Effects of geometrical parameters on performance of plate-fin heat exchanger: Vortex-generator as core surface and nanofluid as working media

Abstract

Forced convective heat transfer with laminar and steady-state flow of copper-base deionized water nanofluid inside the vortex-generator plate-fin channels was studied experimentally and also numerically using CFD method. In the experimental section, a setup with capability to provide a constant wall temperature condition was fabricated. Single-phase (homogeneous) and two different two-phase (mixture and Eulerian) models were accomplished for temperature dependent thermo-physical properties in the numerical section. For the case under consideration, the mixture model gives closer predictions of the convective heat transfer coefficient to the experimental data than the homogeneous and Eulerian models. For nanofluids under consideration, the average relative error of Nusselt number between experimental data and CFD results based on mixture model was about 3.0%. Also, it was illustrated that the homogeneous and Eulerian models underestimated Nusselt number. Influences of two operating factors (i.e. Reynolds number and nanoparticles concentration) and seven geometrical parameters (i.e. wing height, wing width, channel length, longitudinal wings pitch, transverse wings pitch, wings attach angle, and wings attack angle) were investigated on performance of a plate-fin heat exchanger with vortex-generator channels. Finally, two correlations were developed for Colburn factor and Fanning friction factor variations based on Reynolds number, nanoparticles weight fraction, and geometrical parameters.