SMART-HEAT - Surfaces Micro And nanometRically Treated for HEAt Transfer enhancement

Publications

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

Publication . Cruz, Gonçalo G.; Mendes, Miguel A. A.; Pereira, José M. C.; Santos, H.; Nikulin, A.; Moita, Ana S.

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<500) in the laminar regime. Overall, the corrugated tube with the lowest pitch showed a clearly better performance for the intermediate range of Reynolds numbers (1000

2021-07-19Journal article

Open access

Keywords

Surface micro and nano-coatings,Biomimetics,Reverse wettability,Phase-change systems, Engineering and technology ,Engineering and technology/Nano-technology

Funding agency

Fundação para a Ciência e a Tecnologia, I.P.

Funding programme

2º Concurso para Projetos Colaborativos para Programa do Joint Innovation Center for Advanced Materials - 2017

Funding Award Number

JICAM/0003/2017