钠液面高度对氩气空间耦合传热特性影响的实验研究

Experimental Study on Influence of Sodium Liquid Level on Coupled Heat Transfer Characteristic in Argon Space

锥顶盖作为快堆主容器重要的压力边界之一,其结构的完整性对快堆的安全运行至关重要。锥顶盖结构完整性与其温度载荷密切相关,而温度载荷受氩气空间自然对流与辐射耦合传热特性影响显著,有必要开展深入研究。基于钠液面上部氩气空间传热特性实验台架,开展了氩气空间传热特性实验研究,测量了锥顶盖、氩气空间和主泵支承的温度分布,阐明钠液面高度对传热特性的影响。实验结果表明,随着钠液面高度的增加,锥顶盖和氩气空间的温度随之升高,而且在高钠温时现象更加明显。此外,钠液面高度对主泵支承的温度分布和周向温差影响微弱。通过开展氩气空间钠液面高度对传热规律的影响研究,可为建立实验装置与原型反应堆之间的温度映射关系提供参考。

The cone top cover,as one of the critical pressure boundaries of the fast reactor primary vessel,is crucial for the safe operation of the fast reactor.The structural integrity of the cone top cover is closely related to the temperature load,which is significantly influenced by the coupled heat transfer characteristics of natural convection and thermal radiation in the argon space.It is necessary to conduct in-depth research.A scaled experimental platform,with a 1∶5 scale,of the heat transfer characteristics of the argon space above the sodium liquid level was designed and constructed.Based on this platform,experimental research on the coupled heat transfer characteristics of natural convection and thermal radiation in the argon space was conducted.The temperature distribution of the cone top cover,argon space,and main pump support under different sodium liquid level conditions was measured to elucidate the influence of the sodium liquid level on the heat transfer characteristics.The experimental results show that the temperature distribution along the dimensionless radius direction of the cone top cover may exhibit various patterns such as increase,plateau,or first increase and then decrease,which are related to the intensity of natural convection heat transfer,radiation heat transfer,and the geometric characteristics at different positions.The temperature of the cone top cover increases with the increase of the sodium liquid level,and due to the proportionality of thermal radiation to the fourth power of thermodynamic temperature,the influence of the sodium liquid level on the temperature of the cone top cover is more significant at high temperatures.Furthermore,the overall temperature of the argon space increases with the increase of the sodium liquid level,but only increases significantly near the sodium liquid level,and the temperature gradient along the height direction of the gas cavity is very small.This experimental result indicates the presence of a layer of sodium vapor near the sodium liquid level,which absorbs thermal radiation.The experiment also finds that the temperature of the main pump support increases overall with the increase of the sodium liquid level.Within the range of experimental parameters conducted,the influence of the sodium liquid level on the circumferential temperature difference of the main pump support is very weak.By conducting research on the effect of the sodium liquid level on the heat transfer law in the argon space,it can provide a basis for establishing the temperature mapping relationship between the experimental device and the prototype reactor and provide a reference for the design and safe operation of sodium-cooled fast reactors in our country.