This paper reports both experiments and analyses of supercritical CO₂ in two heated vertical parallel channels. The intent of the present experiments was to search for static instability in an up-flow system. However, no static instability was found using CO₂. A total of 18 experiments at different flow conditions were performed with supercritical CO₂ flowing upwards. Eleven were already published by Saini et al. [1] and 7 new cases are presented here. For all cases, oscillatory flow instability was observed. The 18 flow instability cases were numerically modeled to assess the performance of the in-house developed linear, frequency-domain program without and with wall-heat storage. The predicted numerical results agreed well with the experimental results in all cases. The study showed that including wall-heat storage, for this two channel systems, has a very minor effect on the flow instability boundary. Additionally, the accuracy of the supercritical flow dimensionless parameters proposed by Ambrosini and Sharabi [2], to convert experimental CO₂ instability data to water within the same loop, was examined. The dimensionless parameters performed very well. There was also very good agreement between experiment and code on the oscillation period.

本文报道了在两个加热的垂直平行通道中超临界CO _2的实验和分析。本实验的目的是在上流系统中寻找静态不稳定性。但是，使用CO _2时未发现静态不稳定性。使用超临界CO ₂在不同流动条件下进行了总共18个实验向上流动。Saini等人已经出版了11个。[1]和7个新案例在这里介绍。在所有情况下，都观察到振荡流动的不稳定性。对18个流动不稳定的情况进行了数值建模，以评估内部开发的不带壁热存储和带壁热存储的线性频域程序的性能。在所有情况下，预测的数值结果均与实验结果吻合良好。研究表明，对于这两个通道系统，包括壁热存储，对流动不稳定性边界的影响很小。此外，Ambrosini和Sharabi [2]提出的超临界流无量纲参数的精度可转换实验CO ₂检查了同一回路中水的不稳定性数据。无量纲参数的表现非常好。实验和代码之间在振荡周期上也有很好的一致性。