Experimental investigation of post-dryout heat transfer in an annulus with spacers
2004 (English)In: Proceedings of the 42th European Two-Phase Flow Group Meeting, 2004, 1-6 p.Conference paper (Other academic)
Experimental investigation of the post-dryout heat transfer in annulus test section has been performed in the high-pressure two-phase loop at the Royal Institute of Technology (KTH), Nuclear Reactor Technology division. The test section has an annular geometry with 10 mm rod outer diameter and 22.1 mm tube inner diameter. Seven spacers are located along the test section to keep the rod and the tube equidistant along the test section. Both the tube and the rod are manufactured of Inconel 600 to withstand high temperatures. The experiments indicate a very strong influence of spacers on post-dryout heat transfer. In particular, for several cases with relatively low local quality the dryout spot was limited to a direct proximity (upstream) of spacers. Only for relatively high powers the dryout patch could cover the whole distance between two neighboring spacers. For low mass flow rates dryout and post-dryout occurred near the test section outlet. With increasing mass flow rates the location of the dryout spot moved upstream of the upper-most spacer, for the cases when dryout occurred on the outer tube. The present experimental data give a new insight into the mechanism of dryout occurrence in annuli with spacers as well as indicate a strong ability of spacers to quench dryout spots and enhance the heat-transfer coefficient in the post-dryout heat transfer regime.
Place, publisher, year, edition, pages
2004. 1-6 p.
Heat transfer, boiling crisis, spacer effect
Research subject SRA - Energy
IdentifiersURN: urn:nbn:se:kth:diva-79209OAI: oai:DiVA.org:kth-79209DiVA: diva2:495239
QC 201202162012-02-162012-02-082012-02-16Bibliographically approved