Experimental and theoretical study of post-dryout heat transfer in annuli with flow obstacle
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
An experimental study on post dryout heat transfer regime in annuli with flow obstacles wasconducted in the High-pressure Water Test (HWAT) loop at the Royal Institute of Technologyin Stockholm, Sweden. An annulus with flow obstacles, consisting of two concentric heatedpipes (12.7x24.3) mm, with total heated length equal to 3650 mm was employed as a testsection. The experimental investigations were performed in a wide range of the operationalconditions: mass flux (500-1750) kg/(m2s), inlet subcooling (10-40) K and system pressure(5-7) MPa. The wall superheat was measured at 88 different axial positions. A significanteffect of the flow obstacles on the wall temperature has been observed. A new correlation toevaluate the wall superheat in the post-dryout developing region and downstream of the flowobstacles was suggested. The new approach is taking into account in a combined manner theonset of the dryout point and the flow obstacle location. The coefficients and constants of thecorrelation have been optimized based on 1211 points obtained experimentally. Thecorrelation is applicable starting with the point of the onset of the dryout towards fullydeveloped post-dryout heat transfer regime and shows a correct asymptotical trend. Toaccount for the flow obstacle effect on the critical quality, an expression similar to theLevitan-Lanstman dryout correlation is suggested. The newly developed methodology can beused to predict the wall temperature in the post-dryout heat transfer regime over a wide rangeof mass fluxes and pressures typical for boiling water reactors.
Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2013. , ix, 53 p.
TRITA-FYS, ISSN 0280-316X ; 2013:60
annulus, flow obstacles, critical heat flux, post-dryout, thermal margins, boiling water reactor
Research subject Physics
IdentifiersURN: urn:nbn:se:kth:diva-143210ISBN: 978-91-7501-909-3OAI: oai:DiVA.org:kth-143210DiVA: diva2:706045
2014-03-28, FB42, AlbaNova, Roslagstullsbacken 29, Stockholm, 10:00 (English)
Mikielewicz, Dariusz, Professor
Anglart, Henryk, Professor
QC 201403192014-03-192014-03-182014-03-24Bibliographically approved
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