DNS of turbulent droplet-laden heated channel flow with phase transition at different initial relative humidities

Bukhvostova, A; Russo, E Emanuele; Kuerten, Johannes G.M.; Geurts, BJ Bernard

doi:10.1016/j.ijheatfluidflow.2014.10.015

Cited by 10 publications

(9 citation statements)

References 17 publications

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“…In this case, this total particle contribution is now negative, and combined with the small reduction in the total turbulent flux, the forcing is small to moderate given the specified initial mass loading of φ i = 0.1. This is generally consistent with other studies (Russo et al, 2014;Bukhvostova et al, 2014b) despite differences in boundary conditions and numerical setups.…”

Section: Enthalpy Fluxessupporting

confidence: 92%

“…As will be noted throughout, the simulations presented herein are generally similar to those of Russo et al (2014) and Bukhvostova et al (2014b), but extends the analysis to probe specific thermodynamic feedback mechanisms between the droplets and the surrounding flow. We focus particularly on the breakdown of total enthalpy flux into the sensible and latent components, with emphasis on the difference between droplet effects on each component independently versus the overall droplet effect on the sum -a breakdown with implications on accurate model development.…”

Section: Introductionsupporting

confidence: 55%

“…They found significant modifications to the mean temperature and moisture profiles, and, using the same breakdown of heat transport as used by Kuerten et al (2011), demonstrated a substantial increase in the bulk nondimensional cross-channel Nusselt number after adding thermodynamically coupled droplets -an effect driven by particle/ambient temperature differences, which is enhanced when the droplets are allowed to evaporate. Subsequent studies by Bukhvostova et al (2014b) and Kuerten and Vreman (2015) illustrate the influence of relative humidity and particle collisions, respectively.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Turbulent latent and sensible heat flux in the presence of evaporative droplets

Helgans

Richter

2016

International Journal of Multiphase Flow

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Direct numerical simulations of an Eulerian-based carrier phase are performed which are two-way coupled in momentum and energy to Lagrangian droplets within a Boussinesq-type incompressible formulation, where the droplets are allowed to evaporate and condense and are thus coupled to the vapor field of the carrier phase. Turbulent planar Couette flow is simulated under varying boundary forcings to understand the degree to which evaporating droplets modify vertical fluxes of energy in horizontally homogeneous systems. In particular, the separate influences on both sensible and latent heat are substantial but opposite in sign, and the local relative humidity can result in droplet-induced heat or moisture fluxes which counteract the prescribed background gradients. The influence of droplet Stokes number is also considered, where it is shown that both clustering and turbophoresis play important roles in determining the magnitude of the droplet-induced sensible and latent heat fluxes.

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Section: Enthalpy Fluxessupporting

confidence: 92%

Section: Introductionsupporting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

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Turbulent latent and sensible heat flux in the presence of evaporative droplets

Helgans

Richter

2016

International Journal of Multiphase Flow

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“…For mild initial conditions the results of the incompressible and compressible formulation do not show significant differences. However, a lower initial relative humidity, leading to fast initial evaporation of droplets, results in differences on the order of 15 % in mean thermal properties of the system [22]. A drawback of the compressible formulation is the severe restriction on the time step if an explicit time-marching method is applied, since realistic Mach numbers are very small.…”

Section: Dns With Point-particle Approachmentioning

confidence: 99%

Point-Particle DNS and LES of Particle-Laden Turbulent flow - a state-of-the-art review

Kuerten

2016

Flow Turbulence Combust

162

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Particle-laden or droplet-laden turbulent flows occur in many industrial applications and in natural phenomena. Knowledge about the properties of these flows can help to improve the design of unit operations in industry and to predict for instance the occurrence of rain showers. This knowledge can be obtained from experimental research and from numerical simulations. In this paper a review is given of numerical simulation methods for particle-laden flows. There are various simulation methods possible. They range from methods in which all details, including the flow around each particle, are resolved, via point-particle methods, in which for each particle an equation of motion is solved, to Eulerian methods in which equations for particle concentration and velocity are solved. This review puts the emphasis on the intermediate class of methods, the Euler-Lagrange methods in which the continuous phase is described by an Eulerian approach and the dispersed phase in a Lagrangian way with equations of motion for each individual particle.

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“…The aerodynamic forces governing the point-droplet motion and the thermodynamic variables driving the vaporization rate are computed as a function of the continuous Eulerian variables by means of interpolating kernels. In the framework of DNS, the hybrid Eulerian-Lagrangian approach can be achieved through well-established models meant to take into account the mutual effects of the two phases (Mashayek 1998;Miller and Bellan 1999;Mashayek and Pandya 2003;Bukhvostova et al 2014;Sardina et al 2015). Nonetheless, when dealing with large eddy simulation (LES) or Reynolds Averaged Navier Stokes (RANS) approaches, in which only the larger scales are resolved, the interaction of the small-scale turbulent motion with the dispersed drops requires proper modeling (Pozorski and Apte 2009;Li et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Direct Numerical Simulations of the Evaporation of Dilute Sprays in Turbulent Swirling Jets

Ciottoli

Battista

Galassi

et al. 2020

Flow Turbulence Combust

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The effects of swirled inflows on the evaporation of dilute acetone droplets dispersed in turbulent jets are investigated by means of direct numerical simulation. The numerical framework is based on a hybrid Eulerian–Lagrangian approach and the point-droplet approximation. Phenomenological and statistical analyses of both phases are presented. An enhancement of the droplet vaporization rate with increasing swirl velocities is observed and discussed. The key physical drivers of this augmented evaporation, namely dry air entrainment and swirl-induced centrifugal forces acting on the droplets, are isolated with the aid of additional simulations in which the inertial properties of the droplets are neglected. The correlation between swirl and dry air entrainment rate is found to be responsible for the increase of the global evaporation rate and the spray penetration length reduction, while swirl-induced centrifugal forces are found to be effective only in the jet shear layer, close to the injection orifice, for the analyzed cases.

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DNS of turbulent droplet-laden heated channel flow with phase transition at different initial relative humidities

Cited by 10 publications

References 17 publications

Turbulent latent and sensible heat flux in the presence of evaporative droplets

Turbulent latent and sensible heat flux in the presence of evaporative droplets

Point-Particle DNS and LES of Particle-Laden Turbulent flow - a state-of-the-art review

Direct Numerical Simulations of the Evaporation of Dilute Sprays in Turbulent Swirling Jets

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