https://doi.org/10.1140/epjp/s13360-024-05425-3
Regular Article
Heat transfer across an array of cylinders arranged in inline and staggered formation in a heat exchanger: effect of nanoparticle volume fraction, nanoparticle diameter, and Richardson number
Computational Fluid Dynamics Laboratory, Chemical Engineering Department, Indian Institute of Technology Roorkee, 247667, Roorkee, Uttarakhand, India
Received:
14
May
2024
Accepted:
3
July
2024
Published online:
9
July
2024
This study investigates the influence of nanoparticle volume fraction, nanoparticle diameter, and Richardson number on the heat transfer across an array of cylinders arranged in inline and staggered formation in a heat exchanger. The Richardson number and the diameter of the nanoparticles varied from −1.5 to 1.5 and from 10 to 50 nm, respectively. The Reynolds number is fixed at 100. The investigation involves exploring different volume fractions of nanoparticles dispersed in the nanofluid, ranging from 0 to 0.05. The results show a stark increase in heat transfer rates when opposing buoyancy is introduced. A combination of opposing buoyancy, small nanoparticle diameter, and high volume fraction of nanoparticles can cause a significant increment in heat transfer rates. Opposing buoyancy induces chaotic flow with larger recirculation zones, leading to higher temperature gradients near the cylinders and elevated heat transfer rates. However, the rate of heat transfers in all operating conditions is notably lower when aiding buoyancy prevails. This behavior can be attributed to the stabilizing effect of aiding buoyancy in the flow, consequently reducing temperature gradients in the vicinity of cylinders and the nanofluid. The heat transfer rates are quantified using the mean Nusselt number of the arrays and the local Nusselt numbers on each cylinder within the arrays.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
