Optimization and Automated Parameter Study for Cavitating Multiphase Flows in Venturi - CFD Analysis

Abstract

In recent years falling demand for print paper and ambitious targets for reduction of energy use have been major factors that has caused the pulp and paper industry to develop state of the art technologies for reducing energy consumption drastically. A method for achieving the same is to develop and design energy efficient refiners by utilizing hydrodynamic cavitation technology. A parameter study of a venturi design with a flow obstruction body is conducted in order to investigate the critical parameters for inducing hydrodynamic cavitation. To reduce computational time and thereby the costs, a second-level optimization algorithm using a Neural Network for a fixed set of samples is applied and investigated. To create a real-life application for the design of venturi, outlet pressure, obstruction size and its position are found to be critical for maximizing cavitational zone in the centre axis of the flow field. This research work does not consider fibres in the flow through the venturi. The project has been conducted at AF Industry AB and is financed by Energimyndigheten, Stora Enso, Holmen, SCA and AF Industry AB