基于Modelica Fluid库修改无摩擦管道模型仿真未达预期

模型修改内容 #

我基于dynamicPipe模型构建无摩擦管道模型，具体修改如下：

1. 修改dynamicPipe模型代码 #

extends PartialStraightPipe_noFric(final port_a_exposesState = (modelStructure == ModelStructure.av_b) or (modelStructure == ModelStructure.av_vb), final port_b_exposesState = (modelStructure == ModelStructure.a_vb) or (modelStructure == ModelStructure.av_vb));
  // extending PartialTwoPortFlow
  extends PartialTwoPortFlow_noFric(final lengths = fill(length/n, n), final crossAreas = fill(crossArea, n), final dimensions = fill(4*crossArea/perimeter, n), final roughnesses = fill(roughness, n), final dheights = height_ab*dxs);
  // Wall heat transfer

2. 替换PartialStraightPipe_noFric和PartialTwoPortFlow_noFric中的FlowModel #

// Pressure loss model
replaceable model FlowModel = Modelica.Fluid.Pipes.BaseClasses.FlowModels.DetailedPipeFlow constrainedby PartialStaggeredFlowModel_noFric "Wall friction, gravity, momentum flow"

3. 修改PartialStaggeredFlowModel_noFric的动量平衡逻辑 #

// Momentum balances
if momentumDynamics == Modelica.Fluid.Types.Dynamics.SteadyState then
  zeros(m) = Ib_flows - Fs_p;
else
  der(Is) = Ib_flows - Fs_p;
end if;

4. 移除dynamicPipe能量方程中的摩擦项 #

示例修改代码：

Wb_flows[1] = vs[1]*crossAreas[1]*(mediums[2].p - mediums[1].p)/2;

存在的问题 #

模型编译已通过，但在带指定泵的测试场景中，修改管道长度或直径时，流量值仍会发生变化。按照无摩擦管道的预期，流量不应受这些参数影响，目前仿真未达到预期效果。

内容的提问来源于stack exchange，提问作者pionao