EXPERIMENTAL STUDY OF THE FLOW FIELD OF AN ANNULAR JET COALESCING AT THE EXIT

Abstract

An experimental investigation has been carried out to analyze the jet development and performance characteristics issuing from different configurations of annular nozzles at Re = 4e4, 8.4e4, and 1.2e5. Yaw-meter pressure measurements were carried out along the jet centerline for various vertical distances to quantify the potential core and characteristic decay of the jets. Flow visualization was performed by vector plotting to analyze jet structure at different cross-sections along the jet axis, which was used to study the behaviour of the flow development. The flow features reveal that the axisymmetric annular structure of the jet results in enhanced mixing of the jet. It is also evident from the yaw meter measurement that the jet spread is 50% and 20% lower than Re = 1.2e5 for Re = 4e4 and 8.4e4, respectively. For a particular Reynolds number, in most of the cases, the spread rate in an annular jet was decreased. Overall, the magnitude of centerline velocity in annular jets has also decreased. Furthermore, the existence of a potential core is found in free jet only.