experimental study and cfd modeling of heat transfer using boehmite-water nanofluid in a pilot scale shell and tube heat exchanger

In the current research, heat transfer within a pilot scale shell and tube heat exchanger is investigated. the heat exchanger consist of a shell and five copper tubes. water as the cold stream and boehmite-water nanofluid as the hot stream passes through the shell and tube side, respectively. the effect of nanofluid concentration (0.35, 0.7, and 1.5 %wt.), volume flowrate of the cold stream (0.6, 3, and 6 l/min), and the inlet temperature of the hot stream (40, 50, 60  were investigated on the overall heat transfer coefficient. moreover, the computational fluid dynamics (cfd) modeling of heat transfer within the pilot scale was performed to study the hydrodynamics of flow inside the heat exchanger. the experimental results and cfd predictions indicates that as the concentration of the nanofluid increases, the overall heat transfer coefficient will increase. this can be attributed to higher thermal conductivity of nanoparticles and the brownian motion of the particles in the base fluid. moreover, when the volume flowrate of the fluid increases, reynolds number will increase, which cause the convection heat transfer coefficient and consequently the overall heat transfer coefficient to be enhanced. also, at higher inlet temperature of the hot fluid, higher overall heat transfer coefficient was resulted. the maximum deviation between the overall heat transfer coefficients evaluated base on the cfd predictions and its value based on experimental measurements was 16.7%. this proves the ability of cfd technique in pursuing the experimental data. cfd simulation provide a meaningful knowledge about the hydrodynamics of each stream in the heat exchanger, which help us to optimize the performance of heat exchanger.