Experimental investigation of thermo-hydraulic performance of conical helical spring turbulators with different geometries in turbulent airflow
International Journal of Heat and Fluid Flow, cilt.121, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 121
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.ijheatfluidflow.2026.110528
- Dergi Adı: International Journal of Heat and Fluid Flow
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Conical helical springs, Energy efficiency, Heat exchangers, Heat transfer, Pressure drop, Turbulators, Turbulent flow
- İnönü Üniversitesi Adresli: Evet
Özet
Enhancing heat transfer efficiency in thermal systems is critical for energy conservation and the development of compact heat exchangers. In this study, the effects of helical conical spring turbulators placed inside a copper tube on heat transfer and friction factor were experimentally investigated. Within the scope of the experimental matrix, the Nusselt number and friction factor were calculated for six different Reynolds numbers (4126 to 24,756) across nine distinct configurations, consisting of three different spring lengths (L200, L250, L300) and three different spring quantities (N1, N2, N3). The obtained results were compared with plain tube experiments performed under identical conditions. To simultaneously evaluate the enhancement in heat transfer and the associated hydraulic losses, the thermo-hydraulic performance was analyzed based on the Performance Evaluation Criterion (PEC). It was observed that the use of helical conical spring turbulators significantly enhances heat transfer compared to the plain tube. Conversely, friction factor values increased due to the additional flow resistance created by the helical conical springs in the flow path, with the fa/f0 ratio ranging between 3.16 and 18.76. In the thermo-hydraulic evaluation, single-turbulator configurations (L200-N1, L250-N1, L300-N1) failed to provide a clear thermo-hydraulic advantage, as their PEC values remained below 1 under all conditions. In contrast, all configurations featuring two or three turbulators yielded PEC values greater than 1. The highest PEC value was determined as 1.156 for the L300-N3 configuration. The study demonstrates that helical conical spring turbulators effectively enhance heat transfer in internal flow applications. However, it is concluded that the target thermal improvement and permissible hydraulic losses must be evaluated together to determine the optimal design.