HEXvle2gas L3 2ph BU simple

Created Monday 10 June 2013

A block-shaped steam to air preheater model with flue gas/air medium at shell side and steam/water medium at the tube side. A block-geometry for low pressure air preheaters with U-type tube bundles is assumed. The tube side phases are modelled separately.

1. Purpose of Model


This model is well suited to model transients of commonly designed low pressure air preheaters. This model will be the right choice if the separation processes at the tube side are of interest.

2. Level of Detail, Physical Effects Considered and Physical Insight


2.1 Level of Detail

Referring to Brunnemann et al. [1], this model refers to the level of detail L3 because the system is modelled with the use of balance equations applied to three different zones of the component: gas component at shell side, vapour and liquid volume at tube side.

2.2 Physical Effects Considered


2.3 Level of Insight


Heat Transfer


shell side

tube side:

Pressure Loss


shell side

tubes side




Phase Separation


shell side

intrinsic ideally mixed gas flow.

tube side:

Basics:ControlVolumes:Fundamentals:SpatialDistributionAspects:RealSeparated : level dependent phase separation



3. Limits of Validity

4. Interfaces


5. Nomenclature

- no model specific nomenclature -

6. Governing Equations


6.1 System Description and General model approach


This model is composed by instantiation of the following classes:

6.2 General Model Equations


Summary

A record summarising the most important variables is provided. Please be aware of the boolean showExpertSummary in the parameter dialog tab "Summary and Visualisation". Setting this parameter to true will give you more detailed information on the components behaviour. The summary consists of the outline:

and the summaries of the class instances named in section 6.1


7. Remarks for Usage


7.1 Naming

The naming of heat exchangers in this package follows some specific form that is defined as follows:

7.2 Heat Transfer Modelling

In most cases the heat transfer from one fluid to the other will be dominated by the heat transfer at one of fluid boundary layers. In that cases the heat transfer coefficient α at this side will be considerably smaller than on the other side. From a numerical point of view it is disadvantageous to have very high (close to infinite) heat transfer coefficients on either sides. If you want to take nearly ideal heat transfer at one of the sides into account please consider the corresponding replaceable model instead of defining arbitrary large heat transfer coefficients in the model.

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 Simulation of 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

- corrected calculation of shell side A_heat: previous versions used lateral shell surface instead of tube bundle lateral surface
- propagated parameters level_rel_start, h_liq_start, h_vap_start
- removed unused parameters verticalTubes and mainOrientation
- corrected tube side A_heat and volume which is now in consonance with the shell side definition and depends on both parameters, flowOrientation and parallelTubes.
- changed default values of z_in_shell and z_out_shell, to avoid newly introduced asserts (e.g. z_in_shell>max height). Furthermore, the new values are in consonance with the default flow orientation.
- T.Hoppe, F.Gottelt, XRG Simulation
- added optional measurement conectors - Friedrich Gottelt, XRG Simulation GmbH
- new heat transfer models can be chosen - Timm Hoppe and Annika Kuhlmann, XRG Simulation GmbH, Lasse Nielsen TLK Thermo GmbH