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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-469-4

ISBN Online: 978-1-56700-470-0

Second Thermal and Fluids Engineering Conference
April, 2-5, 2017, Las Vegas, NV, USA

SINGLE-PHASE CONVECTIVE HEAT TRANSFER IN A ROD BUNDLE CONTAINING PARTIAL BLOCKAGE

Get access (open in a dialog) pages 3159-3164
DOI: 10.1615/TFEC2017.tpo.017900

Abstract

In the hypothesis of a large break loss-of-coolant accident (LB LOCA), during the early stage of reflooding phase, the dominant heat transfer mechanism is mainly single-phase convective heat transfer to vapor. A series of experiments on the wall-to-vapor convective heat transfer has been conducted in 5×5 rod bundles containing 3×3 ballooned rods of 90% flow blockage ratio. The experimental results showed significant increase in local heat transfer downstream of the blockage. The increase in heat transfer might result from flow separation occurred due to the expansion at the top end of the blockage. The single-phase heat transfer enhancement models implemented in the COBRA-TF code underestimated local heat transfer in the blockage downstream region. Therefore, a new flow blockage correlation was proposed to improve the prediction capability of the conventional models in the COBRA-TF code by more accurately describing the effect of flow separation. The new correlation showed good agreement with the experimental data.