矩形通道自然循环流动不稳定性实验研究

Experimental Study of Natural Circulation Flow Instability in Rectangle Channels

分别对40×5 mm和40×10 mm矩形通道内自然循环不稳定性进行了实验研究,得到了自然循环流量随加热功率的变化。结果表明:系统流量与压差的周期是相同并且反相;在矩形通道内,边角位置及二次流的存在,矩形通道会使流体的扰动加强,换热系数增加,特别是在饱和区域内,气泡与流体之间的扰动增强,容易形成搅拌流;5 mm通道与10 mm通道相比,由于其通道更窄阻力更大,在过冷区域更不容易形成稳定自然循环,且流动不稳定性的脉动更剧烈。

Results under different heating power conditions were conducted in rectangle channels with 5mm and 10mm. Results for different heating powers were obtained. The results showed that the oscillation period of pressure value and volume flow are the same, but their phase positions are opposite. The existence of edge position and secondary flow will strengthen the disturbance of fluid flow in rectangle channels, which contributes to the heat transfer. The disturbance of bubble and fluid will be strengthened, especially in the saturated boiling section, which makes it possible for the mixing flow. The results also showed that the resistance in 5mm channel is bigger than that in 10 mm channel, and it is less likely to form stable natural circulation in the subcooled region.