Mehrdad zolfalizadeh - Faculty of Chemical and Petroleum Engineering, University of Tabriz, Tabriz, Iran
Saeed zeinali heris - Faculty of Chemical and Petroleum Engineering, University of Tabriz, Tabriz, Iran
Mousa Mohammadpourfard - Faculty of Chemical and Petroleum Engineering, University of Tabriz, Tabriz, Iran
Mohammad Marfavi - Abadan Oil Refining Company, Abadan, Iran.

This research, presents the results of an experimental study on the effect of nanofluid stability by controlling the concentration of nanoparticles and surfactant on heat transfer coefficients. The water based nanofluids of graphene prepared at concentrations of ۰.۰۱ to ۰.۱ wt%. A shell and tube heat exchanger has been used to investigation the heat transfer coefficients. By studying the optimal concentration of nanoparticles dispersed in the base fluid, it was concluded that low and high concentration of nanoparticles and surfactants can affect the heat transfer coefficients. By using an appropriate of nanoparticle concentration and surfactant, the convective and overall heat transfer coefficient has improved by ۲۲.۴۷% than the base fluid at highest concentrations

Nanofluid, Nanoparticle, Graphene, Heat transfer coefficient, Overall heat transfer coefficient