Alleviating the fouling issue on internally helical enhanced tubes

Alleviating the fouling issue of internally helical enhanced tubes within the cooling system has important implications for reducing energy consumption in data centers. To address the limitations of experimental investigations, such as the insufficient number of test tubes, numerical simulations of the fouling deposition characteristics of 25 internally helical enhanced tubes with different micro-rib geometric parameters are conducted employing the Eulerian–Eulerian method in this study. The response mechanisms and the sensitivity of fouling deposition to the enhancement of each single micro-rib geometric parameter on the enhanced tube are identified. The results demonstrate that the amount of combined fouling deposition for internally helical enhanced tubes increases with the decrease in the inner diameter (Di), the axial element pitch and rib height ratio (p/e), the increase in the number of ridges (Nsi), helix angle (αi), rib height (ei), which is consistent with the change in the heat transfer performance with each single micro-rib geometric parameter on the heat transfer surface. Meanwhile, under the typical cooling water velocity (1.6 m/s) and medium fouling potential water conditions, the impact of the overall variation of each single micro-rib geometric parameter on the asymptotic fouling thermal resistance in descending order: the number of ridges (Nsi), helix angle (αi), rib height (ei), and inner diameter (Di), with the corresponding range (Rj) of average asymptotic fouling thermal resistance being 2.44 × 10−5–8.01 × 10−5 (m2 · K)/W. In addition, a fouling prediction model related to the micro-rib geometric parameter was developed, which has an average accuracy of 4.91% for predicting the fouling resistance ratio. This work is valuable in understanding and alleviating the problem of fouling deposition for internally helical enhanced tubes from the viewpoint of structural parameters.