Numerical study of nanofluid flow and heat transfer through a non-uniformly heated converging duct

Fundamental understanding on the enhancement of heat transfer rate and decreasing the maximum operating temperature is crucial for proper design of thermal systems. The present study discusses the influence of non-uniform heating on the forced convective flow of nanofluid through converging miniduct. Numerical simulations are performed using the Euler-Lagrangian two-phase flow model by finite volume method to find the effects of Reynolds number (Re), nanofluid volume fraction (φ), and amplitude (A) of sinusoidal heat flux on the heat transfer. The effect of various parameters on the magnitude of crest and trough of local Nusselt numbers is found to be a crucial factor in determining the total heat transfer. The results indicate a considerable increase in average Nusselt number (Nuav) with φ and Re. At Re = 100 the increments in Nuav are 3.4%, 6.7%, and 13.4% when φ is increased from 0 to 1, 3, and 5%, respectively, while it increases by 107%, 114%, and 116% for amplitudes of 0, 0.75, and 1, respectively, when Re is increased from 100 to 800. Increasing A reduces the heat transfer rate. The highest performance factor is found to be 0.945 at Re = 600, φ = 5% and A = 0.