapourDensity(Properties.Cold.Average.T,Properties.Cold.Average.P,Inlet.Cold.z);
138
139"Cold Stream Inlet Mass Density"
140        Properties.Cold.Inlet.rho       =       PP.VapourDensity(Inlet.Cold.T,Inlet.Cold.P,Inlet.Cold.z);
141
142"Cold Stream Outlet Mass Density"       
143        Properties.Cold.Outlet.rho      =       PP.VapourDensity(Outlet.Cold.T,Outlet.Cold.P,Outlet.Cold.z);
144
145"Cold Stream Average Viscosity "
146        Properties.Cold.Average.Mu      =       PP.VapourViscosity(Properties.Cold.Average.T,Properties.Cold.Average.P,Inlet.Cold.z);
147
148"Cold Stream Inlet Viscosity " 
149        Properties.Cold.Inlet.Mu        =       PP.VapourViscosity(Inlet.Cold.T,Inlet.Cold.P,Inlet.Cold.z);
150
151"Cold Stream Outlet Viscosity "
152        Properties.Cold.Outlet.Mu       =       PP.VapourViscosity(Outlet.Cold.T,Outlet.Cold.P,Outlet.Cold.z);
153
154"Cold Stream Average Conductivity "
155        Properties.Cold.Average.K       =       PP.VapourThermalConductivity(Properties.Cold.Average.T,Properties.Cold.Average.P,Inlet.Cold.z);
156
157"Cold Stream Inlet Conductivity "
158        Properties.Cold.Inlet.K         =       PP.VapourThermalConductivity(Inlet.Cold.T,Inlet.Cold.P,Inlet.Cold.z);
159
160"Cold Stream Outlet Conductivity "
161        Properties.Cold.Outlet.K        =       PP.VapourThermalConductivity(Outlet.Cold.T,Outlet.Cold.P,Outlet.Cold.z);
162       
163"Cold Stream Heat Capacity at Wall Temperature"
164        Properties.Cold.Wall.Cp         =       PP.VapourCp(Properties.Cold.Wall.Twall,Properties.Cold.Average.P,Inlet.Cold.z);
165
166
167"Cold Stream Viscosity at Wall Temperature"
168        Properties.Cold.Wall.Mu         =       PP.VapourViscosity(Properties.Cold.Wall.Twall,Properties.Cold.Average.P,Inlet.Cold.z);
169
170"Cold Stream Conductivity at Wall Temperature"
171        Properties.Cold.Wall.K          =       PP.VapourThermalConductivity(Properties.Cold.Wall.Twall,Properties.Cold.Average.P,Inlet.Cold.z);
172       
173       
174       
175end
176
177if Inlet.Hot.v equal 0
178
179        then
180
181"Hot Stream Average Heat Capacity"
182        Properties.Hot.Average.Cp       =               PP.LiquidCp(Properties.Hot.Average.T,Properties.Hot.Average.P,Inlet.Hot.z);
183
184"Hot Stream Inlet Heat Capacity"
185        Properties.Hot.Inlet.Cp         =               PP.LiquidCp(Inlet.Hot.T,Inlet.Hot.P,Inlet.Hot.z);
186
187"Hot Stream Outlet Heat Capacity"
188        Properties.Hot.Outlet.Cp        =               PP.LiquidCp(Outlet.Hot.T,Outlet.Hot.P,Outlet.Hot.z);
189
190"Hot Stream Average Mass Density"
191        Properties.Hot.Average.rho      =               PP.LiquidDensity(Properties.Hot.Average.T,Properties.Hot.Average.P,Inlet.Hot.z);
192
193"Hot Stream Inlet Mass Density"
194        Properties.Hot.Inlet.rho        =               PP.LiquidDensity(Inlet.Hot.T,Inlet.Hot.P,Inlet.Hot.z);
195
196"Hot Stream Outlet Mass Density"       
197        Properties.Hot.Outlet.rho       =               PP.LiquidDensity(Outlet.Hot.T,Outlet.Hot.P,Outlet.Hot.z);
198
199"Hot Stream Average Viscosity"
200        Properties.Hot.Average.Mu       =               PP.LiquidViscosity(Properties.Hot.Average.T,Properties.Hot.Average.P,Inlet.Hot.z);     
201
202"Hot Stream Inlet Viscosity"
203        Properties.Hot.Inlet.Mu         =               PP.LiquidViscosity(Inlet.Hot.T,Inlet.Hot.P,Inlet.Hot.z);       
204
205"Hot Stream Outlet Viscosity"
206        Properties.Hot.Outlet.Mu        =               PP.LiquidViscosity(Outlet.Hot.T,Outlet.Hot.P,Outlet.Hot.z);     
207
208"Hot Stream Average Conductivity"
209        Properties.Hot.Average.K        =               PP.LiquidThermalConductivity(Properties.Hot.Average.T,Properties.Hot.Average.P,Inlet.Hot.z);   
210
211"Hot Stream Inlet Conductivity"
212        Properties.Hot.Inlet.K          =               PP.LiquidThermalConductivity(Inlet.Hot.T,Inlet.Hot.P,Inlet.Hot.z);     
213
214"Hot Stream Outlet Conductivity"
215        Properties.Hot.Outlet.K         =               PP.LiquidThermalConductivity(Outlet.Hot.T,Outlet.Hot.P,Outlet.Hot.z);   
216
217"Hot Stream Heat Capacity at Wall Temperature"
218        Properties.Hot.Wall.Cp          =               PP.LiquidCp(Properties.Hot.Wall.Twall,Properties.Hot.Average.P,Inlet.Hot.z);
219
220"Hot Stream Viscosity  at Wall Temperature"
221        Properties.Hot.Wall.Mu          =               PP.LiquidViscosity(Properties.Hot.Wall.Twall,Properties.Hot.Average.P,Inlet.Hot.z);     
222
223"Hot Stream Conductivity at Wall Temperature"
224        Properties.Hot.Wall.K           =               PP.LiquidThermalConductivity(Properties.Hot.Wall.Twall,Properties.Hot.Average.P,Inlet.Hot.z);   
225       
226
227        else
228
229"Hot Stream Average Heat Capacity"
230        Properties.Hot.Average.Cp       =               PP.VapourCp(Properties.Hot.Average.T,Properties.Hot.Average.P,Inlet.Hot.z);
231
232"Hot Stream Inlet Heat Capacity"
233        Properties.Hot.Inlet.Cp         =               PP.VapourCp(Inlet.Hot.T,Inlet.Hot.P,Inlet.Hot.z);
234
235"Hot Stream Outlet Heat Capacity"
236        Properties.Hot.Outlet.Cp        =               PP.VapourCp(Outlet.Hot.T,Outlet.Hot.P,Outlet.Hot.z);
237
238"Hot Stream Average Mass Density"
239        Properties.Hot.Average.rho      =               PP.VapourDensity(Properties.Hot.Average.T,Properties.Hot.Average.P,Inlet.Hot.z);
240
241"Hot Stream Inlet Mass Density"
242        Properties.Hot.Inlet.rho        =               PP.VapourDensity(Inlet.Hot.T,Inlet.Hot.P,Inlet.Hot.z);
243
244"Hot Stream Outlet Mass Density"
245        Properties.Hot.Outlet.rho       =               PP.VapourDensity(Outlet.Hot.T,Outlet.Hot.P,Outlet.Hot.z);
246
247"Hot Stream Average Viscosity"
248        Properties.Hot.Average.Mu       =               PP.VapourViscosity(Properties.Hot.Average.T,Properties.Hot.Average.P,Inlet.Hot.z);
249
250"Hot Stream Inlet Viscosity"
251        Properties.Hot.Inlet.Mu         =               PP.VapourViscosity(Inlet.Hot.T,Inlet.Hot.P,Inlet.Hot.z);
252
253"Hot Stream Outlet Viscosity"
254        Properties.Hot.Outlet.Mu        =               PP.VapourViscosity(Outlet.Hot.T,Outlet.Hot.P,Outlet.Hot.z);
255
256"Hot Stream Average Conductivity"
257        Properties.Hot.Average.K        =               PP.VapourThermalConductivity(Properties.Hot.Average.T,Properties.Hot.Average.P,Inlet.Hot.z);   
258
259"Hot Stream Inlet Conductivity"
260        Properties.Hot.Inlet.K          =               PP.VapourThermalConductivity(Inlet.Hot.T,Inlet.Hot.P,Inlet.Hot.z);     
261       
262"Hot Stream Outlet Conductivity"
263        Properties.Hot.Outlet.K         =               PP.VapourThermalConductivity(Outlet.Hot.T,Outlet.Hot.P,Outlet.Hot.z);   
264
265"Hot Stream Heat Capacity at Wall Temperature"
266        Properties.Hot.Wall.Cp          =               PP.VapourCp(Properties.Hot.Wall.Twall,Properties.Hot.Average.P,Inlet.Hot.z);
267
268"Hot Stream Viscosity at Wall Temperature"
269        Properties.Hot.Wall.Mu          =               PP.VapourViscosity(Properties.Hot.Wall.Twall,Properties.Hot.Average.P,Inlet.Hot.z);
270
271"Hot Stream Conductivity at Wall Temperature"
272        Properties.Hot.Wall.K           =               PP.VapourThermalConductivity(Properties.Hot.Wall.Twall,Properties.Hot.Average.P,Inlet.Hot.z);   
273
274
275end
276
277
278#=====================================================================
279#       Thermal Details
280#=====================================================================
281"Hot Stream Heat Capacity"
282        Details.Ch =Inlet.Hot.F*Properties.Hot.Average.Cp;
283       
284"Cold Stream Heat Capacity"
285        Details.Cc =Inlet.Cold.F*Properties.Cold.Average.Cp;
286
287"Minimum Heat Capacity"
288        Details.Cmin  = min([Details.Ch,Details.Cc]);
289
290"Maximum Heat Capacity"
291        Details.Cmax  = max([Details.Ch,Details.Cc]);
292
293"Heat Capacity Ratio"   
294        Details.Cr    = Details.Cmin/Details.Cmax;
295#=====================================================================
296#       Energy Balance
297#=====================================================================
298"Energy Balance Hot Stream"
299        Details.Q = Inlet.Hot.F*(Inlet.Hot.h-Outlet.Hot.h);
300
301"Energy Balance Cold Stream"
302        Details.Q =-Inlet.Cold.F*(Inlet.Cold.h-Outlet.Cold.h);
303
304#=====================================================================
305#       Material Balance
306#=====================================================================
307"Flow Mass Inlet Cold Stream"
308        Properties.Cold.Inlet.Fw        =  sum(M*Inlet.Cold.z)*Inlet.Cold.F;
309
310"Flow Mass Outlet Cold Stream"
311        Properties.Cold.Outlet.Fw       =  sum(M*Outlet.Cold.z)*Outlet.Cold.F;
312
313"Flow Mass Inlet Hot Stream"
314        Properties.Hot.Inlet.Fw         =  sum(M*Inlet.Hot.z)*Inlet.Hot.F;
315
316"Flow Mass Outlet Hot Stream"   
317        Properties.Hot.Outlet.Fw        =  sum(M*Outlet.Hot.z)*Outlet.Hot.F;
318
319"Molar Balance Hot Stream"
320        Inlet.Hot.F  = Outlet.Hot.F;
321       
322"Molar Balance Cold Stream"
323        Inlet.Cold.F = Outlet.Cold.F;
324
325#======================================
326#       Constraints
327#======================================
328"Hot Stream Molar Fraction Constraint"
329        Outlet.Hot.z=Inlet.Hot.z;
330       
331"Cold Stream Molar Fraction Constraint"
332        Outlet.Cold.z=Inlet.Cold.z;
333       
334#"No Phase Change In Cold Stream"
335#       Inlet.Cold.v=Outlet.Cold.v;
336
337#"No Phase Change In Hot Stream"
338#       Inlet.Hot.v=Outlet.Hot.v;
339
340#======================================
341#       Pressure Drop
342#======================================
343
344"Pressure Drop Hot Stream"
345        Outlet.Hot.P  = Inlet.Hot.P - PressureDrop.Hot.Pdrop;
346       
347"Pressure Drop Cold Stream"
348        Outlet.Cold.P  = Inlet.Cold.P - PressureDrop.Cold.Pdrop;
349       
350"Fraction of Inlet Pressure : Hot Stream"
351        PressureDrop.Hot.Pdrop  = Inlet.Hot.P*PressureDrop.Hot.FPdrop;
352       
353"Fraction of Inlet Pressure : Cold Stream"
354        PressureDrop.Cold.Pdrop  = Inlet.Cold.P*PressureDrop.Cold.FPdrop;
355       
356end
357
358Model Heatex_Basic_NTU   as HeatExchangerSimplified_Basic
359
360ATTRIBUTES
361        Pallete         = false;
362        Brief           = "Basic Model for Heat Exchangers - NTU Method";
363        Info            =
364        "write some information";
365
366VARIABLES
367
368Eft       as positive (Brief="Effectiveness",Default=0.05,Lower=1e-8, Upper=1);
369
370EQUATIONS       
371
372"Energy Balance"
373        Details.Q       = Eft*Details.Cmin*(Inlet.Hot.T-Inlet.Cold.T); 
374
375
376end
377
378Model Heatex_Basic_LMTD  as HeatExchangerSimplified_Basic
379
380ATTRIBUTES
381        Pallete         = false;
382        Brief           = "Basic Model for Heat Exchangers - LMTD Method";
383        Info            =
384        "write some information";
385
386VARIABLES
387
388DT0             as temp_delta   (Brief="Temperature Difference at Inlet",Lower=1);
389DTL             as temp_delta   (Brief="Temperature Difference at Outlet",Lower=1);
390LMTD            as temp_delta   (Brief="Logarithmic Mean Temperature Difference",Lower=1);
391Fc                      as positive             (Brief="LMTD Correction Factor",Lower=0.5);
392MTD             as temp_delta   (Brief="Mean Temperature Difference",Lower=1);
393
394EQUATIONS
395#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++#
396#                       Log Mean Temperature Difference
397#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++#
398if abs(DT0 - DTL) > 0.05*max(abs([DT0,DTL]))
399       
400        then
401"Log Mean Temperature Difference"
402        LMTD= (DT0-DTL)/ln(DT0/DTL);
403
404        else
405       
406if DT0*DTL equal 0
407       
408        then
409"Log Mean Temperature Difference"
410        LMTD = 0.5*(DT0+DTL);
411       
412        else
413"Log Mean Temperature Difference"
414        LMTD = 0.5*(DT0+DTL)*(1-(DT0-DTL)^2/(DT0*DTL)*(1+(DT0-DTL)^2/(DT0*DTL)/2)/12);
415       
416end
417       
418end
419
420"Exchange Surface Area"
421        Details.Q = Details.Ud*Details.A*MTD;   
422       
423"Mean Temperature Difference"   
424        MTD   = Fc*LMTD;
425
426end
427
428
429#=====================================================================
430#       Concrete Models for Simplified Heat Exchangers
431#=====================================================================
432
433#=====================================================================
434# LMTD Method
435#=====================================================================
436
437Model HeatExchanger_LMTD        as Heatex_Basic_LMTD
438
439ATTRIBUTES
440        Pallete         = true;
441        Brief           = "Heat Exchanger Block - LMTD Method";
442        Info            =
443        "write some information";
444       
445PARAMETERS
446
447        FlowDirection as Switcher(Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent");
448
449EQUATIONS
450
451switch FlowDirection
452       
453        case "cocurrent":
454
455"Temperature Difference at Inlet"
456        DT0 = Inlet.Hot.T - Inlet.Cold.T;
457
458"Temperature Difference at Outlet"
459        DTL = Outlet.Hot.T - Outlet.Cold.T;
460
461case "counter":
462       
463"Temperature Difference at Inlet"
464        DT0 = Inlet.Hot.T - Outlet.Cold.T;
465
466"Temperature Difference at Outlet"
467        DTL = Outlet.Hot.T - Inlet.Cold.T;
468end
469
470end
471
472Model E_Shell_LMTD                      as Heatex_Basic_LMTD       
473
474ATTRIBUTES
475        Pallete         = true;
476        Brief           = "Shell and Tubes Heat Exchanger with 1 shell pass - LMTD Method";
477        Info            =
478        "write some information";
479       
480EQUATIONS
481"Temperature Difference at Inlet"
482        DT0 = Inlet.Hot.T - Outlet.Cold.T;
483
484"Temperature Difference at Outlet"
485        DTL = Outlet.Hot.T - Inlet.Cold.T;
486       
487"LMTD Correction Factor"
488        Fc = HE.EshellCorrectionFactor(Inlet.Hot.T,Outlet.Hot.T,Inlet.Cold.T,Outlet.Cold.T);
489
490end
491
492Model F_Shell_LMTD              as Heatex_Basic_LMTD
493       
494ATTRIBUTES
495        Pallete         = true;
496        Brief           = "Shell and Tubes Heat Exchanger with 2 shell pass - LMTD Method";
497        Info            =
498        "write some information";
499       
500EQUATIONS
501"Temperature Difference at Inlet"
502        DT0 = Inlet.Hot.T - Outlet.Cold.T;
503
504"Temperature Difference at Outlet"
505        DTL = Outlet.Hot.T - Inlet.Cold.T;
506       
507"LMTD Correction Factor"
508        Fc = HE.FshellCorrectionFactor(Inlet.Hot.T,Outlet.Hot.T,Inlet.Cold.T,Outlet.Cold.T);
509
510end
511
512#=====================================================================
513# NTU Method
514#=====================================================================
515
516Model HeatExchanger_NTU         as Heatex_Basic_NTU
517
518ATTRIBUTES
519        Pallete         = true;
520        Brief           = "Heat Exchanger Block - NTU Method";
521        Info            =
522        "write some information";
523       
524PARAMETERS
525
526        FlowDirection as Switcher(Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent");
527
528EQUATIONS
529
530if Details.Cr equal 0
531       
532        then
533       
534        Eft = 1-exp(-Details.NTU);
535       
536        else
537
538switch  FlowDirection
539
540        case "cocurrent":
541       
542"Effectiveness in Cocurrent Flow"
543        Eft = (1-exp(-Details.NTU*(1+Details.Cr)))/(1+Details.Cr);
544
545        case "counter":
546
547if Details.Cr equal 1
548       
549        then
550"Effectiveness in Counter Flow"
551        Eft = Details.NTU/(1+Details.NTU);
552       
553        else
554"Effectiveness in Counter Flow"
555        Eft*(1-Details.Cr*exp(-Details.NTU*(1-Details.Cr))) = (1-exp(-Details.NTU*(1-Details.Cr)));
556       
557end
558
559end
560
561
562end
563
564end
565
566Model E_Shell_NTU                       as Heatex_Basic_NTU
567       
568ATTRIBUTES
569        Pallete         = true;
570        Brief           = "Shell and Tubes Heat Exchanger with 1 shell pass - NTU Method";
571        Info            =
572        "write some information";
573
574EQUATIONS
575"TEMA E Shell Effectiveness"
576        Eft = 2*(1+Details.Cr+sqrt(1+Details.Cr^2)*((1+exp(-Details.NTU*sqrt(1+Details.Cr^2)))/(1-exp(-Details.NTU*sqrt(1+Details.Cr^2)))) )^-1;
577
578end
579
580Model F_Shell_NTU               as Heatex_Basic_NTU
581
582ATTRIBUTES
583        Pallete         = true;
584        Brief           = "Shell and Tubes Heat Exchanger with 2 shell pass - NTU Method";
585        Info            =
586        "write some information";
587       
588VARIABLES
589
590Eft1    as positive (Brief="Effectiveness Correction",Lower=0.01,Upper=1,Default=0.5);
591
592EQUATIONS
593
594"Effectiveness Correction"
595        Eft1 = 2*(1+Details.Cr+sqrt(1+Details.Cr^2)*((1+exp(-Details.NTU*sqrt(1+Details.Cr^2)))/(1-exp(-Details.NTU*sqrt(1+Details.Cr^2)))) )^-1;
596
597"TEMA F Shell Effectiveness"
598        Eft = ( ((1-Eft1*Details.Cr)/(1-Eft1))^2 -1  )*( ((1-Eft1*Details.Cr)/(1-Eft1))^2 - Details.Cr )^-1;
599
600end
Note: See TracBrowser for help on using the repository browser.