Time-resolved velocity and concentration measurements in variable-viscosity turbulent jet flow

Talbot, B; Mazellier, Nicolas; Renou, Bruno; Danaila, Luminita; Boukhalfa, Mourad

doi:10.1007/s00348-009-0729-z

Cited by 17 publications

(8 citation statements)

References 44 publications

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“…An excellent collapse is observed in both the mean and r.m.s. and the profiles follow closely the results of Talbot et al (2009). Furthermore, the scaling r = r/(x − x 0 ), where x 0 is the virtual origin of the jet, seems to collapse the data obtained at different axial locations very well.…”

Section: Resultssupporting

confidence: 67%

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Conditional statistics of the turbulent/non-turbulent interface in a jet flow

et al. 2013

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Using two-dimensional high-speed measurements of the mixture fraction Z in a turbulent round jet with nozzle-based Reynolds numbers Re 0 between 3000 and 18 440, we investigate the scalar turbulent/non-turbulent (T/NT) interface of the flow. The mixture fraction steeply changes from Z = 0 to a final value which is typically larger than 0.1. Since combustion occurs in the vicinity of the stoichiometric mixture fraction, which is around Z = 0.06 for typical fuel/air mixtures, it is expected to take place largely within the turbulent/non-turbulent interface. Therefore, deep understanding of this part of the flow is essential for an accurate modelling of turbulent non-premixed combustion. To this end, we use a composite model developed by Effelsberg & Peters (Combust. Flame, vol. 50, 1983, pp. 351-360) for the probability density function (p.d.f.) P(Z) which takes into account the different contributions from the fully turbulent as well as the turbulent/non-turbulent interface part of the flow. A very good agreement between the measurements and the model is observed over a wide range of axial and radial locations as well as at varying intermittency factor γ and shear. Furthermore, we observe a constant mean mixture fraction value in the fully turbulent region. The p.d.f. of this region is thus of non-marching character, which is attributed physically to the meandering nature of the fully turbulent core of the jet flow. Finally, the location and in particular the scaling of the thickness δ of the scalar turbulent/non-turbulent interface are investigated. We provide the first experimental results for the thickness of the interface over the above-mentioned Reynolds number range and observe δ/L ∼ Re −1 λ , where L is an integral length scale and Re λ the local Reynolds number based on the Taylor scale λ, meaning that δ ∼ λ. This result also supports the assumption often made in modelling of the stoichiometric scalar dissipation rate χ st being a Reynolds-number-independent quantity.

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Section: Resultssupporting

confidence: 67%

“…The resulting profile as shown in figure 4(a) is usually approximated using an exponential function, see for instance Talbot et al (2009). As the p.d.f.…”

Section: 2mentioning

confidence: 99%

Conditional statistics of the turbulent/non-turbulent interface in a jet flow

et al. 2013

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“…The nozzle in the present experiment has a diameter of 1.5 mm. It is unclear if the empirical correlation given by Talbot et al [93] can be extrapolated to very small nozzles. To our knowledge, no other experiments at such small nozzle diameters are available for reference.…”

Section: Mixture Fractionmentioning

confidence: 99%

“…provided by Talbot et al [93] is used in this work to provide an additional reference. In this equation Z, denotes the mixture fraction, Z 0 the mixture fraction at the nozzle exit (which is one), ρ j the density of the jet, ρ c the density of the coflow, and d the nozzle diameter.…”

Section: Mixture Fractionmentioning

confidence: 99%

“…In this equation Z, denotes the mixture fraction, Z 0 the mixture fraction at the nozzle exit (which is one), ρ j the density of the jet, ρ c the density of the coflow, and d the nozzle diameter. Equation 22 Talbot et al [93] use a significantly larger nozzle in their experiments with an inner diameter of 5 mm. The nozzle in the present experiment has a diameter of 1.5 mm.…”

Section: Mixture Fractionmentioning

confidence: 99%

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Transported PDF simulation of auto-ignition of a turbulent methane jet in a hot, vitiated coflow

Fiolitakis

Arndt

2019

Combustion Theory and Modelling

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In the current work, the auto-ignition of a turbulent round methane jet is studied numerically by means of a transported probability density function (PDF) method. The methane jet is issued into a hot, vitiated coflow, where it ignites to form a steady lifted flame. For this flame, experimental data of hydroxyl, temperature and mixture fraction are provided in the area where the fuel auto-ignites. To model this experiment, the transport equation for the thermochemical PDF is solved using a hybrid finite volume / Lagrangian Monte-Carlo method. Turbulence is modeled using the k-ε turbulence model including a jet-correction. Computational results are compared to experimental data in terms of mean quantities, variances and liftoff height. Moreover, the structure of the one-point, one-time marginal PDF of temperature is analyzed and compared to experimental data which are provided in this work. It is found that the transported PDF method in conjunction with the k-ε model is capable of reproducing these statistical data very well. In particular the effect of ignition on the marginal PDF of temperature can be well reproduced with this approach. To further analyze the relevant processes in the evolution of the temperature PDF, a statistically homogeneous system is studied both numerically and analytically.

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