Finite element analysis of double pipe heat exchanger using nanofluids Viswanadhapalli Balaji, Sridhar Padala, Sanjeev Kumar Josh, Muntadar Muhsen, Satyendra Singh, Baxtjon Isroilova and Dildora Israilova E3S Web Conf., 563 (2024) 01004 Published online: 30 August 2024 DOI: 10.1051/e3sconf/202456301004