疏水网覆盖的开放微管道中的液体输运

Abstract

Because unstable transportation of the fluid in an open microchannel restrains the integration of sampling and detection for bioaerosols,this paper proposes an open microchannel covered with a hydrophobic mesh to transport water in stability.On the basis of theoretical calculation,it gives a estimation formula of fluid transportation characteristics for the open microchannel and analyzes experimentally the fluid transportation characteristics by taking the water as transported media.The results in analysis and experiments demonstrate that the stability is dependent on the mesh properties and flow velocity,and is sensitive to the geometric parameters and the surface properties of the microchannel.The more hydrophobic the mesh is and the smaller the mesh holes are,the higher the maximum allowable pressure in the microchannel is and thus the water transportation is more stable.For a Teflon-coated mesh with a hole size of 50μm,the maximum allowable pressure is up to about 2 000Pa.Furthermore,the maximum allowable flow velocity in the channel is determined by the channel geometric parameters and the maximum allowable pressure of the mesh film.The maximum allowable velocity decreases with the decreasing height and increasing length of the microchannel.For a hydrophobic channel,the capillary pressure originated from the surface tension deteriorates the stability of the water transportation,and the adverse effect is more significant in a smaller channel.