The study aimed to establish a comprehensive understanding of the photocatalytic process and optimize the reactor design for efficient ethylene regulation to improve the shelf-life of fruits and vegetables. For this, it was performed 2D computational fluid dynamics modeling at two different reactor geometry (conventional cylindric reactor and annular cylindric reactor) using the conservation equations combined with Langmuir-Hinshelwood mechanism. A continuous single-phase multicomponent fluid flow with the reactor surface supported with a thin-film catalyst under UV-A light irradiation was simulated for initial ethylene concentration at 0.479–4.234 × 10⁻³ mol_C2H4 m⁻³ and inlet axial velocity at 0.0085–0.1019 m s⁻¹. In the 2D CFD results, it was observed that the difference in ethylene concentration between the microreactor bulk and surface is only significant for high initial concentrations and axial velocities. Furthermore, it was found that the parabolic conversion profile remains unchanged for lengths greater than 10% of the reactor length across all geometries studied. The variation in reactor diameters resulted in a substantial reduction in ethylene conversion; however, the incorporation of an annular cylinder coated with a catalyst led to an enhancement in conversion rates, with improvements of approximately 28%, 17%, and 6% observed for diameters of 5 mm, 10 mm, and 20 mm, respectively. This reduction in improvement as diameter increase can be attributed to the laminar flow dynamics that impede the diffusion of ethylene molecules from the bulk to the catalytic surface. Consequently, the simulated data highlight the potential of employing a catalyst-doped annular cylinder as a promising strategy to increase ethylene conversion and extend the shelf life of fruits. However, it should be noted that the addition of an annular cylinder, while enhancing conversion, also introduces operational complexities and cost implications due to the significant increase in pressure drop associated with lower diameters.

该研究旨在全面了解光催化过程，并优化反应器设计，以实现有效的乙烯调节，从而提高水果和蔬菜的保质期。为此，利用守恒方程结合 Langmuir-Hinshelwood 机制，对两种不同的反应器几何形状（传统圆柱形反应器和环形圆柱形反应器）进行了二维计算流体动力学建模。在 UV-A 光照射下，模拟了反应器表面负载薄膜催化剂的连续单相多组分流体流动，初始乙烯浓度为 0.479–4.234 × 10 -3 mol C2H4 m -3 ^，入口_轴向速度^为0.0085 –0.1019 米·秒⁻¹。在 2D CFD 结果中，观察到微反应器本体和表面之间的乙烯浓度差异仅在高初始浓度和轴向速度时才显着。此外，我们发现，在所有研究的几何形状中，当长度大于反应器长度的 10% 时，抛物线转化曲线保持不变。反应器直径的变化导致乙烯转化率大幅降低；然而，采用涂有催化剂的环形圆柱体可以提高转化率，对于直径为 5 毫米、10 毫米和 20 毫米的转化率分别提高约 28%、17% 和 6%。这种随着直径增加而改善的减少可归因于层流阻碍乙烯分子从本体扩散到催化表面的动力学。因此，模拟数据凸显了采用掺杂催化剂的环形圆柱体作为提高乙烯转化率和延长水果保质期的有前景策略的潜力。然而，应该指出的是，添加环形气缸在提高转化率的同时，也会由于与较小直径相关的压降显着增加而带来操作复杂性和成本影响。