Experimental and numerical study on the drainage performance and fluid flow of Venturi tubes

Venturi tubes have been widely applied to the mixture and drainage of fluid due to the Venturi effect. In this work, an experimental investigation and a numerical simulation are conducted to analyze the fluid flow processing and drainage performance of Venturi tubes. A Venturi experimental installation is also established, and it consists of stainless steel and Plexiglas venturi tubes, pressure gauges, and flowmeters. The relationship between pressure evolution and volume flux is experimentally measured during the fluid flow proceeding in the Venturi tubes. Fluent software is used to model the optimization of drainage efficiency in the Venturi tube. Pressure is found to increase as the volume flux of the working fluid ascends. In a contraction section, the static pressure is transformed into the velocity of fluid, and the static pressure drops. In a diffusion section, the velocity of fluid is transformed into the static pressure, and the static pressure improves. A gas–water stratification phenomenon easily occurs; that is, the gas–water stratification region moves backward as the volume flux of the working fluid increases. Numerical results show that the drainage efficiency first increases and then decreases as the diameters of the throat and drainage tubes and the diffusion angle increase. When the diameter of the throat, drainage, and diffusion tubes are 48, 18, and 70 mm to 79 mm, respectively, the drainage efficiency is in a steady state and reach 0.5, which is significantly higher than the reported value of 0.2 from the reference. Drainage efficiency shows an M-shaped change as the drainage location varies. Setting a drainage tube in the contraction section is helpful in drainage; the diameter of the drainage tube is 17.5–18.5 mm.