https://doi.org/10.1140/epjp/s13360-026-07332-1
Regular Article
Phase change heat transfer in a square enclosure containing a power-law nanofluid and a circular cylinder at various vertical positions
1
Department of Mathematics Education, Universitas Islam Negeri Sultan Syarif Kasim Riau, Pekanbaru, Indonesia
2
Department of Electrical Engineering, Universitas Islam Negeri Sultan Syarif Kasim Riau, Pekanbaru, Indonesia
a
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Received:
24
August
2025
Accepted:
16
January
2026
Published online:
31
January
2026
This study explores the thermal optimization of a cold square enclosure containing a heated circular cylinder, where the cylinder’s position varies along the vertical centerline of the enclosure. The cavity is filled with a suspension of nano-encapsulated phase change materials (NEPCMs) in a non-Newtonian fluid to enhance thermal performance. The primary aim is to examine the flow patterns, phase change dynamics, and overall thermal efficiency of the system. The governing equations for the NEPCMs nanofluid are reformulated into a dimensionless form and solved using the finite element method. Key parameters such as the cylinder’s position (
), the power-law index (n), the NEPCMs particle volume fraction (
), the fusion temperature (
), and the Rayleigh number (Ra) are systematically analyzed to assess their influence on thermal performance. The findings of the study indicate that the region of active NEPCM fusion grows with increasing NEPCM concentration, except in the case of pseudoplastic fluids. The vertical position of the heated cylinder acts as an effective passive control parameter. Increasing NEPCM concentration consistently enhances overall heat transfer for all fluid types.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2026
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.
