source: trunk/eml/heat_exchangers/HeatExchangerDetailed.mso @ 990

Last change on this file since 990 was 737, checked in by gerson bicca, 14 years ago

added sample STHE (shell and Tube Heat Exchanger)

File size: 43.4 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* Author: Gerson Balbueno Bicca
16* $Id: HeatExchangerDetailed.mso 197 2007-03-08 14:31:57Z bicca $
17*------------------------------------------------------------------*#
18using "heat_exchangers/HEX_Engine";
19
20Model ShellandTubesBasic
21
22ATTRIBUTES
23        Pallete = false;
24        Brief  = "Basic Model for Detailed Shell and Tube Heat Exchanger.";
25        Info  =
26"to be documented.
27       
28== Assumptions ==
29* to be documented
30
31== Specify ==
32* to be documented
33
34== Setting Parameters ==
35* to be documented
36
37== References ==
38[1] E.A.D. Saunders, Heat Exchangers: Selection, Design and
39 Construction, Longman, Harlow, 1988.
40
41[2] Taborek, J., Shell-and-tube heat exchangers, in Heat Exchanger Design Handbook, Vol. 3
42 Hemisphere Publishing Corp., New York, 1988.
43
44[3] Bell, K. J., Mueller, A. C., Wolverine Engineering Data Book II. Wolverine Tube, Inc., <www.wlv.com>, 2001.
45
46[4] Fakheri, A. , Alternative approach for determining log mean temperature difference correction factor
47 and number of shells of shell and tube heat exchangers, Journal of Enhanced Heat Transfer, v. 10, p. 407- 420, 2003.
48
49[5] Gnielinski, V., Forced convection in ducts, in Heat Exchanger Design Handbook, Vol. 2
50 Hemisphere Publishing Corp., New York, 1988.";
51
52PARAMETERS
53
54HotSide                 as Switcher     (Brief="Hot Side in the Exchanger",Hidden=true, Valid=["shell","tubes"],Default="shell");
55ShellType       as Switcher     (Brief="TEMA Designation",Valid=["Eshell","Fshell"],Default="Eshell");
56Pattern         as Switcher     (Brief="Tube Layout Characteristic Angle",Valid=["Triangle","Rotated Square","Square"],Default="Triangle");
57
58VARIABLES
59
60        Tubes                   as Tube_Side_Main               (Brief="Tube Side Section" , Symbol="^{tube}");
61        Shell                   as Shell_Side_Main      (Brief="Shell Side Section" , Symbol="^{shell}");       
62        Baffles                 as Baffles_Main                         (Brief="Baffle Section", Symbol=" ");
63        Clearances      as Clearances_Main      (Brief="Diametral Clearances", Symbol=" ");
64       
65in  InletTube           as stream                                       (Brief="Inlet Tube Stream", PosX=0.13, PosY=0, Symbol="_{in }^{tube}");
66out OutletTube  as streamPH                             (Brief="Outlet Tube Stream", PosX=0.13, PosY=1, Symbol="_{out }^{tube}");
67in  InletShell          as stream                                       (Brief="Inlet Shell Stream", PosX=0.31, PosY=1, Symbol="_{in }^{shell}");
68out OutletShell as streamPH                             (Brief="Outlet Shell Stream", PosX=0.81, PosY=0, Symbol="_{out }^{shell}");
69        Details                         as Details_Main                         (Brief="Details in Heat Exchanger", Symbol = " ");
70       
71#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++#
72#                               Auxiliar Variables - Must be hidden                                             
73#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++#
74        Nc              as Real                                 (Brief = "Number of Tube rows Crossed in one Crossflow Section", Hidden = true, Lower=1);
75        Ncw     as Real                                 (Brief = "Number of Effective Crossflow rows in Each Window", Hidden = true, Lower=1);
76        a                       as Real                                 (Brief = "Variable for calculating Ji heat transfer correction Factor", Hidden = true, Lower=1e-3);
77        b                       as Real                                 (Brief = "Variable for calculating shell side pressure drop friction Factor", Hidden = true, Lower=1e-3);
78        Rb              as Real                                 (Brief = "ByPass Correction Factor for Pressure Drop", Hidden = true, Lower=1e-3);
79        Rss             as Real                                 (Brief = "Correction Factor for Pressure Drop", Hidden = true, Lower=1e-3);
80        Rspd    as Real                                 (Brief = "Pressure Drop Correction Factor for Unequal Baffle Spacing", Hidden = true, Lower=1e-3);
81        mw              as Real                                 (Brief = "Mass Velocity in Window Zone", Hidden = true, Unit='kg/m^2/s');
82        Ji                      as constant                     (Brief="Shell Side Ji Factor", Symbol ="J_i", Hidden = true, Default=0.05);
83        Jr                      as positive                     (Brief="Shell Side Jr Factor",  Symbol ="J_r", Hidden = true, Lower=10e-6);
84        Jl                      as positive                     (Brief="Shell Side Jl Factor",  Symbol ="J_l", Hidden = true, Lower=10e-6);
85        Jb                      as positive                     (Brief="Shell Side Jb Factor", Symbol ="J_b", Hidden = true, Lower=10e-6);
86        Jc                      as positive                     (Brief="Shell Side Jc Factor", Symbol ="J_c", Hidden = true, Lower=10e-6);
87        Js                      as positive                     (Brief="Shell Side Js Factor", Symbol ="J_s", Hidden = true, Lower=10e-6);
88        Jtotal  as positive                     (Brief="Shell Side Jtotal Factor", Symbol ="J_{total}", Hidden = true, Lower=10e-6);
89        Sm              as area                                 (Brief="Shell Side Cross Flow Area", Symbol ="S_m", Hidden = true, Default=0.05,Lower=10e-6);
90
91PARAMETERS
92outer PP                        as Plugin               (Brief="External Physical Properties",Type = "PP");
93outer NComp     as Integer      (Brief="Number of Components");
94       
95M(NComp)        as molweight (Brief="Component Mol Weight");
96
97TubeFlowRegime           as Switcher            (Brief="Tube Side Flow Regime ",Hidden=true,Valid=["laminar","transition","turbulent"],Default="laminar");
98ShellFlowRegime                 as Switcher             (Brief="Shell Side Flow Regime ",Hidden=true,Valid=["deep laminar","laminar","turbulent"],Default="deep laminar");
99ShellRange                              as Switcher             (Brief="Shell Side Flow Regime Range for Correction Factor",Hidden=true,Valid=["range1","range2","range3", "range4","range5"],Default="range1");
100Side                                                            as Switcher             (Brief="Flag for Fluid Alocation ",Hidden=true,Valid=["shell","tubes"],Default="shell");
101LaminarCorrelation      as Switcher             (Brief="Tube Heat Transfer Correlation in Laminar Flow",Valid=["Hausen","Schlunder"],Default="Hausen");
102TransitionCorrelation   as Switcher             (Brief="Tube Heat Transfer Correlation in Transition Flow",Valid=["Gnielinski","ESDU"],Default="Gnielinski");
103TurbulentCorrelation    as Switcher             (Brief="Tube Heat Transfer Correlation in Turbulent Flow",Valid=["Petukhov","SiederTate"],Default="Petukhov");
104
105#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++#
106#                               Auxiliar Parameters     - Must be hidden                                                       
107#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++#
108Pi                                                      as constant   (Brief="Pi Number", Hidden = true, Default=3.14159265, Symbol = "\pi");
109Aonozzle_Shell          as area                 (Brief="Shell Outlet Nozzle Area", Hidden = true, Lower=1E-6 ,  Symbol ="A_{nozzle\_out }^{shell}");
110Ainozzle_Shell          as area                 (Brief="Shell Inlet Nozzle Area", Hidden = true, Lower=1E-6 ,  Symbol ="A_{nozzle\_in }^{shell}");
111Aeonozzle_Shell         as area                 (Brief="Shell Outlet Escape Area Under Nozzle", Hidden = true, Lower=1E-6 ,  Symbol ="Aescape_{nozzle\_out }^{shell}");
112Aeinozzle_Shell         as area                 (Brief="Shell Inlet Escape Area Under Nozzle",Hidden = true, Lower=1E-6 ,  Symbol ="Aescape_{nozzle\_in }^{shell}");
113Aonozzle_Tube   as area                 (Brief="Tube Outlet Nozzle Area", Hidden = true, Lower=1E-6 ,  Symbol ="A_{nozzle\_out }^{tube}");
114Ainozzle_Tube           as area                 (Brief="Tube Inlet Nozzle Area", Hidden = true, Lower=1E-6 ,  Symbol ="A_{nozzle\_in }^{tube}");
115Kinlet_Tube             as positive     (Brief="Tube Inlet Nozzle Pressure Loss Coeff", Hidden = true, Default=1.1, Symbol ="K_{in }^{tube}");
116Koutlet_Tube            as positive     (Brief="Tube Outlet Nozzle Pressure Loss Coeff",Hidden = true, Default=0.7, Symbol ="K_{out }^{tube}");
117Ods                                             as Real                 (Brief="Baffle cut angle in degrees", Symbol = "\theta _{ds}", Hidden = true);
118Octl                                    as Real                 (Brief="Baffle cut angle relative to the centerline in degrees", Symbol = "\theta _{ctl}", Hidden = true);
119Ftw                                             as Real                 (Brief="Fraction of number of tubes in baffle window", Symbol = "F _{tw}", Hidden = true);
120Scd                                             as area                 (Brief="Shell to baffle leakage area", Symbol = "S _{cd}", Hidden = true);
121Std                                             as area                 (Brief="Tube to baffle hole leakage area", Symbol = "S _{td}", Hidden = true);
122Rs                                              as Real                 (Brief="Ratio of the shell to baffle leakage area", Symbol = "R_s", Hidden = true);
123Dw                                      as length               (Brief="Hydraulic diameter of the baffle window", Symbol = "D _w", Hidden = true);
124
125SET
126
127#"Molecular weight"
128        M       = PP.MolecularWeight();
129       
130#"Pi Number"
131        Pi      = 3.14159265;
132
133#"Baffle cut angle in degrees"
134        Ods     = (360/Pi)*acos(1-0.02*Baffles.BaffleCut);
135
136#"Baffle cut angle relative to the centerline"
137        Octl    = (360/Pi)*acos((Shell.ShellID/(Shell.ShellID - Clearances.BundleToShell - Tubes.TubeOD))*(1-0.02*Baffles.BaffleCut));
138
139#"Fraction of number of tubes in baffle window"
140        Ftw     = (Octl/360)-sin(Octl*Pi/180)/(2*Pi);
141
142#"Shell to baffle leakage area"
143        Scd     = Pi*Shell.ShellID*Clearances.BaffleToShell *((360-Ods)/720);
144
145#"Tube to baffle hole leakage area"
146        Std     = Pi*0.25*((Clearances.TubeToBaffle + Tubes.TubeOD)^2-Tubes.TubeOD*Tubes.TubeOD)*Tubes.NumberOfTubes*(1-Ftw);
147
148#"comments"
149        Rs              = Scd/(Scd+Std);
150
151#"comments"
152        Dw      = (4*abs((Pi*Shell.ShellID*Shell.ShellID*((Ods/360)-sin(Ods*Pi/180)/(2*Pi))/4)-(Tubes.NumberOfTubes*Pi*Tubes.TubeOD*Tubes.TubeOD*Ftw/4)))/(Pi*Tubes.TubeOD*Tubes.NumberOfTubes*Ftw+ Pi*Shell.ShellID*Ods/360);
153
154#"Tube Side Inlet Nozzle Area"
155        Ainozzle_Tube = 0.25*Pi*Tubes.InletNozzleID^2;
156
157#"Tube Side Outlet Nozzle Area"
158        Aonozzle_Tube = 0.25*Pi*Tubes.OutletNozzleID^2;
159
160#"Tube Inlet Nozzle Pressure Loss Coeff"
161        Kinlet_Tube   = 1.1;
162
163#"Tube Outlet Nozzle Pressure Loss Coeff"
164        Koutlet_Tube  = 0.7;
165
166#"Shell Outlet Nozzle Area"
167        Aonozzle_Shell  = 0.25*Pi*Shell.OutletNozzleID^2;
168
169#"Shell Inlet Nozzle Area"
170        Ainozzle_Shell  = 0.25*Pi*Shell.InletNozzleID^2;
171
172#"Shell Outlet Escape Area Under Nozzle"
173        Aeonozzle_Shell = Pi*Shell.OutletNozzleID*Clearances.Honozzle_Shell + 0.6*Aonozzle_Shell*(1-(Tubes.TubeOD/Tubes.TubePitch));
174
175#"Shell Inlet Escape Area Under Nozzle"
176        Aeinozzle_Shell = Pi*Shell.InletNozzleID*Clearances.Hinozzle_Shell + 0.6*Ainozzle_Shell*(1-(Tubes.TubeOD/Tubes.TubePitch));
177
178EQUATIONS
179
180"Shell Stream Average Temperature"
181        Shell.Properties.Average.T = 0.5*InletShell.T + 0.5*OutletShell.T;
182       
183"Tube Stream Average Temperature"
184        Tubes.Properties.Average.T = 0.5*InletTube.T + 0.5*OutletTube.T;
185       
186"Shell Stream Average Pressure"
187        Shell.Properties.Average.P = 0.5*InletShell.P+0.5*OutletShell.P;
188       
189"Tube Stream Average Pressure"
190        Tubes.Properties.Average.P = 0.5*InletTube.P+0.5*OutletTube.P;
191       
192"Shell Stream Average Molecular Weight"
193        Shell.Properties.Average.Mw = sum(M*InletShell.z);
194
195"Tube Stream Average Molecular Weight"
196        Tubes.Properties.Average.Mw = sum(M*OutletTube.z);
197       
198if InletTube.v equal 0
199       
200        then   
201       
202"Tube Stream Average Heat Capacity"
203        Tubes.Properties.Average.Cp     =       PP.LiquidCp(Tubes.Properties.Average.T,Tubes.Properties.Average.P,OutletTube.z);
204
205"Tube Stream Average Mass Density"
206        Tubes.Properties.Average.rho =  PP.LiquidDensity(Tubes.Properties.Average.T,Tubes.Properties.Average.P,OutletTube.z);
207
208"Tube Stream Inlet Mass Density"
209        Tubes.Properties.Inlet.rho      =       PP.LiquidDensity(OutletTube.T,OutletTube.P,OutletTube.z);
210
211"Tube Stream Outlet Mass Density"
212        Tubes.Properties.Outlet.rho     =       PP.LiquidDensity(OutletTube.T,OutletTube.P,OutletTube.z);
213
214"TubeStream Average Viscosity"
215        Tubes.Properties.Average.Mu     =       PP.LiquidViscosity(Tubes.Properties.Average.T,Tubes.Properties.Average.P,OutletTube.z);
216
217"Tube Stream Average Conductivity"
218        Tubes.Properties.Average.K      =       PP.LiquidThermalConductivity(Tubes.Properties.Average.T,Tubes.Properties.Average.P,OutletTube.z);
219
220"Tube Stream Viscosity at Wall Temperature"
221        Tubes.Properties.Wall.Mu        =       PP.LiquidViscosity(Tubes.Properties.Wall.Twall,Tubes.Properties.Average.P,OutletTube.z);
222
223        else
224
225"Tube Stream Average Heat Capacity"
226        Tubes.Properties.Average.Cp     =       PP.VapourCp(Tubes.Properties.Average.T,Tubes.Properties.Average.P,OutletTube.z);
227
228"Tube Stream Average Mass Density"
229        Tubes.Properties.Average.rho =  PP.VapourDensity(Tubes.Properties.Average.T,Tubes.Properties.Average.P,OutletTube.z);
230
231"Tube Stream Inlet Mass Density"
232        Tubes.Properties.Inlet.rho      =       PP.VapourDensity(OutletTube.T,OutletTube.P,OutletTube.z);
233
234"Tube Stream Outlet Mass Density"       
235        Tubes.Properties.Outlet.rho     =       PP.VapourDensity(OutletTube.T,OutletTube.P,OutletTube.z);
236
237"Tube Stream Average Viscosity "
238        Tubes.Properties.Average.Mu     =       PP.VapourViscosity(Tubes.Properties.Average.T,Tubes.Properties.Average.P,OutletTube.z);
239
240"Tube Stream Average Conductivity "
241        Tubes.Properties.Average.K      =       PP.VapourThermalConductivity(Tubes.Properties.Average.T,Tubes.Properties.Average.P,OutletTube.z);
242
243"Tube Stream Viscosity at Wall Temperature"
244        Tubes.Properties.Wall.Mu        =       PP.VapourViscosity(Tubes.Properties.Wall.Twall,Tubes.Properties.Average.P,OutletTube.z);
245
246end
247
248if InletShell.v equal 0
249
250        then
251
252"Shell Stream Average Heat Capacity"
253        Shell.Properties.Average.Cp     =               PP.LiquidCp(Shell.Properties.Average.T,Shell.Properties.Average.P,InletShell.z);
254
255"Shell Stream Average Mass Density"
256        Shell.Properties.Average.rho    =               PP.LiquidDensity(Shell.Properties.Average.T,Shell.Properties.Average.P,InletShell.z);
257
258"ShellStream Inlet Mass Density"       
259        Shell.Properties.Inlet.rho      =               PP.LiquidDensity(InletShell.T,InletShell.P,InletShell.z);
260
261"Shell Stream Outlet Mass Density"     
262        Shell.Properties.Outlet.rho     =               PP.LiquidDensity(OutletShell.T,OutletShell.P,OutletShell.z);
263
264"Shell Stream Average Viscosity"
265        Shell.Properties.Average.Mu     =               PP.LiquidViscosity(Shell.Properties.Average.T,Shell.Properties.Average.P,InletShell.z);
266
267"Shell Stream Average Conductivity"
268        Shell.Properties.Average.K      =               PP.LiquidThermalConductivity(Shell.Properties.Average.T,Shell.Properties.Average.P,InletShell.z);       
269
270"ShellStream Viscosity  at Wall Temperature"
271        Shell.Properties.Wall.Mu                =               PP.LiquidViscosity(Shell.Properties.Wall.Twall,Shell.Properties.Average.P,InletShell.z);       
272
273
274        else
275
276"Shell Stream Average Heat Capacity"
277        Shell.Properties.Average.Cp     =               PP.VapourCp(Shell.Properties.Average.T,Shell.Properties.Average.P,InletShell.z);
278
279"Shell Stream Average Mass Density"
280        Shell.Properties.Average.rho    =               PP.VapourDensity(Shell.Properties.Average.T,Shell.Properties.Average.P,InletShell.z);
281
282"Shell Stream Inlet Mass Density"       
283        Shell.Properties.Inlet.rho      =               PP.VapourDensity(InletShell.T,InletShell.P,InletShell.z);
284
285"Shell Stream Outlet Mass Density"
286        Shell.Properties.Outlet.rho     =               PP.VapourDensity(OutletShell.T,OutletShell.P,OutletShell.z);
287
288"Shell Stream Average Viscosity"
289        Shell.Properties.Average.Mu     =               PP.VapourViscosity(Shell.Properties.Average.T,Shell.Properties.Average.P,InletShell.z);
290
291"Shell Stream Average Conductivity"
292        Shell.Properties.Average.K      =               PP.VapourThermalConductivity(Shell.Properties.Average.T,Shell.Properties.Average.P,InletShell.z);       
293
294"Shell Stream Viscosity at Wall Temperature"
295        Shell.Properties.Wall.Mu                =               PP.VapourViscosity(Shell.Properties.Wall.Twall,Shell.Properties.Average.P,InletShell.z);
296
297end
298
299switch Side
300       
301        case "shell":
302       
303"Energy Balance Hot Stream"
304        Details.Q = InletShell.F*(InletShell.h-OutletShell.h);
305
306"Energy Balance Cold Stream"
307        Details.Q =-InletTube.F*(InletTube.h-OutletTube.h);
308
309        when InletTube.T > InletShell.T switchto "tubes";
310
311        case "tubes":
312       
313"Energy Balance Hot Stream"
314        Details.Q = InletTube.F*(InletTube.h-OutletTube.h);
315
316"Energy Balance Cold Stream"
317        Details.Q =-InletShell.F*(InletShell.h-OutletShell.h);
318       
319        when InletTube.T < InletShell.T switchto "shell";
320       
321end
322
323"Flow Mass Inlet Tube Stream"
324        Tubes.Properties.Inlet.Fw               =  sum(M*InletTube.z)*InletTube.F;
325
326"Flow Mass Outlet Tube Stream"
327        Tubes.Properties.Outlet.Fw      =  sum(M*OutletTube.z)*OutletTube.F;
328
329"Flow Mass Inlet Shell Stream"
330        Shell.Properties.Inlet.Fw               =  sum(M*InletShell.z)*InletShell.F;
331
332"Flow Mass Outlet Shell Stream"
333        Shell.Properties.Outlet.Fw              =  sum(M*OutletShell.z)*OutletShell.F;
334
335"Molar Balance Shell Stream"
336        OutletShell.F  = InletShell.F;
337       
338"Molar Balance Tube Stream"
339        OutletTube.F = InletTube.F;
340
341"Shell  Stream Molar Fraction Constraint"
342        OutletShell.z=InletShell.z;
343       
344"Tube Stream Molar Fraction Constraint"
345        OutletTube.z=InletTube.z;
346       
347"Jc Factor"
348        Jc = 0.55+0.72*(1-2*Ftw);
349
350"Jl Factor"
351        Jl = 0.44*(1-Rs)+(1-0.44*(1-Rs))*exp(-2.2*(Scd + Std)/Sm);
352
353"Total J Factor"
354        Jtotal = Jc*Jl*Jb*Jr*Js;
355
356"Mass Velocity in Window Zone"
357        mw      = Shell.Properties.Inlet.Fw/sqrt(abs(Sm*abs((Pi*Shell.ShellID*Shell.ShellID*((Ods/360)-sin(Ods*Pi/180)/(2*Pi))/4)-(Tubes.NumberOfTubes*Pi*Tubes.TubeOD*Tubes.TubeOD*Ftw/4))));
358
359switch TubeFlowRegime
360       
361        case "laminar":
362       
363"Friction Factor for heat Transfer: Not Necessary in Laminar Correlation - Use any one equation that you want"
364        Tubes.HeatTransfer.fi   = 16/Tubes.HeatTransfer.Re;
365       
366"Friction Factor for Pressure Drop in Laminar Flow"
367        Tubes.PressureDrop.FricFactor  = 16/Tubes.HeatTransfer.Re;
368       
369switch LaminarCorrelation
370       
371        case "Hausen":
372
373"Nusselt Number in Laminar Flow - Hausen Equation"
374        Tubes.HeatTransfer.Nu = 3.665 + ((0.19*((Tubes.TubeID/Tubes.TubeLength)*Tubes.HeatTransfer.Re*Tubes.HeatTransfer.PR)^0.8)/(1+0.117*((Tubes.TubeID/Tubes.TubeLength)*Tubes.HeatTransfer.Re*Tubes.HeatTransfer.PR)^0.467));
375       
376        case "Schlunder":
377       
378"Nusselt Number in Laminar Flow - Schlunder Equation"
379        Tubes.HeatTransfer.Nu = (49.027896+4.173281*Tubes.HeatTransfer.Re*Tubes.HeatTransfer.PR*(Tubes.TubeID/Tubes.TubeLength))^(1/3);
380
381end
382       
383        when Tubes.HeatTransfer.Re > 2300 switchto "transition";
384       
385        case "transition":
386       
387"Friction Factor for heat Transfer : for use in Gnielinski Equation"
388        Tubes.HeatTransfer.fi   = 1/(0.79*ln(Tubes.HeatTransfer.Re)-1.64)^2;
389       
390"Friction Factor for Pressure Drop in Transition Flow"
391        Tubes.PressureDrop.FricFactor  = 0.0122;
392       
393switch TransitionCorrelation
394       
395        case "Gnielinski":
396       
397"Nusselt Number in Transition Flow - Gnielinski Equation"
398        Tubes.HeatTransfer.Nu*(1+(12.7*sqrt(0.125*Tubes.HeatTransfer.fi)*((Tubes.HeatTransfer.PR)^(2/3) -1))) = 0.125*Tubes.HeatTransfer.fi*(Tubes.HeatTransfer.Re-1000)*Tubes.HeatTransfer.PR;
399
400        case "ESDU":
401       
402"Nusselt Number in Transition Flow - ESDU Equation"
403        Tubes.HeatTransfer.Nu =1;#to be implemented
404       
405end
406
407        when Tubes.HeatTransfer.Re < 2300 switchto "laminar";
408        when Tubes.HeatTransfer.Re > 10000 switchto "turbulent";
409
410        case "turbulent":
411
412"Friction Factor for heat Transfer : for use in Petukhov Equation"
413        Tubes.HeatTransfer.fi   = 1/(1.82*log(Tubes.HeatTransfer.Re)-1.64)^2;
414
415"Friction Factor for Pressure Drop in Turbulent Flow"
416        Tubes.PressureDrop.FricFactor  = 0.0035 + 0.264*Tubes.HeatTransfer.Re^(-0.42);
417
418switch TurbulentCorrelation
419       
420        case "Petukhov":
421       
422"Nusselt Number in Turbulent Flow - Petukhov Equation"
423        Tubes.HeatTransfer.Nu*(1.07+(12.7*sqrt(0.125*Tubes.HeatTransfer.fi)*((Tubes.HeatTransfer.PR)^(2/3) -1))) = 0.125*Tubes.HeatTransfer.fi*Tubes.HeatTransfer.Re*Tubes.HeatTransfer.PR;
424       
425        case "SiederTate":
426
427"Nusselt Number in Transition Flow - Sieder Tate Equation"
428        Tubes.HeatTransfer.Nu = 0.027*(Tubes.HeatTransfer.PR)^(1/3)*(Tubes.HeatTransfer.Re)^(4/5);
429
430end
431       
432        when Tubes.HeatTransfer.Re < 10000 switchto "transition";
433
434end
435
436switch Pattern
437       
438case "Triangle":
439
440"Shell Side Cross Flow Area"
441        Sm= Baffles.Central_Spacing*(Clearances.BundleToShell+((Shell.ShellID-Clearances.BundleToShell-Tubes.TubeOD)/Tubes.TubePitch)*(Tubes.TubePitch-Tubes.TubeOD));
442
443"Number of Tube rows Crossed in one Crossflow Section"
444        Nc      = Shell.ShellID*(1-0.02*Baffles.BaffleCut)/(0.866*Tubes.TubePitch);
445
446"Number of Effective Crossflow rows in Each Window"
447        Ncw = 0.8*(Shell.ShellID*0.01*Baffles.BaffleCut-(Clearances.BundleToShell + Tubes.TubeOD)*0.5)/(0.866*Tubes.TubePitch);
448
449"Variable for calculating Ji heat transfer correction Factor"
450        a       =       1.45/(1+0.14*Shell.HeatTransfer.Re^0.519);
451       
452"Variable for calculating Shell Side Pressure Drop Friction Factor"
453        b=7/(1+0.14*Shell.HeatTransfer.Re^0.5);
454
455"Correction Factor for Pressure Drop"
456        Rss     = Clearances.SealStrip/(Shell.ShellID*(1-0.02*Baffles.BaffleCut)/(0.866*Tubes.TubePitch)) ;
457       
458"Ideal Shell Side Pressure Drop"
459        Shell.PressureDrop.Ideal= 2*Shell.PressureDrop.FricFactor*(Shell.ShellID*(1-0.02*Baffles.BaffleCut)/(0.866*Tubes.TubePitch))*(Shell.Properties.Inlet.Fw/Sm)^2/(Shell.Properties.Average.rho*Shell.HeatTransfer.Phi);
460
461"Shell Pressure End Zones"
462        Shell.PressureDrop.EndZones = Shell.PressureDrop.Ideal*(1+ (Ncw/(Shell.ShellID*(1-0.02*Baffles.BaffleCut)/(0.866*Tubes.TubePitch))))*Rb*Rspd;
463
464switch ShellRange
465       
466        case "range1":
467       
468"Ji Factor"
469        Ji =1.40*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^0.667;
470       
471"Shell Side Pressure Drop Friction Factor"
472        Shell.PressureDrop.FricFactor=48*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-1);
473       
474        when Shell.HeatTransfer.Re > 10 switchto "range2";
475       
476        case "range2":
477       
478"Ji Factor"
479        Ji =1.36*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.657);
480       
481"Shell Side Pressure Drop Friction Factor"
482        Shell.PressureDrop.FricFactor=45.10*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.973);
483       
484        when Shell.HeatTransfer.Re > 100 switchto "range3";
485       
486        case "range3":
487
488"Ji Factor"
489        Ji =0.593*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.477);
490       
491"Shell Side Pressure Drop Friction Factor"
492        Shell.PressureDrop.FricFactor=4.570*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.476);
493       
494        when Shell.HeatTransfer.Re > 1000 switchto "range4";
495       
496        case "range4":
497
498"Ji Factor"
499        Ji =0.321*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.388);
500       
501"Shell Side Pressure Drop Friction Factor"
502        Shell.PressureDrop.FricFactor=0.486*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.152);
503
504        when Shell.HeatTransfer.Re > 10000 switchto "range5";
505
506        case "range5":
507
508"Ji Factor"
509        Ji =0.321*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.388);
510
511"Shell Side Pressure Drop Friction Factor"
512        Shell.PressureDrop.FricFactor=0.372*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.123);
513       
514        when Shell.HeatTransfer.Re < 10000 switchto "range4";
515       
516end
517
518case "Rotated Square":
519
520"Shell Side Cross Flow Area"
521        Sm= Baffles.Central_Spacing*(Clearances.BundleToShell+((Shell.ShellID-Clearances.BundleToShell-Tubes.TubeOD)/(0.707*Tubes.TubePitch))*(Tubes.TubePitch-Tubes.TubeOD));
522
523"Number of Tube rows Crossed in one Crossflow Section"
524        Nc      = Shell.ShellID*(1-0.02*Baffles.BaffleCut)/(0.707*Tubes.TubePitch);
525
526"Number of Effective Crossflow rows in Each Window"
527        Ncw = 0.8*(Shell.ShellID*0.01*Baffles.BaffleCut-(Clearances.BundleToShell + Tubes.TubeOD)*0.5)/(0.707*Tubes.TubePitch);
528
529"Variable for calculating Ji heat transfer correction Factor"
530        a       =       1.930/(1+0.14*Shell.HeatTransfer.Re^0.500);
531
532"Variable for calculating Shell Side Pressure Drop Friction Factor"
533        b=6.59/(1+0.14*Shell.HeatTransfer.Re^0.52);
534
535"Correction Factor for Pressure Drop"
536        Rss     = Clearances.SealStrip/(Shell.ShellID*(1-0.02*Baffles.BaffleCut)/(0.707*Tubes.TubePitch)) ;
537
538"Ideal Shell Side Pressure Drop"
539        Shell.PressureDrop.Ideal= 2*Shell.PressureDrop.FricFactor*(Shell.ShellID*(1-0.02*Baffles.BaffleCut)/(0.707*Tubes.TubePitch))*(Shell.Properties.Inlet.Fw/Sm)^2/(Shell.Properties.Average.rho*Shell.HeatTransfer.Phi);
540
541"Shell Pressure End Zones"
542        Shell.PressureDrop.EndZones = Shell.PressureDrop.Ideal*(1+ (Ncw/(Shell.ShellID*(1-0.02*Baffles.BaffleCut)/(0.707*Tubes.TubePitch))))*Rb*Rspd;
543
544switch ShellRange
545       
546        case "range1":
547
548"Ji Factor"
549        Ji =1.550*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^0.667;
550
551"Shell Side Pressure Drop Friction Factor"
552        Shell.PressureDrop.FricFactor=32*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-1);
553       
554        when Shell.HeatTransfer.Re > 10 switchto "range2";
555       
556        case "range2":
557
558"Ji Factor"
559        Ji =0.498*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^0.656;
560
561"Shell Side Pressure Drop Friction Factor"
562        Shell.PressureDrop.FricFactor=26.20*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.913);
563       
564        when Shell.HeatTransfer.Re > 100 switchto "range3";
565       
566        case "range3":
567
568"Ji Factor"
569        Ji =0.730*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^0.500;
570
571"Shell Side Pressure Drop Friction Factor"
572        Shell.PressureDrop.FricFactor=3.50*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.476);
573       
574        when Shell.HeatTransfer.Re > 1000 switchto "range4";
575       
576        case "range4":
577       
578"Ji Factor"
579        Ji =0.370*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.396);
580       
581"Shell Side Pressure Drop Friction Factor"
582        Shell.PressureDrop.FricFactor=0.333*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.136);
583
584        when Shell.HeatTransfer.Re > 10000 switchto "range5";
585
586        case "range5":
587
588"Ji Factor"
589        Ji =0.370*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.396);
590       
591"Shell Side Pressure Drop Friction Factor"
592        Shell.PressureDrop.FricFactor=0.303*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.126);
593       
594        when Shell.HeatTransfer.Re < 10000 switchto "range4";
595       
596end
597
598case "Square":
599
600"Shell Side Cross Flow Area"
601        Sm= Baffles.Central_Spacing*(Clearances.BundleToShell+((Shell.ShellID-Clearances.BundleToShell-Tubes.TubeOD)/Tubes.TubePitch)*(Tubes.TubePitch-Tubes.TubeOD));
602
603"Number of Tube rows Crossed in one Crossflow Section"
604        Nc      = Shell.ShellID*(1-0.02*Baffles.BaffleCut)/Tubes.TubePitch;
605       
606"Number of Effective Crossflow rows in Each Window"
607        Ncw = 0.8*(Shell.ShellID*0.01*Baffles.BaffleCut-(Clearances.BundleToShell + Tubes.TubeOD)*0.5)/Tubes.TubePitch;
608
609"Variable for calculating Ji heat transfer correction Factor"
610        a       =       1.187/(1+0.14*Shell.HeatTransfer.Re^0.370);
611
612"Variable for calculating Shell Side Pressure Drop Friction Factor"
613        b=6.30/(1+0.14*Shell.HeatTransfer.Re^0.38);
614
615"Correction Factor for Pressure Drop"
616        Rss     = Clearances.SealStrip/(Shell.ShellID*(1-0.02*Baffles.BaffleCut)/Tubes.TubePitch) ;
617
618"Ideal Shell Side Pressure Drop"
619        Shell.PressureDrop.Ideal= 2*Shell.PressureDrop.FricFactor*(Shell.ShellID*(1-0.02*Baffles.BaffleCut)/Tubes.TubePitch)*(Shell.Properties.Inlet.Fw/Sm)^2/(Shell.Properties.Average.rho*Shell.HeatTransfer.Phi);
620
621"Shell Pressure End Zones"
622        Shell.PressureDrop.EndZones = Shell.PressureDrop.Ideal*(1+ (Ncw/(Shell.ShellID*(1-0.02*Baffles.BaffleCut)/Tubes.TubePitch)))*Rb*Rspd;
623
624switch ShellRange
625       
626        case "range1":
627
628"Ji Factor"
629        Ji =0.970*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.667);
630       
631"Shell Side Pressure Drop Friction Factor"     
632        Shell.PressureDrop.FricFactor=35*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-1);
633
634        when Shell.HeatTransfer.Re > 10 switchto "range2";
635       
636        case "range2":
637
638"Ji Factor"
639        Ji =0.900*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.631);
640
641"Shell Side Pressure Drop Friction Factor"     
642        Shell.PressureDrop.FricFactor=32.10*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.963);
643
644        when Shell.HeatTransfer.Re > 100 switchto "range3";
645       
646        case "range3":
647
648"Ji Factor"
649        Ji =0.408*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.460);
650
651"Shell Side Pressure Drop Friction Factor"     
652        Shell.PressureDrop.FricFactor=6.090*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.602);
653
654        when Shell.HeatTransfer.Re > 1000 switchto "range4";
655       
656        case "range4":
657       
658"Ji Factor"
659        Ji =0.107*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.266);
660
661"Shell Side Pressure Drop Friction Factor"     
662        Shell.PressureDrop.FricFactor=0.0815*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^0.022;
663
664        when Shell.HeatTransfer.Re > 10000 switchto "range5";
665
666        case "range5":
667       
668"Ji Factor"
669        Ji =0.370*((1.33*Tubes.TubeOD/Tubes.TubePitch)^a)*Shell.HeatTransfer.Re^(-0.395);
670
671"Shell Side Pressure Drop Friction Factor"     
672        Shell.PressureDrop.FricFactor=0.391*((1.33*Tubes.TubeOD/Tubes.TubePitch)^b)*Shell.HeatTransfer.Re^(-0.148);
673
674        when Shell.HeatTransfer.Re < 10000 switchto "range4";
675       
676end
677
678end
679
680switch ShellFlowRegime
681
682        case "deep laminar":
683
684"Jr Factor"     
685        Jr = (10/((Nc +Ncw)*(Baffles.NumberOfBaffles+1)))^0.18;
686
687"Js Factor"
688        Js = (Baffles.NumberOfBaffles-1+(Baffles.Inlet_Spacing/Baffles.Central_Spacing)^0.7 + (Baffles.Outlet_Spacing/Baffles.Central_Spacing)^0.7)/(Baffles.NumberOfBaffles-1+(Baffles.Inlet_Spacing/Baffles.Central_Spacing) + (Baffles.Outlet_Spacing/Baffles.Central_Spacing));
689
690"Jb Factor"
691        Jb =    exp(-1.35*( Clearances.BundleToShell+ Tubes.TubeOD)*Baffles.Central_Spacing/Sm*(1-(2*(Clearances.SealStrip/Nc)^(1/3))));
692
693"ByPass Correction Factor for Pressure Drop"
694        Rb      = exp(-4.7*((Clearances.BundleToShell + Tubes.TubeOD)*Baffles.Central_Spacing/Sm)*(1-(2*Rss)^(1/3)));
695
696"Pressure Drop Correction Factor for Unequal Baffle Spacing"
697        Rspd = (Baffles.Central_Spacing/Baffles.Outlet_Spacing) + (Baffles.Central_Spacing/Baffles.Inlet_Spacing);
698
699"Shell Pressure Drop Baffle Window"
700        Shell.PressureDrop.Window    = Baffles.NumberOfBaffles*((26/Shell.Properties.Average.rho)*mw*Shell.Properties.Average.Mu*(Ncw/(Tubes.TubePitch-Tubes.TubeOD)+ Baffles.Central_Spacing/(Dw*Dw))+ 0.5*mw*mw/Shell.Properties.Average.rho)*exp(-1.33*(1+Rs)*((Scd + Std)/Sm)^(-0.15*(1+Rs) + 0.8));
701
702        when Shell.HeatTransfer.Re > 20 switchto "laminar";
703
704        case "laminar":
705
706"Jr Factor"     
707        Jr = (10/((Nc +Ncw)*(Baffles.NumberOfBaffles+1)))^0.18 + (0.25-0.0125*Shell.HeatTransfer.Re)*((10/((Nc +Ncw)*(Baffles.NumberOfBaffles+1)))^0.18 - 1);
708
709"Js Factor"
710        Js = (Baffles.NumberOfBaffles-1+(Baffles.Inlet_Spacing/Baffles.Central_Spacing)^0.7 + (Baffles.Outlet_Spacing/Baffles.Central_Spacing)^0.7)/(Baffles.NumberOfBaffles-1+(Baffles.Inlet_Spacing/Baffles.Central_Spacing) + (Baffles.Outlet_Spacing/Baffles.Central_Spacing));
711
712"Jb Factor"
713        Jb =    exp(-1.35*( Clearances.BundleToShell+ Tubes.TubeOD)*Baffles.Central_Spacing/Sm*(1-(2*(Clearances.SealStrip/Nc)^(1/3))));
714
715"ByPass Correction Factor for Pressure Drop"
716        Rb      = exp(-4.7*((Clearances.BundleToShell+ Tubes.TubeOD)*Baffles.Central_Spacing/Sm)*(1-(2*Rss)^(1/3)));
717
718"Pressure Drop Correction Factor for Unequal Baffle Spacing"
719        Rspd = (Baffles.Central_Spacing/Baffles.Outlet_Spacing) + (Baffles.Central_Spacing/Baffles.Inlet_Spacing);
720
721"Shell Pressure Drop Baffle Window"
722        Shell.PressureDrop.Window    = Baffles.NumberOfBaffles*((26/Shell.Properties.Average.rho)*mw*Shell.Properties.Average.Mu*(Ncw/(Tubes.TubePitch-Tubes.TubeOD)+ Baffles.Central_Spacing/(Dw*Dw))+ 0.5*mw*mw/Shell.Properties.Average.rho)*exp(-1.33*(1+Rs)*((Scd + Std)/Sm)^(-0.15*(1+Rs) + 0.8));
723
724        when Shell.HeatTransfer.Re < 20 switchto "deep laminar";
725        when Shell.HeatTransfer.Re > 100 switchto "turbulent";
726
727        case "turbulent":
728
729"Jr Factor"     
730        Jr = 1;
731
732"Js Factor"
733        Js = (Baffles.NumberOfBaffles-1+(Baffles.Inlet_Spacing/Baffles.Central_Spacing)^0.4 + (Baffles.Outlet_Spacing/Baffles.Central_Spacing)^0.4)/(Baffles.NumberOfBaffles-1+(Baffles.Inlet_Spacing/Baffles.Central_Spacing) + (Baffles.Outlet_Spacing/Baffles.Central_Spacing));
734
735"Jb Factor"
736        Jb =    exp(-1.25*( Clearances.BundleToShell+ Tubes.TubeOD)*Baffles.Central_Spacing/Sm*(1-(2*(Clearances.SealStrip/Nc)^(1/3))));
737
738"ByPass Correction Factor for Pressure Drop"
739        Rb      = exp(-3.7*((Clearances.BundleToShell + Tubes.TubeOD)*Baffles.Central_Spacing/Sm)*(1-(2*Rss)^(1/3)));
740
741"Pressure Drop Correction Factor for Unequal Baffle Spacing"
742        Rspd = (Baffles.Central_Spacing/Baffles.Outlet_Spacing)^1.8 + (Baffles.Central_Spacing/Baffles.Inlet_Spacing)^1.8;
743
744"Shell Pressure Drop Baffle Window"
745        Shell.PressureDrop.Window    = Baffles.NumberOfBaffles*((2+0.6*Ncw)*0.5*mw*mw/Shell.Properties.Average.rho)*exp(-1.33*(1+Rs)*((Scd + Std)/Sm)^(-0.15*(1+Rs) + 0.8));
746       
747        when Shell.HeatTransfer.Re < 100 switchto "laminar";
748       
749end
750
751"Shell Pressure Drop Cross Flow"
752        Shell.PressureDrop.CrossFlow= Shell.PressureDrop.Ideal*Rb*(Baffles.NumberOfBaffles-1)*exp(-1.33*(1+Rs)*((Scd + Std)/Sm)^(-0.15*(1+Rs) + 0.8));
753
754"Shell Side Phi correction"
755        Shell.HeatTransfer.Phi  = (Shell.Properties.Average.Mu/Shell.Properties.Wall.Mu)^0.14;
756
757"Tube Side Phi correction"
758        Tubes.HeatTransfer.Phi  = (Tubes.Properties.Average.Mu/Tubes.Properties.Wall.Mu)^0.14;
759       
760"Shell Side inlet Nozzle rho-V^2"
761        Shell.PressureDrop.RVsquare_in = Shell.Properties.Inlet.rho*(Shell.PressureDrop.Vnozzle_in)^2;
762
763"Shell Side Outlet Nozzle rho-V^2"
764        Shell.PressureDrop.RVsquare_out = Shell.Properties.Outlet.rho*(Shell.PressureDrop.Vnozzle_out)^2;
765
766"Tube Side Pressure Drop"
767        Tubes.PressureDrop.TubeFriction         = 2*Tubes.PressureDrop.FricFactor*Tubes.TubeLength*Tubes.Properties.Average.rho*(Tubes.HeatTransfer.Vtube^2)*Tubes.Tubepasses/(Tubes.TubeID*Tubes.HeatTransfer.Phi);
768
769"Pressure Drop Tube Side Inlet Nozzle"
770        Tubes.PressureDrop.InletNozzle  = 0.5*Kinlet_Tube*Tubes.Properties.Inlet.rho*Tubes.PressureDrop.Vnozzle_in^2;
771
772"Velocity Tube Side Inlet Nozzle"
773        Tubes.PressureDrop.Vnozzle_in   = Tubes.Properties.Inlet.Fw/(Tubes.Properties.Inlet.rho*Ainozzle_Tube);
774
775"Pressure Drop Tube Side Outlet Nozzle"
776        Tubes.PressureDrop.OutletNozzle = 0.5*Koutlet_Tube*Tubes.Properties.Outlet.rho*Tubes.PressureDrop.Vnozzle_out^2;
777
778"Velocity Tube Side Outlet Nozzle"
779        Tubes.PressureDrop.Vnozzle_out  = Tubes.Properties.Inlet.Fw/(Tubes.Properties.Outlet.rho*Aonozzle_Tube);
780
781"Shell Pressure Drop Inlet Nozzle"
782        Shell.PressureDrop.InletNozzle  = (0.5*Shell.Properties.Inlet.Fw^2/Shell.Properties.Inlet.rho)*((1/Ainozzle_Shell^2)+(1/Aeinozzle_Shell^2));
783
784"Velocity Shell Side Inlet Nozzle"
785        Shell.PressureDrop.Vnozzle_in   = Shell.Properties.Inlet.Fw/(Shell.Properties.Inlet.rho*Ainozzle_Shell);
786
787"Shell Pressure Drop Outlet Nozzle"
788        Shell.PressureDrop.OutletNozzle = (0.5*Shell.Properties.Outlet.Fw^2/Shell.Properties.Outlet.rho)*((1/Ainozzle_Shell^2)+(1/Aeinozzle_Shell^2));
789
790"Velocity Shell Side Outlet Nozzle"
791        Shell.PressureDrop.Vnozzle_out  = Shell.Properties.Outlet.Fw/(Shell.Properties.Outlet.rho*Aonozzle_Shell);
792
793"Pressure Drop Shell Stream"
794        OutletShell.P  = InletShell.P - Shell.PressureDrop.Total;       
795       
796"Pressure Drop Tube Stream"
797        OutletTube.P  = InletTube.P - Tubes.PressureDrop.Total;
798
799"Shell Wall Temperature"
800        Shell.Properties.Wall.Twall     = (Shell.Properties.Average.T+Tubes.Properties.Average.T)/2;
801
802"Tube Wall Temperature"
803        Tubes.Properties.Wall.Twall  = (Shell.Properties.Average.T+Tubes.Properties.Average.T)/2;
804
805"Tube Side Velocity"
806        Tubes.HeatTransfer.Vtube        = Tubes.Properties.Inlet.Fw*Tubes.Tubepasses/((Pi*Tubes.TubeID*Tubes.TubeID/4)*Tubes.Properties.Average.rho*Tubes.NumberOfTubes);
807
808"Tube Side Reynolds Number"
809        Tubes.HeatTransfer.Re           = (Tubes.Properties.Average.rho*Tubes.HeatTransfer.Vtube*Tubes.TubeID)/Tubes.Properties.Average.Mu;
810       
811"Tube Side Prandtl Number"
812        Tubes.HeatTransfer.PR           = ((Tubes.Properties.Average.Cp/Tubes.Properties.Average.Mw)*Tubes.Properties.Average.Mu)/Tubes.Properties.Average.K;
813
814"Tube Side Film Coefficient"
815        Tubes.HeatTransfer.htube= (Tubes.HeatTransfer.Nu*Tubes.Properties.Average.K/Tubes.TubeID)*Tubes.HeatTransfer.Phi;
816
817"Shell Side Prandtl Number"
818        Shell.HeatTransfer.PR           = ((Shell.Properties.Average.Cp/Shell.Properties.Average.Mw)*Shell.Properties.Average.Mu)/Shell.Properties.Average.K;
819
820"Overall Heat Transfer Coefficient Dirty"
821        Details.Ud=1/(Tubes.TubeOD/(Tubes.HeatTransfer.htube*Tubes.TubeID)+Shell.Fouling+Tubes.Fouling*(Tubes.TubeOD/Tubes.TubeID)+(Tubes.TubeOD*ln(Tubes.TubeOD/Tubes.TubeID)/(2*Tubes.Kwall))+(1/(Shell.HeatTransfer.hshell)));
822
823"Overall Heat Transfer Coefficient Clean"
824        Details.Uc=1/(Tubes.TubeOD/(Tubes.HeatTransfer.htube*Tubes.TubeID)+(Tubes.TubeOD*ln(Tubes.TubeOD/Tubes.TubeID)/(2*Tubes.Kwall))+(1/(Shell.HeatTransfer.hshell)));
825
826"Exchange Surface Area"
827        Details.A=Pi*Tubes.TubeOD*Tubes.NumberOfTubes*Tubes.TubeLength;
828
829"Baffle Spacing Constraint"
830        Tubes.TubeLength = Baffles.Inlet_Spacing+Baffles.Outlet_Spacing+Baffles.Central_Spacing*(Baffles.NumberOfBaffles-1);
831
832"Shell Side Reynolds Number"
833        Shell.HeatTransfer.Re = (Tubes.TubeOD*Shell.Properties.Inlet.Fw/Sm)/Shell.Properties.Average.Mu;
834
835"Shell Heat Transfer Coefficient"
836        Shell.HeatTransfer.hshell                       = Ji*(Shell.Properties.Average.Cp/Shell.Properties.Average.Mw)*(Shell.Properties.Inlet.Fw/Sm)*(Shell.HeatTransfer.PR^(-2/3))*Jtotal*Shell.HeatTransfer.Phi;
837
838end
839
840Model ShellandTubes_NTU         as ShellandTubesBasic
841
842ATTRIBUTES
843        Pallete = true;
844        Icon    = "icon/STHE"; 
845        Brief  = "Shell and Tubes Heat Exchangers";
846        Info  =
847        "to be documented";
848
849VARIABLES
850
851Method as NTU_Basic (Brief="NTU Method");
852
853EQUATIONS
854
855"Number of Units Transference"
856        Method.NTU*Method.Cmin = Details.Ud*Pi*Tubes.TubeOD*Tubes.NumberOfTubes*Tubes.TubeLength;
857
858"Minimum Heat Capacity"
859        Method.Cmin  = min([Method.Ch,Method.Cc]);
860       
861"Maximum Heat Capacity"
862        Method.Cmax  = max([Method.Ch,Method.Cc]);
863
864"Thermal Capacity Ratio"
865        Method.Cr    = Method.Cmin/Method.Cmax;
866       
867switch HotSide
868       
869        case "shell":
870
871"Duty"
872        Details.Q       = Method.Eft*Method.Cmin*(InletShell.T-InletTube.T);
873
874"Hot Stream Heat Capacity"
875        Method.Ch  = InletShell.F*Shell.Properties.Average.Cp;
876       
877"Cold Stream Heat Capacity"
878        Method.Cc = InletTube.F*Tubes.Properties.Average.Cp;
879
880        when InletTube.T > InletShell.T switchto "tubes";
881       
882        case "tubes":
883
884"Duty"
885        Details.Q       = Method.Eft*Method.Cmin*(InletTube.T-InletShell.T);
886
887"Hot Stream Heat Capacity"
888        Method.Cc = InletShell.F*Shell.Properties.Average.Cp;
889       
890"Cold Stream Heat Capacity"
891        Method.Ch = InletTube.F*Tubes.Properties.Average.Cp;
892       
893        when InletTube.T < InletShell.T switchto "shell";
894       
895end
896
897switch ShellType
898       
899        case "Fshell":
900       
901"Effectiveness Correction for 2 pass shell side"
902        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);
903
904"TEMA F Shell Effectiveness"
905        Method.Eft = ( ((1-Method.Eft1*Method.Cr)/(1-Method.Eft1))^2 -1  )*( ((1-Method.Eft1*Method.Cr)/(1-Method.Eft1))^2 - Method.Cr )^(-1);
906
907        case "Eshell":
908       
909"TEMA E Shell Effectiveness"
910        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);
911#       Method.Eft = 1;
912
913"Variable not in use when 1 Pass Shell Side"
914        Method.Eft1     = 1;
915       
916end
917
918end
919
920Model ShellandTubes_LMTD        as ShellandTubesBasic
921
922ATTRIBUTES
923        Pallete = true;
924        Icon    = "icon/STHE"; 
925        Brief  = "Shell and Tubes Heat Exchangers";
926        Info  =
927        "to be documented.";
928
929PARAMETERS
930
931LMTDcorrection  as Switcher     (Brief="LMTD Correction Factor Model",Valid=["Bowmann","Fakeri" , "User Specified"],Default="Bowmann");
932FLMTDcorrection  as fraction (Default = 0.8);
933
934VARIABLES
935
936Method  as LMTD_Basic;
937R                       as positive     (Brief=" Capacity Ratio for LMTD Correction Fator",Lower=1e-6);
938P                       as positive     (Brief="Non - Dimensional Variable for LMTD Correction Fator ",Lower=1e-6);
939Pc                      as positive     (Brief="Non - Dimensional Variable for LMTD Correction Fator when 2 Pass Shell Side",Lower=1e-6);
940Rho             as positive     (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation",Lower=1e-6);
941Phi     as positive     (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation",Lower=1e-6);
942lambdaN as positive     (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equation when 2 Pass Shell Side",Lower=1e-6);
943lambda1 as positive  (Brief="Non - Dimensional Variable for LMTD Correction Fator in Fakeri Equationwhen 2 Pass Shell Side",Lower=1e-6);
944
945EQUATIONS
946
947"Exchange Surface Area"
948        Details.Q   = Details.Ud*Pi*Tubes.TubeOD*Tubes.NumberOfTubes*Tubes.TubeLength*Method.LMTD*Method.Fc;
949
950switch HotSide
951       
952        case "shell":
953
954"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation "
955        Phi*(2*((InletShell.T+ OutletShell.T)-(InletTube.T+ OutletTube.T)))  = (sqrt(((InletShell.T- OutletShell.T)*(InletShell.T- OutletShell.T))+((OutletTube.T - InletTube.T)*(OutletTube.T - InletTube.T))));
956
957"R: Capacity Ratio for LMTD Correction Fator"
958        R*(OutletTube.T - InletTube.T ) = (InletShell.T-OutletShell.T);
959
960"P: Non - Dimensional Variable for LMTD Correction Fator"
961        P*(InletShell.T- InletTube.T)= (OutletTube.T-InletTube.T);
962       
963"Temperature Difference at Inlet"
964        Method.DT0 = InletShell.T - OutletTube.T;
965
966"Temperature Difference at Outlet"
967        Method.DTL = OutletShell.T - InletTube.T;
968
969        when InletTube.T > InletShell.T switchto "tubes";
970       
971        case "tubes":
972
973"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation "
974        Phi*(2*((InletShell.T+ OutletShell.T)-(InletTube.T+ OutletTube.T)))  = (sqrt(((InletShell.T- OutletShell.T)*(InletShell.T- OutletShell.T))+((OutletTube.T - InletTube.T)*(OutletTube.T - InletTube.T))));
975
976"R: Capacity Ratio for LMTD Correction Fator"
977        R*(OutletShell.T - InletShell.T ) = (InletTube.T-OutletTube.T);
978
979"P: Non - Dimensional Variable for LMTD Correction Fator"
980        P*(InletTube.T- InletShell.T)= (OutletShell.T-InletShell.T);
981       
982"Temperature Difference at Inlet"
983        Method.DT0 = InletTube.T - OutletShell.T;
984
985"Temperature Difference at Outlet"
986        Method.DTL = OutletTube.T - InletShell.T;
987
988       
989        when InletTube.T < InletShell.T switchto "shell";
990       
991end
992
993switch ShellType
994       
995        case "Fshell":
996       
997switch LMTDcorrection
998       
999        case "User Specified": #Just For Initialization
1000       
1001        Method.Fc = FLMTDcorrection;
1002       
1003" Variable not in use with this equation"
1004        lambdaN =1;
1005       
1006" Variable not in use with this equation"
1007        lambda1 =1;
1008
1009#" Variable not in use with this equation"
1010#       Phi = 1;
1011
1012" Variable not in use with this equation"
1013        Rho =1;
1014
1015" Variable not in use with this equation"
1016        Pc = P;
1017
1018        case "Bowmann":
1019       
1020" Variable not in use with Bowmann equation"
1021        lambdaN =1;
1022       
1023" Variable not in use with Bowmann equation"
1024        lambda1 =1;
1025
1026#" Variable not in use with Bowmann equation"
1027#       Phi = 1;
1028
1029" Variable not in use with Bowmann equation"
1030        Rho =1;
1031
1032if R equal 1
1033       
1034        then
1035       
1036"Non Dimensional Variable for LMTD Correction Fator when 2 Pass Shell Side"
1037        Pc*(2-P)= P;
1038
1039"LMTD Correction Fator when 2 Pass Shell Side"
1040        Method.Fc= (sqrt(2)*Pc)/((1-Pc)*ln( abs( ( 2-Pc*0.585786)/( 2-Pc*3.414214))));
1041       
1042        else
1043       
1044"Non Dimensional Variable for LMTD Correction Fator when 2 Pass Shell Side"
1045        Pc = (sqrt(abs(( 1-P*R)/(1-P)))-1)/(sqrt(abs(( 1-P*R)/(1-P)))-R);
1046
1047"LMTD Correction Fator when 2 Pass Shell Side"
1048        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))))));
1049       
1050end
1051
1052        case "Fakeri":
1053       
1054" Variable not in use with Fakeri equation"
1055        Pc = P;
1056       
1057"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
1058        Rho*(1-P*R) = (1-P);
1059
1060#"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation "
1061#       Phi = (sqrt(((Inlet.Hot.T - Outlet.Hot.T)*(Inlet.Hot.T- Outlet.Hot.T))+((Outlet.Cold.T -  Inlet.Cold.T)*(Outlet.Cold.T -  Inlet.Cold.T))))/(2*((Inlet.Hot.T + Outlet.Hot.T)-( Inlet.Cold.T + Outlet.Cold.T)));
1062
1063if Rho equal 1
1064       
1065        then
1066       
1067" Variable not in use when Rho = 1"
1068        lambdaN =       1;
1069       
1070" Variable not in use when Rho = 1"
1071        lambda1 =       1;
1072       
1073"LMTD Correction Fator when 2 Pass Shell Side"
1074        Method.Fc = (2*Phi )/(ln(abs((1+Phi )/(1-Phi ))));
1075       
1076        else
1077
1078"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
1079        lambdaN = (1/ln(sqrt(abs(Rho))))*((2*sqrt(abs(Rho))-2)/(sqrt(abs(Rho))+1));
1080       
1081"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
1082        lambda1 = (1/ln(abs(Rho)))*((2*Rho-2)/(Rho+1));
1083
1084"LMTD Correction Fator when 2 Pass Shell Side"
1085        Method.Fc =     ((2*Phi *(lambdaN/lambda1))/(ln(abs((1+Phi *(lambdaN/lambda1))/(1-Phi *(lambdaN/lambda1))))))*(1/lambdaN);
1086
1087end
1088
1089
1090end
1091
1092        case "Eshell":
1093       
1094" Variable not in use when 1 Pass Shell Side"
1095        lambdaN =1;
1096
1097" Variable not in use when 1 Pass Shell Side"
1098        lambda1 =1;
1099       
1100" Variable not in use when 1 Pass Shell Side"
1101        Pc = P;
1102       
1103switch LMTDcorrection
1104
1105        case "User Specified": #Just For Initialization
1106       
1107        Method.Fc = FLMTDcorrection;
1108       
1109#" Variable not in use with this equation"
1110#       lambdaN =1;
1111       
1112#" Variable not in use with this equation"
1113#       lambda1 =1;
1114
1115#" Variable not in use with this equation"
1116#       Phi = 1;
1117
1118" Variable not in use with this equation"
1119        Rho =1;
1120       
1121        case "Bowmann":
1122
1123#" Variable not in use with Bowmann equation"
1124#       Phi  = 1;
1125       
1126" Variable not in use with Bowmann equation"
1127        Rho = 1;
1128
1129
1130 if R equal 1
1131       
1132    then
1133       
1134"LMTD Correction Fator when 1 Pass Shell Side"
1135        Method.Fc = (sqrt(2)*P)/((1-P)*ln( abs( ( 2-P*0.585786)/( 2-P*3.414214))));
1136
1137        else
1138       
1139"LMTD Correction Fator when 1 Pass Shell Side"
1140        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))))));
1141
1142end
1143
1144        case "Fakeri":
1145
1146#"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation "
1147#       Phi  = (sqrt(((Inlet.Hot.T- Outlet.Hot.T)*(Inlet.Hot.T- Outlet.Hot.T))+((Outlet.Cold.T - Inlet.Cold.T)*(Outlet.Cold.T - Inlet.Cold.T))))/(2*((Inlet.Hot.T+ Outlet.Hot.T)-(Inlet.Cold.T+ Outlet.Cold.T)));
1148
1149"Non Dimensional Variable for LMTD Correction Fator in Fakeri Equation"
1150        Rho*(1-P*R) = (1-P);
1151
1152if Rho equal 1
1153       
1154        then
1155       
1156"LMTD Correction Fator when 1 Pass Shell Side"
1157        Method.Fc = (4*Phi)/(ln(abs((1+2*Phi)/(1-2*Phi))));
1158
1159        else
1160
1161"LMTD Correction Fator when 1 Pass Shell Side"
1162        Method.Fc = (2*Phi*(Rho+1)*ln(abs(Rho)))/( ln(abs((1+2*Phi)/(1-2*Phi)))*(Rho-1));
1163       
1164end
1165
1166end
1167
1168       
1169end
1170
1171end
1172
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