Mechanism analysis of quasi-static dense pebble flow in pebble bed reactor using phenomenological approach

• Published in: Nuclear engineering and design Vol. 250; pp. 247 - 259
• Main Authors: Yang, X.T., Hu, W.P., Jiang, S.Y., Wong, K.K.L., Tu, J.Y.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-09-2012; Elsevier
• Subjects: Applied sciences; Availability; Collapse; Controled nuclear fusion plants; Design engineering; Discrete element method; Energy; Energy. Thermal use of fuels; Equivalence; Exact sciences and technology; Fission nuclear power plants; Friction; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear engineering; Nuclear fuels; Pebble bed reactors; Pebble bed reactor; Flow field; Nuclear reactor
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2012.06.011

► We introduced four basic forms of phenomenological method for pebble flow. ► We discussed the physical nature of the quasi-static pebble flow. ► We verified the applicability of the discrete element method. ► We investigated the parameter effects on quasi-static pebble flow.
By means of the four basic forms of the phenomenological method, experimental results have intuitionally disclosed the physical mechanism from various views of the quasi-static pebble flow in a pebble bed reactor and successfully verified the availability of the discrete element method, on which the parameter effects have been investigated, including different base cone angle and different friction coefficient. The flow fields under different parameters have been discussed. On the basis of these researches, a framework of the general understanding of pebble flow mechanism has been drawn; many essential problems are discussed, including the interpretation of the quasi-static pebble flow, force analysis inside the pebble packing, propagation and distribution of the voids, internal equilibrium arches, competition mechanism, internal collapse, self-organization, equivalent shear force, equivalent normal force, the physical process of stagnant zone's influence on the overall flow field, and so on. All of these are very helpful to understand the physical mechanism of the quasi-static pebble flow in a pebble bed reactor.