Document Type : Research Paper
Abstract
In this research, the positive mixing length and trajectory characteristics of a buoyant jet was investigated. Jet flux is dependent on parameters such as initial velocity, port diameter, concentration of jet and flow conditions in the receiving fluid. A buoyant jet fluid governing equation with relevant logical assumptions was used to drive the required dimensionless functions using dimensional analysis. A physical model was built to evaluate the function of these parameters. Testing was done at varying velocities, concentrations and initial port diameters. The length of the falling jet trajectory was analyzed as the ratio of trajectory length to port diameter versus relative trajectory elevation. The results showed that increasing jet diameter and jet momentum had a significant effect on jet trajectory. Increasing jet fluid density caused a density gradient between the jet and receiving fluid and a change in the buoyancy forces involved which had a major influence on the length of the falling jet trajectory. Hence at a given density, increasing the diameter from 5-8 mm or 8-15 mm decreased the densimetric Froude number 30-40% for different velocities and the ratio of the length of positive flux buoyancy to port diameter decreased 20-35%. Findings showed that doubling the increase in density decreased the length of positive flux buoyancy 5-20%.
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