AixLib.Fluid.FixedResistances.BaseClasses.PlugFlowCore

# .AixLib.Fluid.FixedResistances.BaseClasses.PlugFlowCore

Pipe model using spatialDistribution for temperature delay with modified delay tracker

## Information

Pipe with heat loss using the time delay based heat losses and plug flow for the transport delay of the fluid.

#### Implementation

The `spatialDistribution` operator is used for the temperature wave propagation through the length of the pipe. This operator is contained in BaseClasses.PlugFlow.

This model does not include thermal inertia of the pipe wall. The wall inertia is implemented in PlugFlowPipe, which uses this model.
The removal of the thermal inertia with a mixing volume can be desirable in the case where mixing volumes are added manually at the pipe junctions.

The model PlugFlowHeatLoss implements a heat loss in design direction, but leaves the enthalpy unchanged in opposite flow direction. Therefore it is used in front of and behind the time delay.

#### References

Full details on the model implementation and experimental validation can be found in:

van der Heijde, B., Fuchs, M., Ribas Tugores, C., Schweiger, G., Sartor, K., Basciotti, D., Müller, D., Nytsch-Geusen, C., Wetter, M. and Helsen, L. (2017).
Dynamic equation-based thermo-hydraulic pipe model for district heating and cooling systems.
Energy Conversion and Management, vol. 151, p. 158-169. doi: 10.1016/j.enconman.2017.08.072 .

## Revisions

- April 14, 2020, by Michael Wetter:
  Changed `homotopyInitialization` to a constant.
  This is for AixLib, #1341.
- October 20, 2017, by Michael Wetter:
  Replaced model that lumps flow resistance and transport delays with two separate models, as these are physically distinct processes. This also avoids one more layer of models.
  Revised variable names and documentation to follow guidelines.
- July 4, 2016 by Bram van der Heijde:
  Introduce `pipVol`.
- October 10, 2015 by Marcus Fuchs:
  Copy Icon from KUL implementation and rename model. Replace resistance and temperature delay by an adiabatic pipe.
- September, 2015 by Marcus Fuchs:
  First implementation.

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