$k$	Thermal conductivity of nanofluid ($\mathrm{W}/\left(\mathrm{m}·\mathrm{K}\right))$
$v$	Kinematic viscosity (m2/s)
$k_b$	Boltzmann Constant (-)
$T$	Temperature (K)
$A$	Empirical constant (-)
$Re$	Reynolds number (-)
$Pr$	Prandtl number of base fluids (-)
$M$	Empirical constant (-)
$T_0$	Reference temperature (K)
$c_p$	Specific heat ($\mathrm{J}/\mathrm{kg}·\mathrm{K})$
$R_b$	Thermal boundary resistance ($({\mathrm{m}}^2·\mathrm{K})/\mathrm{W})$
$r$	Radius ($\mathrm{m})$
$n$	Empirical shape factor (-)
$Bi$	Biot number (-)
$d$	Diameter ($\mathrm{m})$
$l_{bf}$	Mean free path ($\mathrm{nm})$
Greek Symbols
$\varphi$	Volume fraction of nanoparticle in base fluid(-)
${\delta }_{nl}$	Nanolayer thickness (-)
${\beta }_{nl}$	Dimensionless nanolayer parameter (-)
$\beta$	Empirical correlation (-)
$\gamma$	Ratio of nanolayer thickness to nanoparticle radius (-)
$\rho$	Density ($\mathrm{kg}/{\mathrm{m}}^3)$
$\zeta$	Empirical constant (-)
$\alpha$	Thermal diffusivity (${\mathrm{m}}^2/\mathrm{s})$
$\mu$	Dynamic viscosity ($\mathrm{mPa}·\mathrm{s})$
Subscripts
$p$	Particle
$bf$	Base fluid
$m$	Matrix
$nf$	Nanofluid