论文题目：Experimental study on the flow mixing in T-junctions with an impeller

杂志：          Physics of Fluids 36, 025110 (2024)

连接网址：https://doi.org/10.1063/5.0180142

作者：Yuzhuo Yin(殷钰卓), Kexin Huang(黄可欣), Bo Su (苏博), Mei Lin*^,a)(林梅), Qiuwang Wang(王秋旺)

          ​​​​​​​E-mail address: janeylinm@mail.xjtu.edu.cn

ABSTRACT

A good understanding of the mixing mechanism of hot and cold fluids in T-junctions is of great importance in ensuring the safe operation of T-junction piping systems. An impeller is added to T-junction ducts and experiments are conducted using particle image velocimetry without considering the temperature difference between two fluids. The velocity field, vorticity field, and impeller speed are obtained for blade numbers N_p = 3 and 4 at different momentum ratios (M_R). When the impeller rotates passively in T-junctions under the impact of a branch jet, the values of M_R required to initiate impeller rotation are M_R = 0-0.5 for N_p = 3, and 0-0.125 for N_p = 4. However, an impeller with two blades cannot rotate at any momentum ratio. The relationship between the rotation speed and the flow rates of the main and branch fluids is obtained. An impeller with three blades rotates at a non-uniform speed, while that with four blades rotates uniformly. The jet flow pattern in T-junctions is converted from the impinging jet to the deflecting jet at M_R≥0.1. The average and root-mean-square velocity are essentially the same for a given momentum ratio, whereas the impeller speed increases with increasing flow rate for the main and branch ducts. As the momentum ratio decreases, the impeller speed also increases. For an impinging jet, the addition of an impeller effectively reduces the velocity fluctuation area and transfers the zone of the highest velocity fluctuation from the bottom wall to the middle of the main duct.