bug in Modelica.Fluid.Pipes.DynamicPipe

[modelica-trac-importer]

Reported by kilian_link on 23 Sep 2009 15:23 UTC
discretization of linear pressure drop correlation fails, i.e. linear pressure drop depends on nNodes and is wrong for nNodes>1

---

Migrated-From: https://trac.modelica.org/Modelica/ticket/215

[modelica-trac-importer]

Comment by kilian_link on 1 Oct 2009 09:32 UTC
Fixed bug in Modelica.Fluid.Pipes.BaseClasses.FlowModels.NominalLaminarFlow and its sub models to work correctly with the DynamicPipe model. Changes might corrupt other models, hence this should be double checked by an expert.

Modelica.Fluid.Pipes.BaseClasses.FlowModels.NominalTurbulentPipeFlow seems to be still buggy and should be fixed by someone who is familar with the model layout in Fluid.

[modelica-trac-importer]

Comment by rfranke on 2 Oct 2009 13:59 UTC
Thank you for the investigation of the DynamicPipe model and for the example testDynamicPipeLinearPressureLoss.mo illustrating your issue.

It turns out that there were two bugs in the NominalLaminarFlow model:

1. the number of flow segments was not considered
2. the number of parallel pipes was considered incorrectly.
   Thank you for the fix.

The NominalTurbulentPipeFlow model was facing the first bug only. It now considers the number of flow segments as well. The NominalTurbulentPipeFlow model is more complex because it uses the regular TurbulentPipeFlow and adapts the pipe length such that the specified nominal pressure drop is fulfilled.

This ticket also covers another bug: the consideration of the number of parallel pipes for the velocity of fluid flow. The flow velocity should not be adapted in the flow model, but in the overall pipe models. Also there one wants to see the correct velocity. This is why I reverted your changes in PartialStaggeredFlowModel. The pipe models PartialTwoPortFlow (base class of DynamicPipe) and StaticPipe have been corrected instead.

See SVN, 9663715.

[modelica-trac-importer]

Comment by dietmarw on 2 Oct 2009 15:50 UTC
Was also applied to maintenance/3.1 (d3d07d9).

[modelica-trac-importer]

Comment by dietmarw on 25 Nov 2009 11:53 UTC
Milestone MSL3.1.1 deleted