Abstract:

The heat transfer performance for a copper plate installed with single-phase natural circulation loop (SPNCL) was experimentally and numerically studied. Firstly, the heat transfer experiments between hot and cold air steams flow counter-currently in a rectangular channel separated by a copper plate installed with SPNCLs and a smooth copper plate were conducted, respectively. The results showed that, at the same power consumption, the heat transfer rate of the copper plate with SPNCLs is about 1.1—1.3 times as large as that of the smooth copper plate. In addition, the numerical simulations were performed for a comparison between the heat transfer rates of the SPNCL and the copper fin with the same shape and size. The effects of size, inclination angle and temperature difference between hot and cold air on the heat transfer rate were investigated in detail. The results showed that the heat transfer rate of the SPNCL can only be larger than that of the copper fin while the temperature difference is over an equivalent temperature difference. With the decrease of size and the increase of the inclination angle, the equivalent temperature difference between the SPNCL and the copper fin increases.

Key words: single-phase natural circulation loop, enhanced heat transfer, numerical simulation, heat transfer capability, enhanced heat transfer ratio

摘要：

通过实验对比分析了带有单相自然循环回路元件的铜板与光滑铜板相隔冷热空气逆流换热的换热效果。 结果表明，相同泵耗功情况下，加装单相自然循环回路元件的换热板的换热量是光滑铜板的1.1~1.3倍。在此基础上，本文通过数值模拟进一步对比分析了加装单相自然循环回路元件与相同形状、尺寸的铜翅片换热效果，针对影响自然循环回路传热性能的主要因素，如循环回路高度、横向与轴向倾斜角度、冷热源温差等，进行了数值模拟研究。结果表明：只有当温差超过等效温差点后，自然循环回路元件的换热效果才强于相同形状和尺寸的铜翅片；随着几何尺寸减少以及倾斜角度的增加，自然循环元件与铜翅片的等效温差点随之升高。

关键词: 单相自然循环回路, 强化传热, 数值模拟, 换热性能, 强化传热比