Abstract: Effective heat transfer has been a favorite issue in industrial applications as industrial equipment trends towards high performance and density. Although static mixers are widely employed for heat transfer enhancement, research on tongue groove type static mixer (TGSM) remains limited. Thus the TGSM is chosen to examine the thermal and hydraulic characteristics. Both nanoparticles and liquid metal are popular thermal management materials today. As an emerging heat transfer enhancement material, liquid metal avoids common drawbacks of nanoparticles (e.g., agglomeration and precipitation). However, comparative studies between liquid metal and nanofluids remain scarce. Therefore, three hybrid nanofluids (SiC/SWCNT-H2O, Al2O3/SWCNT-H2O, and Al2O3/SiC-H2O) and liquid metal solution are selected to evaluate and analyze the heat transfer and flow characteristics in terms of heat transfer efficiency, energy consumption, and economy. The simulation is carried out using ANSYS fluent 16.1 with SST k-ω and Mixture model selected under turbulent conditions. It is found that the TGSM has a significant pressure drop advantage over the Kenics static mixer (KSM). Although the heat transfer efficiency of TGSM is not as good as that of KSM, the performance evaluation criteria (PEC) is more significant. The addition of liquid metal/nanoparticles improves the convective heat transfer coefficient of the fluid, which increases linearly with Reynolds number (Re). Among the four working fluids, SiC/SWCNT-H2O shows the largest Nusselt number (Nu, strength of convective heat transfer relative to pure thermal conductivity), followed by Al2O3/SWCNT-H2O, Al2O3/SiC-H2O and liquid metal solution. This suggests that SiC/SWCNT-H2O is an effective fluid to increase the heat transfer rate in TGSM. Meanwhile, SiC/SWCNT-H2O also demonstrates the best performance as a working fluid in terms of field synergy and entropy production within the TGSM. The PEC ranges from 4.67~7.33, while increasing the field synergy number by 5.09~6.81 times and reducing entropy generation ST by 87.2%~89.2%.

Key words: heat transfer enhancement, static mixer, nanofluid, convective heat transfer coefficient, field synergy, entropy production

摘要： 随着工业设备向高性能和高密度方向发展，有效换热已成为工业应用的重中之重。针对Re=2000~17 000的湍流工况，采用计算流体动力学(CFD)方法开展数值模拟研究。通过引入舌槽型静态混合器(TGSM)作为强化换热、降低能耗的设备，对比分析了SiC/SWCNT-H2O, Al2O3/SWCNT-H2O和Al2O3/SiC-H2O三种新型混合纳米流体及液态金属溶液的流动与换热特性。结果表明，与Kenics静态混合器(KSM)相比，TGSM具有显著的压降优势，在相同工况下KSM的流动阻力比TGSM高出3.5~4.9倍。液态金属/纳米颗粒的加入使流体的对流换热系数(h)提高0.08~8.64倍。SiC/SWCNT-H2O在TGSM内展现出最优的换热性能，其综合性能评价标准(PEC)的范围为4.67~7.33，同时能使场协同数提高5.09~6.81倍，并使熵产ST降低87.2%~89.2%。

关键词: 强化换热, 静态混合器, 纳米流体, 对流换热系数, 场协同, 熵产