Falling film configurations have widely been used in various types of refrigeration systems, and wettability has played an important role in characterizing the heat and mass transfer due to varying hydrodynamic behavior. The present paper focuses on a three-dimensional computational fluid dynamics (CFD) simulation to investigate the effect of hydrophilic circular surface on hydrodynamic behavior of liquid falling film over the heated horizontal circular tubes. First, the thickness of the liquid falling film and the liquid distribution around the circumferential and axial directions were analyzed at a feed water temperature of 20 °C for three film Reynolds numbers of 12, 24, and 36 (50 ≤ Q̇_feed ≤ 150 ml·min^-1) and three heat fluxes of 5, 10, and 15 kW m^-2. The influences of the contact angle on the liquid film hydrodynamics and heat transfer were then analyzed. The results showed that at a low feed film Reynolds number, even for super-hydrophilic nature (e.g., contact angles of 0° or 10°), the liquid film failed to cover the first-row tube surface. Increasing the feed film Reynolds number enhanced the liquid film distribution over the tubes and the dry spot decreased, which enhanced the heat transfer performance. At relatively higher contact angles of 30° and 60° (but still hydrophilic nature), the wetted area decreased and dry spots covered most of the second- and third-row tubes, which significantly influenced the thermal performance. Validation of the CFD model based on the volume-of-fluid approach was achieved by comparison with the experimental data, and the experimentally measured values of local heat transfer coefficient were employed for the comparison to support the validity of the present study.

降膜结构已广泛用于各种类型的制冷系统中，由于流体动力学行为的变化，润湿性在表征传热和传质方面起着重要作用。本文着重于三维计算流体动力学（CFD）模拟，以研究亲水性圆形表面对加热的水平圆形管上降膜的流体动力学行为的影响。首先，在进水温度为20°C的情况下，针对12、24和36的三个膜雷诺数（50≤Q̇_进料 ≤150 ml， ·min ^-1）和5、10和15 kW m ^-2的三个热通量。然后分析了接触角对液膜流体动力学和传热的影响。结果表明，在低进料膜雷诺数下，即使对于超亲水性质（例如，接触角为0°或10°），液膜也无法覆盖第一行试管表面。进料膜雷诺数的增加增强了液膜在试管上的分布，干点减少，从而提高了传热性能。在30°和60°的相对较高的接触角（但仍具有亲水性）下，润湿面积减少，干点覆盖了大多数第二排和第三排管，这显着影响了热性能。通过与实验数据进行比较，验证了基于流体体积方法的CFD模型的有效性，