[1] | 1 | #*------------------------------------------------------------------- |
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| 2 | * Model of tanks |
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| 3 | *-------------------------------------------------------------------- |
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| 4 | * Streams: |
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| 5 | * * an inlet stream |
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| 6 | * * an outlet stream |
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| 7 | * |
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| 8 | * Specify: |
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| 9 | * * the Inlet stream |
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| 10 | * * the Outlet flow |
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| 11 | * * the tank Q |
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| 12 | * |
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| 13 | * Initial: |
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| 14 | * * the tank temperature (OutletL.T) |
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| 15 | * * the tank level (h) |
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| 16 | * * (NoComps - 1) Outlet compositions |
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| 17 | *---------------------------------------------------------------------- |
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| 18 | * Author: Paula B. Staudt |
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| 19 | * $Id: tank.mso 42 2006-10-26 19:44:05Z paula $ |
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| 20 | *--------------------------------------------------------------------*# |
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| 21 | |
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| 22 | using "streams"; |
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| 23 | |
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| 24 | Model tank |
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| 25 | |
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| 26 | PARAMETERS |
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| 27 | ext PP as CalcObject; |
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| 28 | ext NComp as Integer; |
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| 29 | Across as area (Brief="Tank cross section area", Default=2); |
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| 30 | |
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| 31 | VARIABLES |
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| 32 | in Inlet as stream; |
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| 33 | out Outlet as stream_therm; |
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| 34 | |
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[42] | 35 | in Q as heat_rate (Brief="Rate of heat supply"); |
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[1] | 36 | Level as length(Brief="Tank level"); |
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| 37 | M(NComp) as mol (Brief="Molar Holdup in the tank"); |
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| 38 | E as energy (Brief="Total Energy Holdup on tank"); |
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| 39 | vL as volume_mol (Brief="Liquid Molar Volume"); |
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| 40 | |
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| 41 | EQUATIONS |
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| 42 | "Mass balance" |
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| 43 | diff(M) = Inlet.F*Inlet.z - Outlet.F*Outlet.z; |
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| 44 | |
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| 45 | "Energy balance" |
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| 46 | diff(E) = Inlet.F*Inlet.h - Outlet.F*Outlet.h + Q; |
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| 47 | |
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| 48 | "Energy Holdup" |
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| 49 | E = sum(M)*Outlet.h; |
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| 50 | |
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| 51 | "Mechanical Equilibrium" |
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| 52 | Inlet.P = Outlet.P; |
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| 53 | |
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| 54 | "Liquid Volume" |
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| 55 | vL = PP.LiquidVolume(Outlet.T, Outlet.P, Outlet.z); |
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| 56 | |
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| 57 | "Composition" |
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| 58 | M = Outlet.z*sum(M); |
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| 59 | |
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| 60 | "Level of liquid phase" |
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| 61 | Level = sum(M)*vL/Across; |
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| 62 | |
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| 63 | "Vapourisation Fraction" |
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| 64 | Outlet.v = Inlet.v; |
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| 65 | end |
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| 66 | |
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| 67 | Model tank_cylindrical |
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| 68 | |
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| 69 | PARAMETERS |
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| 70 | ext PP as CalcObject; |
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| 71 | ext NComp as Integer; |
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| 72 | radius as length(Brief="Tank radius"); |
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| 73 | L as length(Brief="Tank length"); |
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| 74 | |
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| 75 | VARIABLES |
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| 76 | in Inlet as stream; |
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| 77 | out Outlet as stream_therm; |
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| 78 | |
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[42] | 79 | in Q as heat_rate (Brief="Rate of heat supply"); |
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[1] | 80 | Level as length(Brief="Tank level"); |
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| 81 | Across as area (Brief="Tank cross section area", Default=2); |
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| 82 | M(NComp) as mol (Brief="Molar Holdup in the tank"); |
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| 83 | E as energy (Brief="Total Energy Holdup on tank"); |
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| 84 | vL as volume_mol (Brief="Liquid Molar Volume"); |
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| 85 | |
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| 86 | EQUATIONS |
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| 87 | "Mass balance" |
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| 88 | diff(M) = Inlet.F*Inlet.z - Outlet.F*Outlet.z; |
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| 89 | |
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| 90 | "Energy balance" |
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| 91 | diff(E) = Inlet.F*Inlet.h - Outlet.F*Outlet.h + Q; |
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| 92 | |
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| 93 | "Energy Holdup" |
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| 94 | E = sum(M)*Outlet.h; |
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| 95 | |
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| 96 | "Mechanical Equilibrium" |
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| 97 | Inlet.P = Outlet.P; |
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| 98 | |
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| 99 | "Liquid Volume" |
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| 100 | vL = PP.LiquidVolume(Outlet.T, Outlet.P, Outlet.z); |
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| 101 | |
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| 102 | "Composition" |
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| 103 | M = Outlet.z*sum(M); |
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| 104 | |
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| 105 | "Cylindrical Area" |
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| 106 | Across = radius^2 * (asin(1) - asin((radius-Level)/radius) ) + |
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| 107 | (Level-radius)*sqrt(Level*(2*radius - Level)); |
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| 108 | |
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| 109 | "Level of liquid phase" |
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| 110 | Level = sum(M)*vL/Across; |
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| 111 | |
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| 112 | "Vapourisation Fraction" |
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| 113 | Outlet.v = Inlet.v; |
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| 114 | end |
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| 115 | |
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| 116 | Model tank_simplified |
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| 117 | PARAMETERS |
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| 118 | k as Real (Brief="Valve Constant", Unit = "m^2.5/h", Default=4); |
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| 119 | A as area (Brief="Tank area", Default=2); |
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| 120 | |
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| 121 | VARIABLES |
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| 122 | h as length(Brief="Tank level"); |
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| 123 | in Fin as flow_vol(Brief="Input flow"); |
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| 124 | out Fout as flow_vol(Brief="Output flow"); |
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| 125 | |
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| 126 | EQUATIONS |
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| 127 | "Mass balance" |
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| 128 | diff(A*h) = Fin - Fout; |
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| 129 | |
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| 130 | "Valve equation" |
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| 131 | Fout = k*sqrt(h); |
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| 132 | end |
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