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Effects of vertically ribbed surface roughness on the forced convective heat losses in central receiver systems

Uhlig, Ralf and Frantz, Cathy and Fritsch, Andreas (2016) Effects of vertically ribbed surface roughness on the forced convective heat losses in central receiver systems. AIP Conference Proceedings, 1743. American Institute of Physics (AIP). DOI: http://dx.doi.org/10.1063/1.4949088 ISSN 0094-243X

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Official URL: http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.4949088

Abstract

External receiver configurations are directly exposed to ambient wind. Therefore, a precise determination of the convective losses is a key factor in the prediction and evaluation of the efficiency of the solar absorbers. Based on several studies, the forced convective losses of external receivers are modeled using correlations for a roughened cylinder in a cross-flow of air. However at high wind velocities, the thermal efficiency measured during the Solar Two experiment was considerably lower than the efficiency predicted by these correlations. A detailed review of the available literature on the convective losses of external receivers has been made. Three CFD models of different level of detail have been developed to analyze the influence of the actual shape of the receiver and tower configuration, of the receiver shape and of the absorber panels on the forced convective heat transfer coefficients. The heat transfer coefficients deduced from the correlations have been compared to the results of the CFD simulations. In a final step the influence of both modeling approaches on the thermal efficiency of an external tubular receiver has been studied in a thermal FE model of the Solar Two receiver.

Item URL in elib:https://elib.dlr.de/109152/
Document Type:Article
Title:Effects of vertically ribbed surface roughness on the forced convective heat losses in central receiver systems
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Uhlig, RalfRalf.Uhlig (at) dlr.deUNSPECIFIED
Frantz, Cathycathy.frantz (at) dlr.deUNSPECIFIED
Fritsch, AndreasAndreas.Fritsch (at) dlr.deUNSPECIFIED
Date:2016
Journal or Publication Title:AIP Conference Proceedings
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Volume:1743
DOI :http://dx.doi.org/10.1063/1.4949088
Publisher:American Institute of Physics (AIP)
ISSN:0094-243X
Status:Published
Keywords:Molten salt, external receiver, convective losses, Solar Two, CFD, FEM
HGF - Research field:Energy
HGF - Program:Renewable Energies
HGF - Program Themes:Concentrating Solar Thermal Technology
DLR - Research area:Energy
DLR - Program:E SF - Solar research
DLR - Research theme (Project):E - Advanced Heat Transfer Media (old)
Location: Stuttgart
Institutes and Institutions:Institute of Solar Research > Punktfokussierende Systeme
Deposited By: Uhlig, Tamara
Deposited On:12 Dec 2016 15:18
Last Modified:08 Mar 2018 18:19

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