In order to explore the best extraction technology of flavonoids from Maoyanberry tea, the extraction conditions of flavonoids from Maoyanberry tea were optimized by using the method of single factor and response surface. The results showed that the optimal extraction conditions were as follows: Ethanol volume fraction 80%, liquid?solid ratio 25 mL/g, water bath temperature 85 ℃, water bath time 40 min. Under these conditions, the yield of flavonoids was 162.72 mg/g, which was close to the predicted value of the model, indicating that the optimized method was reasonable and feasible.

The single?phase and two?phase flow friction pressure drops of oil and water phase fluids in a rectangular copper?based microchannel with a hydraulic diameter of 895 μm were tested, and the experimental data were also compared with the existing single?phase and two?phase flow friction pressure drop prediction models. The effects of mass flux and ratio between oil and water on friction coefficient and pressure drop were investigated. The results show that the friction coefficient of oil is significantly higher than that of water, and Hagen?Poiseuille equation can accurately predict the pressure drop of oil or water single?phase fluid flow in the channel. The mass flux of both oil phase and water phase affect the pressure drop of the liquid?liquid two?phase flow significantly, and the friction pressure drop of the two?phase flow increases with the increasing working fluid flow rate and oil phase content. The homogeneous flow model established by Cicchitti (1960) can predict the mixing viscosity of oil?water two?phase fluids relatively accurately. In order to improve the prediction accuracy, a prediction correlation formula for the friction coefficient of oil?water two?phase flow is established, and the predicted value is in good agreement with the experimental value.