Numerical investigation on Double Tube Counter Flow Heat Exchanger Ravi Shankar Raman, Swathi B, Alekhya V, Shrikant Zade, Ashwani Kumar, Sonali Jayronia and Laith H. Alzubaidi E3S Web of Conf., 507 (2024) 01027 Published online: 29 March 2024 DOI: 10.1051/e3sconf/202450701027