Influence of the Venturi Tube Geometry on Fine Bubble Generation

Abstract

Venturi tube fine bubble generator has been focused in the recent studies due to its simple structure, high generation efficiency and low power consumption. The generated fine bubbles with the properties such as cleaning, sterilization, disinfection, and deodorization, have been applied in many fields including the environment, agriculture, food, medical fields, etc. In this work, an oral irrigator utilizing fine bubble technology for oral purification is developed. The venturi tube is embedded in irrigator for fine bubble generation. We design venturi tubes with different geometrical combinations to improve the performance of fine bubble generation including bubble size and volume by experiment and numerical simulation. In the experiment, the flow states in the nozzle are photographed with a high-speed camera, and the area ratios of the bubbles in the tank are calculated to analyze the production volume of the bubbles. In numerical simulation, the models with the same geometrical parameters are made and Ansys Fluent is used to implement 3D CFD simulation to analyze the internal flow state and evaluate the generation performance. Both the experimental results and simulation results show that the generation performance is dependent on the geometrical parameters of venturi tube, and the venturi tubes with divergent angle of 1.2°, divergent length of 40 mm, and the one with divergent angle of 5°, divergent length of 20 mm demonstrate the best performance compared with others.