📙 Turbulent nanofluids flows in Rib-Groove channel are numerically investigated. The continuity, momentum and energy equations were solved by means of a finite volume method (FVM). A commercial CFD package, FLUENT, is used to perform the modeling and simulation. Different Rib-Groove shapes are used (Rectangular Rib, Triangular Rib,Trapezoidal Rib, Rectangular Groove, Triangular Groove, and Trapezoidal Groove). Four different types of Nanoparticles (Al2O3, CuO, SiO2, and ZnO) with different volumes fractions in the range (0-4)% and different nanoparticle diameters in the range (25-80)nm, are dispersed in the base fluid (water, glycerin and engine oil) are used. In this study, several parameters such as different Reynolds numbers in the range of 5000 < Re < 20000, and different aspect ratios in the range of 0.5 ? AP ? 4 mm are investigated to identify their effect on the heat transfer and fluid flow characteristics.