Euler–Euler numerical model for transport phenomena modeling in a natural circulation loop operated by nanofluidsKamenik, Blaž (Avtor) Vovk, Nejc (Avtor) Elcioglu, Elif Begum (Avtor) Sezgin, Firat (Avtor) Ozyurt, Erdem (Avtor) Karadeniz, Ziya Haktan (Avtor) Turgut, Alpaslan (Avtor) Ravnik, Jure (Avtor) CFD · Euler–Eulermultiphase fownanofluidnatural circulation loopthermophoresisThis paper explores a computational approach to model multiphase heat transfer and fuid fow in a natural circulation loop utilizing nanofuids. We propose and implement an Euler–Euler framework in a CFD environment, incorporating an innovative boundary condition to preserve mass conservation during thermophoretic particle fux. The model’s accuracy is verifed through a one-dimensional example, by comparing results against both an Euler–Lagrange model and an in-house fnite volume solution. Experimental validation is conducted with aluminum oxide nanofuids at varying nanoparticle concentrations. We prepared the nanofuids and measured their thermophysical properties up to 60◦C. We assess the thermal performance of the nanofuid in natural circulation loop at diferent heating powers via experiment and numerical simulations. The fndings reveal that the heat transfer enhancement ofered by the nanofuid is modest, with minimal diferences observed between the proposed Euler–Euler approach and a simpler single-phase model. The results underscore that while the Euler–Euler model ofers detailed particle–fuid interactions, its practical thermal advantage is limited in this context.Springer20252025-03-12 12:11:32Članek v reviji92031sl© The Author(s) 2025