图书馆订购 Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Implementation of the SUN Model for Radiation Heat Transfer in Packed Pebble Bed Gas Cooled Reactors

Get access (open in a dialog) DOI: 10.1615/IHTC15.rad.009143
pages 7207-7221

摘要

The effective thermal conductivity is a crucial parameter in determining the inherent safety of packed pebble bed cooled reactors. Radiation heat transfer plays an important role in this phenomenon, especially at high temperatures. Empirical data suggests that the effective conductivity should not only be correlated as a function of the local temperature level but also of the macro temperature gradient through the bed. This is addressed in the Spherical Unit Nodalization (SUN) methodology which was proposed recently as a basis to model the radiation heat transfer. However, a generic implementation methodology has not yet been presented. The SUN model is similar to the zonal method that has been used extensively for engineering problems in radiating gases such as combustion chambers. The bed is subdivided into a number of control volumes containing surface areas which are assumed to be isothermal. An energy balance is performed for the radiation heat transfer between each pair of zones using pre-calculated direct exchange areas. This results in a radiosityirradiation network representation that may be solved to obtain the unknown surface temperatures and heat fluxes. The direct exchange areas are derived based on effective view factors calculated via a Monte Carlo ray tracing method applied to representative discrete geometries. This paper describes the methodology for the implementation of the SUN model within generic threedimensional geometries and presents the results of case studies that illustrate its applicability and highlight further refinements that are required.