Experimental investigation of rarefied flows through supersonic nozzles

Patel, Milaan; Thomas, Jinto; Joshi, H. C.

doi:10.1016/j.vacuum.2023.111909

Cited by 3 publications

(3 citation statements)

References 21 publications

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“…For pulse duration of 1-5 ms, Ṅ is 45% of the theoretical value (calculated using 1D isentropic approach 23 ) and the orifice diameter which results in experimental value of flow rate is 0.6 mm. The absolute density determined by free expansion model with this approach has been substantiated experimentally 24 . Equation ( 7) thus gives the value of g • N c at each spatial location of the jet.…”

Section: Theoretical Approachmentioning

confidence: 85%

“…However, the contribution of Brillouin scattering only comes when the mean free path of the gas is comparable or smaller than the wavelength 20,21 . For = 532 nm, Brillouin contribution may affect if the number density is higher than 2 × 10 24 No./cu.m. The total density is always smaller than the limiting value in our measurements.…”

Section: Experiments Setupmentioning

confidence: 99%

“…where, Ṅ is the flow rate, u ∞ is the terminal velocity, γ is the ratio of specific heats at constant pressure and volume, κ is the "peaking factor" (1.98 for monoatomic gas), b is the angular factor (3 for monoatomic gas) and θ PM is the angle of Prandtl-Meyer expansion fan for sonic nozzle. To account for the effects of sudden contraction and boundary layer formation in the finite length of the orifice, flow rate is measured experimentally using approach described in Appendix-2 24 . For pulse duration of 1-5 ms, Ṅ is 45% of the theoretical value (calculated using 1D isentropic approach 23 ) and the orifice diameter which results in experimental value of flow rate is 0.6 mm.…”

Section: Theoretical Approachmentioning

confidence: 99%

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Spatial mapping of low pressure cluster jets using Rayleigh scattering

Patel

Geethika

Thomas

et al. 2023

Sci Rep

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In this work, we report evolution of atomic clusters in a highly under-expanded supersonic jet of Argon. A high resolution and sensitive Rayleigh scattering based experimental set-up is designed to overcome the limitations encountered in conventional set-ups. Further, the measurement range could be extended from a few nozzle diameters to 50 nozzle diameters. Simultaneously, we had been able to generate 2D profiles of the distribution of clusters inside the jet. This paves the way to track the growth of clusters along the flow direction experimentally, which until now was limited to few nozzle diameters. The results show that spatial distribution of clusters inside the supersonic core deviates considerably from the prediction of the free expansion model. We exploit this to estimate cluster growth along the expansion direction. Further, it is observed that the growth of the clusters gets saturated after a certain distance from the nozzle. At the jet boundary, we see substantial cluster strengthening immediately upstream of barrel shock while the normal shock exhibits disintegration of clusters. These observations are noticed for the first time, which, we believe will further the understanding of cluster dynamics in a supersonic jet.

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Section: Theoretical Approachmentioning

confidence: 85%

Section: Experiments Setupmentioning

confidence: 99%

Section: Theoretical Approachmentioning

confidence: 99%

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Spatial mapping of low pressure cluster jets using Rayleigh scattering

Patel

Geethika

Thomas

et al. 2023

Sci Rep

Self Cite

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Specific Features of Formation of Supersonic Jets of Rarefied Gases Under Conditions of Developed Condensation

Dubrovin,

Zarvin,

Rebrov

2023

J Appl Mech Tech Phy

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Influence of the shape of the anode assembly inner channel on plasma flow velocity

Okulov,

Krashaninin,

Gelchinsky

et al. 2024

jour

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This article considers how the shape of the inner channel in the anode assembly affects plasma flow velocity in a plasma torch. Three different shapes of the anode assembly were analyzed, all with a conical confusor part of 50 mm in length: with a diameter transition from 12 to 6 mm, from 12 to 8 mm, and from 12 to 10 mm. A computer experiment was performed using the finite element method and then validated by the subsequent full-scale experiment on a laboratory plasma unit. The obtained results were verified. The verification outcomes showed a satisfactory convergence and were consistent with the published data. A review of the existing plasma unit designs for powder production, application of functional coatings, and surface modification was carried out. The software packages implementing the finite element method to solve these problems were examined. The study yielded practical recommendations for consumers and developers of plasma equipment and identified the shapes of the anode assembly enabling both supersonic and subsonic plasma flow regimes.

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Experimental investigation of rarefied flows through supersonic nozzles

Cited by 3 publications

References 21 publications

Spatial mapping of low pressure cluster jets using Rayleigh scattering

Spatial mapping of low pressure cluster jets using Rayleigh scattering

Specific Features of Formation of Supersonic Jets of Rarefied Gases Under Conditions of Developed Condensation

Influence of the shape of the anode assembly inner channel on plasma flow velocity

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