Numerical Study on Supersonic Co-flowing Jet with Varying Lip Thickness

Shankar, M. Ravi; Kumar, K. Sathish; Raja, N. Dilip; Shekar, Kamal Raj Chandra; Raj, Nishant Kumar; Gupta, Dipranjan

doi:10.1007/978-981-15-6619-6_37

Cited by 5 publications

(5 citation statements)

References 7 publications

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“…The numerical study was done for the following LTs: 1.0 D p , 1.5 D p , 2.0 D p , 2.5 D p , 3.0 D p , 3.5 D p , 4.0 D p , 4.5 D p , 5.0 D p , 6.0 D p , 7.0 D p , 8.0 D p , 10.0 D p and 15.0 D p . The results for LT 1.0 D p and 1.5 D p obtained from the experimental study correlates well with CFD results (Naren Shankar et al, 2016;Naren Shankar, 2017;Naren Shankar et al, 2018;Thanigaiarasu et al, 2018). In all the cases of the present study, exit dimensions for the primary and secondary jet are maintained constant.…”

Section: Numerical Studysupporting

confidence: 86%

“…At the same time, eddies begin appearing between the gap separating the two jet streams. Wake dominance causes to form a recirculation zone that bends the secondary jet toward primary jet, enhancing mixing (Naren Shankar et al, 2016;Naren Shankar et al, 2018;Thanigaiarasu et al, 2018;Naren Shankar and Dilip Raja, 2019;Naren Shankar, 2019). It is Figure 9 Axial total pressure decay for single jet and CFJ with LT 0.2 D p , 0.5 D p and1.0 D p worth noting that there occurs no IWZ for this LT, which in other way inferred that this LT is not sufficient to produce an influential wake region.…”

Section: Resultsmentioning

confidence: 99%

“…The numerical simulations are made using a density-based solver. More details can be obtained from Naren Shankar (2017). The turbulence model comparison is shown in Figure 8.…”

Section: Numerical Studymentioning

confidence: 99%

“…Wake dominance increases with an increase in LT and BR reducing the PCL. In the characteristic decay region, the total pressure decays to a greater extent because of the increase in wake dominance (Naren Shankar et al, 2016;Naren Shankar, 2017;Naren Shankar et al, 2018;Thanigaiarasu et al, 2018).…”

Section: Total Pressure Contoursmentioning

confidence: 99%

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Characteristics of a co-flowing jet with varying lip thickness and constant velocity ratio

Krishnan

Raja

et al. 2020

AEAT

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Purpose This study aims to analyze co-flowing jets (CFJs) with constant velocity ratio (VR) and varying primary nozzle lip thickness (LT) to find a critical LT in CFJs below which mixing enhances and beyond which mixing inhibits. Design/methodology/approach CFJs were characterized with a constant VR and varying LTs. A single free jet with a diameter equal to that of a primary nozzle of the CFJ was used for characteristic comparison. Numerical simulation is carried out and is validated with the experimental results. Findings The results show that within a critical limit, the mixing enhanced with an increase in LT. This was signified by a reduction in potential core length (PCL). Beyond this limit, mixing inhibited leading to the elongation of PCL. This limit was controlled by parameters such as LT and constant VR. A new region termed as influential wake zone is identified. Practical implications In this study, the VR is maintained constant and bypass ratio (BR) was varied from low value to very high values. Presently, subsonic commercial turbo fan operates under low to ultra-high BR. Hence the present study becomes vital to the current scenario. Originality/value To the best of the authors’ knowledge, this is the first effort to find the critical value of LT for a constant VR for compressible co-flow jets. The CFJs with constant VR and varying LT have not been studied in the past. The present study focuses on finding a critical LT below which mixing enhances and above which mixing inhibits.

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Section: Numerical Studysupporting

confidence: 86%

Section: Resultsmentioning

confidence: 99%

“…The numerical simulations are made using a density-based solver. More details can be obtained from Naren Shankar (2017). The turbulence model comparison is shown in Figure 8.…”

Section: Numerical Studymentioning

confidence: 99%

Section: Total Pressure Contoursmentioning

confidence: 99%

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Characteristics of a co-flowing jet with varying lip thickness and constant velocity ratio

Krishnan

Raja

et al. 2020

AEAT

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“…CFJs with LTs 2 and 7.75 mm, primary Mach number 2, secondary Mach number 1.6, AR 3.6, BPR 3.1 for NPRs 3 and 5 were studied. Supersonic core length reduced compared with single jet by 18% and 65% for NPRs 3 and 5, respectively (Naren Shankar et al , 2021b).…”

Section: Introductionmentioning

confidence: 99%

Lip thickness effect on high bypass co-flowing jet mixing

Krishnan

Ganesan

2022

AEAT

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Purpose The purpose of this study is to analyse numerically and experimentally the effects of lip thickness (LT) and bypass ratio on co-flowing nozzle under subsonic and correctly expanded sonic jet decay at different Mach numbers. Design/methodology/approach Co-flowing jets from co-flowing nozzles of different LTs, 0.2, 1 and 1.5 Dp (where Dp is the primary nozzle exit diameter = 10 mm), with an annular gap of 10 mm at main jet exit Mach numbers 0.6 have been studied experimentally and the other cases have been performed numerically. The co-flowing jet with 2 mm LT was used for comparison. Findings Co-flowing jet axial pitot pressure decay, axial static pressure decay, axial velocity decay, radial velocity decay and streamline velocity contours were analyzed. The results illustrate that the mixing of the co-flowing jet with profound LT is prevalent to the co-flowing jet with 2 mm LT, at all Mach numbers of the current study. Also, the LT of the co-flowing jet has a strong impact on jet mixing. Co-flowing jets with 10 mm and 15 mm LT with a constant co-flow width of 10 mm experience a considerably advanced mixing than co-flowing jets with 2 mm LT and a co-flow width of 10 mm. Practical implications The application of bypassed co-flow jet is in turbofan engine operates efficiently in modern civil aircraft. Originality/value All subsonic jets are considered correctly expanded with negligible variation in axial static pressure. However, in the present study, static pressure along the centerline varies sinusoidally up to 9% and 12% above and below atmospheric pressure, respectively, for primary jet exit Mach number 1.0. The sinusoidal variation is less for primary jet exit Mach numbers 0.6 and 0.8 in static pressure decay.

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