Poiseuille flow in a nano channel for different wall surface patterns

• A weak wall–fluid interaction enhances the fluid flow through a nano channel driven by the pressure, while a strong wall–fluid interaction deteriorates it.
• Inhomogeneous wall surfaces may be better than homogeneous wall surfaces for the pressure driven mass transfer through a nano channel.
• Even a very small tilting angle θ between the coupled wall surfaces is very beneficial for the pressure driven fluid flow through a nano channel.

The mass flow rate of the Poiseuille flow through a nano channel was analytically studied for different wall surface patterns, by using the flow factor approach model. It was found that a weak wall–fluid interaction enhances the mass transfer through a nano channel, while a strong wall–fluid interaction otherwise degrades it. A very weak wall–fluid interaction might be difficult to obtain for homogeneous wall surfaces, in this circumstance inhomogeneous wall surfaces are recommended for generating a significantly larger Poiseuille flow through the channel than normal homogeneous wall surfaces give. When taking inhomogeneous wall surfaces, the W–M and M–S types of the wall–fluid interactions are recommended for generating the Poiseuille flow through the channel, and they respectively give the wall–fluid interaction in the outlet zone of the channel considerably weaker than that in the inlet zone of the channel. It was also found that the increase of the tilting angle between the coupled wall surfaces can significantly increase the Poiseuille flow through a nano channel.