Confined coaxial jets have been widely used in gas turbine combustors, where the requirement is t... more Confined coaxial jets have been widely used in gas turbine combustors, where the requirement is to achieve better mixing between two streams - fuel and air - prior to ignition so as to provide stable and complete combustion. Two shear layers, one between the central jet and the annular jet and other between the annular jet and the stagnant fluid outside the annular jet help in the mixing process for confined coaxial jets. Therefore, for improved mixing, a configuration of one central jet and two co-annular jets, called multi-annular or multicoaxial jets, has been considered. To understand mixing of these streams in a confinement (mixing chamber), the mean axial velocity profiles at different axial locations of the mixing chamber and the static pressure along the wall of the mixing chamber are measured for expansion ratio of 1 and 1.3. These quantities are also computed using CFD software, FLUENT, with Standard k-ε turbulence model. After validation of the CFD code, parametric studie...
Abstract The development of swirling, cold flow through multi-annular jets in non-expanding confi... more Abstract The development of swirling, cold flow through multi-annular jets in non-expanding confinement has been studied by providing swirling flow through the central jet by using hubless vane swirlers with vane angles of 30o and 45o. The mean axial and tangential velocity in radial planes at different axial locations of the mixing chamber, have been measured using a three-hole probe. The wall static pressures have also been measured along the length of the mixing chamber. The experimental results show the influence of swirl in enhancing the mixing process and its effect on centerline axial velocity through the occurrence of negative velocity zone on the axis under the influence of swirl.
The flow and performance characteristics of a S-shaped diffusing duct having an area ratio of 1.9... more The flow and performance characteristics of a S-shaped diffusing duct having an area ratio of 1.9, length of 300 mm and turning angle of 22.5°/22.5° have been experimentally investigated to establish the effect of swirl. The static pressure, total pressure, velocity and turbulence intensity are measured using a calibrated five-hole probe and constant-temperature hot-wire probe. The performance parameters are evaluated based on the mass-averaged quantities. A significant improvement in the pressure recovery coefficient is observed for swirl flow from 0.36 to 0.54. The improvement is observed for both, clockwise and anti-clockwise swirl, the improvement being higher for clockwise swirl. Flow uniformity at the exit is more uniform for clockwise swirl at the inlet.
Confined coaxial jets have been widely used in gas turbine combustors, where the requirement is t... more Confined coaxial jets have been widely used in gas turbine combustors, where the requirement is to achieve better mixing between two streams - fuel and air - prior to ignition so as to provide stable and complete combustion. Two shear layers, one between the central jet and the annular jet and other between the annular jet and the stagnant fluid outside the annular jet help in the mixing process for confined coaxial jets. Therefore, for improved mixing, a configuration of one central jet and two co-annular jets, called multi-annular or multicoaxial jets, has been considered. To understand mixing of these streams in a confinement (mixing chamber), the mean axial velocity profiles at different axial locations of the mixing chamber and the static pressure along the wall of the mixing chamber are measured for expansion ratio of 1 and 1.3. These quantities are also computed using CFD software, FLUENT, with Standard k-ε turbulence model. After validation of the CFD code, parametric studie...
Abstract The development of swirling, cold flow through multi-annular jets in non-expanding confi... more Abstract The development of swirling, cold flow through multi-annular jets in non-expanding confinement has been studied by providing swirling flow through the central jet by using hubless vane swirlers with vane angles of 30o and 45o. The mean axial and tangential velocity in radial planes at different axial locations of the mixing chamber, have been measured using a three-hole probe. The wall static pressures have also been measured along the length of the mixing chamber. The experimental results show the influence of swirl in enhancing the mixing process and its effect on centerline axial velocity through the occurrence of negative velocity zone on the axis under the influence of swirl.
The flow and performance characteristics of a S-shaped diffusing duct having an area ratio of 1.9... more The flow and performance characteristics of a S-shaped diffusing duct having an area ratio of 1.9, length of 300 mm and turning angle of 22.5°/22.5° have been experimentally investigated to establish the effect of swirl. The static pressure, total pressure, velocity and turbulence intensity are measured using a calibrated five-hole probe and constant-temperature hot-wire probe. The performance parameters are evaluated based on the mass-averaged quantities. A significant improvement in the pressure recovery coefficient is observed for swirl flow from 0.36 to 0.54. The improvement is observed for both, clockwise and anti-clockwise swirl, the improvement being higher for clockwise swirl. Flow uniformity at the exit is more uniform for clockwise swirl at the inlet.
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