Buoyancy-Induced Convection Driven by Frontal Polymerization
Buoyancy-Induced Convection Driven by Frontal Polymerization
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DOI：
10.1103/physrevlett.130.028101
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发表时间：
2023-01-09
影响因子：
8.6
通讯作者：
Geubelle, P. H.
中科院分区：
文献类型：
--
作者：
Gao, Y.;Paul, J. E.;Geubelle, P. H.
在这封信中，我们研究了在垂直于重力方向上传播的自持放热反应前沿和低粘度单体树脂前沿聚合（FP）过程中浮力驱动的对流之间的相互作用。随着聚合前沿将液体单体转化为固体聚合物，与传播前沿相关的大的热梯度维持前沿前面的流体的自然对流。流体对流反过来影响反应扩散（RD）动力学和形状的前。详细的多物理场数值分析和粒子图像测速实验揭示了自然对流和锋面聚合之间的耦合。锋面瑞利数影响速度场的大小和锋面的倾角。较高的Ra数在FP期间驱动不稳定性，导致观察到具有可调谐波长和幅度的热化学图案。
In this Letter, we study the interaction between a self-sustaining exothermic reaction front propagating in a direction perpendicular to that of gravity and the buoyancy-driven convective flow during frontal polymerization (FP) of a low-viscosity monomer resin. As the polymerization front transforms the liquid monomer into the solid polymer, the large thermal gradients associated with the propagating front sustain a natural convection of the fluid ahead of the front. The fluid convection in turn affects the reaction-diffusion (RD) dynamics and the shape of the front. Detailed multiphysics numerical analyses and particle image velocimetry experiments reveal this coupling between natural convection and frontal polymerization. The frontal Rayleigh (Ra) number affects the magnitude of the velocity field and the inclination of the front. A higher Ra number drives instability during FP, leading to the observation of thermal-chemical patterns with tunable wavelengths and magnitudes.