 Timestamp:
 Oct 10, 2007, 5:45:23 PM (16 years ago)
 Location:
 trunk/eml/heat_exchangers
 Files:

 2 edited
Legend:
 Unmodified
 Added
 Removed

trunk/eml/heat_exchangers/HEX_Engine.mso
r384 r386 449 449 end 450 450 451 Model Thermal_PHE as LMTD_Basic451 Model Thermal_PHE 452 452 453 453 ATTRIBUTES 
trunk/eml/heat_exchangers/PHE.mso
r384 r386 54 54 55 55 == Setting The PHE Option Parameters == 56 *Method: NTU or LMTD57 56 *SideOne: cold or hot 58 57 … … 72 71 outer NComp as Integer (Brief="Number of Chemical Components"); 73 72 Pi as constant (Brief="Pi Number",Default=3.14159265, Symbol = "\pi"); 74 Kp1(15) as constant (Brief="First constant in Kumar calculation for Pressure Drop"); 75 Kp2(15) as constant (Brief="Second constant in Kumar calculation for Pressure Drop"); 76 Kc1(14) as constant (Brief="First constant in Kumar calculation for Heat Transfer"); 77 Kc2(14) as constant (Brief="Second constant Kumar calculation for Heat Transfer"); 73 N1 as Integer (Brief="Auxiliar Constant"); 74 N2 as Integer (Brief="Auxiliar Constant"); 75 Kp1(N1) as constant (Brief="First constant in Kumar calculation for Pressure Drop"); 76 Kp2(N1) as constant (Brief="Second constant in Kumar calculation for Pressure Drop"); 77 Kc1(N2) as constant (Brief="First constant in Kumar calculation for Heat Transfer"); 78 Kc2(N2) as constant (Brief="Second constant Kumar calculation for Heat Transfer"); 78 79 M(NComp) as molweight (Brief="Component Mol Weight"); 79 80 80 81 ChevronAngle as Switcher (Brief="Chevron Corrugation Inclination Angle in Degrees ",Valid=["30 Deg","45 Deg","50 Deg","60 Deg","65 Deg"],Default="30 Deg"); 81 Method as Switcher (Brief="Method of Thermal Calculation",Valid=["NTU","LMTD"],Default="NTU");82 82 SideOne as Switcher (Brief="Fluid Alocation in the Side I  (The odd channels)",Valid=["hot","cold"],Default="hot"); 83 83 Nchannels as Integer (Brief="Total Number of Channels in The Whole Heat Exchanger"); … … 115 115 116 116 SET 117 #"Vector Length of constants for Kumar's calculating Pressure Drop" 118 N1 = 15; 119 120 #"Vector Length of constants for Kumar's calculating Heat Transfer" 121 N2 = 14; 117 122 118 123 #"First constant for Kumar's calculating Pressure Drop" … … 147 152 148 153 #"Ports Area" 149 Aports= Pi*Dports*Dports/4;154 Aports=0.25*Pi*Dports*Dports; 150 155 151 156 #"Channel Area" … … 659 664 Thermal.Ud*(1/HotSide.HeatTransfer.hcoeff +pt/Kwall+1/ColdSide.HeatTransfer.hcoeff + Rfc + Rfh)=1; 660 665 661 switch Method 662 663 case "LMTD": 664 665 "Duty" 666 Thermal.Q = Thermal.Ud*Atotal*Thermal.LMTD*Thermal.Fc; 667 668 case "NTU": 669 670 "Duty" 666 "Duty" 671 667 Thermal.Q = Thermal.Eft*Thermal.Cmin*(InletHot.TInletCold.T); 672 668 673 end 674 675 "Temperature Difference at Inlet  Counter Flow" 676 Thermal.DT0 = InletHot.T  OutletCold.T; 677 678 "Temperature Difference at Outlet  Counter Flow" 679 Thermal.DTL = OutletHot.T  InletCold.T; 680 681 "Heat Capacity Ratio" 669 "Heat Capacity Ratio" 682 670 Thermal.Cr =Thermal.Cmin/Thermal.Cmax; 683 671 … … 703 691 ColdSide.HeatTransfer.NTU*ColdSide.HeatTransfer.WCp = Thermal.Ud*Atotal; 704 692 705 693 if Thermal.Cr equal 1 # To be Fixed: Effectiveness in true counter flow ! 706 694 707 695 then 708 696 "Effectiveness in Counter Flow" 709 Thermal.Eft = Thermal.NTU/(1+Thermal.NTU); 710 711 "LMTD Correction Factor" 712 Thermal.Fc =Thermal.Eft/(1.0001Thermal.Eft)/Thermal.NTU; 697 Thermal.Eft*(1+Thermal.NTU) = Thermal.NTU; 713 698 714 699 else 715 700 "Effectiveness in Counter Flow" 716 Thermal.Eft = (1exp(Thermal.NTU*(1Thermal.Cr)))/(1Thermal.Cr*exp(Thermal.NTU*(1Thermal.Cr))); 717 718 "LMTD Correction Factor" 719 Thermal.Fc =(ln(abs(1Thermal.Eft*Thermal.Cr))ln(abs(1Thermal.Eft)))/(Thermal.NTU*(1Thermal.Cr)); 720 721 end 701 Thermal.NTU = (1/(Thermal.Cr1))*ln(abs((Thermal.Eft1)/(Thermal.Cr*Thermal.Eft1))); 722 702 723 703 end 704 705 end
Note: See TracChangeset
for help on using the changeset viewer.