Experimental Study On Solid-fluid Two Phase Flow In Microchannel

Fluid flow through small channels has become a popular research topic due to the emergence of biochemical lab-on-the-chip systems and micro electromechanical system fabrication technologies. But the characteristics of fluid flow in microchannel have not been found. Recently, several researchers have suggested that the well-accepted no-slip boundary condition may not be suitable for flows at the micro/nano scale. First, interface properties of the microchannel wall have been treated, and the interface properties' effect on the flow slippage character of the deionized water in the microchannel, whose inner radius is 25μm and 50μm, length is 40mm and 70mm, is studied. The interface properties is changed by coating the wall of the capillary with octadecyltrichlorosilane (OTS), and the slip observed by measure the flux and pressure drop of deionized water flow under pressure driven in hydrophilic and hydrophobic microchannel. As the result shown that, when the deionized water flow in the hydrophobic capillary, the flux increased obviously. That because the deionized water slips over hydrophobic surface.In this paper, the characteristics for two-phase fluids flow over microchannel were studied. Preparation of nanofluids is the first key step in experiment. This paper presents a preparation method of nanofluids by directly mixing nanophase powers and base fluids. Some auxiliary dispersants are necessary to obtain the even distributed and suspensions. With this method, several nanofluids with different volume fraction have been prepared. In order to research the problem of two-phase fluids flow over channel, this paper adopt nanofluid as experimental medium, and study the characteristics of the flow rate and pressure driven for nanofluids flow over microchannel, which inner radius is 25μm and 50μm, length rang from 40mm to 100mm. This characteristics of nanofluids compare with the deionized water flow over the same microchannel. The result indicated that the flow rate didn't monished compared with deionized water, and the flow characteristics of nanofluids in the microchannel in agreement to the macroscopic two-phase liquid flow characteristics. So the flow resistance for nanofluids flow over microchannel don't increase, and don't change along with mass fraction.