Numerical Analysis of Surfactant Influence on Heat Transfer Behavior of TiO2 Nanocolloid in Laminar Flow

Nanocolloid research has undergone a complete transformation, renouncing the empirical estimation of properties and relying on real case scenarios. The main objective of this paper is to compare a large number of samples that were experimentally studied in terms of thermophysical properties in order to be able to draw a conclusion in terms of the heat transfer efficiency of a certain surfactant addition to a 2 wt.% TiO2 nanoparticle-enhanced fluid. The analysis discusses both the advantages and drawbacks in terms of surfactant type and concentration influence over the Prandtl number, thermal diffusivity, and Nusselt number, as well as the heat transfer coefficient for different Reynolds numbers in laminar flow. The investigation also includes a different figure of merits and performance evaluation criteria that are extensively employed in the literature in order to have a complete overview of the efficiency of surfactants in improving nanocolloids. In conclusion, even if surfactants are considered for improving nanocolloid stability, their drawbacks have not been debated in depth in the open literature. The main conclusion that arises from this study outlines that among all tested samples, F127 at a concentration of 0.25 wt.% consistently demonstrates the best overall performance, achieving an optimal balance between enhanced thermal properties and acceptable pumping requirements.