H. Abazari Bahnemiri - Department of Mechanical Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran
S. A. A. Oloomi - Department of Mechanical Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran
S. A. A. Mirjalily - Department of Mechanical Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran
A. Zare-Shahabadi - Department of Mechanical Engineering,Technical and Vocational University (TVU), Tehran, Iran

In the present research, effects of nanoparticles and changing of tube diameter have been scrutinized on heat transfer parameters in the shell and helically coiled tube heat exchanger. A CFD analysis and also a modeling of the mentioned heat exchager have carried out by writing a code in MATLAB software for two regimes involving forced convection heat trasnfer in single phase fluid flow and sub-cooled boiling. In the case under analysis, considered nanoparticles in this research was Nickel nanoparticles with ۰.۱ and ۱% volumetric concentration. Based on the results, both going up of volume concentration of nanoparticles and increasing of tube diameter are cause to make better heat transfer parameters. In truth, heat transfer coefficient and Nusselt number have been enhanced by ۰.۱ and ۱ % volumetric concentration of Nickel nanoparticles.

heat exchanger, Heat Transfer Coefficient, Helically coiled tube, Nanoparticles, Sub-cooled boiling flow