In vitro digestion models and bionic reactors are usually made of soft elastic materials, which can be expanded in certain cases. However, little is known about the expansion of these models and reactors and the effect of the expansion on the fluid flow and concentration distribution. In this study, the expansion of a simplified small intestine model reactor is investigated using COMSOL Multiphysics. The results showed that the expansion rate significantly increased as Young’s modulus decreased; the influence of Poisson’s ratio on the expansion of the model with similar materials can be neglected. The model’s expansion rate increases significantly as the inlet velocity and fluid viscosity increase. However, the expansion rate decreases as the model’s spherical coefficient increases. The maximum expansion rate of the model in the given scope of the factors can be predicted using the regression equation obtained from Response Surface Methodology (RSM). It can also be concluded that the higher maximum expansion rate caused the velocity in radial and axial directions to be reduced and the pressure slightly reduced. Meanwhile, the model’s expansion would result in a nonuniform concentration distribution of the fluid in the model, which leads to a longer residence time of the fluid.

体外消化模型和仿生反应器通常由柔软的弹性材料制成，在某些情况下可以扩展。然而，人们对这些模型和反应器的膨胀以及膨胀对流体流动和浓度分布的影响知之甚少。在本研究中，使用 COMSOL Multiphysics 研究了简化的小肠模型反应器的膨胀。结果表明，随着杨氏模量的降低，膨胀率显着增加；泊松比对材料相似的模型膨胀的影响可以忽略不计。随着入口速度和流体粘度的增加，模型的膨胀率显着增加。但是，随着模型球面系数的增加，膨胀率会降低。可以使用从响应面方法 (RSM) 获得的回归方程来预测模型在给定因子范围内的最大扩展率。还可以得出结论，较高的最大膨胀率导致径向和轴向速度降低，压力略有降低。同时，模型的扩展会导致模型中流体的浓度分布不均匀，从而导致流体的停留时间变长。