Convection finnedTubes L2
Created Monday 11 April 2016
A model used to calculate the heat transfer coefficient inside a finned tube bank according to [1].
1. Purpose of Model
A model used to calculate the heat transfer coefficient inside a finned tube bank, for example used in economizers, according to[1].
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
No limits of validity known.
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 number of fins is calculated as follows:
The surface of one fin:
The tube segment surface:
The overall finned surface is calculated as follows:
The tube surface as it were without tubes is calculated as follows:
The number parallel tubes:
The narrowed cross section is calculated as follows:
The mean free velocity of the gas is calculated as follows:
With the free velocity the velocity inside the narrowed cross section can be calculated:
With the velocity, the tube diameter, dynamic viscosity and density the Reynolds number is calculated:
The factors for aligned and staggered tubes are depending on the number of tube rows:
The Nußelt number is calculated for staggered and aligned tubes separately:
The heat transfer coefficient is then calculated as follows:
The fin geometry can be set to circular or rectangular fins. For circular fins the factors are calculated as follows:
and for rectangular fins:
The fin efficiency factor is then calculated as follows:
With this value the fin efficiency can be calculated:
The fin temperature is calculated as follows:
With these values the heat flow can be calculated:
7. Remarks for Usage
Usage inside limits of validity recommended.
8. Validation
9. References
[1] Helmut Effenberger: "Dampferzeugung", Springer-Verlag Berlin Heidelberg New York, 2000, ISBN:3-450-64175-0
[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
Backlinks: ClaRa:Components:HeatExchangers:HEXvle2gas L3 1ph BU ntu ClaRa:Components:HeatExchangers:HEXvle2gas L3 1ph BU simple ClaRa:Components:HeatExchangers:HEXvle2gas L3 2ph BU simple ClaRa:Components:Furnace:FlameRoom:FlameRoomWithTubeBundle L2 Dynamic ClaRa:Components:Furnace:FlameRoom:FlameRoomWithTubeBundle L2 Static