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

ABSTRACT

In the present study, an experimental investigation of performance evaluation of plate heat exchanger (PHE) with the rough surface using AL₂O₃/water nanofluid was achieved. The experiments were developed for different surface roughnesses of 0.978 µm (smooth surface), 1.276 µm, 2.825 µm and 3.657 µm 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 µm, 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%.

KEYWORDS:

• Plate heat exchanger
• surface roughness
• Al₂O₃/water nanofluid
• heat transfer
• pressure drop
• heat transfer enhancement factor

Highlights

• Heat transfer and pressure drop analysis inside a PHE are studied.

• AL₂O₃/water nanofluid is used inside PHE with a rough surface.

• Heat transfer enhancement factor is reported.

• New empirical correlation for predicting the Nusselt number is obtained.

• Surface roughness effects significantly on PHE performance than volume fraction.