The effect of mixing rates on the formation and growth of condensation aerosols in a model stagnation flow

Alshaarawi, Amjad; Bisetti, Fabrizio

doi:10.1016/j.jaerosci.2014.11.004

Cited by 3 publications

(4 citation statements)

References 29 publications

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“…with z * i = ψ −1 (ζ * i ), ⌊x⌋ = floor(x) and where h l (z) is a function expressing a moment of z, with 1 ≤ l ≤ Q . Relations (19) or (20) give a number of Q equations (i.e., one for each l), each containing a number of Q weights a k with which the solution at time level m + 1 at the kth representative size is assigned. We can solve system (19) or (20) to find all a k .…”

Section: Solution To the Condensational Growth Equationmentioning

confidence: 99%

“…Given the notation used in (19), the contribution to the solution at time level m + 1 of the droplets originally located at z l may, for the four-moment scheme, be written as…”

Section: Condensational Growthmentioning

confidence: 99%

“…However, such an assumption may be too restrictive. A popular alternative to mitigate this problem is the Quadrature Method Of Moments (QMOM) (e.g., see [12][13][14][15][16][17][18][19]), in which higher order moments are related to lower order ones using quadrature integration. The QMOM method may become numerically challenging and suffers from a non-uniqueness problem [20].…”

Section: Introductionmentioning

confidence: 99%

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Characteristics-based sectional modeling of aerosol nucleation and condensation

Frederix

Stanić

Kuczaj

et al. 2016

Journal of Computational Physics

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Section: Solution To the Condensational Growth Equationmentioning

confidence: 99%

“…Given the notation used in (19), the contribution to the solution at time level m + 1 of the droplets originally located at z l may, for the four-moment scheme, be written as…”

Section: Condensational Growthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characteristics-based sectional modeling of aerosol nucleation and condensation

Frederix

Stanić

Kuczaj

et al. 2016

Journal of Computational Physics

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“…8 Recently, the nucleation and growth of condensing aerosols have been investigated numerically in a counterflow by one of the authors. 9 In the range of operating conditions relevant to laminar flow applications, the flow field is inviscid and irrotational over most of the domain (see Figure 1(b)). Vorticity and viscous effects are confined to the wall boundary layer on the interior of the nozzles and along the external shear layer that extends from the nozzle wall outwards in the radial direction.…”

Section: Introductionmentioning

confidence: 99%

Reynolds number and geometry effects in laminar axisymmetric isothermal counterflows

Scribano

Bisetti

2016

Physics of Fluids

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The counterflow configuration is a canonical stagnation flow, featuring two opposed impinging round jets and a mixing layer across the stagnation plane. Although counterflows are used extensively in the study of reactive mixtures and other applications where mixing of two streams is required, quantitative data on the scaling properties of the flow field are lacking. The aim of this work is to characterize the velocity and mixing fields in isothermal counterflows over a wide range of conditions. The study features both experimental data from particle image velocimetry and results from detailed axisymmetric simulations. The scaling laws for the nondimensional velocity and mixture fraction are obtained as a function of an appropriate Reynolds number and the ratio of the separation distance of the nozzles to their diameter. In the range of flow configurations investigated, the nondimensional fields are found to depend primarily on the separation ratio and, to a lesser extent, the Reynolds number. The marked dependence of the velocity field with respect to the separation ratio is linked to a high pressure region at the stagnation point. On the other hand, Reynolds number effects highlight the role played by the wall boundary layer on the interior of the nozzles, which becomes less important as the separation ratio decreases. The normalized strain rate and scalar dissipation rate at the stagnation plane are found to attain limiting values only for high values of the Reynolds number. These asymptotic values depend markedly on the separation ratio and differ significantly from the values produced by analytical models. The scaling of the mixing field does not show a limiting behavior as the separation ratio decreases to the smallest practical value considered. Published by AIP Publishing. [http://dx

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Effects of inlet flow non-uniformities on thermochemical structures and quasi-one-dimensional simulation of sooting counterflow diffusion flames

et al. 2023

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Counterflow flames are routinely used for investigating fundamental flame and fuel properties such as laminar flame speeds, autoignition temperature, extinction strain rate and chemistries of soot formation. The primary merit of counterflow flame is that the essentially two-dimensional (2D) configuration can be mathematically treated as a one-dimensional (1D) problem with certain assumptions made. In this work, we performed a comprehensive investigation on the performance of the 1D modelling by comparing the results with experimental measurements and the more rigorous 2D models. We focused on the effects of inlet flow uniformities which are frequency assumed in the 1D model but challenging to realize in experiments. Parametric studies on effects of nozzle flow rates, nozzle separation distances as well as curtain flow rates on inlet flow uniformities and the 1D modelling were performed. The results demonstrated the importance to specify actual velocity boundary conditions, either obtained from experiments or from two-dimensional modelling to the 1D model. An additional novel contribution of this work is a quantitative presentation of the fact that the presence of the curtain flow would exert a notable influence on the core counterflow through modifying the radial distribution of the nozzle exit velocity although the effects can be accounted for by using the correct velocity boundaries in the quasi-1D model. This work provides recommendation for various geometry and operational parameters of the counterflow flame to facilitate researchers to select proper burner configuration and flow conditions that are ameable for accurate 1D modelling.

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The effect of mixing rates on the formation and growth of condensation aerosols in a model stagnation flow

Cited by 3 publications

References 29 publications

Characteristics-based sectional modeling of aerosol nucleation and condensation

Characteristics-based sectional modeling of aerosol nucleation and condensation

Reynolds number and geometry effects in laminar axisymmetric isothermal counterflows

Effects of inlet flow non-uniformities on thermochemical structures and quasi-one-dimensional simulation of sooting counterflow diffusion flames

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