Combination Effect of Baffle Arrangement and Hybrid Nanofluid on Thermal Performance of a Shell and Tube Heat Exchanger Using 3-D Homogeneous Mixture Model

In this study, thermal performance and flow characteristics of a shell and tube heat exchanger equipped with various baffle angles were studied. The heat exchanger was operated with distilled water, and a hybrid nanofluid at three concentrations of 0.04% and 0.10% of GNP-Ag/water within Reynolds numbers ranged between 10,000 and 20,000. The thermophysical properties of nanofluid varied with temperature and nanoparticles' concentration. The baffle angles were set at 45 degrees, 90 degrees, 135 degrees, and 180 degrees. Results showed that the calculated Nusselt number (Nu) could be improved by adding nanoparticles to the distilled water or increasing the fluid's Reynolds number. At a low Re number, the Nu corresponding to baffle angle of 135 degrees was very close to that recorded for the angle of 180 degrees. At Re = 20,000, the Nu number was the highest (by 35% compared to the reference case), belonging to a baffle angle of 135 degrees. Additionally, results related to friction factor and pressure drop showed that more locations with fluid blocking were observed by increasing the baffle angle, resulting in increased pressure drop value and friction. Finally, the temperature streamlines counter showed that the best baffle angle could be 135 degrees in which maximum heat removal and the best thermal performance can be observed.

Automated summary

The study found that adding nanoparticles to the distilled water or increasing the fluid's Reynolds number can improve the heat transfer performance in shell and tube heat exchangers, especially at a baffle angle of 135 degrees. Additionally, increasing the baffle angle resulted in more fluid blocking areas, leading to increased pressure drop and friction.