Helium advantages: Small-bore tube

Gas flow through a tube is either laminar (parabolic velocity profile) or turbulent (flat velocity profile). The nature of flow is dependent on several physical properties of the gas (density, viscosity) as well as of the flow itself (velocity, length of tubing), all of which can be combined mathematically into the Reynold’s number, Re (Re = ρUL/visc., where ρ is the density of the fluid, U is the mean flow velocity, L is length of flow, and visc. is the viscosity). [More…]