Initial Scaling Studies and Conceptual Thermal Fluids Experiments for the Prismatic NGNP Point Design

McEligot, D. M. ; McCreery, G. E.

Idaho National Laboratory

关键词: Thermal Fluids;    Heat Transfer;    Temperature Distribution;    Forced Convection;    Geometry;   

DOI  :  10.2172/910959
RP-ID  :  INEEL/EXT-04-02367
RP-ID  :  DE-AC07-99ID-13727
RP-ID  :  910959

美国|英语

来源: UNT Digital Library

【 摘 要 】

The objective of this report is to document the initial high temperature gas reactor scaling studies and conceptual experiment design for gas flow and heat transfer. The general approach of the project is to develop new benchmark experiments for assessment in parallel with CFD and coupled CFD/ATHENA/RELAP5-3D calculations for the same geometry. Two aspects of the complex flow in an NGNP are being addressed: (1) flow and thermal mixing in the lower plenum ("hot streaking" issue) and (2) turbulence and resulting temperature distributions in reactor cooling channels ("hot channel" issue). Current prismatic NGNP concepts are being examined to identify their proposed flow conditions and geometries over the range from normal operation to decay heat removal in a pressurized cooldown. Approximate analyses are being applied to determine key non-dimensional parameters and their magnitudes over this operating range. For normal operation, the flow in the coolant channels can be considered to be dominant forced convection with slight transverse property variation. The flow in the lower plenum can locally be considered to be a situation of multiple buoyant jets into a confined density-stratified crossflow -- with obstructions. Experiments are needed for the combined features of the lower plenum flows. Missing from the typical jet experiments are interactions with nearby circular posts and with vertical posts in the vicinity of vertical walls - with near stagnant surroundings at one extreme and significant crossflow at the other. Two heat transfer experiments are being considered. One addresses the "hot channel" problem, if necessary. The second experiment will treat heated jets entering a model plenum. Unheated MIR (Matched-Index-of-Refraction) experiments are first steps when the geometry is complicated. One does not want to use a computational technique which will not even handle constant properties properly. The MIR experiment will simulate flow features of the paths of jets as they mix in flowing through the array of posts in a lower plenum en route to the single exit duct. Initial conceptual designs for such experiments are described.