Fluid Dynamics Experiments on Core Formation

地球内部的主要结构-致密的富含铁的金属核心被密度较低的硅酸盐和氧化物地幔包围-是在行星吸积过程中建立的，当时大型撞击释放的大量能量产生了广泛的熔化，使密度较高的金属从熔融的硅酸盐中分离出来并形成核心。这项研究的目的是量化流体力学过程中的核心形成的金属部分混合，后来从地幔形成的硅酸盐在早期地球分离。 将进行一系列实验室流体动力学实验，使用硅油和蔗糖溶液模拟熔融硅酸盐，使用液态镓和其他致密流体模拟岩浆海洋中的成核金属。实验将分别测量在重力稳定和不稳定条件下两种流体之间的热量和化学示踪剂的湍流交换。这项研究的重要成果是实验校准的液体金属和非金属之间的湍流热和化学交换的法律。我们打算将我们的实验结果外推到早期地球的条件下，从而对深部内部的初始状态进行限制，包括核心和地幔之间的热量和化学物质的初始分配。

The primary structure of Earth's interior -- the dense iron-rich metallic core surrounded by the less dense silicate and oxide mantle -- was established during planetary accretion, when the vast amounts of energy released by large impacts produced widespread melting, allowing the denser metals to segregate from the molten silicates and form the core. The purpose of this research is to quantify the fluid mechanical processes by which the core-forming metals partially mixed with and later segregated from the mantle-forming silicates in the early Earth. A series of laboratory fluid dynamical experiments will be made using silicone oils and sucrose solutions to model the molten silicates and liquid gallium and other dense fluids to model the core-forming metals in a magma ocean. The experiments will measure the turbulent exchange of heat and chemical tracers between the two fluids under gravitationally stable and unstable conditions, respectively. Important outcomes of this research are experimentally calibrated laws for turbulent heat and chemical exchange between liquid metals and non-metals. We intend to extrapolate our experimental results to the conditions of the early Earth, thereby placing constraints on the initial state of the deep interior, including the initial partitioning of heat and chemical species between the core and the mantle.