Influence of Knudsen number on fluid viscosity for analysis of divergence in fluid conveying nano-tubes

In this paper, the effects of Knudsen number (Kn) and slip boundary condition have been addressed on the viscosity of a nano-flow passing through a nano-tube. The dimensionless parameter, Kn, as a small size parameter, influences the stability behavior and critical flow velocity of a nano-tube conveying gas fluid considerably, as compared to a purely continuum and size-free formulation. Consequently, a Kn-dependent viscosity affects both directly on viscosity values and indirectly on a dimensionless parameter, velocity correction factor, VCF, defined as a ratio of no-slip boundary flow velocity to slip boundary flow velocity. The effect of viscosity on critical flow velocity is so large that for a numerical study reaches one-fourth of that velocity, ignoring viscosity effect on slip boundary condition. These variations in critical flow velocity of a nano-pipe conveying fluid may affect structural design of nano-devices remarkably specifically, targeted drug delivery systems.