In Situ light scattering dissymmetry measurements of the evolution of the aerosol size distribution in flames

Chang, Hyuksang; Biswas, Pratim

doi:10.1016/0021-9797(92)90307-8

Cited by 26 publications

(28 citation statements)

References 26 publications

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“…The total volume concentration increases rapidly near the burner exit where the formation of silica particles occurs actively due to hydrolysis and oxidation of SiCl 4 and increases slowly in the upper region beyond 10 mm. There are signi cant differences between calculations and experimental data (Chang and Biswas 1992). The volume concentration measured at x D 50 mm corresponds to the SiCl 4 concentration of 5.3 £ 10 ¡4 mol/l that is much higher than the inlet concentration of 2.87 £ 10 ¡4 mol/l.…”

Section: Comparison Of Particle Size and Number Density With The Exismentioning

confidence: 89%

“…Inlet conditions are shown in Table 2. To compare to experimental data (Chang and Biswas 1992), the analysis of heat and mass transfer has also been carried out without chemical reactions of SiCl 4 because ame temperature measurements were done by thermocouple without SiCl 4 . Predicted temperatures were in agreement with experimental data as shown in Figure 2a.…”

Section: Sectional Methods and Sensitivity Testsmentioning

confidence: 99%

“…Hurd and Flower (1988) measured the fractal dimension of silica aggregates in a premixed at ame using a light scattering technique and observed the decrease of primary particle size along the ame height. Chang and Biswas (1992) determined the size distribution of silica particles in a methane/air at ame using the method of angular dissymmetry light scattering. Yang and Biswas (1997) evaluated the sintering characteristic times using light scattering data in conjunction with a computer simulation of cluster aggregation and sintering.…”

Section: Introductionmentioning

confidence: 99%

“…The observed primary particle size of the titania agreed well with predictions, but the primary particle size of silica was found to be signi cantly underpredicted. Nonspherical silica and titania particles formed at the early stage usually grow and coalesce due to the sintering effect and then become more spherical in shape at a later stage (Chang and Biswas 1992;Cho et al 1998;Cho and Choi 2000). Therefore it is very important to understand the evolution of nonspherical particles in ames for proper control of size and morphology of ame generated particles (Lee and Choi 2000).…”

Section: Introductionmentioning

confidence: 99%

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Simulation of Growth of Nonspherical Silica Nanoparticles in a Premixed Flat Flame

Lee¹,

Oh²,

Choi³

2001

Aerosol Science and Technology

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The growth of nonspherical silica nanoparticles in a premixed at ame has been simulated, including the effects of convection, diffusion, thermophoresis, chemical reactions, coagulation, and coalescence. Considering both radiation effect and multistep chemical reactions of methane/air including both oxidation and hydrolysis of SiCl 4 , combustion analysis in a premixed at ame was done rst to obtain temperature, concentration of gas species, and ow elds. The predicted ame temperatures were in good agreement with the previous experimental data. Two-dimensional aerosol dynamics in which both particle volume and surface area are independent variables was then analyzed to investigate the growth of nonspherical silica particles. Several different models of coalescence of silica particles were studied: viscous ow sintering, atomistic diffusion sintering, fast sintering, and hybrid sintering models. Since the residence time was short and temperatures were not high enough for perfect coalescence of silica particles in the present study, the resulting particles were partially sintered or open-structured aggregates. The variations of total volume/number concentration and diameter of average volume along the ame height were obtained and compared with experimental data. Bi-modal size distributions were obtained at some ame heights.

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Section: Comparison Of Particle Size and Number Density With The Exismentioning

confidence: 89%

Section: Sectional Methods and Sensitivity Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Simulation of Growth of Nonspherical Silica Nanoparticles in a Premixed Flat Flame

Lee¹,

Oh²,

Choi³

2001

Aerosol Science and Technology

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“…The dry nickel nitrate particles in our experiments were premixed with the fuel-air mixture before it entered the ame region. The premixed burner (Chang and Biswas 1992) cross section had a honeycomb structure so that a wellcontrolled at ame was obtained that resulted in a one-dimensional temperature pro le along the burner axis ( Figure 2). Table 1(a) summarizes the experimental parameters for the tests.…”

Section: Methodsmentioning

confidence: 99%

Nickel Speciation and Aerosol Formation During Combustion of Kerosene Doped with Nickel Nitrate Aerosol in a Premixed Burner

Wang

Biswas

2000

Aerosol Science and Technology

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ABSTRACT. A controlled laboratory scale burner was used to combust kerosene oil doped with varying concentrations of sulfur (organic form) and nickel (as an atomized 0.23 µ m nickel nitrate aerosol). The resultant size distribution and speciation of the nickel aerosol was determined as a function of the distance from the burner outlet. In the high temperature region, nickel oxide was the dominant species formed, followed by a conversion to amorphous nickel sulfate at lower temperatures. The presence of sulfur in the fuel resulted in a greater degree of volatilization and formation of a higher concentration of smaller sized nickel species aerosol. Thermogravimetric analyzer tests were also used to establish the rst order reaction rate constant for NiO formation. A mechanistic description for the formation of the submicrometer mode is proposed which includes volatilization/nucleation, direct conversion to NiO, and possible breakage.

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Evaluation of optical detection methods for waterborne suspensions

Sethi¹,

Patnaik²,

Biswas³

et al. 1997

Journal AWWA

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Making design criteria for turbidimeters more stringent would enable an integrated approach to turbidity measurement and particle detection. Turbidimeters and optical particle counters (OPCs) are used to monitor particulate matter in water. The response from these instruments is governed by the optical properties of the suspension and the instrument design. The recommended design criteria for turbidimeters allow for large tolerances that lead to variations in measurements from different instruments. OPCs provide size‐specific information but may inaccurately size microorganisms or particles having optical properties different from those of the calibration particles. The authors evaluate the effects of optical design parameters in turbidimeters and OPCs. Performance data from two OPCs are presented. A multiple‐angle light‐scattering method was developed to obtain “optical signatures” from suspensions of monodisperse spheres and several microorganism isolates. Such “signatures” provide more optical information on waterborne particles and may also be used to identify specific types of microorganisms in real time.

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In Situ light scattering dissymmetry measurements of the evolution of the aerosol size distribution in flames

Cited by 26 publications

References 26 publications

Simulation of Growth of Nonspherical Silica Nanoparticles in a Premixed Flat Flame

Simulation of Growth of Nonspherical Silica Nanoparticles in a Premixed Flat Flame

Nickel Speciation and Aerosol Formation During Combustion of Kerosene Doped with Nickel Nitrate Aerosol in a Premixed Burner

Evaluation of optical detection methods for waterborne suspensions

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