Phase Change Cooling of Spacecraft Electronics: Terrestrial Reference Experiments Prior to ISS Microgravity Experiments
Phase Change Cooling of Spacecraft Electronics: Terrestrial Reference Experiments Prior to ISS Microgravity Experiments
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DOI：
10.1109/itherm45881.2020.9190438
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发表时间：
2020-07
期刊：
影响因子：
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通讯作者：
K. Sridhar;Ryan Smith;V. Narayanan;S. Bhavnani
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文献类型：
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作者：
K. Sridhar;Ryan Smith;V. Narayanan;S. Bhavnani
这项实验性地面研究是在国际空间站原始微重力条件下进行广泛研究之前通过增强航天器电子设备中的池沸腾来消散增加的热通量的更大努力的一部分。微重力中缺乏浮力会导致气泡生长到非常大的尺寸，从而导致过早出现临界热通量 (CHF)。使用工程表面改性（即不对称锯齿棘轮）来产生蒸汽质量的流动性可以缓解这个问题。不锈钢 (SS 316L) 测试表面采用粉末床熔合（一种金属增材制造工艺）制造。本研究中探索的不对称锯齿结构在面向下的配置中观察到了蒸气流动性。当气泡沿着微结构滑动时，在气泡下方观察到一层薄液膜。使用锯齿波峰和波谷的高速成像来探索这种液膜的不对称性质。所提出的不对称锯齿微结构是一种潜在的技术，当减小的浮力不会使蒸汽泡从表面分离时，可以诱导蒸汽泡在电子元件上运动。
This experimental, terrestrial study is part of a larger effort to dissipate increased heat fluxes through enhanced pool boiling in spacecraft electronics prior to an extensive study to be conducted on the International Space Station under pristine microgravity conditions. The absence of buoyancy forces in microgravity causes vapor bubbles to grow to a very large size, leading to premature critical heat flux (CHF). Using an engineered surface modification, namely an asymmetric sawtooth ratchet, to create mobility of the vapor mass can alleviate this problem. The stainless steel (SS 316L) test surfaces were fabricated using powder bed fusion, a metal additive manufacturing process. Vapor mobility was observed in the downward-facing configuration for the asymmetric sawtooth structure explored in the stud y. A thin liquid film was observed underneath the vapor bubbles as they slid along the microstructure. The asymmetric nature of this liquid film is explored using high-speed imaging at the crest and trough of the sawtooth. The proposed asymmetric saw-tooth microstructure is a potential technique to induce motion of vapor bubbles across electronic components when reduced buoyancy forces do not detach vapor bubbles from the surface.