Abstract The second law performance of the ecofriendly graphene-based nanofluid inside the tubes fitted with novel rotary coaxial cross double-twisted tape (RCCDTT) is studied. Indeed, this study examines the effects of using both active and passive heat transfer enhancement methods simultaneously. Several weight fractions are examined and effects of the twisted ratio are also considered. The combination of these two techniques results in great decrement in the total entropy generation and exergy destruction, such that at weight fraction of 0.025% and twisted ratio of 3.5, the thermal entropy generation decreases up to 80% by rising the angular velocity from 0 to 900 rpm. Increasing the concentration results in the less irreversibility and the maximum decrement in the exergy destruction rate is about 24%. Moreover, the twisted ratio increment augments the entropy generation caused by heat transfer. The entropy generation due to the friction has a minute contribution and increases slightly by rising the angular velocity and weight fraction. The second law efficiency has ascending trend by the weight fraction increase and profoundly augments with increasing the angular velocity. The highest second law efficiency is attained 0.935 at concentration of 0.1%, angular velocity of 900 rpm, and twisted ratio of 2.5.

中文翻译：

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用新型旋转同轴交叉双绞带增强管内生物功能化石墨烯纳米片纳米流体流动的熵产生和火用破坏

摘要 研究了装有新型旋转同轴交叉双绞带（RCCDTT）的管内生态友好型石墨烯纳米流体的第二定律性能。事实上，这项研究检验了同时使用主动和被动传热增强方法的效果。检查了几个重量分数，并考虑了扭曲比的影响。这两种技术的结合导致总熵产生和火用破坏大大减少，例如在重量分数为 0.025% 和扭曲比为 3.5 时，通过将角速度从 0 增加到 3.5，热熵产生减少了 80% 900转。增加浓度导致更小的不可逆性，火用破坏率的最大减少量约为 24%。而且，扭曲比增量增加了由传热引起的熵产生。由于摩擦产生的熵的贡献很小，并且随着角速度和重量分数的增加而略微增加。第二定律效率随着重量分数的增加呈上升趋势，并随着角速度的增加而显着增加。在浓度为 0.1%、角速度为 900 rpm 和扭曲比为 2.5 时获得最高的第二定律效率为 0.935。