Thermal performance enhancement of a double tube heat exchanger using ternary nanofluid and disk-type turbulators: a numerical studyNabil Jlidi, Zouhaier Mehrez and Afif El CafsiEur. Phys. J. Plus, 141 5 (2026) 487DOI: https://doi.org/10.1140/epjp/s13360-026-07721-6