Stainless steel heat pipes have attracted increasing attentions for applications in extreme environments. The stainless steel wick structure as the key component is of high importance for the thermal performance of stainless steel heat pipe. Here, sintered porous wicks using stainless steel powders are developed to evaluate the capillary performance that directly governs the liquid circulation in heat pipes. Systematical experiments of permeability tests and capillary rise tests are conducted for porous wicks with spherical and irregular morphologies in different powder sizes. Water droplets spread entirely on both kinds of porous samples in tens of milliseconds, implying the sintered powder wicks present excellent wetting property. The irregular powder samples show a permeability improvement with a factor of 1.5–4.8 compared to the spherical powder ones with the same powder size, whereas they provide smaller capillary pressures. This is attributed to the more complicated morphologies of the irregular powders that are easier to form larger interconnected inner pores. The wicks with medium powder size of 90–120 um, maintaining a good balance between permeability and capillary pressure, exhibit the optimal capillary performance, which is indicated by the highest capillary factor that can comprehensively reflects the combined effects.

中文翻译：

---

不锈钢热管用多孔烧结不锈钢粉末吸芯的毛细管性能表征


不锈钢热管在极端环境下的应用越来越受到关注。不锈钢毛细结构作为关键部件，对于不锈钢热管的热性能至关重要。在这里，开发了使用不锈钢粉末的烧结多孔芯，以评估直接控制热管中液体循环的毛细管性能。对不同粒径的球形和不规则形貌的多孔芯进行了系统的渗透性测试和毛细管上升测试实验。水滴在数十毫秒内完全铺展在两种多孔样品上，这意味着烧结粉末芯具有优异的润湿性能。与相同粉末尺寸的球形粉末相比，不规则粉末样品的渗透性提高了 1.5-4.8 倍，但毛细管压力更小。这归因于不规则粉末的形态更加复杂，更容易形成更大的互连内部孔隙。中等粉末尺寸为90-120 um的吸芯，在渗透性和毛细管压力之间保持良好的平衡，表现出最佳的毛细管性能，这通过能够综合反映综合效果的最高毛细管因子来表示。