#*------------------------------------------------------------------- * Model of tanks *-------------------------------------------------------------------- * Streams: * * an inlet stream * * an outlet stream * * Specify: * * the Inlet stream * * the Outlet flow * * the tank Q * * Initial: * * the tank temperature (OutletL.T) * * the tank level (h) * * (NoComps - 1) Outlet compositions *---------------------------------------------------------------------- * Author: Paula B. Staudt * \$Id: tank.mso 64 2006-11-24 02:48:08Z arge \$ *--------------------------------------------------------------------*# using "streams"; Model tank PARAMETERS ext PP as CalcObject; ext NComp as Integer; Across as area (Brief="Tank cross section area", Default=2); VARIABLES in Inlet as stream; out Outlet as stream_therm; in Q as heat_rate (Brief="Rate of heat supply"); Level as length(Brief="Tank level"); M(NComp) as mol (Brief="Molar Holdup in the tank"); E as energy (Brief="Total Energy Holdup on tank"); vL as volume_mol (Brief="Liquid Molar Volume"); EQUATIONS "Mass balance" diff(M) = Inlet.F*Inlet.z - Outlet.F*Outlet.z; "Energy balance" diff(E) = Inlet.F*Inlet.h - Outlet.F*Outlet.h + Q; "Energy Holdup" E = sum(M)*Outlet.h; "Mechanical Equilibrium" Inlet.P = Outlet.P; "Liquid Volume" vL = PP.LiquidVolume(Outlet.T, Outlet.P, Outlet.z); "Composition" M = Outlet.z*sum(M); "Level of liquid phase" Level = sum(M)*vL/Across; "Vapourisation Fraction" Outlet.v = Inlet.v; end Model tank_cylindrical PARAMETERS ext PP as CalcObject; ext NComp as Integer; radius as length(Brief="Tank radius"); L as length(Brief="Tank length"); VARIABLES in Inlet as stream; out Outlet as stream_therm; in Q as heat_rate (Brief="Rate of heat supply"); Level as length(Brief="Tank level"); Across as area (Brief="Tank cross section area", Default=2); M(NComp) as mol (Brief="Molar Holdup in the tank"); E as energy (Brief="Total Energy Holdup on tank"); vL as volume_mol (Brief="Liquid Molar Volume"); EQUATIONS "Mass balance" diff(M) = Inlet.F*Inlet.z - Outlet.F*Outlet.z; "Energy balance" diff(E) = Inlet.F*Inlet.h - Outlet.F*Outlet.h + Q; "Energy Holdup" E = sum(M)*Outlet.h; "Mechanical Equilibrium" Inlet.P = Outlet.P; "Liquid Volume" vL = PP.LiquidVolume(Outlet.T, Outlet.P, Outlet.z); "Composition" M = Outlet.z*sum(M); "Cylindrical Area" Across = radius^2 * (asin(1) - asin((radius-Level)/radius) ) + (Level-radius)*sqrt(Level*(2*radius - Level)); "Level of liquid phase" Level = sum(M)*vL/Across; "Vapourisation Fraction" Outlet.v = Inlet.v; end Model tank_simplified PARAMETERS k as Real (Brief="Valve Constant", Unit = "m^2.5/h", Default=4); A as area (Brief="Tank area", Default=2); VARIABLES h as length(Brief="Tank level"); in Fin as flow_vol(Brief="Input flow"); out Fout as flow_vol(Brief="Output flow"); EQUATIONS "Mass balance" diff(A*h) = Fin - Fout; "Valve equation" Fout = k*sqrt(h); end Model tank_feed PARAMETERS ext PP as CalcObject; ext NComp as Integer; Across as area (Brief="Tank cross section area", Default=2); VARIABLES in Feed as stream; in Inlet as stream; out Outlet as stream_therm; in Q as heat_rate (Brief="Rate of heat supply"); Level as length(Brief="Tank level"); M(NComp) as mol (Brief="Molar Holdup in the tank"); E as energy (Brief="Total Energy Holdup on tank"); vL as volume_mol (Brief="Liquid Molar Volume"); EQUATIONS "Mass balance" diff(M) = Feed.F*Feed.z + Inlet.F*Inlet.z - Outlet.F*Outlet.z; "Energy balance" diff(E) = Feed.F*Feed.h + Inlet.F*Inlet.h - Outlet.F*Outlet.h + Q; "Energy Holdup" E = sum(M)*Outlet.h; "Mechanical Equilibrium" Inlet.P = Outlet.P; "Liquid Volume" vL = PP.LiquidVolume(Outlet.T, Outlet.P, Outlet.z); "Composition" M = Outlet.z*sum(M); "Level of liquid phase" Level = sum(M)*vL/Across; "Vapourisation Fraction" Outlet.v = Inlet.v; end