Mixing enhancement using chevron nozzle: studies on free jets and confined jets

Subramanian, Gurulingam; Nagarjun, CH V S; Kumar, Kunal; Kumar, B Ashish; Srikanth, Vishal; Srikrishnan, A R

doi:10.1007/s12046-018-0898-7

Cited by 8 publications

(7 citation statements)

References 28 publications

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“…The simulation results were validated with the experimental work of Subramanian et al [30] and Sadeghia and Pollard [31]. The referred studies investigated mixing enhancement in a confined/free jet using a tabbed chevron nozzle and passive ring.…”

Section: Model Validationmentioning

confidence: 69%

“…The downstream region consists of the potential core and the rapid decay portion. The stretch of the core, characterised by momentum mixing [30], gave an estimate of the entrainment period. The growth of the vortex ring, responsible for the air entrainment, commenced at the nozzle exit (𝑋 𝑑𝑁 = 5 ⁄ ) and spanned the length of the potential core.…”

Section: Velocity Analysismentioning

confidence: 99%

See 1 more Smart Citation

Changes in Primary Nozzle Contours and Ejector Performance- A Numerical Study

Chukwunonso,

Humphrey,

Chukwunenye

et al. 2024

IJASE

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This study numerically investigated the changes in the behaviour of fluid flowing through an ejector in response to modifications in the nozzle design. The investigation involved constant mass flow of the primary stream through four nozzles (PN1-PN4) formed with a combination of straight lines and sine functions. The area of the nozzle streamwise section varied with each contour. The PN4 nozzle refers to the reference nozzle, and its contours were straight lines only. The velocity decay, turbulence, entrainment, and mixing data were used to measure the flow behaviour. The decay rate were increased by ≈ 1.7%, entrainment by≈ 8%, and the maximum turbulence intensity by 16% in the PN3 nozzle. Only a 0.5% increase in decay rate was recorded in PN1 and PN2.The PN3 nozzle had the lowest streamwise area of the four nozzles and performed best per entrainment and mixing. This was because the increase in the velocity of the primary stream at the nozzle trailing edge due to the reduced streamwise area, improved the momentum transfer to the secondary stream and its entrainment into the primary stream.

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Section: Model Validationmentioning

confidence: 69%

Section: Velocity Analysismentioning

confidence: 99%

Changes in Primary Nozzle Contours and Ejector Performance- A Numerical Study

Chukwunonso,

Humphrey,

Chukwunenye

et al. 2024

IJASE

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“…An active control method includes pulsed jets (Knowles and Saddington, 2005), micro jets (Khan and Rathakrishnan, 2004) and synthetic jets (Zaman and Milanovic, 2003). Passive technology includes tabs (Gandhinathan and Subramanian, 2022; Suseela et al , 2022) and chevron nozzle (Subramanian et al , 2018). The vortex generated by the active control techniques generates vortices that will not travel longer distances downstream of the jets.…”

Section: Introductionmentioning

confidence: 99%

Investigation of slanted perforation diameter in tabs for supersonic jet control

Ezhilmaran¹,

Sekar²,

K.³

et al. 2023

AEAT

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Purpose This study aims to investigate the effect of slanted perforation diameter in tabs for the control of Mach 1.4 underexpanded supersonic jet flow characteristics. Design/methodology/approach Numerical investigation was carried out for NPR 5 to analyze the effect of slanted perforation diameter in tabs to control the Mach 1.4 jet. Four sets of tabs with slanted circular perforation geometries (Φp = 1, 1.5, 2 and 2.5 mm) were considered in this study. The inclination angle of 20° (αP) with reference to the jet axis was maintained constant for all the four tabs considered. Findings Determined value indicates there is a 68%, 71%, 73% and 75% drop in supersonic core for the Φp = 1, 1.5, 2.0 and 2.5 mm, respectively. The results show that the tabs with 2.5 mm perforation diameter were found to be efficient in reducing the supersonic jet core in comparison with other tab cases. The reduction in supersonic core length is due to the extent of miniscule vortices exuviating from slanted small and large diameter perforation in the tabs. Practical implications The concept of slanted perforation can be applied in scramjet combustion, which finds its best application in hypersonic vehicles and in noise suppression in fighter aircraft. Originality/value Slanted perforation and circular shapes with different diameters have not been studied in the supersonic regime. Examining the effect of circular diameter in slanted perforation is an innovation in this research paper.

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“…The use of a chevron configuration is a popular approach adopted for the mitigation of jet noise. A chevron nozzle [7,8] is a nozzle with a saw-tooth pattern at the exit which introduces streamwise vortices [9]. Axial vortices induced by these serrations cause a very rapid increase in the width of the mixing layer, resulting in a reduction of the peak turbulence.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Modeling of Compressible Jet from Chevron Nozzle: A Comparison of URANS, LES and DES Models

et al. 2022

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Chevron nozzles, which are characterized by the serrations at the nozzle exit, are widely used for suppressing jet noise in aircraft engines. The noise suppression is accomplished by the enhanced mixing of the exhaust streams, which, in turn, is a result of the streamwise vorticity induced by the serrations. The present study focuses on the numerical modeling of the acoustic field in a compressible jet issuing from a chevron nozzle at a Mach number of 0.8. The study evaluates the effectiveness of turbulence modeling approaches of Large Eddy Simulation and Detached Eddy Simulation methods and compares them with the less computationally intensive Unsteady Reynolds Averaged Navier–Stokes (URANS) formulation. The Ffowcs Williams–Hawkings noise model was used to predict the overall sound pressure level in the far field. The LES predictions of the acoustic signature were found to match well with the experimental data, whereas the URANS model grossly underpredicted the sound pressure levels in the compressible jet flow field.

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Mixing enhancement using chevron nozzle: studies on free jets and confined jets

Cited by 8 publications

References 28 publications

Changes in Primary Nozzle Contours and Ejector Performance- A Numerical Study

Changes in Primary Nozzle Contours and Ejector Performance- A Numerical Study

Investigation of slanted perforation diameter in tabs for supersonic jet control

Acoustic Modeling of Compressible Jet from Chevron Nozzle: A Comparison of URANS, LES and DES Models

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