Modelica.Fluid.Examples.ControlledTankSystem

Information

Package Content

Name	Description
ControlledTanks	Demonstrating the controller of a tank filling/emptying system
Utilities

Modelica.Fluid.Examples.ControlledTankSystem.ControlledTanks

Information

With this example, the controller of a tank filling/emptying system is demonstrated.

The basic operation is to fill and empty the two tanks:

1. Valve 1 is opened and tank 1 is filled.
2. When tank 1 reaches its fill level limit, valve 1 is closed.
3. After a waiting time, valve 2 is opened and the fluid flows from tank 1 into tank 2.
4. When tank 1 reaches its minimum level, valve 2 is closed.
5. After a waiting time, valve 3 is opened and the fluid flows out of tank 2
6. When tank 2 reaches its minimum level, valve 3 is closed

The above "normal" process can be influenced by three buttons:

• Button start starts the above process. When this button is pressed after a "stop" or "shut" operation, the process operation continues.
• Button stop stops the above process by closing all valves. Then, the controller waits for further input (either "start" or "shut" operation).
• Button shut is used to shutdown the process, by emptying at once both tanks by opening valve 2 and valve 3. When this is achieved, the process goes back to its start configuration where all 3 valves are closed. Clicking on "start", restarts the process.

The demo-run uses the following button presses:

• Button start pressed at 20 s.
• Button stop pressed at 220 s
• Button start pressed at 280 s
• Button stop pressed at 650 s
• Button shut pressed at 700 s
• Simulate for 900 s

This example is based on

Dressler I. (2004):

Code Generation From JGrafchart to Modelica. Master thesis, supervisor: Karl-Erik Arzen, Department of Automatic Control, Lund Institute of Technology, Lund, Sweden, March 30, 2004
 

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica definition

model ControlledTanks 
  "Demonstrating the controller of a tank filling/emptying system"
  extends Modelica.Icons.Example;
  package Medium = Modelica.Media.Water.ConstantPropertyLiquidWater;

  Modelica.Fluid.Examples.ControlledTankSystem.Utilities.TankController
    tankController(
    waitTime=50,
    maxLevel=0.9*tank1.height,
    minLevel=0.01);
  Modelica.Fluid.Examples.ControlledTankSystem.Utilities.RadioButton start(
                                                         reset={stop.on,shut.on},
      buttonTimeTable={20,280});
  Modelica.Fluid.Examples.ControlledTankSystem.Utilities.RadioButton stop(
                                                        reset={start.on,shut.on},
      buttonTimeTable={220,650});
  Modelica.Fluid.Examples.ControlledTankSystem.Utilities.RadioButton shut(
                                                        reset={start.on,stop.on},
      buttonTimeTable={700});
  Modelica.Fluid.Valves.ValveDiscrete valve1(                     redeclare 
      package Medium = Medium,
    m_flow_nominal=40,
    dp_nominal=100000);
  Modelica.Fluid.Vessels.OpenTank tank1(
    level_start=0.05,
    redeclare package Medium = Medium,
    crossArea=6,
    height=4,
    nPorts=2,
    portsData={Modelica.Fluid.Vessels.BaseClasses.VesselPortsData(
          diameter=0.2,
          height=4,
          zeta_out=0,
          zeta_in=1),Modelica.Fluid.Vessels.BaseClasses.VesselPortsData(
          diameter=0.2,
          height=0,
          zeta_out=0,
          zeta_in=1)});
  Modelica.Blocks.Sources.RealExpression level1(y=tank1.level);
  Modelica.Fluid.Valves.ValveDiscrete valve2(        redeclare package Medium
      = Medium,
    dp_nominal(displayUnit="Pa") = 1,
    m_flow_nominal=100);
  Modelica.Fluid.Valves.ValveDiscrete valve3(        redeclare package Medium
      = Medium,
    dp_nominal(displayUnit="Pa") = 1,
    m_flow_nominal=10);
  Modelica.Fluid.Vessels.OpenTank tank2(
    level_start=0.05,
    redeclare package Medium = Medium,
    height=5,
    crossArea=6,
    nPorts=2,
    portsData={Modelica.Fluid.Vessels.BaseClasses.VesselPortsData(
          diameter=0.2,
          height=5,
          zeta_out=0,
          zeta_in=1),Modelica.Fluid.Vessels.BaseClasses.VesselPortsData(
          diameter=0.2,
          height=0,
          zeta_out=0,
          zeta_in=1)});
  Modelica.Fluid.Sources.Boundary_pT ambient1(redeclare package Medium =
        Medium,nPorts=1,
    p=system.p_ambient,
    T=system.T_ambient);
  Modelica.Blocks.Sources.RealExpression level2(y=tank2.level);
  Modelica.Fluid.Sources.Boundary_pT source(redeclare package Medium =
        Medium, p=2.5e6,nPorts=1,
    T=system.T_ambient);
  inner Modelica.Fluid.System system;
equation 
  connect(shut.on, tankController.shut);
  connect(stop.on, tankController.stop);
  connect(start.on, tankController.start);
  connect(tankController.valve1, valve1.open);
  connect(level1.y, tankController.level1);
  connect(tankController.valve2, valve2.open);
  connect(tankController.valve3, valve3.open);
  connect(level2.y, tankController.level2);

  connect(source.ports[1], valve1.port_a);
  connect(valve3.port_b, ambient1.ports[1]);
  connect(tank2.ports[2], valve3.port_a);
  connect(valve2.port_b, tank2.ports[1]);
  connect(valve1.port_b, tank1.ports[1]);
  connect(tank1.ports[2], valve2.port_a);
end ControlledTanks;