Experimental and numerical characterization of single-phase pressure drop and heat transfer enhancement in helical corrugated tubes

• Published in: International journal of heat and mass transfer 2021-11, Vol.179, p.121632, Article 121632
• Main Authors: Cruz, Gonçalo G., Mendes, Miguel A.A., Pereira, Jos M.C., Santos, H., Nikulin, A., Moita, Ana S.
• Format: Article
• Language: English
• Subjects: Computational fluid dynamics (CFD); Convective heat transfer; Corrugated tubes; Corrugation; Experimental setup; Fluid dynamics; Fluid flow; Heat flux; Heat transfer; Heat transfer enhancement; Internal flow; Mathematical models; Numerical models; Pressure drop; Reynolds number; Three dimensional flow; Transitional flow regime; Tubes; Turbulence; Turbulent flow; Working fluids
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2021.121632

•Single-phase flow on helical corrugated tubes of different pitch.•Measurement of pressure drop and heat transfer characteristics.•3D CFD model simulations in the transition from laminar to turbulent.•Model successfully validated against experimental results for all tested tubes.•Model allowed phenomenological interpretation of enhanced thermal performance. The internal flow in corrugated tubes of different helical pitch, covering from the laminar to turbulent regime, was studied in order to characterize the three-dimensional flow and the influence of corrugation geometry on pressure drop and convective heat transfer. With water as working fluid and an imposed wall heat flux, ranging from around 4 to 33 kW/m2, a numerical model was developed with a CFD commercial software, where k−ω SST was used to model turbulence. Experimental tests were performed covering Reynolds numbers in the range from around 300 up to 5000, which allowed to identify the transition region and validate the numerical model. The results show that due to the swirl induced by the corrugation, the critical Reynolds number for the start of transition to turbulent flow is reduced. The thermal performance factor, which quantifies the heat transfer enhancement at the expense of pressure drop, was used to compare the corrugated tubes against the reference case of smooth tube. Based on this, all investigated corrugated geometries performed better than the smooth tube, except for low Reynolds numbers (Re