An experimental study on heat transfer and fluid flow of rough plate heat exchanger using Al2O3/water nanofluid

In the present study, an experimental investigation of performance evaluation of plate heat exchanger (PHE) with the rough surface using AL(2)O(3)/water nanofluid was achieved. The experiments were developed for different surface roughnesses of 0.978 mu m (smooth surface), 1.276 mu m, 2.825 mu m and 3.657 mu m with different volume fractions of nanoparticles of 1.2 vol.%, 1.9 vol.% and 2.6 vol.% at Reynolds number of 500 <= Re <= 5000. The Nusselt number (Nu), the friction factor (f) and the heat transfer enhancement factor (HTEF) were estimated. The results show that increasing the volume fraction of nanoparticles and surface roughness enhances the heat transfer rate as well as increases the pressure drop in PHE. Hence, the influence of surface roughness is more considerable than that of volume fraction of nanoparticles on PHE performance. Furthermore, for smooth surface, the HTEF is improved by 2%, 3.7% and 5.4% for volume fraction of nanoparticles of 1.2 vol.%, 1.9 vol.% and 2.6 vol.%, respectively; while these values for the highest value of surface roughness, i.e., 3.657 mu m, are 9.4%, 11.8% and 13.7%. Based on the experimental results, a new empirical correlation to predict Nu for base fluid is obtained with a maximum deviation of 2.87%.