Simultaneous temperature and multispecies measurement in a lifted hydrogen diffusion flame

Cheng, T. S.; Wehrmeyer, Joseph A.; Pitz, Robert W.

doi:10.1016/0010-2180(92)90061-s

Cited by 120 publications

(36 citation statements)

References 29 publications

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“…2,[22][23][24][25][26] In high temperature H 2 /O 2 combustion, for example, collisions of the highly energized product H 2 O molecules with H 2 reactant provide an important mechanism for heat flow as well as establishing local thermodynamic equilibrium in the flames. 3 As a result, there is a broad set of energy dependent cross sections and temperature dependent kinetic rates for such processes at the stateto-state level that prove critical in achieving the desired optimal combustion efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…3 As a result, there is a broad set of energy dependent cross sections and temperature dependent kinetic rates for such processes at the stateto-state level that prove critical in achieving the desired optimal combustion efficiency. 22,23,27 The number of such potential pathways under typical high temperature combustion conditions is enormous, far too large to be tackled via detailed state-to-state measurement efforts. On the other hand, many of the desired energy transfer and collisional properties can be calculated from first principles, based on knowledge of a sufficiently accurate potential energy surface in high dimensionality.…”

Section: Introductionmentioning

confidence: 99%

“…24,26,[28][29][30] The need for high level predictive understanding for such high pressure/temperature combustion phenomena is clearly important, which in turn depends pivotally on benchmark accuracy of the full 9D potential H 2 + H 2 O energy surface. 1,15,17,[20][21][22][23] Of particular interest in the interstellar medium (ISM) is the corresponding weakly bound complex, H 2 -H 2 O, due in part to predominance of atomic and molecular hydrogen in the universe. 31 Indeed, certain regions of the ISM depleted in deep ultraviolet radiation tend to have appreciable concentrations of H 2 molecules rather than H atoms, 32 which can in fact trigger chemical synthesis into higher molecular weight species.…”

Section: Introductionmentioning

confidence: 99%

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Overtone vibrational spectroscopy in H2-H2O complexes: A combined high level theoretical ab initio, dynamical and experimental study

Ziemkiewicz

Pluetzer

Nesbitt

et al. 2012

The Journal of Chemical Physics

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First results are reported on overtone (v OH = 2 ← 0) spectroscopy of weakly bound H 2 -H 2 O complexes in a slit supersonic jet, based on a novel combination of (i) vibrationally mediated predissociation of H 2 -H 2 O, followed by (ii) UV photodissociation of the resulting H 2 O, and (iii) UV laser induced fluorescence on the nascent OH radical. In addition, intermolecular dynamical calculations are performed in full 5D on the recent ab initio intermolecular potential of Valiron et al. [J. Chem. Phys. 129, 134306 (2008)] in order to further elucidate the identity of the infrared transitions detected. Excellent agreement is achieved between experimental and theoretical spectral predictions for the most strongly bound van der Waals complex consisting of ortho (I = 1) H 2 and ortho (I = 1) H 2 O (oH 2 -oH 2 O). Specifically, two distinct bands are seen in the oH 2 -oH 2 O spectrum, corresponding to internal rotor states in the upper vibrational manifold of and rotational character. However, none of the three other possible nuclear spin modifications (pH 2 -oH 2 O, pH 2 -pH 2 O, or oH 2 -pH 2 O) are observed above current signal to noise level, which for the pH 2 complexes is argued to arise from displacement by oH 2 in the expansion mixture to preferentially form the more strongly bound species. Direct measurement of oH 2 -oH 2 O vibrational predissociation in the time domain reveals lifetimes of 15(2) ns and <5(2) ns for the and states, respectively. Theoretical calculations permit the results to be interpreted in terms of near resonant energy levels and intermolecular alignment of the H 2 and H 2 O wavefunctions, providing insight into predissociation dynamical pathways from these metastable levels.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Overtone vibrational spectroscopy in H2-H2O complexes: A combined high level theoretical ab initio, dynamical and experimental study

Ziemkiewicz

Pluetzer

Nesbitt

et al. 2012

The Journal of Chemical Physics

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“…The transport properties depend on temperature and local species concentration. The flame lift-off height is about 5.7D from the nozzle exit in the DNS while it was 7D in the experiments of Cheng et al (1992Cheng et al ( , 2007. The comparison of flame brush structure, in terms of mean species mass fractions and temperature, obtained from the DNS to that measured was shown to be good by Ruan et al (2012).…”

Section: Dns and Data Processingmentioning

confidence: 81%

“…An experimentally investigated (Cheng et al, 1992(Cheng et al, , 2007 turbulent lifted flame established above a hydrogen jet issuing from a round nozzle into quiescent air was simulated using direct numerical simulation methodology. The jet Mach number is 0.54 and its Reynolds number based on the nozzle diameter is 13,600.…”

Section: Dns and Data Processingmentioning

confidence: 99%

Investigation of Flame Stretch in Turbulent Lifted Jet Flame

Ruan

Swaminathan

Mizobuchi

2014

Combustion Science and Technology

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DNS data of a laboratory-scale turbulent lifted hydrogen jet flame has been analysed to show that this flame has mixed mode combustion not only at the flame base but also in downstream locations. The mixed mode combustion is observed in instantaneous structures as in earlier studies and in averaged structure, in which the predominant mode is found to be premixed combustion with varying equivalence ratio. The nonpremixed combustion in the averaged structure is observed only in a narrow region at the edge of the jet shear layer. The analyses of flame stretch show large probability for negative flame stretch leading to negative surface averaged flame stretch. The displacement speed-curvature correlation is observed to be negative contributing to the negative flame stretch and partial premixing resulting from jet entrainment acts to reduce the negative correlation. The contribution of turbulent straining to the flame stretch is observed to be negative when the scalar gradient aligns with the most extensive principal strain rate. The physics behind the negative flame stretch resulting from turbulent straining is discussed and elucidated through a simple analysis of the flame surface density transport equation.

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One-dimensional imaging of H2 densities and of temperatures via rotational Raman scattering of narrow-band, 248 nm, laser light

Rothe

Reck

1997

J. Raman Spectrosc.

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It is demonstrated that the well known rotational Raman spectrum of H2 can be used to find the relative densities of hydrogen and the gas temperature as a function of position. A line‐shaped beam from a tunable excimer laser intersects H2–air flames. Scattered light is acquired with an imaging spectrograph. This produces both Stokes and anti‐Stokes spectra. By adjusting the laser beam’s polarization, the interfering Rayleigh intensity is sufficiently reduced without the use of a filter. The temperature measurements can be from below room temperature to about 1200 K. The method also works at temperatures >1200 K, but the use of vibrational Raman spectroscopy is probably better there. Also shown is an image that has simultaneously acquired, spatially resolved spectra from rotational Raman, vibrational Raman and laser‐induced fluorescence. Such combined information might be used to diagnose a gaeous system in some detail. © 1997 John Wiley & Sons, Ltd.

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Simultaneous temperature and multispecies measurement in a lifted hydrogen diffusion flame

Cited by 120 publications

References 29 publications

Overtone vibrational spectroscopy in H2-H2O complexes: A combined high level theoretical ab initio, dynamical and experimental study

Overtone vibrational spectroscopy in H2-H2O complexes: A combined high level theoretical ab initio, dynamical and experimental study

Investigation of Flame Stretch in Turbulent Lifted Jet Flame

One-dimensional imaging of H2 densities and of temperatures via rotational Raman scattering of narrow-band, 248 nm, laser light

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