a, b, c	Lattice constants (Å)
B.E.	Binding Energy (eV)
CP	Isobaric specific heat (J kg−1 K−1)
h	Convective heat transfer coefficient (W m−2 K−1)
k	Thermal conductivity (W m−1 K−1)
$q_s^{″}$	Heat flux (W m−2)
Tm,o	Mean temperature of the fluid at the pipe outlet (K)
Ts	Temperature on the surface of the pipe (K)
α	Thermal diffusivity (m2 s−1)
ϕ	Volume fraction (vol.%)
μ	Dynamic viscosity (Pa s)
ρ	Density (kg m−3)
Subscripts
bf	Base fluid
nf	Nanofluid
np	Nanoparticle