An Immersed Boundary Method for flows with evaporating droplets

Lupo, Giandomenico; Ardekani, Mehdi Niazi; Brandt, Luca; Duwig, Christophe

doi:10.1016/j.ijheatmasstransfer.2019.118563

Cited by 28 publications

(12 citation statements)

References 40 publications

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“…Note that for an ideal gas, the isothermal compressibility coefficient β = 1/T and, thus, (1 − βT) = 0, which can be omitted. Considering the term varying with the composition Y v l,j , this can be recast as (see Lupo et al (2019) for details)…”

Section: Discussionmentioning

confidence: 99%

“…We start our analysis by assessing the influence on the evaporation dynamics of the type of thermodynamic model employed to evaluate the gas thermophysical properties. A common approach (Abramzon & Sirignano 1989;Lupo et al 2019 is to consider the thermophysical properties of the gas phase uniform, constant and evaluate them at an intermediate temperature, T m = T g,0 + m(T g,0 − T l,0 ). Hubbard et al (1975) show that the value m = 1/3 guarantees a good agreement between experimental results and the theoretical predictions based on the d 2 -law (Langmuir 1918).…”

Section: Comparison Of the Three Thermodynamic Modelsmentioning

confidence: 99%

“…The initial size, ranging between 10.5η and 21.5η, is chosen to focus on evaporation enhancement by turbulence (Verwey & Birouk 2020) and to elucidate the effects of the interface deformation. This last aspect is less discussed in literature and, so far, the spherical assumption has been invoked to describe the droplet shape also in fully resolved simulations (Lupo et al 2019. Given the large parameter space which characterizes evaporating flows, here we focus on changing the ratio between the droplet initial diameter and the Kolmogorov scale (d 0 /η), the surface tension and the initial gas temperature.…”

Section: Introductionmentioning

confidence: 99%

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Finite-size evaporating droplets in weakly compressible homogeneous shear turbulence

et al. 2022

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We perform interface-resolved simulations of finite-size evaporating droplets in weakly compressible homogeneous shear turbulence. The study is conducted by varying three dimensionless physical parameters: the initial gas temperature over the critical temperature $T_{g,0}/T_c$, the initial droplet diameter over the Kolmogorov scale $d_0/\eta$ and the surface tension, i.e. the shear-based Weber number, $We_{\mathcal {S}}$. For the smallest $We_{\mathcal {S}}$, we first discuss the impact on the evaporation rate of the three thermodynamic models employed to evaluate the gas thermophysical properties: a constant property model and two variable-properties approaches where either the gas density or all the gas properties are allowed to vary. Taking this last approach as reference, the model assuming constant gas properties and evaluated with the ‘1/3’ rule is shown to predict the evaporation rate better than the model where the only variable property is the gas density. Moreover, we observe that the well-known Frössling/Ranz-Marshall correlation underpredicts the Sherwood number at low temperatures, $T_{g,0}/T_c=0.75$. Next, we show that the ratio between the actual evaporation rate in turbulence and the one computed in stagnant conditions is always much higher than one for weakly deformable droplets: it decreases with $T_{g,0}/T_c$ without approaching unity at the highest $T_{g,0}/T_c$ considered. This suggests an evaporation enhancement due to turbulence also in conditions typical of combustion applications. Finally, we examine the overall evaporation rate and the local interfacial mass flux at higher $We_{\mathcal {S}}$, showing a positive correlation between evaporation rate and interfacial curvature, especially at the lowest $T_{g,0}/T_c$.

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Section: Discussionmentioning

confidence: 99%

Section: Comparison Of the Three Thermodynamic Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Finite-size evaporating droplets in weakly compressible homogeneous shear turbulence

et al. 2022

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“…In the above set of equations, [29]. In the energy equation, the enthalpy is given by h while W is the molar mass of the gas phase and q is the heat flux.…”

Section: Methodsmentioning

confidence: 99%

Drag force for a burning particle

Zhang

Luo

Haugen

et al. 2020

Combustion and Flame

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This study aims to study the effect of reactions and temperature on the drag force coefficient in the process of char combustion. For this purpose, two-dimensional fully resolved simulations are performed using the ghost cell immersed boundary method.Heat and mass transfer, together with the corresponding Stefan flow, is accounted for.Reactive particles with different reaction rates, temperatures and diameters are compared with a non-reactive adiabatic particle and a particle with outflow. For a char particle, results show that reactions tend to increase the drag force, which is converse to the effect observed for non-reactive particles with a pure outflow. This discrepancy is due to the fact that species and temperature distribution play an important role, and both of them can affect the property of the fluid. Hence, a reactive particle cannot be simplified as a particle with only outflow. Based on the current study, a new drag force correlation for a single reactive particle is obtained. The correlation shows a good agreement with the simulation results. A posterior analysis is also performed to verify the accuracy of the correlation.

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“…The effects of Stefan flow were superimposed through an explicit source term deposition into the Eulerian flow field. Lupo et al (2019) presented a new direct-forcing IB method based on Breugem's study (2012), which can fully capture the momentum, energy, and mass exchanges at the interface. Several validation cases of evaporating droplets were performed, including fixed rate and free evaporation of a static droplet, displacement of a droplet by Stefan flow, and evaporation of a hydrocarbon droplet in homogeneous isotropic turbulence.…”

Section: Mass Transfer With Heterogeneous Reactionsmentioning

confidence: 99%

Immersed boundary method for multiphase transport phenomena

Wei

Zhang

Luo

et al. 2020

Reviews in Chemical Engineering

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Multiphase flows with momentum, heat, and mass transfer exist widely in a variety of industrial applications. With the rapid development of numerical algorithms and computer capacity, advanced numerical simulation has become a promising tool in investigating multiphase transport problems. Immersed boundary (IB) method has recently emerged as such a popular interface capturing method for efficient simulations of multiphase flows, and significant achievements have been obtained. In this review, we attempt to give an overview of recent progresses on IB method for multiphase transport phenomena. Firstly, the governing equations, the basic ideas, and different boundary conditions for the IB methods are introduced. This is followed by numerical strategies, from which the IB methods are classified into two types, namely the artificial boundary method and the authentic boundary method. Discussions on the implementation of various boundary conditions at the interphase surface with momentum, heat, and mass transfer for different IB methods are then presented, together with a summary. Then, the state-of-the-art applications of IB methods to multiphase flows, including the isothermal flows, the heat transfer flows, and the mass transfer problems are outlined, with particular emphasis on the latter two topics. Finally, the conclusions and future challenges are identified.

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An Immersed Boundary Method for flows with evaporating droplets

Cited by 28 publications

References 40 publications

Finite-size evaporating droplets in weakly compressible homogeneous shear turbulence

Finite-size evaporating droplets in weakly compressible homogeneous shear turbulence

Drag force for a burning particle

Immersed boundary method for multiphase transport phenomena

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