Wake Flow and Heat Transfer Due to a Spherical Viscous Droplet

Bhattacharyya, Souvik; Singh, Ashok

doi:10.1080/10407780903582927

Cited by 8 publications

(3 citation statements)

References 18 publications

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“…Examples include, sediment grains in rivers, cloud particles in the atmosphere, fluidized beds, and fluid-solid cyclone separators [1][2][3][4]. Comprehending the major mean particle-laden flow phenomena, such as fluid-solid interaction and particles removal or mixing, is crucial for the environmental management and design and operation of such engineering equipment.…”

Section: Introductionmentioning

confidence: 99%

The Use of Thermal Lattice Boltzmann Numerical Scheme for Particle-Laden Channel Flow with a Cavity

Jahanshaloo

Sidik

Salimi

et al. 2014

Numerical Heat Transfer, Part A: Applications

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In this article, particle-laden flow in a channel with heated cavity has been investigated. Calculations were performed using a point force scheme for particle dynamics, while the process of fluid renewal was modeled using the double-population thermal lattice Boltzmann method. Point-particle formulation accounts for the finite-size dispersed phase and the forces acting on the particles were modeled through drag force correlations. Two-way interactions of solid-fluid calculation were considered by adding an external force term for feedback that forced particles in the evolution of fluid distribution function. The method was first validated with steady state flow in a channel with cavity in the presence and absence of a heat source. It was then applied to mixed convection flow laden with particles at various Grashof numbers. The particle dispersion characteristics were examined in detail, where the particle removal rate from cavity upon cavity aspect ratio was emphasized. The effect of the Reynolds number on particle distribution was further investigated numerically by varying the speed of inlet flow into the channel.

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Section: Introductionmentioning

confidence: 99%

The Use of Thermal Lattice Boltzmann Numerical Scheme for Particle-Laden Channel Flow with a Cavity

Jahanshaloo

Sidik

Salimi

et al. 2014

Numerical Heat Transfer, Part A: Applications

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“…A cooled vortex street [13] with large SPs was discovered at Re 44. The buoyancy-assisted thermal flow from a liquid droplet falling in the fluid medium has been studied numerically [14]. At Re ¼ 70 [9] and 300 [2], the heated wakes are qualitatively and extremely different from each other.…”

Section: Introductionmentioning

confidence: 99%

Direct Numerical Simulation of Air Heated Cylinder Wake in Transitional State. Part I: Cylinder Heating Effect on Strong Turbulence Anisotropy (STA), and Determination of STA Suppression

Noto

2014

Numerical Heat Transfer, Part B: Fundamentals

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A variation of strong turbulence anisotropy (STA) with cylinder heating, and, as a result, STA suppression, are here first elucidated in the air heated wake in the transitional state at Reynolds number Re ¼ 300 and Richardson number Ri ¼ 0.3. Simultaneously, new facts for variations of velocities u, v, and w, i.e., the upward, horizontal, and spanwise directions, and wake motion by cylinder heating are first elucidated. Here STA is defined such that, in velocities u, v, and w, laminar velocities arise in at least one directions but turbulence arises in the remainder of directions.1. STA is determined to arise in isothermal and heated wakes by employing the new method. With cylinder heating, STA is found to be suppressed because the turbulent region in w is decreased, the three-dimensionality is suppressed, but the twodimensionality and laminarization are enhanced in the heated wake. 2. With cylinder heating, the spanwise velocity jwj is found to be suppressed strongly in the probability density function (PDF), whose peak value is decreased strongly near w % 0, and becomes 20% of that in the isothermal wake. 3. The above decrease in jwj is found to be equivalent to the increase of laminar state in time records. With cylinder heating, the laminar region is increased, but the region with turbulence is decreased. 4. The wake stability is extremely different in thermal flows with or without turbulence in w. When w has turbulence, here u and v are laminar, STA arises, and the thermal flow field becomes the transitional state, has instability, and is destabilized. 5. When w does not have turbulence, and is laminar, velocities u, v, and w are all laminar, form only 3-D flow, and do not have turbulence anisotropy. The wake does not have instability, and is stabilized.

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“…Yan et al (2002) used a moving mesh to calculate the flows inside and outside a droplet. Bhattacharyya and Singh (2010) studied a liquid droplet falling in a continuous phase by solving the Navier-Stokes equations and the energy equation to simulate the buoyancy-assisted flow and heat transfer and the interaction between the wake flow and the heat transfer have been outlined. However, the process of solute absorption by droplets were absent in these studies.…”

Section: Introductionmentioning

confidence: 99%

A Simplified Model of Predicting SO2 Absorption by Single Atmospheric Raindrops with Chemical Dissociation and Internal Circulation

Chen

Hung

2011

Aerosol Air Qual. Res.

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A simplified model of predicting chemical SO 2 absorption by single freely falling raindrops with internal circulation in the atmosphere is developed in the present study. By multiplying a modification factor α into the model of interfacial velocity established from creeping flow, it is found that the relative error between the simplified model and the two-phase simulation method is less than 4%. Accordingly, the simplified model enables us to simulate the atmospheric SO 2 absorption process with less computational effort and without losing accuracy. The simulated results indicate that the dissociation of H 2 SO 3 governs the mass transfer process and the concentration of HSO 3 − is by far larger than those of SO 3 2− and H 2 SO 3 . As a result, the chemical absorption takes a much longer period of time to achieve the uptake process. Specifically, for the raindrop radius in the range of 200-500 μm, the absorption time of chemical absorption is larger than that of physical absorption by the factors of 70-290. From the perspective of characteristic time, mass diffusion is the controlling mechanism for SO 2 absorption. When chemical absorption is carried out, the absorption period is 28-33 folds of the characteristic time of mass diffusion, implying that the former is always larger than the latter by over an order of magnitude.

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Wake Flow and Heat Transfer Due to a Spherical Viscous Droplet

Cited by 8 publications

References 18 publications

The Use of Thermal Lattice Boltzmann Numerical Scheme for Particle-Laden Channel Flow with a Cavity

The Use of Thermal Lattice Boltzmann Numerical Scheme for Particle-Laden Channel Flow with a Cavity

Direct Numerical Simulation of Air Heated Cylinder Wake in Transitional State. Part I: Cylinder Heating Effect on Strong Turbulence Anisotropy (STA), and Determination of STA Suppression

A Simplified Model of Predicting SO2 Absorption by Single Atmospheric Raindrops with Chemical Dissociation and Internal Circulation

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