Two tubular microreactor geometries—straight tube reactor (STR) and coil flow inverter reactor (CFIR)—are numerically studied with unmixed feed condition for the synthesis of poly(methyl methacrylate) and poly(styrene) by free radical polymerization. A new transformation rendering model dimensionless in terms of concentration is used during computational fluid dynamics modeling. For decoupled case of constant fluid thermo‐physical properties (FTPP) (density, viscosity, and thermal conductivity), significant differences between the two types of reactor are observed. CFIR is found to achieve higher number‐average chain lengths (DPn) while keeping polydispersity index (PDI) lower compared to STR. For the case of coupled FTPP variables with conversion (X_M) and temperature, X_M and DPn are found to have similar trends as in decoupled case but have systematically higher values while PDI values follows a different trend. CFIR is found to show better mixing compared to STR under similar conditions, thus allowing a better control over PDI under unmixed feed condition. An anomalous case of increased mixing in STR at low diffusion coefficient for coupled case is also observed. Overall, the importance of modeling the coupled case is clearly emphasized.

中文翻译：

---

非混合进料条件下合成聚合物的管状微反应器几何形状的数值研究

在未混合进料条件下，通过自由基聚合对两种管状微反应器几何形状进行了研究，即直管反应器（STR）和盘管流转化器反应器（CFIR）。在计算流体动力学建模过程中，使用了一种新的变换渲染模型，该模型在浓度方面无因次。对于恒定流体热物理性质（FTPP）（密度，粘度和热导率）解耦的情况，观察到两种反应器之间存在显着差异。与STR相比，发现CFIR可以实现更高的数均链长（DPn），同时保持较低的多分散指数（PDI）。对于具有转换（X _M）和温度的FTPP变量耦合的情况，X _M发现DPn和DPn具有与解耦情况相似的趋势，但是具有系统地较高的值，而PDI值遵循不同的趋势。发现CFIR与STR在相似条件下相比显示出更好的混合，因此在未混合进料条件下可以更好地控制PDI。还观察到了在偶合情况下以低扩散系数在STR中增加混合的异常情况。总体而言，明确强调了对耦合案例进行建模的重要性。