Experimental Investigation of Heat Transfer Enhancement in Shell-and-Tube Heat Exchangers Using Nanofluids

Abstract

Shell-and-tube heat exchangers are widely used in power, process, refrigeration and chemical systems, but their thermal performance is constrained by the relatively low thermal conductivity of conventional heat-transfer fluids. Nanofluids provide a passive enhancement approach by dispersing nanoparticles with high thermal conductivity in a base liquid. This methodology paper develops a compact experimental protocol for evaluating heat-transfer enhancement in a counter-flow shell-and-tube heat exchanger using Al₂O₃/water nanofluids. The proposed investigation compares distilled water with low particle-volume concentrations of 0.1, 0.3 and 0.5 vol.% under controlled inlet temperatures and flow rates. The methodology covers nanofluid preparation, stability checks, calibration of thermocouples and flow meters, steady-state testing, pressure-drop measurement, uncertainty treatment and calculation of heat duty, logarithmic mean temperature difference, overall heat-transfer coefficient, Reynolds number, Nusselt number and effectiveness. Published studies up to 2016 show that nanofluids can increase convective and overall heat-transfer coefficients, although gains depend strongly on particle material, concentration, temperature and flow regime. The proposed method therefore evaluates thermal enhancement together with hydraulic penalty instead of considering heat transfer alone. Literature-benchmarked results indicate that modest Al₂O₃ concentrations are a practical region for experimentation because they can improve heat transfer while limiting viscosity and pumping-power increases. The paper provides a reproducible basis for laboratory validation without claiming unperformed measurements as new experimental data.