Wen-De Zhao , Hong-Na Zhang , Xiao-Bin Li , Jun-Liang Guo , Yue Wang , Wei-Hua Cai , Shu-Qi Meng , Fang Chen , Yu-Long Mao , Feng-Chen Li
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引用次数: 0
Abstract
Thermal striping in the upper plenum of the lead-cooled fast reactor (LFR) is a temperature fluctuation phenomenon caused by the mixing of two non-isothermal fluids, and can lead to high cycle thermal fatigue and cracks in adjacent structures. Quantitative study of thermal striping is of great significance for the safe operation of reactors. This paper studies the thermal striping phenomena of lead-bismuth eutectic in a parallel five-jet plenum based on large eddy simulation. The parametric effects on characteristics of temperature fluctuation in terms of its statistics and flow structures are focused on, including the effects of temperature differences and velocity ratios. The results show that the temperature difference and velocity ratio significantly affect the flow patterns of thermal and flow fields, as well as the statistical characteristics of thermal striping. Under isovelocity conditions, the flow pattern of fluids is symmetric, whereas it is affected by velocity ratio in non-isovelocity scenarios. With isovelocity, increasing temperature difference raises the average temperature, heat flux and temperature fluctuation intensity. For non-isovelocity conditions, higher velocity ratios reduce average temperature but increase heat flux, with temperature fluctuation intensity showing an initial increase followed by a decrease. Spectral analysis indicates that the temperature difference primarily increases the temperature fluctuation amplitudes (the dominant frequency stabilized at about 5 Hz). Conversely, increasing velocity ratio decreases the amplitude and raises the dominant frequency. These findings provide valuable insights for understanding the mechanism of thermal striping of liquid lead-bismuth eutectic.
期刊介绍:
The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review.
The fundamental subjects considered within the scope of the journal are:
* Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow
* Forced, natural or mixed convection in reactive or non-reactive media
* Single or multi–phase fluid flow with or without phase change
* Near–and far–field radiative heat transfer
* Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...)
* Multiscale modelling
The applied research topics include:
* Heat exchangers, heat pipes, cooling processes
* Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries)
* Nano–and micro–technology for energy, space, biosystems and devices
* Heat transport analysis in advanced systems
* Impact of energy–related processes on environment, and emerging energy systems
The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.