Simulation and optimization of Venturi type bubble generator to improve cavitation

Abstract

This study carried out the simulation and optimization of a Venturi tube with the aim of producing more micro-nanobubbles (MNBs) and preventing their aggregation to increase mass transfer. In the first step, fluid flow in a steady state in a simple Venturi tube was simulated. In the next step, a tube will be added to the throat. The test design will investigate and optimize the effects of three geometrical parameters: length, diameter, and rotation angle of the tube on two responses pressure and velocity in the throat. Also, from the design of the experiment, it was found that the angle of rotation and the diameter of the tube, compared to the length of the tube, have a greater effect on increasing the velocity and reducing the pressure in the throat, and their values ​​were 90°, 1.5 mm, and 5 mm, respectively. From the simulation of the Venturi tube in the second state with the optimal values ​​obtained, a 51 % reduction in the cavitation number was achieved, which has an inverse ratio with the cavitation intensity. In general, with the increase in cavitation intensity, the production of MNBs increases, and their accumulation is minimized.