中文摘要：

为认识超临界二氧化碳自然循环基本特性,开展超临界二氧化碳在简单矩形回路内自然循环特性的实验研究,研究系统压力和冷热段流体温差对自然循环流量的影响,分析回路结构对自然循环特性的影响。结果表明：循环流量存在峰值;峰值点前,随加热功率增加流量快速上升,峰值点后流量变化平缓;在本试验参数条件下未观测到流动不稳定现象;压力对循环流量影响与亚临界自然循环类似,压力越高循环流量峰值越大,回路冷热段温差对循环流量影响较大;加热段出口流体温度接近拟临界温度时,很小的回路温差变化即可引起循环流量较大变化;加热段布置方式对超临界二氧化碳自然循环流量变化特性影响较大,对回路稳定性的影响需要进一步进行实验验证。

英文摘要：

Experiments were carried Out in a rectangular loop to study the characteristics of supercritical carbon dioxide natural circulation. The influence of pressure and temperature difference on the mass flow rate was investigated and the effect of geometric of test loop was also preliminarily studied. Results show that no flow instability was found under the experimental condition. There-was a peak for mass flow rate. Mass flow increased quickly before the peak point and decreased very slowly after the peak point. The effect of system pressure on mass flow rate was similar to subcritical natural circulation and higher mass flow rate was obtained in higher pressure. Temperature difference had vital effect on mass flow rate. Just small temperature difference between hot leg and cold leg could result in apparent change of mass flow rate. Geometric of test loop had vital effect on the characteristics of supercritical carbon dioxide natural circulation and more in-depth experimental research should be done to study it.