Effect of non-uniform heating on conjugate heat transfer performance for nanofluid flow in a converging duct by a two-phase Eulerian-Lagrangian method

In this paper, the effect of non-uniform heating on the conjugate thermal and hydraulic characteristics for Al2O3-water nanofluid flow through a converging duct is examined numerically. An Eulerian-Lagrangian model is employed to simulate the two-phase flow for the following range of parameters: Reynolds number (100 <= Re <= 800), nanoparticle volume fraction (0% <= phi <= 5%) and amplitude of the sinusoidal heat flux (A = 0, 0.5 and 1). The results reveal a similar affinity between the applied heat flux and local Nusselt number variation qualitatively, mainly at the middle of the duct. The results also indicate that there is a considerable enhancement of Nusselt number with the increase in Reynolds number and the thermal conductivity of wall materials. In addition, increasing the particle loading contributes to an enhanced rate of heat transfer. The heat transfer rate is lower for non-uniform heating when compared with the constant heat flux and the same can be compensated by the application of volume fraction of nanoparticles