Effect of The Surface Pits on The Performance of a Double-Tube Heat Exchanger. NTU Journal of Renewable Energy, [S. l.], v. 9, n. 1, p. 63–72, 2025. DOI: 10.56286/ehgdyk62. Disponível em: https://journals.ntu.edu.iq/index.php/NTU-JRE/article/view/1609.. Acesso em: 5 dec. 2025.