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

Abstract

AbstractThis paper examines the turbulent hydrothermal performance of boehmite/water–ethylene glycol$$(\upgamma -\mathrm{AlO}(\mathrm{OH})/{\mathrm{H}}_{2}\mathrm{O}-\mathrm{EG})$$(γ-AlO(OH)/H2O-EG)nanofluid flowing through a square duct fitted with various coiled-wire inserts (CWIs) using the finite volume method. The turbulent flow of$$\upgamma -\mathrm{AlO}(\mathrm{OH})/{\mathrm{H}}_{2}\mathrm{O}-\mathrm{EG}$$γ-AlO(OH)/H2O-EGnanofluid is modeled using single-phase and$$k-\varepsilon$$k-εmodel. A parametric study is carried out on the effect of Reynolds number ($$5.0\times {10}^{3}\le \mathrm{Re}\le 4.0\times {10}^{4}$$5.0×103≤Re≤4.0×104), the geometry of wire (circular, triangular, square, square-diamond, hexagon, octagon, and decagon), nanoparticle volume ratio ($$0\le \varphi \le 4\%$$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$$\mathrm{Re}=5.0\times {10}^{3}$$Re=5.0×103, the square CWI has the highest normalized$${\mathrm{Nu}}^{\mathrm{G}}$$NuG(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$${\mathrm{Nu}}^{\mathrm{N}}$$NuN(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$$\mathrm{Re}$$Re, as the values of their hydrothermal performance evaluation criteria are greater than unity.