Transient heat transfer from a wire to a forced flow of subcooled liquid hydrogen passing through a vertically- mounted pipe
Transient heat transfer from a wire to a forced flow of subcooled liquid hydrogen passing through a vertically- mounted pipe
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从电线到通过垂直安装管道的过冷液氢强制流的瞬态热传递
DOI：
10.1088/1757-899x/101/1/012177
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
S Nonaka and Y Inatani
中科院分区：
文献类型：
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作者：
H Tatsumoto;Y Shirai;M Shiotsu;Y Naruo;H Kobayashi;S Nonaka and Y Inatani
在压力为0.7 MPa、入口温度为21 K的条件下，通过增加不同时间段的指数热量输入，测量了Pt-Co线加热器插入垂直安装的管道中，强迫流动过冷液氢通过管道的瞬态传热。流速范围为0.3 ~ 7 m/s。Pt-Co线加热器的直径为1.2 mm，长度为60mm、120mm和200mm，分别安装在直径为5.7 mm、8.0 mm和5.0 mm的管道中，这些管道由纤维增强塑料制成，具有隔热作用。随着热通量的增加，表面温度沿Dittus-Boelter相关预测的曲线上升，且时间更长，几乎可以视为稳态。在较短的时间内，换热高于Dittus-Boelter相关。在有核沸腾状态下，热流密度急剧上升至瞬态临界热流密度，并在较短的时间内升高。阐明了流速、周期和加热几何形状对瞬态CHF热流密度的影响。
Transient heat transfers from Pt-Co wire heaters inserted into vertically-mounted pipes, through which forced flow subcooled liquid hydrogen was passed, were measured by increasing the exponential heat input with various time periods at a pressure of 0.7 MPa and inlet temperature of 21 K. The flow velocities ranged from 0.3 to 7 m/s. The Pt-Co wire heaters had a diameter of 1.2 mm and lengths of 60 mm, 120 mm and 200 mm and were inserted into the pipes with diameters of 5.7 mm, 8.0 mm, and 5.0 mm, respectively, which were made of Fiber reinforced plastic due to thermal insulation. With increase in the heat flux to the onset of nucleate boiling, surface temperature increased along the curve predicted by the Dittus-Boelter correlation for longer period, where it can be almost regarded as steady-state. For shorter period, the heat transfer became higher than the Dittus-Boelter correlation. In nucleate boiling regime, the heat flux steeply increased to the transient CHF (critical heat flux) heat flux, which became higher for shorter period. Effect of flow velocity, period, and heated geometry on the transient CHF heat flux was clarified.