Abstract

Inertial confinement fusion (ICF) is one of the main ways to achieve controlled nuclear fusion. ICF experiments use high peak-power laser systems to compress the capsule with a layer of solid hydrogen inside, making the ice layer highly compressed so as to initiate ignition. To achieve an ignition with a cryogenic target, the fuel ice layer (DT or D2) in the target needs to be highly symmetrical, uniform and smooth. For a better control of the ice preparation process, there is a need to develop a deep understanding on the mechanism of the crystal growth process. Based on VOF model, Solidification/Melting model and the Evaporation/Condensation model, we establish a numerical model to simulate the coupled process of fluid flow, heat transfer, solidification and condensation of D2 fuel. Through assigning different temperature boundary and initial liquid fraction conditions, the impacts of temperature distribution and liquid volume on the crystal growth process are investigated. The results show that higher temperature gradient, bigger liquid volume and larger coefficient of heat transfer promotes the formation of radial temperature gradient in the capsule, which helps to ensure the global coverage of liquid film. Our work can help to optimize the relevant parameters in in the preparation process of D2 ice layer.

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