Batch hydrothermal reactor is known as a closed system, and what happens in this “black box” is mysterious. Now, by using the tendency of graphene oxide (GO) to align along the flow and the fixation effect of thermoset resin, the hydrothermal annular convection can be inferred from the axisymmetric poloidal structure and GO-assembled annular distribution. Temperature difference and geometric symmetricity of the reactor account for the annular convection, which is also found to be affected by solution viscosity and reactor parameters. Numerical simulations reproduce the annular convection and are used to investigate the parameter space beyond experiments. Plume flows occur at the bottom of the reactor due to flow instability. Irregular and intensive flow is against the synthesis of high-aspect-ratio nanomaterials and monolithic gels. It is noteworthy that large-scale batch hydrothermal synthesis may not be feasible for some nanowires, nanosheets, and particularly gels due to the non-negligible flow influence.

间歇式热液反应堆被称为封闭系统，在这个“黑匣子”中发生的事情是神秘的。现在，通过利用氧化石墨烯（GO）沿着流动方向排列的趋势和热固性树脂的固定效果，可以从轴对称多倍体结构和GO组装的环状分布中推断出水热环状对流。反应器的温差和几何对称性是环形对流的原因，也发现它受溶液粘度和反应器参数的影响。数值模拟再现了环形对流，并用于研究实验之外的参数空间。由于流动的不稳定性，羽流在反应器的底部发生。不规则和密集的流动不利于高纵横比纳米材料和整体凝胶的合成。