Influence of Nanoparticle Shapes of Boehmite Alumina on the Thermal Performance of a Straight Microchannel Printed Circuit Heat Exchanger

Abstract

The efficiency and irreversibility defined based on the second law ofthermodynamics provide a new path for heat exchangers design and makeperformance analysis more straightforward and elegant. The second lawof thermodynamics is applied in a Straight Microchannel Printed Circuitheat exchanger to determine the thermal performance of different shapes ofBoehmite Alumina compared to Al2O3 aluminum oxide. The various formsof non-spherical Boehmite Alumina are characterized dynamically andthermodynamically through dynamic viscosity and thermal conductivity,using empirical coefficients. The non-spherical shape includes platelet,cylindrical, blades, and bricks forms. Graphical results are presented forthermal efficiency, thermal irreversibility, heat transfer rate, and nanofluidexit temperature. The non-spherical shapes of Boehmite Alumina showdifferent thermal characteristics concerning the spherical shape whenthere are variations in fluid flow rates and the nanoparticles fraction.Furthermore, it was theoretically demonstrated that non-spherical particleshave higher heat transfer rates than spherical particles, emphasizingplatelets and cylindrical shapes for the low volume fraction of nanoparticlesand bricks and blades for high volume fraction.