Single-phase convection heat transfer characteristics of pebble-bed channels with internal heat generation

• Published in: Nuclear engineering and design Vol. 252; pp. 121 - 127
• Main Authors: Meng, Xianke, Sun, Zhongning, Xu, Guangzhan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2012; Elsevier
• Subjects: Applied sciences; Channels; Controled nuclear fusion plants; Density; Deviation; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Heat transfer; Heat transfer coefficients; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; Nuclear reactor components; Pebble bed; Refrigerants; Theoretical studies. Data and constants. Metering; Water cooled reactor; Pebble bed reactor; Stainless steel; Heat flow; Heat transfer coefficient; Carbon; Heat transfer; Reactor core; Nuclear reactor
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2012.05.041

The core of the water-cooled pebble bed reactor is the porous channels which stacked with spherical fuel elements. The gaps between the adjacent fuel elements are complex because they are stochastic and often shift. We adopt electromagnetic induction heating method to overall heat the pebble bed. By comparing and analyzing the experimental data, we get the rule of power distribution and the rule of heat transfer coefficient with particle diameter, heat flux density, inlet temperature and working fluid's Re number. [Display omitted] ► We adopt electromagnetic induction heating method to overall heat the pebble bed to be the internal heat source. ► The ball diameter is smaller, the effect of the heat transfer is better. ► With Re number increasing, heat transfer coefficient is also increasing and eventually tends to stabilize. ► The changing of heat power makes little effect on the heat transfer coefficient of pebble bed channels. The reactor core of a water-cooled pebble bed reactor includes porous channels that are formed by spherical fuel elements. This structure has notably improved heat transfer. Due to the variability and randomness of the interstices in pebble bed channels, heat transfer is complex, and there are few studies regarding this topic. To study the heat transfer characters of pebble bed channels with internal heat sources, oxidized stainless steel spheres with diameters of 3 and 8mm and carbon steel spheres with 8mm diameters are used in a stacked pebble bed. Distilled water is used as a refrigerant for the experiments, and the electromagnetic induction heating method is used to heat the pebble bed. By comparing and analyzing the experimental results, we obtain the governing rules for the power distribution and the heat transfer coefficient with respect to particle diameter, heat flux density, inlet temperature and working fluid Re number. From fitting of the experimental data, we obtain the dimensionless average heat transfer coefficient correlation criteria and find that the deviation between the fitted results and the experimental results is 12% or less.