The heat transfer characteristics of gravity heat pipes (GHPs) with internal helical microfins (IHMs) were investigated experimentally, in comparison with smooth GHPs. The influence of different IHM arrangements on the GHPs was obtained. Four types of GHPs were designed and fabricated: GH-PIHM1 (GHP with IHM arranged only in the condenser section); GHPIHM2 (GHP with IHM arranged in both the condenser and adiabatic sections); GHPIHM3 (GHP with IHM arranged in all inner surfaces); and GHP (smooth GHP). The results showed that applying IHMs on the inner surface enhances the performance of the GHP; typically, by lowering the operating temperature and thermal resistance. All of the GHPs with IHMs demonstrated lower working temperatures than the smooth GHP; in particular, GHPIHM2 and GHPIHM3 decreased the working temperature by 23°C at 240 W. For most of the tested cases, the thermal resistance of GHPs with IHMs was reduced, as presented in ascending order: GHPIHM3 < GHPIHM2 < GHPIHM1 < GHP. For the condensation heat transfer coefficient, all three GHPs with IHMs can be improved; for the evaporation heat transfer coefficient, GHPIHM1 became worse while GHPIHM2 and GHPIHM3 performed better.

中文翻译：

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分段内螺旋微重力传热管的传热强化特性。

与光滑的GHP进行比较，通过实验研究了带有内部螺旋微翅片（IHM）的重力热管（GHP）的传热特性。获得了不同的IHM安排对GHP的影响。设计和制造了四种类型的GHP：GH-PIHM1（仅在冷凝器部分装有IHM的GHP）；GHPIHM2（冷凝器和绝热段均装有带IHM的GHP）；GHPIHM3（在所有内表面都装有IHM的GHP）；和GHP（平滑GHP）。结果表明，在内表面上施加IHM可以提高GHP的性能。通常，通过降低工作温度和热阻。具有IHM的所有GHP均比光滑的GHP表现出更低的工作温度；特别是GHPIHM2和GHPIHM3在240 W下将工作温度降低了23°C。对于大多数测试情况，具有IHM的GHP的热阻降低，按升序排列：GHPIHM3 <GHPIHM2 <GHPIHM1 <GHP。对于凝结传热系数，所有三个带有IHM的GHP都可以得到改善。在蒸发传热系数方面，GHPIHM1变差，而GHPIHM2和GHPIHM3表现更好。