RT Journal Article
T1 Thermal stress and fatigue damage of central receiver tubes during their preheating
A1 Pérez Álvarez, Rafael
A1 González Gómez, Pedro Ángel
A1 Acosta Iborra, Antonio
A1 Santana Santana, Domingo José
AB Preheating of the absorber tubes of a central receiver is a crucial operation in the start-up of current solar power tower plants (SPT) working with molten salt as a heat transfer fluid. In the preheating, a subset of the heliostat field is aimed at the receiver to produce an incident heat flux capable of heating the tube walls before they are filled with the molten salt. Incident radiation should be kept above a minimum as an insufficient level of preheating may lead to the freezing of the incoming flow of molten salt, interrupting the receiver operation. However, too much incident heat flux in the preheating causes severe thermal gradients in the walls of the tubes, leading to extremely high thermal-stresses and the eventual fatigue damage of the receiver. The present work numerically characterizes the temporal evolution of the temperature and thermal-stresses in the absorber tubes made of Haynes 230 alloy. This is done for two examples of SPT plants, i.e. Gemasolar and Dunhuang, with the aim of detecting when and where the largest temperature gradients and mechanical stresses appear during the tube preheating and evaluate their impact on the fatigue damage of the receiver tubes. The results show that during the first seconds of preheating, the front side to the tube is rapidly heated but the temperature at rear side of the tube is barely modified, causing a great non-uniformity of temperatures. This effect is enhanced when the tube diameter is increased because the heat requires more time to reach the rear side of the tubes. The peak values of the temperature gradient and the von Mises stress are reached during the first minutes of the preheating. Besides, under windy conditions, the preheating procedure proposed by Vant-Hull may be insufficient to preheat the receiver. Furthermore, in all the cases analyzed, the estimated fatigue damage of the tube is much less than the  upper limit to avoid significant creep-fatigue interaction. This indicates the Vant-Hull algorithm does not compromise the structural integrity of the studied receiver tubes.
PB Elsevier
SN 1359-4311
YR 2021
FD 2021-08-01
LK https://hdl.handle.net/10016/32889
UL https://hdl.handle.net/10016/32889
LA eng
NO The authors are grateful to acknowledge the financial support provided by  Spanish Government for  the project ENE2015-69486-R (MINECO/FEDER, UE), RTI2018-096664-B-C21 (MICINN, FEDER/UE) and the scholarship "Ayudas para contratos predoctorales para la formación de doctores” BES-2016–078455 awarded by the Ministerio de Economía, Industria y Competitividad and the fellowship "Programa de apoyo a la realización de proyectos interdisciplinares de I+D para jóvenes investigadores de la Universidad Carlos III de Madrid 2019–2020” under the Project ZEROGASPAIN-CM-UC3M (2020/00033/001) funded on the frame of "Convenio Plurianual Comunidad de Madrid-Universidad Carlos III de Madrid 2019–2022”
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RD 1 sept. 2024