Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Advancing Nanofluid Numerical Modelling: a Novel Euler–Lagrange Method With Experimental Validation(Elsevier Ltd, 2025) Vovk, N.; Kamenik, B.; Elcioglu, E. Begum; Ozyurt, E.; Karadeniz, Z. H.; Turgut, A.; Ravnik, J.We present a novel approach to numerical modelling of thermal nanofluids based on the Euler-Lagrange method. This approach overcomes the challenge of extremely fine temporal discretization, which previous Euler-Lagrange nanofluid numerical models struggled to address, while also avoiding the need for too many Lagrangian nanoparticles. A numerical uncertainty assessment method is adapted for the proposed approach. The model is validated with a simple verification case and applied to simulate a closed natural circulation loop heat exchanger operating with heating power ranging from 10 W to 50 W and nanoparticle volume fractions of 0.5% to 2%, using an Al2O3-water nanofluid. Results are compared with experimental temperature measurements and an Euler-Euler implementation of the same nanofluid. The model is also applied to simulate the natural convection inside a vertical enclosure, studied experimentally by other authors. The proposed novel approach demonstrates agreement with both experimental data and the Euler-Euler implementation, effectively capturing the overall behaviour of nanofluids. We establish, that the interplay of multiple transport phenomena, that occur in nanofluid operated devices, can be difficult to completely reproduce numerically within the framework of current modelling assumptions.Article Citation - WoS: 1Citation - Scopus: 1Euler–Euler Numerical Model for Transport Phenomena Modeling in a Natural Circulation Loop Operated by Nanofluids(Springer, 2025) Kamenik, B.; Vovk, N.; Elcioglu, E.B.; Sezgin, F.; Ozyurt, E.; Karadeniz, Z.H.; Ravnik, J.This paper explores a computational approach to model multiphase heat transfer and fluid flow in a natural circulation loop utilizing nanofluids. We propose and implement an Euler–Euler framework in a CFD environment, incorporating an innovative boundary condition to preserve mass conservation during thermophoretic particle flux. The model’s accuracy is verified through a one-dimensional example, by comparing results against both an Euler–Lagrange model and an in-house finite volume solution. Experimental validation is conducted with aluminum oxide nanofluids at varying nanoparticle concentrations. We prepared the nanofluids and measured their thermophysical properties up to 60∘C. We assess the thermal performance of the nanofluid in natural circulation loop at different heating powers via experiment and numerical simulations. The findings reveal that the heat transfer enhancement offered by the nanofluid is modest, with minimal differences observed between the proposed Euler–Euler approach and a simpler single-phase model. The results underscore that while the Euler–Euler model offers detailed particle–fluid interactions, its practical thermal advantage is limited in this context. © The Author(s) 2025.