如何使用 Modelica 标准库的 SimpleGenericOrifice 在管道中施加压力损失？

Question

我想模拟一个液压管网，我在其中使用 Modelica.Fluid.Fittings.SimpleGenericOrifice 作为密封件，这样我就可以施加管道的压力损失。使用文档中的公式，我可以计算出孔口的 zeta 系数。

这是一个简化的例子，在这里我尝试在我的管道 1 内施加 50 bar 的压力损失。因为端口处的压力应该相等，所以我认为它应该可以工作：

但是我在管道和孔口中没有任何压力损失。

有谁知道如何进行这项工作？

示例代码如下

model Joints_HD

replaceable package Medium=Modelica.Media.Water.StandardWater constrainedby
    Modelica.Media.Interfaces.PartialMedium;

  Modelica.Fluid.Pipes.StaticPipe pipe(redeclare package Medium = Medium,diameter = 0.15, length = 1)  annotation(
    Placement(visible = true, transformation(origin = {-38, 10}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  
  inner Modelica.Fluid.System system annotation(
    Placement(visible = true, transformation(origin = {-70, 42}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  
  Modelica.Fluid.Sources.Boundary_pT boundary(redeclare package Medium = Medium,T = 328.15, p = 157e5, nPorts = 1)  annotation(
    Placement(visible = true, transformation(origin = {-66, 10}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  Modelica.Fluid.Sources.MassFlowSource_T boundary1(redeclare package Medium = Medium,T = 328.15, m_flow = -0.17, nPorts = 1)  annotation(
    Placement(visible = true, transformation(origin = {72, 10}, extent = {{10, -10}, {-10, 10}}, rotation = 0)));
  
  Modelica.Fluid.Pipes.StaticPipe pipe2(redeclare package Medium = Medium,diameter = 0.15, length = 1)  annotation(
    Placement(visible = true, transformation(origin = {44, 10}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  
  Modelica.Fluid.Fittings.SimpleGenericOrifice orifice(redeclare package Medium = Medium,diameter = 0.15, dp_nominal = 5e+06, m_flow_nominal = 2.34e-9, use_zeta = false)  annotation(
    Placement(visible = true, transformation(origin = {2, 10}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));
  
  Modelica.Fluid.Pipes.StaticPipe pipe1(redeclare package Medium = Medium, diameter = 0.15, length = 1)  annotation(
    Placement(visible = true, transformation(origin = {2, -18}, extent = {{-10, -10}, {10, 10}}, rotation = 0)));

equation
  
  connect(boundary.ports[1], pipe.port_a) annotation(
    Line(points = {{-56, 10}, {-48, 10}}, color = {0, 127, 255}));
  connect(pipe.port_b, orifice.port_a) annotation(
    Line(points = {{-28, 10}, {-8, 10}}, color = {0, 127, 255}));
  connect(pipe2.port_b, boundary1.ports[1]) annotation(
    Line(points = {{54, 10}, {62, 10}}, color = {0, 127, 255}));
  connect(orifice.port_b, pipe2.port_a) annotation(
    Line(points = {{12, 10}, {34, 10}}, color = {0, 127, 255}));
  connect(pipe.port_b, pipe1.port_a) annotation(
    Line(points = {{-28, 10}, {-20, 10}, {-20, -18}, {-8, -18}}, color = {0, 127, 255}));
  connect(pipe1.port_b, pipe2.port_a) annotation(
    Line(points = {{12, -18}, {26, -18}, {26, 10}, {34, 10}}, color = {0, 127, 255}));
  annotation(
    uses(Modelica(version = "3.2.3")));

end Joints_HD;

此致，马克西姆

Answer 1

pipe1 尺寸（直径、长度、粗糙度等）“错误”，因为它只会产生非常小的压降。

验证模型的其余部分是否正常 - 并且在 boundary1（0.17 kg/s 中设置的流量下，您可以在 pipe1 上压降 50 巴) — 使用 m_flow_nominal=0.17 和 dp_nominal=50 bar.

暂时将 pipe1.FlowModel 更改为 NominalTurbulentPipeFlow

随后，将流模型切换回默认（详细）模型并调整管道几何形状。

顺便说一句，即使未使用，您也应该为 orifice.zeta 提供一个值。

如何使用 Modelica 标准库的 SimpleGenericOrifice 在管道中施加压力损失？

How can I use the SimpleGenericOrifice of the Modelica Standard Library to impose pressure loss in a pipe?

modelica

openmodelica

fluid-dynamics