NominalPoint L4
Created Mittwoch 21 Oktober 2015
A heat transfer model based on the mean heat transfer coefficient (htc) which is user-defined by a nominal point and mass flow dependent (simple empirical correlation)
1. Purpose of Model
This model allows a simple and robust definition of the heat transfer coefficient by a nominal point. The model is appropriate when dependencies of the fluid properties on the heat transfer are negligible. The heat transfer coefficient is mass flow dependent, which is expressed by a simple, empirical correlation. Therefore, load changes which affect the heat transfer can be covered to a limited extend.
2. Physical Insight
This replaceable model is compatible to models of level of detail L4 according to Brunnemann et al. [1] because the system is modelled with the use of balance equations, which are spatially averaged over the component.
3. Limits of Validity
- no dependencies of fluid properties, e.g. from density or Prandtl - number
- empirical correlation
- points away from the nominal point should be cross-checked with physical correlations if htc is of importance
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 L4
5. Nomenclature
6. Governing Equations
Each element of the heat transfer coefficient array α is equal to the user-defined nominal heat transfer coefficient. The mass flow dependency is expressed with the exponent 0.8.
7. Remarks for Usage
- Avoid very large values for
as it will cause numerical problems without gaining extra precision. Use IdealHeatTransfer L4 instead. - Points away from the nominal point should be cross-checked with physical correlations if htc is of importance.
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 - Friedrich Gottelt, XRG Simulation
Backlinks: ClaRa:Components:HeatExchangers:RegenerativeAirPreheaterSecAir L4 ClaRa:Components:HeatExchangers:RegenerativeAirPreheater L4 ClaRa:Basics:ControlVolumes:GasVolumes:VolumeGas L4 ClaRa:Components:VolumesValvesFittings:Pipes:PipeFlowGas L4 Simple