NusseltPipe1ph L2

Created Thursday 13 June 2013

Heat transfer model based on Nusselt Number for one-phase pipe flow. Takes Geometry data, flow data and media data into account

1. Purpose of Model

A detailed model that takes all relevant dependencies into account. This model is numerically less robust than other models, e.g HeatTransport:Generic HT:CharLine L2 since it takes fluid states and flow regimes into account. Phase change is not supported and will lead to unphysical heat transfer coefficients.

2. Level of Detail and Physical Effects Considered

2.1 Level of Detail

Referring to Brunnemann et al. [1], this model refers to the level of detail L2 because the system is modeled with the use of balance equations, which are spatially averaged over the component.

2.2 Physical Effects Considered

dependencies of the heat transfer coefficient on the Reynolds Number
dependencies of the heat transfer coefficient on the Prandtl Number
reverse flow
flow regime change

3. Limits of Validity

simplified transition regime
no two phase flow supported

4. Interfaces

The model communicates via outer models and records. Thus its expects to have:

an outer model named geo as defined Fundamentals:Geometry:GenericGeometry
an outer record named iCom as defined in Basics:Records:IComBase L2

It has further a Basics:Interfaces:HeatPort a heat that shall be connected with the applying component model.

5. Nomenclature

6. Governing Equations

The mean temperature difference is defined as follows, based on the user's choice in the boolean parameter temperatureDifference:

Please note that for the choice temperatureDifference="Logarithmic mean" a number of means is applied to make the equation regular also for zero heat flow and reversing heat flows. If an unsupported string for temperatureDifference is provided an assert would raise.

The mean heat transfer coefficients according to [2] for the laminar and the turbulent regime are calculated as follows:

with

A smooth transtion between of laminar and turbulent heat transfer coefficient is applied.

7. Remarks for Usage

If the computing effort has to be reduced or the model can be made responsible for numerical unstable behavior, use this model to tune e.g. HeatTransport:Generic HT:Constant L2 and replace it.

8. Validation

9. References

[1] Johannes Brunnemann and Friedrich Gottelt, Kai Wellner, Ala Renz, André Thüring, Volker Röder, Christoph Hasenbein, Christian Schulze, Gerhard Schmitz, Jörg Eiden: "Status of ClaRaCCS: Modelling and Simulationof Coal-Fired Power Plants with CO2 capture", 9th Modelica Conference, Munich, Germany, 2012

10. Authorship and Copyright Statement for original (initial) Contribution

Author:
DYNCAP/DYNSTART development team, Copyright 2011 - 2022.
Remarks:
This component was developed during DYNCAP/DYNSTART projects.
Acknowledgements:
ClaRa originated from the collaborative research projects DYNCAP and DYNSTART. Both research projects were supported by the German Federal Ministry for Economic Affairs and Energy (FKZ 03ET2009 and FKZ 03ET7060).
CLA:
The author(s) have agreed to ClaRa CLA, version 1.0. See https://claralib.com/pdf/CLA.pdf
By agreeing to ClaRa CLA, version 1.0 the author has granted the ClaRa development team a permanent right to use and modify his initial contribution as well as to publish it or its modified versions under the 3-clause BSD License.

11. Version History

2012 - v 0.1 -initial implementation - Ala Renz, Friedrich Gottelt, XRG-Simulation
2019 - v 1.4.0 - bugfix calculation of pipe length - Timm Hoppe, XRG-Simulation