I am trying to add a pressure boundary to my pipe and get the following error during initialization:
Error: Singular inconsistent scalar system for
pipe.h_out = ((if boundary.m_flow > 0.0 then pipe.volume.h else 0.0)-pipe.h[...])/( -(if boundar.m_flow > 0.0 then 0.0 else 1.0)) = 2.38651e-009/-0
HandleRoot:HandleRoot
[...] -> Too long for output in the consol i think
Anyone had a similar problem and knows how to solve this? I am calculating the pressuredifference with a function for dp out of massflow. Could it be that?
Additional Informations:
I am using Dymola with the Library ClaRa. The model in question is a pipe model with the volume splitter for thermal inertia "ClaRa.Components.VolumesValvesFittings.Fittings.SplitVLE_L2_flex". The model is build up from two pressure boundaries. One connecting to a supply pipe and one to the return pipe. The ends of the pipes are connected over the volume to two simple consumer models with each of them having a valve to control the return temperature.
Update: I reduced the error to:
The following error was detected at time: 0
Error: Scalar system is always singular for supply_pipe.volume.p = (0.0)/(0.0) = 0/0
FixInitials:Init
Which only happens when i connect the second consumer to the supply/return pipe. The model computes with only one consumer.
Changing the pressurloss model to one that calculates the massflow from given pressure doesnt solve the issue.
I've found the solution to the problem.
I've had a resistance to resistance connection between the pipes and a shorting between the connectors. Creating another pipe with a volume model at the beginning instead of the end solved it.