Laser-based in situ measurement and simulation of gas-phase temperature and iron atom concentration in a pilot-plant nanoparticle synthesis reactor

Feroughi, Omid M.; Hardt, Sebastian; Wlokas, Irenäus; Hülser, Tim; Wiggers, Hartmut; Dreier, Thomas; Schulz, Christof

doi:10.1016/j.proci.2014.05.039

Cited by 29 publications

(35 citation statements)

References 18 publications

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“…However, an analogous flame synthesis system, iron oxide from iron pentacarbonyl, guides our initial assumptions. Extensive modeling 30,31 and experimental 32,33 studies of conversion of iron pentacarbonyl indicated the metal oxidation process began from metallic iron. It is assumed the manganese tricarbonyl precursor used here also produces metallic Mn.…”

Section: Computationalmentioning

confidence: 99%

Formation of nanocrystalline manganese oxide in flames: oxide phase governed by classical nucleation and size-dependent equilibria

Dasappa

Camacho

2020

CrystEngComm

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Section: Computationalmentioning

confidence: 99%

Formation of nanocrystalline manganese oxide in flames: oxide phase governed by classical nucleation and size-dependent equilibria

Dasappa

Camacho

2020

CrystEngComm

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“…Multi-line NO-LIF was used to determine temperature maps in a pilot-plant flame-synthesis reactor for the generation of nanoparticles in the gas phase operating with a turbulent non-premixed jet flame at pressures between 100 mbar and atmospheric [13]. However, in the present work, only measurements are presented in pure methane/ air flames without the metal-organic precursors that would otherwise be added for nanoparticle synthesis.…”

Section: Transfer To Experimentsmentioning

confidence: 99%

“…In our previous work [13], ensemble-averaged (over the multi-laser shot temporal duration of an excitation scan) mean temperatures were derived, while in the present investigation we focus on the potential errors encountered using the multi-line LIF thermometry technique in these unsteady systems. Therefore, in the following, the temperature field from one of the earlier flame conditions (cf.…”

Section: Transfer To Experimentsmentioning

confidence: 99%

“…Once temperature distributions and flow fields are known, complex chemistry can be simulated along streamlines. For full three-dimensional CFD simulations, on the other hand, the comparison of simulated and measured temperature allows to evaluate the quality of the simulation [13]. Analyzing fluctuations in turbulent flames is one means to characterize the combustion process [14][15][16] because spatial and temporal fluctuations in local concentration and temperature can affect the quality of the produced powders.…”

Section: Introductionmentioning

confidence: 99%

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Effect of fluctuations on time-averaged multi-line NO-LIF thermometry measurements of the gas-phase temperature

et al. 2015

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chemistry and therefore, e.g., combustion efficiency and pollutant formation. Multi-line nitric oxide (NO)-laserinduced fluorescence (LIF) thermometry imaging enables accurate measurements of gas-phase temperature distributions in a spatial plane without the necessity of calibration [1]. The technique relies on the temperature dependence of NO LIF excitation spectra [1][2][3]. In thermal equilibrium, the temperature dependence of the population of the rotational ground state energy levels is described by the Boltzmann distribution. A laser is tuned across the vibronic transitions of the electronic A-X absorption band and the population fractions of individual rotational quantum states are probed by recording the respective LIF signal intensity with an intensified CCD camera. Excitation spectra are then extracted for each pixel from the stack of images taken for each laser wavelength position. Simulated spectra are then fitted to the experimental spectra with absolute temperature as the adjustable parameter. Spectral line broadening and background signals (e.g., scattered laser light or broad-band fluorescence) are included in the fitting routine.Multi-line techniques have demonstrated their robustness in stable low-pressure [4,5], atmospheric pressure [6], and high-pressure flames [7,8] as well as in systems with a large scattering background such as sooting flames [1] and spray systems [9,10]. In contrast to conventional two-color temperature imaging techniques (e.g., [11]), the multi-line approach has the advantage of being calibrationfree and robust against background signal as long as the shape of the excitation spectra can still be distinguished on top of the background signal and the background does not strongly vary with excitation wavelength within the investigated spectral range. Therefore, especially in highpressure flames, NO-LIF transitions must be chosen that do not interfere with LIF from hot O 2 [12]. The method, however, lacks single-shot capability because the spectra Abstract Multi-line NO laser-induced fluorescence (LIF) thermometry enables accurate gas-phase temperature imaging in combustion systems through least-squares fitting of excitation spectra. The required excitation wavelength scan takes several minutes which systematic biases the results in case of temperature fluctuations. In this work, the effect of various types (linear, Gaussian and bimodal) and amplitudes of temperature fluctuations is quantified based on simulated NO-LIF excitation spectra. Temperature fluctuations of less than ±5 % result in a negligible error of less than ±1 % in temperature for all cases. Bimodal temperature distributions have the largest effect on the determined temperature. Symmetric temperature fluctuations around 900 K have a negligible effect. At lower mean temperatures, fluctuations cause a positive bias leading to over-predicted mean temperatures, while at higher temperatures the bias is negative. The results of the theoretical analysis were applied as a guide for interpreting experimental multi-line ...

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“…The limitation of the technique is that it requires a data acquisition period longer than the timescales of turbulence and chemical reaction. Nonetheless, the technique has been applied in mildly turbulent flames to obtain temporally averaged temperatures [14,15]. However, the temperature bias observed in the flame contour region, where the ambient air and burnt gases mix vigorously, could be as high as ±25%.…”

Section: Introductionmentioning

confidence: 99%

The accuracy and precision of multi-line NO-LIF thermometry in a wide range of pressures and temperatures

Foo

Lamoureux

Cessou

et al. 2020

Journal of Quantitative Spectroscopy and Radiative Transfer

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An automated spectral fitting algorithm (named Thermo NO-LIF) designed for the extraction of temperature information from experimental NO-LIF spectra is presented and analysed. With the aid of the Thermo NO-LIF, the high-accuracy (0.5%) of multi-line NO-LIF thermometry are demonstrated in the burnt-gases region of a near-adiabatic Bunsentype premixed flame. The results are compared with the temperature measured using N 2 spontaneous Raman scattering (SRS). The current study also applies and analyses the algorithm and the thermometry technique in a premixed flat-flame under various subatmospheric pressures. The results suggest that choosing a long excitation scan range with as few overlapping lines as possible can maximise the performance of the multi-line NO-LIF thermometry. The uncertainty arising from the overlapping lines is especially crucial at atmospheric pressure. Additionally, the current study compares the performance of multi-line NO-LIF thermometry using narrowband and broadband lasers. Thermo NO-LIF is available to anyone interested in applying multi-line NO-LIF thermometry.

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Laser-based in situ measurement and simulation of gas-phase temperature and iron atom concentration in a pilot-plant nanoparticle synthesis reactor

Cited by 29 publications

References 18 publications

Formation of nanocrystalline manganese oxide in flames: oxide phase governed by classical nucleation and size-dependent equilibria

Formation of nanocrystalline manganese oxide in flames: oxide phase governed by classical nucleation and size-dependent equilibria

Effect of fluctuations on time-averaged multi-line NO-LIF thermometry measurements of the gas-phase temperature

The accuracy and precision of multi-line NO-LIF thermometry in a wide range of pressures and temperatures

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