Abstract This study focused on the photo-thermal energy conversion performance and thermal characteristics of MWCNT/Fe3O4 hybrid nanofluid under an external magnetic field. In addition, the thermal and optimal properties of MWCNT/Fe3O4 hybrid nanofluid were compared to those of MWCNT and Fe3O4 nanofluids. The photo-thermal energy conversion efficiency of Fe3O4, MWCNT nanofluids and MWCNT/Fe3O4 hybrid nanofluid increased with the concentration and decreased with the operating time. An external magnetic field significantly enhanced the photo-thermal energy conversion efficiency at 0.2 wt% MWCNT/Fe3O4 hybrid nanofluid, the photo-thermal energy conversion efficiency was 32.8% and 45.1% with the absence and presence of an external magnetic field. Adding MWCNT nanoparticles can increase the thermal properties of the Fe3O4 nanofluid. In addition, the increase of magnetic force significantly improved the thermal conductivity of the Fe3O4 nanofluid and MWCNT/Fe3O4 hybrid nanofluid.

中文翻译：

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磁效应对提高多壁碳纳米管/Fe3O4杂化纳米流体光热能转换效率的影响

摘要 本研究重点研究了外磁场作用下多壁碳纳米管/Fe3O4杂化纳米流体的光热能转换性能和热特性。此外，还比较了 MWCNT/Fe3O4 混合纳米流体与 MWCNT 和 Fe3O4 纳米流体的热性能和最佳性能。Fe3O4、MWCNT纳米流体和MWCNT/Fe3O4杂化纳米流体的光热能转换效率随着浓度的增加而增加，随着操作时间的延长而降低。外部磁场显着提高了 0.2 wt% MWCNT/Fe3O4 杂化纳米流体的光热能转换效率，在没有和存在外部磁场的情况下，光热能转换效率分别为 32.8% 和 45.1%。添加 MWCNT 纳米粒子可以提高 Fe3O4 纳米流体的热性能。此外，