玻璃化保存降温过程中微通道的热应力数值模拟

Numerical simulation on thermal stress in the microchannel for vitrification preservation cooling process

微通道方法可用于增强玻璃化保存的传热,但在超高速冷却速率下,通道结构可能受到不均匀温度分布产生的热应力影响,导致结构断裂。为研究热应力的变化规律,本研究以ANSYS Workbench为仿真计算平台建立了三维计算流体动力学(computational fluid dynamics,CFD)模型,以模拟微通道中的两相流及其相关热传递过程。对降温过程中的流固耦合传热过程进行整场求解,从而同时得到降温过程的瞬态温度场和瞬态应力场。通过仿真计算在不同冷却条件下通道结构中热应力的最大值,用于评估微通道结构的可靠性。结果表明,本研究提出的CFD方法为预测和优化微通道冷却系统提供了有效的工具。

The microchannel method can be used to enhance the heat transfer for vitrification preservation.But at ultra-high cooling rates,the channel structure can be affected by the thermal stress caused by the uneven temperature distribution,resulting in the fracture of the structure.To study the variation of thermal stress,a three-dimensional computational fluid dynamics(CFD)model was established to simulate the two-phase flow in microchannel and its related heat transfer process by using ANSYS Workbench as simulation calculation platform.The whole process of fluid-solid coupling heat transfer in the cooling process was solved,the transient temperature field and transient stress field of the cooling process were obtained at the same time.The maximum thermal stress in the channel structure under different cooling conditions were calculated by simulation to evaluate the reliability of the microchannel structure.The results show that the proposed CFD method in this paper provides an effective tool for predicting and optimizing the microchannel cooling system.