Hydrothermal performance of a turbulent nanofluid with different nanoparticle shapes in a duct fitted with various configurations of coiled-wire inserts

Abstract

This paper examines the turbulent hydrothermal performance of boehmite/water–ethylene glycol (γ - AlO (OH) / H 2O - EG) nanofluid flowing through a square duct fitted with various coiled-wire inserts (CWIs) using the finite volume method. The turbulent flow of γ - AlO (OH) / H 2O - EG nanofluid is modeled using single-phase and k- ε model. A parametric study is carried out on the effect of Reynolds number (5.0 × 10 3≤ Re ≤ 4.0 × 10 4), the geometry of wire (circular, triangular, square, square-diamond, hexagon, octagon, and decagon), nanoparticle volume ratio (0 ≤ φ≤ 4 %), and nanoparticle shapes (blade, brick, cylinder, platelet, and oblate-spheroid) on hydrodynamic and convective heat transfer performance (CHTP). The results showed that the combination between CWI and nanofluid enhances hydrothermal performance. For instance, among the geometries of CWI considered at Re = 5.0 × 10 3 , the square CWI has the highest normalized Nu G (referencing empty channel) of 2.58, while the decagon has the lowest value of 1.78. Furthermore, regarding the nanoparticle shapes, the platelet shape has a maximum normalized Nu N (referencing base fluid) of 1.53, while the oblate-spheroid has a minimum value of 0.93. Lastly, in terms of application, square and octagon wire-fitted channels are better than empty channel at low Re , as the values of their hydrothermal performance evaluation criteria are greater than unity.