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Advisor(s)
Abstract(s)
Conventional methods for synthesizing metallic nanoparticles face challenges such as instability and environmental concerns. Therefore, new, simpler, and more eco-friendly methods are being explored. In this context, the study reports a green synthesis process to produce magnetic iron oxide nanoparticles using an aqueous extract of the alga Chlorella vulgaris. This process leverages natural resources to create a sustainable nanofluid known as green nanofluid. To evaluate the characteristics of this nanofluid, experimental measurements of wettability,
viscosity, thermal conductivity, and qualitative stability analysis were conducted. An experimental setup consisting
of a heat exchanger made of polydimethylsiloxane (PDMS) was used to assess the thermal performance
and the results were compared to theoretical equations and numerical simulation. Additionally, thermographic
imaging of temperature gradients as the fluids passed over the heated surface of the serpentine channel were
made. The main findings confirmed that the nanofluid was more stable than that obtained by traditional methods
and had a more uniform temperature distribution over the heat exchanger. The higher concentration exhibited
superior thermal performance compared to DI-Water. Moreover, the green nanofluid was used at a weight
concentration of 0.1 wt%, provided thermal performance results of nearly 4.5% superior to those estimated by
the numerical model and 6.4% higher than those experimentally obtained with the base fluid, respectively.
Finally, the results obtained for the nanofluid also showed an average increase of around 5% in the viscosity of
the base fluid, with a more significant sedimentation at a concentration of 0.1 wt%.
Description
Keywords
Green nanofluids PDMS exchanger Thermal conductivity Stability
Citation
Nobrega, Glauco; Souza, Reinaldo; Cardoso, Beatriz; Afonso, Inês; Pereira, José; Cardoso, Elaine; Moita, Ana; Ribeiro, João; Lima, Rui (2024). Experimental evaluation of green nanofluids in heat exchanger made oF PDMS. Thermal Science and Engineering Progress. ISSN 2451-9049. 55, p. 1-13
Publisher
Elsevier