Convection carrierTubes turbulent L2
Created Wednesday 13 Juni 2018
A model used to calculate the heat transfer coefficient for a convection at longitudinal tubes (carrier tubes) according to VDI-Wärmeatlas [1] chapter Gd1. This model usually used for convection at flat walls is calculating more appropriate vales for the heat transfer coefficient than Convection carrierTubes laminar L2.
1. Purpose of Model
A model used to calculate the heat transfer coefficient for a laminar or turbulent flow at longitudinal tubes (carrier tubes) according to VDI-Wärmeatlas [1] chapter Gd1. This model usually used for convection at flat walls is calculating more appropriate vales for the heat transfer coefficient than Convection carrierTubes laminar L2.
2. Level of Detail, Physical Effects Considered and Physical Insight
2.1 Level of Detail
Referring to Brunnemann et al. [2], this model refers to the level of detail L2.
3. Limits of Validity
According to [1] this model is valid for Reynolds numbers in the range of 10¹ < Re < 10⁷ and for Prandtl numbers between 0.6 < Pr < 2000
4. Interfaces
4.1 Physical Connectors
Basics:Interfaces:HeatPort a heat
5. Nomenclature
6. Governing Equations
The mean temperature difference is defined as follows, based on the user's choice in the boolean parameter temperature difference:
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 velocity of the gas is calculated as follows:
The characteristic length is calculated as follows:
With the velocity, the characteristic length, dynamic viscosity and density the Reynolds number is calculated:
The Nusselt numbers are calculated with Reynolds and Prandtl number:
The heat transfer coefficient is then calculated as follows:
7. Remarks for Usage
Usage inside limits of validity recommended.
8. Validation
9. References
[1] Auracher H., et al.: "VDI-Wärmeatlas", 10. erweiterte Auflage, Springer-Verlag Berlin Heidelberg New York, 2000, ISBN: 3-540-25504-4
[2] 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
Date - Version - Description of changes - author/revisor
25.06.2013 - v0.1 - initial implementation of the model - Lasse Nielsen, TLK-Thermo GmbH