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Power Input Measurements in Stirred Bioreactors at Laboratory Scale
Published on: May 16, 2018
地力发电机的功率需求来自数值和实验室动力发电机中的欧姆损失
Ulrich R Christensen1, Andreas Tilgner
1Max-Planck-Institut für Aeronomie, Max-Planck-Strasse 2, 37191 Katlenburg-Lindau, Germany. Christensen@linmpi.mpg.de
Nature
|May 14, 2004
概括
研究人员模拟了地球的核心动力发电机,发现欧姆散射主要与磁力雷诺兹数有关. 这表明能量损失中等,支持更长的内核年龄,并减少对强烈放射性加热的需求.
科学领域:
- 地质物理学 地质物理学
- 地球科学 地球科学 地球科学
- 动力机理论 动力机理论
背景情况:
- 地球的地磁场是由流体外核中的动力发电机过程维持的.
- 欧姆损失 (电阻) 对于维护动力发电机至关重要,估计的差异很大 (0.1-3.5 TW).
- 这些能源需求影响了核心的热预算和演变模型.
研究的目的:
- 为了建立核心消散时间和磁性/水力动力学雷诺兹数之间的缩放关系.
- 为了精确估计地球核心的欧姆散射.
- 评估核心热史和内核年龄的影响.
主要方法:
- 利用数值动力模来推导缩放规律.
- 分析了卡尔斯鲁厄动力发电机实验数据.
- 研究了消散时间对磁力雷诺兹数和流动流的依赖性.
主要成果:
- 为特征性消散时间推导了缩放关系.
- 发现的欧姆散射主要取决于磁力雷诺兹数,而不是流动流.
- 在卡尔斯鲁厄动力发电机实验的支持下,表明流的影响最小.
结论:
- 预计适度的欧姆散射 (0.2-0.5 TW). 预计适度的欧姆散射 (0.2-0.5 TW).
- 这一发现减轻了核心中强烈放射性加热的需要.
- 允许内核年龄超过25亿年.
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