Title

Characteristics of Convective Heat Transport in a Packed Pebble-Bed Reactor

Abstract

Obtaining more precise results and a better understanding of the heat transport mechanism in the dynamic core of packed pebble-bed reactors is needed because this mechanism poses extreme challenges to the reliable design and efficient operation of these reactors. This mechanism can be quantified in terms of a solid-to-gas convective heat transfer coefficient. Therefore, in this work, the local convective heat transfer coefficients and their radial profiles were measured experimentally in a separate effect pilot-plant scale and cold-flow experimental setup of 0.3 m in diameter, using a sophisticated noninvasive heat transfer probe of spherical type. The effect of gas velocity on the heat transfer coefficient was investigated over a wide range of Reynolds numbers of practical importance. The experimental investigations of this work include various radial locations along the height of the bed. It was found that an increase in coolant gas flow velocity causes an increase in the heat transfer coefficient and that effect of the gas flow rate varies from laminar to turbulent flow regimes at all radial positions of the studied packed pebble-bed reactor. The results show that the local heat transfer coefficient increases from the bed center to the wall due to the change in the bed structure, and hence, in the flow pattern of the coolant gas. The findings clearly indicate that one value of an overall heat transfer coefficient cannot represent the local heat transfer coefficients within the bed; therefore, correlations are needed to predict the radial and axial profiles of the heat transfer coefficient.

Department(s)

Chemical and Biochemical Engineering

Comments

The authors acknowledge the financial support provided by the U.S. Department of Energy-Nuclear Energy Research Initiative (DOE-NERI) project (NERI-08-043)for the 4th generation nuclear energy, which made this work possible.

This article is corrected by Erratum: Corrigendum to "Characteristics of Convective Heat Transport in a Packed Pebble-Bed Reactor" (Nuc. Eng. Des. 284 (2015) ,143–152).

International Standard Serial Number (ISSN)

0029-5493

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2015 Elsevier, All rights reserved.

Publication Date

01 Apr 2015

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