The Effect of Impingement on Transitional Behavior in Underexpanded Jets

Inman, Jennifer A.; Danehy, Paul M.; Nowak, Robert J.; Alderfer, David W.

doi:10.2514/6.2009-591

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…If the jet speed at the exit of the orifice is subsonic, the jet is said to be underexpanded, and it will spread into the surrounding environment as shown in Fig. 1 [5].…”

Section: Conditions Necessary For Resonancementioning

confidence: 99%

Analysis Methods for High Energy Line Break Jet Flows in Nuclear Power Plants

Charrouf

Kauffman

Yoon

et al. 2020

Journal of Nuclear Engineering and Radiation Science

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The effects of postulated accidents, including dynamic effects of pipe ruptures, must be analyzed for licensing of nuclear power plants (NPPs). Applicants and licensees of NPPs have struggled to address U.S. Nuclear Regulatory Commission (NRC) expectations to assess if high energy line break (HELB) jet impingement on structures and components can lead to dynamic amplification, and to accurately simulate blast wave-induced loadings. In this paper, evaluation of the potential for load amplification and occurrence of resonance conclusively demonstrates that the phenomenon does not occur. In a HELB, several physical parameters of jets issuing from a ruptured pipe - such as non-equilibrium condensation of steam, unsteady separation between the jet exit and target, non-orthogonal alignment of jet axis to impingement surface, uneven impingement surfaces, or mismatch of jet excitation frequency and target natural frequency - prevent occurrence of the phase lock conditions needed to initiate and maintain a resonance. The analytical approach to evaluate the blast wave-induced loading applied a pressure vessel burst (PVB) correlation instead of performing time consuming CFD analysis for all break locations. Three dimensional CFD analysis of blast wave transient propagation provided the basis to develop benchmarking factors for use with the PVB correlation. The simplified methodology utilizes shockwave reflection, shape, and environment factors for application to impacted targets, which significantly reduces the amount of time to evaluate all break locations. The modified PVB method is also more appropriate than an explosion-type correlation to model the blast wave pressures from steam pipe breaks.

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“…If the jet speed at the exit of the orifice is subsonic, the jet is said to be underexpanded, and it will spread into the surrounding environment as shown in Fig. 1 [5].…”

Section: Conditions Necessary For Resonancementioning

confidence: 99%

Analysis Methods for High Energy Line Break Jet Flows in Nuclear Power Plants

Charrouf

Kauffman

Yoon

et al. 2020

Journal of Nuclear Engineering and Radiation Science

View full text Add to dashboard Cite

show abstract

“…11 In 2010, the large eddy simulation results of stable supersonic jet impinging on flat plate were provided, 12 which agreed well with the PIV data. In 2009, Inman et al 13 studied the effect of impingement on transitional behavior in under-expanded jets using the planar laser-induced fluorescence of nitric oxide. Recently, the oscillatory flow phenomenon in the impinging jet was focused.…”

Section: Introductionmentioning

confidence: 99%

Particle image velocimetry study of the impinging height effect on the overexpanded supersonic impinging free jet of Ma = 1.754. Part 2: detailed velocity distribution

Lin

Jiang

2012

Proceedings of the Institution of Mechanical Engineers, Part G:

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In this article, the flowfield of an overexpanded axisymmetric supersonic impinging jet with exit Mach number 1.754 is studied using particle image velocimetry. In particular, the influence of the impinging height on the detailed flowfield velocity distributions has been investigated. The velocity distribution precisely indicates where the Mach disk and the plate shock are generated. With the increasing impinging height, the plate shock position is found to move away from the impinging wall, until it reaches the maximum of 0.767 D for the dimensionless impinging height of Z/ D = 2.5. With a further increasing of the impinging height, the plate shock moves back to the impinging wall. Furthermore, the shape, position, as well as size of the stagnation bubble zone can also be deduced from the velocity distribution. According to the time-averaged flowfield result, the velocity coefficient of the radial wall jet is found to be as high as 0.8146, which is critical to the ground erosion problem in the application. It indicated that although the radial velocity appeared to be supersonic in the instantaneous result in Part I [Xu J, Lin C and Sha J. Particle image velocimetry study of the impinging height effect on the overexpanded supersonic impinging free jet of Ma = 1.754. Part I: global coherent structure. Proc IMechE, Part G: J Aerospace Engineering 2012; 226(1): 64–73.], it is high subsonic in the mean result in this part. This disagreement is due to the intrinsic highly unsteady nature of the flow under investigation. The vorticity isopleths demonstrate that the stagnation bubble and the recirculating flow are formed due to the impingement of the nozzle inner shear layer of the main jet.

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“…It agreed very well with the PIV data. More recently, NASA Langley Research Center used the art technique of planar laser-induced fluorescence of nitric oxide (NO PLIF) to study the unsteadiness, flow transition, and turbulent features of underexpanded axisymmetric impinging jet flowfield [11]. Also, the transition criteria for free and impinging jets were presented.…”

Section: Introductionmentioning

confidence: 99%

“…Also, the transition criteria for free and impinging jets were presented. It was found that the impingement would 'significantly shorten the distance to transition to turbulence by up to a factor of approximately three, with closer targets resulting in slightly shorter distance to transition and turbulence' [11].…”

Section: Introductionmentioning

confidence: 99%

Particle image velocimetry study of the impinging height effect on an overexpanded supersonic impinging free jet at Ma = 1.754. Part 1: global coherent structure

Lin

Jiang

2011

Proceedings of the Institution of Mechanical Engineers, Part G:

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Results of an experimental study of an overexpanded axisymmetric supersonic impinging jet at Mach 1.754 with particle image velocimetry (PIV) are presented in this article. The focus of Part I is on the influence of the impinging height on the global coherent flow structure, while in Part II the detailed velocity magnitude, both axial and radial, as well as the position variation of the plate shock will be presented. The PIV results clearly demonstrate the formation of the stagnation bubble as well as the presence of the recirculating flow in it. When the impinging height reaches five times the nozzle exit diameter, the stagnation bubble disappears, which is thought to be the result of the increase in the thickness of the shear layer of the main jet and consequently the decrease in the difference of the stagnation pressure between the centre of the stagnation zone and the impinging point of the main jet shear layer. The comparison between instantaneous and mean PIV measurements demonstrates that there exists highly unsteady behaviour of the impinging jet. The shock wave structure and the unsteady entraining vortex of the nozzle jet and the wall jet are all clearly recorded by PIV. All these results are crucial to understand the effects of the impinging height on the global flowfield coherent structure of the overexpanded axisymmetric supersonic jet impingement.

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The Effect of Impingement on Transitional Behavior in Underexpanded Jets

Cited by 5 publications

References 10 publications

Analysis Methods for High Energy Line Break Jet Flows in Nuclear Power Plants

Analysis Methods for High Energy Line Break Jet Flows in Nuclear Power Plants

Particle image velocimetry study of the impinging height effect on the overexpanded supersonic impinging free jet of Ma = 1.754. Part 2: detailed velocity distribution

Particle image velocimetry study of the impinging height effect on an overexpanded supersonic impinging free jet at Ma = 1.754. Part 1: global coherent structure

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