Abstract
Convective heat transfer can be enhanced passively by changing flow geometry and boundary conditions or by improving the thermal conductivity of the working fluid, for example, introducing suspended small solid nanoparticles. In this paper, a numerical investigation on laminar mixed convection in a water-Al2O3-based nanofluid, flowing in a triangular cross-sectioned duct, is presented. The duct walls are assumed at uniform temperature, and the single-phase model has been employed in order to analyze the nanofluid behaviour. The hydraulic diameter is equal to 0.01 m. A fluid flow with different values of Richardson number and nanoparticle volume fractions has been considered. Results show the increase of average convective heat transfer coefficient and Nusselt number for increasing values of Richardson number and particle concentration. However, also wall shear stress and required pumping power profiles grow significantly.
Highlights
Heat transfer enhancement is a significant issue in the research and industry fields
The working fluid flows into a triangular cross-sectioned duct with walls at a uniform temperature; the heat transfer mechanism is different if the bottom wall behaviour is compared with the inclined ones when the buoyancy effects are considered
A numerical investigation about the laminar mixed convection in water/Al2O3-based nanofluids flowing into a triangular sectioned duct is carried out
Summary
Heat transfer enhancement is a significant issue in the research and industry fields. Ali and Al-Ansary [22] analyzed the natural convection in vertical triangular ducts in laminar and transition regime, Advances in Mechanical Engineering giving the critical values of the modified Rayleigh number for the transition to turbulent flow. They underlined the local axial (perimeter averaged) heat transfer coefficient decrease in the laminar region and increase in the transition one. Experimental results for the convective heat transfer of Al2O3 (27–56 nm)/water-based nanofluids flowing through a copper tube in laminar regime was reported in [36]. Different nanoparticle volume fractions are considered and the singlephase model has been assumed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
