CounterFlow
Created Montag 22 Februar 2016
This replaceable model provides geometry specific correction factors for the NTU method to calculate steady state cross flow heat exchangers.
1. Purpose of Model
Calculate the geometry depending correction factor for the NTU-based heat exchanger models described in [2].
2. Level of Detail, Physical Effects Considered and Physical Insight
2.1 Level of Detail
This replaceable model is compatible to models of level of detail L2 or L3 according to Brunnemann et al. [1].
2.2 Physical Effects Considered
3. Limits of Validity
The limits of validity of the applying model SolidVolumes:NTU L2 are applicable.
4. Interfaces
5. Nomenclature
6. Governing Equations
The VDI Wärmeatlas [2] provides an approach for calculating the heat exchanger performance in a simple and uniform way. This approach references the performance of the ideal counter current heat exchanger and applies a correction factor to it. This correction factor is used in SolidVolumes:NTU L2 and calculated here depending on the specific geometry chosen. In [2] a considerable number of heat exchangers is listed which is beyond the scope of this package but can be easily implemented in the future.
The flow type dependent correction factor is defined as the ratio of NTU values for counter current and the actual type.
According to that equation, the 
of a chosen flow type can be simply determined by dividing the 
with the below defined correction factor.
For counter current heat exchanger 
takes the minimum value 1.
The following heat exchanger types are currently featured:
7. Remarks for Usage
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
[2] VDI Wärmeatlas (VDI Heat Atlas), Chapter Ca5, 9th edition 2002
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
17.08.2012 - Version 0.2 - initial implementation - Friedrich Gottelt/ Ala Renz, XRG Simulation
Backlinks: ClaRa:Components:HeatExchangers:HEXvle2gas L3 1ph BU ntu ClaRa:Components:HeatExchangers:HEXvle2vle L3 1ph BU ntu ClaRa:Components:HeatExchangers:HEXvle2vle L3 1ph kA ClaRa:Components:HeatExchangers:PlateHEXvle2vle L3 2ph ntu ClaRa:Basics:ControlVolumes:SolidVolumes:NTU L2