Closed Volume 和 Sweptvolume 的行为 - Modelica

Question

我模拟了一个简单的案例，它由SweptVolume、ClosedVolume和dynamic pipe组成。进入ClosedVolume 当活塞向下运动时，水就会被吸入活塞腔。我模拟了这种情况，我看到 ClosedVolume 内的压力增加随时间减少。会是什么原因呢？

model HD_Closedvolumebisclosedvolume
    //Declaration(s)
    Real V_max = 0.000003;
    Real V_tod = 0.000002;
    Real N = 2800;
    replaceable package medium = Modelica.Media.Water.StandardWater( );
    parameter Real A_Kolben = 0.0001131;
    replaceable package medium_500bar = Modelica.Media.Water.StandardWater( );
    //Component(s)
    Modelica.Fluid.Machines.SweptVolume Swept1 (
        pistonCrossArea = A_Kolben,
        clearance = 0.00000250621,
        redeclare package Medium = Modelica.Media.Water.StandardWater,
        nPorts = 1,
        use_portsData = false,
        p_start = 1e5,
        use_T_start = true,
        T_start = 293.15,
        V(start = 0.005),
        m(start = 0.005));
    inner Modelica.Fluid.System system (p_ambient = 101325);
    Modelica.Mechanics.Translational.Sources.Position Posit1 (exact = true, useSupport = false);
    Modelica.Blocks.Sources.Sine Sine1 (
        amplitude = 0.005567,
        freqHz = 46.66,
        offset = 0.005567,
        phase = -Modelica.Constants.pi/4);
    Modelica.Fluid.Vessels.ClosedVolume ClosedVolume (
        V = 0.000005,
        nPorts = 1,
        redeclare package Medium = medium,
        use_portsData = false);
    Modelica.Fluid.Pipes.DynamicPipe pipe (
        length = 0.005,
        diameter = 0.002,
        redeclare package Medium = medium,
        roughness = 2.5E-4);
    Modelica.Mechanics.Translational.Sensors.PositionSensor position;


equation
    //Connection(s)
    connect(Posit1.flange, Swept1.flange);
    connect(Sine1.y, Posit1.s_ref);
    connect(pipe.port_a, Swept1.ports[1]);
    connect(pipe.port_b, ClosedVolume.ports[1]);
    connect(Posit1.flange, position.flange);
end  HD_Closedvolumebisclosedvolume;`

Answer 1

检查总水量是否恒定，由于数值问题可能是水量减少了。尽量降低耐受性以减少水分流失。

Closed Volume 和 Sweptvolume 的行为 - Modelica

Behaviour of Closed Volume and Sweptvolume - Modelica

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