Ultrasound elicits chemical and physical effects that drive and intensify chemical reactions. It can assist esterification and transesterification reactions for biomass conversion. There is extensive experimental data in the literature that highlight the effects of ultrasound on these reactions, but their numerical investigations are very few. In this work, we simulated an ultrasound-assisted biodiesel transesterification to produce lubricants. We studied the acoustic reactive flow by coupling acoustic, fluid dynamics, and chemical reaction models via the finite element software COMSOL Multiphysics. The Acoustics interface in COMSOL computed the pressure field and the Reacting Turbulent Flow interface simulated the fluid velocity and the lubricant concentration profiles inside the reactor. After validating the numerical model with experimental results, we investigated the effect of the probe immersion depth and diameter, the beaker radius and the frequency of ultrasound on lubricant production. The probe immersion depth at mid-height level (at 3 cm depth) was the optimal position. It produced a higher lubricant yield than the 1 and 4 cm depths (94% versus 86% at 4 cm and 81% at 1 cm). A 1.9 cm diameter probe yielded more lubricant than a 1.3 cm probe, maintaining the ultrasound power constant (e.g., 96% lubricant versus 87%, at 62 W).

超声波引发化学和物理效应，驱动和加强化学反应。它可以辅助生物质转化的酯化和酯交换反应。文献中有大量的实验数据强调了超声波对这些反应的影响，但它们的数值研究很少。在这项工作中，我们模拟了一种超声波辅助生物柴油酯交换反应来生产润滑剂。我们通过有限元软件 COMSOL Multiphysics 耦合声学、流体动力学和化学反应模型来研究声学反应流。COMSOL 中的声学接口计算压力场，反应湍流接口模拟反应器内的流体速度和润滑剂浓度分布。在用实验结果验证了数值模型后，我们研究了探头浸入深度和直径、烧杯半径和超声波频率对润滑剂生产的影响。中等高度（3 cm 深度）的探头浸入深度是最佳位置。它产生了比 1 厘米和 4 厘米深度更高的润滑剂产量（94% 对 4 厘米处的 86% 和 1 厘米处的 81%）。1.9 cm 直径探头比 1.3 cm 探头产生更多润滑剂，保持超声功率恒定（例如，96% 润滑剂对 87%，在 62 W）。它产生了比 1 厘米和 4 厘米深度更高的润滑剂产量（94% 对 4 厘米处的 86% 和 1 厘米处的 81%）。1.9 cm 直径探头比 1.3 cm 探头产生更多润滑剂，保持超声功率恒定（例如，96% 润滑剂对 87%，在 62 W）。它产生了比 1 厘米和 4 厘米深度更高的润滑剂产量（94% 对 4 厘米处的 86% 和 1 厘米处的 81%）。1.9 cm 直径探头比 1.3 cm 探头产生更多润滑剂，保持超声功率恒定（例如，96% 润滑剂对 87%，在 62 W）。