 Timestamp:
 Mar 11, 2008, 5:12:45 PM (14 years ago)
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trunk/eml/heat_exchangers/Hairpin.mso
r441 r484 46 46 OuterTurbulentCorrelation as Switcher (Brief="Heat Transfer Correlation in Turbulent Flow for the Outer Side",Valid=["Petukhov","SiederTate"],Default="Petukhov"); 47 47 48 CalculationApproach as Switcher (Brief="Options for convergence Calculations ",Valid=["Simplified","Full"],Default="Full"); 49 Qestimated as power (Brief="Estimated Duty", Default=70, Lower=1e6, Upper=1e10); 50 48 51 Pi as constant (Brief="Pi Number",Default=3.14159265, Symbol = "\pi"); 49 52 DoInner as length (Brief="Outside Diameter of Inner Pipe",Lower=1e6); … … 474 477 Outer.HeatTransfer.hcoeff= (Outer.HeatTransfer.Nu*Outer.Properties.Average.K/Outer.HeatTransfer.Dh)*Outer.HeatTransfer.Phi; 475 478 479 switch CalculationApproach 480 481 case "Full": 482 476 483 "Total Pressure Drop Outer Stream" 477 484 Outer.PressureDrop.Pdrop = Outer.PressureDrop.Pd_fric+Outer.PressureDrop.Pd_ret; … … 503 510 "Inner Pipe Phi correction" 504 511 Inner.HeatTransfer.Phi = (Inner.Properties.Average.Mu/Inner.Properties.Wall.Mu)^0.14; 512 513 case "Simplified": 514 515 "Total Pressure Drop Outer Stream" 516 Outer.PressureDrop.Pdrop = 0*'kPa'; 517 518 "Total Pressure Drop Inner Stream" 519 Inner.PressureDrop.Pdrop = 0*'kPa'; 520 521 "Pressure Drop Outer Stream" 522 OutletOuter.P = InletOuter.P; 523 524 "Pressure Drop Inner Stream" 525 OutletInner.P = InletInner.P; 526 527 "Outer Pipe Pressure Drop for friction" 528 Outer.PressureDrop.Pd_fric = 0*'kPa'; 529 530 "Inner Pipe Pressure Drop for friction" 531 Inner.PressureDrop.Pd_fric = 0*'kPa'; 532 533 "Outer Pipe Pressure Drop due to return" 534 Outer.PressureDrop.Pd_ret = 0*'kPa'; 535 536 "Inner Pipe Pressure Drop due to return" 537 Inner.PressureDrop.Pd_ret = 0*'kPa'; 538 539 "Outer Pipe Phi correction" 540 Outer.HeatTransfer.Phi = 1; 541 542 "Inner Pipe Phi correction" 543 Inner.HeatTransfer.Phi = 1; 544 545 end 505 546 506 547 "Outer Pipe Prandtl Number" … … 549 590 550 591 FlowDirection as Switcher (Brief="Flow Direction",Valid=["counter","cocurrent"],Default="cocurrent"); 551 592 Eftestimated as positive (Brief="Effectiveness estimate",Default=0.5); 593 552 594 VARIABLES 553 595 … … 555 597 556 598 EQUATIONS 599 600 "Effectiveness Correction" 601 Method.Eft1 = 1; 602 603 switch CalculationApproach 604 605 case "Full": 557 606 558 607 "Number of Units Transference" … … 567 616 "Thermal Capacity Ratio" 568 617 Method.Cr = Method.Cmin/Method.Cmax; 569 570 "Effectiveness Correction"571 Method.Eft1 = 1;572 618 573 619 if Method.Cr equal 0 … … 605 651 end 606 652 653 case "Simplified": 654 655 "Number of Units Transference" 656 Method.NTU = 1; 657 658 "Minimum Heat Capacity" 659 Method.Cmin = min([Method.Ch,Method.Cc]); 660 661 "Maximum Heat Capacity" 662 Method.Cmax = max([Method.Ch,Method.Cc]); 663 664 "Thermal Capacity Ratio" 665 Method.Cr = 1; 666 667 "Effectiveness" 668 Method.Eft = Eftestimated; 669 670 end 671 607 672 switch HotSide 608 673 609 674 case "outer": 675 676 switch CalculationApproach 677 678 case "Full": 610 679 611 680 "Duty" 612 681 Details.Q = Method.Eft*Method.Cmin*(InletOuter.TInletInner.T); 613 682 683 case "Simplified": 684 685 "Duty" 686 Details.Q = Qestimated; 687 688 end 689 614 690 "Hot Stream Heat Capacity" 615 691 Method.Ch = InletOuter.F*Outer.Properties.Average.Cp; … … 622 698 case "inner": 623 699 700 switch CalculationApproach 701 702 case "Full": 703 624 704 "Duty" 625 705 Details.Q = Method.Eft*Method.Cmin*(InletInner.TInletOuter.T); 706 707 case "Simplified": 708 709 "Duty" 710 Details.Q = Qestimated; 711 712 end 626 713 627 714 "Cold Stream Heat Capacity" … … 657 744 EQUATIONS 658 745 659 "Exchange Surface Area" 746 switch CalculationApproach 747 748 case "Full": 749 750 "Duty" 660 751 Details.Q = Details.Ud*Pi*DoInner*(2*Lpipe)*Method.LMTD; 661 752 753 case "Simplified": 754 755 "Duty Estimated" 756 Details.Q = Qestimated; 757 758 end 759 662 760 "LMTD Correction Factor  True counter ou cocurrent flow" 663 761 Method.Fc = 1;
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