Investigating temporal variation in the apparent volume fraction measured by time-resolved laser-induced incandescence

Sipkens, Timothy A.; Menser, Jan; Mansmann, Raphael; Schulz, Christof; Daun, Kyle J.

doi:10.1007/s00340-019-7251-7

Cited by 13 publications

(7 citation statements)

References 56 publications

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Section: Methodsmentioning

confidence: 99%

“…The absorption cross section is also used to infer the instantaneous nanoparticle temperature from the observed incandescence where C is the intensity scaling factor, p ( d p ) denotes the particle size distribution, and I λ,b [ T p ( d p )] is the blackbody spectral intensity for particles of diameter d p . The absorption cross section can be approximated by C abs = −π 2 d p 2 /λ Im([ε – 1]/[ε + 2]), multiplied by a constant that is integrated into C , and therefore does not influence the pyrometric temperature . For the pyrometric temperature estimation, Talebi-Moghaddam et al presented that the application of Rayleigh approximation is reasonable because it utilizes relative intensities and only the relative absorption cross section variation over the spectral measurement range is important.…”

Section: Methodsmentioning

confidence: 99%

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Interrogating Gas-Borne Nanoparticles Using Laser-Based Diagnostics and Bayesian Data Fusion

2021

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We demonstrate how the evaporation properties of gas-borne nanoscale materials, here liquid silicon and germanium nanoparticles, can be obtained through a novel combination of in situ time-resolved laser-induced incandescence (TiRe-LII) and phase-selective laser-induced breakdown spectroscopy (PS-LIBS) based on Bayesian data fusion. This approach reduces the uncertainty in the parameters describing evaporation and condensation by more than a factor of 2 compared to the conventional path and has the capability to provide much needed particle-size-dependent information on nanomaterial phase transitions at high temperature. The inferred parameters are generally consistent with those repeated in the literature but with reduced uncertainty and an extended temperature range.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Interrogating Gas-Borne Nanoparticles Using Laser-Based Diagnostics and Bayesian Data Fusion

2021

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“…where Cλ is the calibration constant, Λ is the intensity scaling factor (ISF) that accounts for the volume fraction of nanoparticles [28,29], and Iλ,b is the blackbody spectral intensity at the aggregate temperature, Tagg(t,Np,dp). In some cases, it is convenient to envision the aerosol as consisting of aggregates having uniform dp and Np.…”

Section: Theoretical Modellingmentioning

confidence: 99%

Time-resolved laser-induced incandescence on metal nanoparticles: effect of nanoparticle aggregation and sintering

2023

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This work examines the excessive absorption and anomalous cooling phenomena reported in laserinduced incandescence measurements on metal nanoparticles by considering the effects of aggregate structure and sintering. Experimental investigations are conducted on iron and molybdenum aerosols, which have different melting points and thus respond differently to the laser pulse. Although aggregation enhances the absorption cross-section of the nanoparticles and allows for higher peak temperatures, this enhancement does not fully explain the observed excessive absorption. Furthermore, as the aggregates of refractory metals such as molybdenum cool, they may sinter through gradual grain boundary diffusion; this change in structure alters their absorption cross-section, manifesting as a rapid drop in the pyrometric temperature, which could explain the anomalous cooling reported for this metal.

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“…Ω SIM ̸ = Ω P P ) in order to quantify the impact of uncertainties in these parameters on the performance of the methods. Numerous works [36,37,38,39,40] numerically treat the quantification of uncertainties of LII-based techniques by combining multiple sources of errors. In this work, a "one parameter at a time" procedure is used to quantify the errors on both E(m λ ) and T 0 associated with uncertainties on multiple LII parameters and to erroneous estimations of the soot peak temperature.…”

Section: Procedures For the Theoretical Study Of The Sp-lii Techniquementioning

confidence: 99%

Estimation of soot absorption function via the two separated pulses laser-induced incandescence technique

2023

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An original in-situ experimental approach is proposed to estimate the absorption function of soot particles in flames: the two Separated Pulses Laser-Induced Incandescence technique (SP-LII). The SP-LII technique is based on measuring the peak temperature of soot particles heated by laser pulses at two different fluences. From these two temperature measurements, the absorption function is estimated by solving the energy equation applied to soot particles during laser energy absorption once the product of soot density and specific heat is known. In order to solve the energy equation, two methods are considered here. The first method, called the "absorption model" (AM), solves the energy equation when all loss terms are neglected during absorption. The second method uses a look-up table (LUT) generated with an LII code in which the main loss terms are modelled. Both methods also provide information on the gas temperature T 0 , assuming that gas and solid phases are at equilibrium. First, the SP-LII technique's accuracy and limits are theoretically explored using peak temperatures from simulations done with an LII code. Overall, the AM method is efficient but is restricted to soot primary particles diameter >∼ 10 nm and low fluences. By contrast, the LUT method has an extended operational range, but it requires more information than the AM method, and its accuracy depends on the validity of the power loss models used to generate the look-up table. It is then concluded that the AM method represents the best compromise between the complexity of the methods and the expected accuracy of the results. Then, the feasibility of the SP-LII technique is proven by performing measurements in a laminar diffusion methane/air sooting flame and post-processing them with the AM method. Results for the absolute value and for the spatial evolution of E(m λ ) are coherent with the literature. Finally, a possible extension of the SP-LII technique to turbulent flames is discussed.

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Investigating temporal variation in the apparent volume fraction measured by time-resolved laser-induced incandescence

Cited by 13 publications

References 56 publications

Interrogating Gas-Borne Nanoparticles Using Laser-Based Diagnostics and Bayesian Data Fusion

Interrogating Gas-Borne Nanoparticles Using Laser-Based Diagnostics and Bayesian Data Fusion

Time-resolved laser-induced incandescence on metal nanoparticles: effect of nanoparticle aggregation and sintering

Estimation of soot absorption function via the two separated pulses laser-induced incandescence technique

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