Two-phase mixture modeling of turbulent forced convective flow of water–silver nanofluid inside a rifled tube: hydrothermal characteristics and irreversibility behavior

This work aims to present a numerical evaluation of the turbulent forced convective flow of water–silver nanofluid (NF) inside a horizontal internally spiral-ribbed heat exchanger tube using the two-phase mixture model. The considered NF is prepared using an environmentally friendly method. The influences of the volume concentration of silver nanoadditives ( $$\varphi$$ ), Reynolds number (Re), rib width (W), rib height (H) and rib pitch (P) on the convection coefficient, pressure loss, irreversibility in fluid friction ( $$\dot{S}_{{{\text{g}},{\text{f}}}}$$ ) and heat transfer ( $$\dot{S}_{{{\text{g}},{\text{h}}}}$$ ) and total irreversibility ( $$\dot{S}_{{{\text{g}},{\text{t}}}}$$ ) are assessed. The outcomes disclosed that the hydrodynamic characteristics and irreversibility behavior of NF flow in the ribbed tube are better than that of the water flow in the plain tube. In addition, it was found that the best first-law performance belongs to the case $$\varphi = 1\%$$ , $${\text{Re}} = 5000$$ , $$W = 2$$ mm, $$H = 2$$ mm, $$P = 4$$ mm, while the best second-law performance occurs at $$\varphi = 0\%$$ , Re = 20,000, $$W = 2$$ mm, $$H = 1$$ mm, $$P = 5$$ mm.