Abstract:

Due to the limited manufacture precision of the current 3D printer, the aperture diameter of the wick is about 300µm. Consequently, steam will penetrate into the compensation chamber through the wick during the initial stage of the loop heat pipe (LHP) start-up process, resulting in severe heat leakage which contributes to a prolonged start-up. To prevent steam penetration through the wick, a newly-developed Tesla-valve-structure with unidirectional flow characteristics was introduced into the design of a 3D-printed wick. In this paper, a Tesla valve channel capillary with a diameter of 300μm were fabricated, and the permeability and start-up performance were compared with that of a cylindrical through hole capillary with the same diameter at different low heat loads. The result showed that the permeabilities of the Tesla-valve-structure wick with two placement directions were of obvious difference, exhibiting an obvious unidirectional flow characteristic, which indicated that the permeability of forward flow was greater than reverse flow under the condition of varies heating power, and the Tesla-valve-structure wick could effectively inhibit steam penetration and achieve a faster start-up. While the heat load increased, the LHP had a faster start-up process, the steam penetration was obviously suppressed by the Tesla-valve-structure wick, which could lead to a better starting performance.

Key words: Tesla valve, 3D printed, wick, loop heat pipe, heat transfer performance

摘要：

受制于3D打印技术的制造精度，其制备的可用毛细芯孔径约为300µm。基于该毛细芯的环路热管（loop heat pipe，LHP）启动初期会产生蒸汽反向穿透毛细芯的现象，造成严重的热泄漏，对LHP的启动性能产生极大的消极影响。为了解决这个问题，本文开创性地将具有单向流动特性的特斯拉阀结构引入3D打印毛细芯中，设计制备了孔径为300μm的特斯拉阀通道结构毛细芯，并与相同孔径的圆柱直通孔毛细芯分别进行了渗透率以及在不同低功率（20W、40W、60W）下启动性能的对比。结果表明：3D打印特斯拉阀毛细芯具有明显的单向流动特征。其渗透率在流动方向上存在明显的差异，正向流动渗透率大于反向流动的渗透率；特斯拉阀毛细芯在不同功率下均能有效抑制蒸汽穿透，实现更快的启动；随着启动功率的增加，LHP的启动速度更快，特斯拉阀毛细芯对蒸汽穿透的抑制效果更明显，启动性能更好。

关键词: 特斯拉阀, 3D打印, 毛细芯, 环路热管, 传热性能