#*-------------------------------------------------------------------
* 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