Heat transfer characteristics of two-phase He I (4.2 K) thermosiphon flow
Heat transfer characteristics of two-phase He I (4.2 K) thermosiphon flow
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DOI：
10.1016/j.ijheatmasstransfer.2006.12.032
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发表时间：
2007-08
影响因子：
5.2
通讯作者：
L. Benkheira;B. Baudouy;M. Souhar
中科院分区：
文献类型：
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作者：
L. Benkheira;B. Baudouy;M. Souhar
以欧洲核子研究中心日内瓦分站在建的大型超导磁体低温冷却系统设计为背景，对两相氦I自然循环回路内的换热进行了实验研究。实验在2m热虹吸环上进行，内径10 mm的铜管在0.95 m的长度上均匀加热。所有数据都是在大气压附近获得的。给出并分析了出口蒸汽质量和壁面过热度随热流密度的变化规律。将本研究测得的两相换热系数hTP与文献中最相关的关联式进行了比较。在此基础上，根据强迫对流和核态沸腾的综合效应，利用幂函数型渐近模型对hTP进行了关联预测。最后，我们介绍了沸腾危机的研究，并提出了一个作为通道高径比(z/D)的函数的临界热流密度关联式来模拟我们的实验结果。
In the framework of the cryogenic cooling system design of a large superconducting magnet under construction at CERN-Geneva, heat transfer in two-phase He I natural circulation loop has been investigated experimentally. The experiments were conducted on a 2m thermosiphon loop with copper tube of 10mm inner diameter uniformly heated over a length of 0.95m. All data were obtained near atmospheric pressure. Evolution of the exit vapour quality and wall superheat as a function of heat flux are presented and analyzed. A comparison between the two-phase heat transfer coefficient hTPdetermined in our study and the most relevant correlations available in literature is made. Further, we predict hTPwith a correlation based on the combining effects of forced convection and nucleate boiling by a power-type asymptotic model. Finally, we present the boiling crisis study and we propose a critical heat flux correlation as a function of channel height to diameter ratio (z/D) to model our experimental results.