An experimental examination of an impulsively started incompressible turbulent jet

Joshi, Anurag; Schreiber, Will

doi:10.1007/s00348-005-0058-9

Cited by 24 publications

(8 citation statements)

References 12 publications

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“…It was found that the individual injection events were extremely reproducible, with a very low scatter of the jet tip position throughout 50 examined injection events. The jet tip position scaled proportionally to time ( t ) at lower axial locations and scaled as ∼ t 1/2 at higher axial positions, as expected from previous studies [33,59] . For a fixed axial position, the fuel jet was found to transition to steady-state behavior less than 1 ms after the jet tip has passed the axial location and prior to the onset of auto-ignition.…”

Section: Discussionmentioning

confidence: 93%

“…However, the jet-exit time can be estimated with sufficient accuracy. In the near field, jet penetration is directly proportional to the time t [33] and the jet penetration can be extrapolated by a linear fit to the first five measured data points, equal to z < 30 mm (blue line in Fig. 8 ).…”

Section: Mixture Fraction Temperature and Scalar Dissipation Rate Fimentioning

confidence: 99%

“…It was shown that the centerline velocity of an impulsivelystarted jet reached the steady-state jet value very quickly (after a few milliseconds) and thus it was concluded that transient jets can be treated quasi-steady. The jet penetration was found to scale linearly with time until the jet tip reaches a certain distance from the nozzle exit; afterwards, the jet penetration scales with the square root of time [33] . Soulopoulos et al [34] performed scalar dissipation rate measurements in a starting jet and found that high values of scalar dissipation rate were concentrated at the jet boundary as well as at random regions in the jet body.…”

Section: Introductionmentioning

confidence: 99%

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The role of temperature, mixture fraction, and scalar dissipation rate on transient methane injection and auto-ignition in a jet in hot coflow burner

Arndt

Papageorge

Fuest

et al. 2016

Combustion and Flame

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a b s t r a c tThe transient injection and subsequent auto-ignition of a methane jet issuing into a laminar coflow of hot exhaust gas from a lean premixed hydrogen air flame was studied using high-speed planar Rayleigh scattering, yielding two-dimensional measurements of mixture fraction, temperature and scalar dissipation rate with high spatio-temporal resolution. The temporal development of the mixing field between the transient fuel jet and the surrounding coflow prior to the occurrence of auto-ignition was examined at a sampling rate of 10 kHz. The impact of the transient jet development on numerical modeling of this test case is discussed. It was found that auto-ignition occurred after the jet transitioned from a transient state into the steady state, thus eliminating the need to model the complete transient fuel injection when the primary focus is on the onset of auto-ignition.Simultaneous high-speed OH * chemiluminescence from two viewing angles was applied to gain 3D-information of the ignition kernel location. This information allowed the selection and analysis of ignition events where the initial kernel formed inside the laser light sheet. Detailed analysis of the dynamics of a single ignition event, as well as statistical analysis of multiple ignition events based on a joint probability density approach, indicated that the ignition kernels occurred at very lean mixture fractions and at locations with low scalar dissipation rates.

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Section: Discussionmentioning

confidence: 93%

Section: Mixture Fraction Temperature and Scalar Dissipation Rate Fimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The role of temperature, mixture fraction, and scalar dissipation rate on transient methane injection and auto-ignition in a jet in hot coflow burner

Arndt

Papageorge

Fuest

et al. 2016

Combustion and Flame

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“…11a plots z B /z versus t/t' for various R 0 . For R 0 < 1.2 (solid lines), a reasonable fit is provided by ln(z B /z ) = 2 ln(t/t ) − 2.3 (11) which results in…”

Section: Penetration Equationmentioning

confidence: 98%

“…The starting pure jet is a configuration of critical importance for many engineering applications (in combustion for example) and has been studied by a number of investigators. Generally, the jet is found to penetrate linearly with time in the PFD [7,8], and with the square root of time in the downstream self-similar phase [9][10][11][12] of the PDF. The other extreme of a starting lazy plume has been studied by Lundgren et al [13], Alahyari and Longmire [14], and Pottebaum and Gharib [15].…”

Section: Introductionmentioning

confidence: 98%

Large-eddy simulation of starting buoyant jets

et al. 2010

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A series of Large Eddy Simulations (LES) are performed to investigate the penetration of starting buoyant jets. The LES code is first validated by comparing simulation results with existing experimental data for both steady and starting pure jets and lazy plumes. The centerline decay and the growth rate of the velocity and concentration fields for steady jets and plumes, as well as the simulated transient penetration rate of a starting pure jet and a starting lazy plume, are found to compare well with the experiments. After validation, the LES code is used to study the penetration of starting buoyant jets with three different Reynolds numbers from 2000 to 3000, and with a wide range of buoyancy fluxes from pure jets to lazy plumes. The penetration rate is found to increase with an increasing buoyancy flux. It is also observed that, in the initial Period of Flow Development, the two penetrative mechanisms driven by the initial buoyancy and momentum fluxes are uncoupled; therefore the total penetration rate can be resolved as the linear addition of these two effects. A fitting equation is proposed to predict the penetration rate by combining the two independent mechanisms.

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