Numerical investigation of heat transfer and pressure drop of water-nanofluid flow in a three-dimensional wavy mini-tube

This research employs three-dimensional simulations to investigate the behavior of pure water and nanofluids consisting of Al 2 O 3 and TiO 2 particles within a sinusoidal mini-tube as a single-phase suspension. The impact of a mini-tube's sinusoidal amplitude and wavelength on laminar flow properties is investigated in Reynolds numbers ranging from 100 to 600. The results present that performance evaluation criterion of mini-tube is more proper in the amplitude of 3 mm and wave length of 16 mm. Performance evaluation criterion of sinusoidal shaped mini-tube with pure water in comparison with straight mini-tube, shows that sinusoidal mini-tube has the proper performance which the performance evaluation criterion is greater than 1. Proper selected mini-tube is also used with nanofluids. In this simulation, proposed nanofluids are water-Al 2 O 3 and water-TiO 2 nanofluids with volume fractions of 2 % and 4 %. The results of this investigation reveal that using nanofluids improves performance evaluation criterion. Also, comparison of two different nanoparticles shows that Al 2 O 3 nanoparticles have better performance in comparison with TiO 2 nanoparticles. By changing geometrical parameters as amplitude and wave length and finding proper mini-tube, it is seen that performance evaluation criterion is increased two times in comparison with straight tube. Also, using nanofluid in proper mini-tube in comparison with pure water in the same mini-tube, leads to improvement of cooling and thermal performance up to of 20 %, in the different Reynolds numbers.