Heat transfer in a turbulent particle-laden channel flow

Arcen, Boris; Tanière, Anne; Khalij, Mohammed

doi:10.1016/j.ijheatmasstransfer.2012.06.058

Cited by 17 publications

(10 citation statements)

References 32 publications

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“…From a practical standpoint, it is important to quantify the influence of non-Oberbeck-Boussinesq assumptions on the computation of transfer rates [5,6]. Benchmarking the importance of NOB-related fluid behavior can be also important for studies in which fluid properties are artificially modified to increase heat transfer coefficient [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Effect of Temperature Dependent Fluid Properties on Heat Transfer in Turbulent Mixed Convection

Zonta¹,

Soldati

2013

Journal of Heat Transfer

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The effect of the uniform fluid properties approximation (Oberbeck-Boussinesq (OB)) in turbulent mixed convection is investigated via direct numerical simulation (DNS) of water flows with viscosity (μ) and thermal expansion coefficient (β) both independently and simultaneously varying with temperature (non-Oberbeck-Boussinesq conditions (NOB)). Mixed convection is analyzed for the prototypical case of Poiseuille-Rayleigh-Bénard (PRB) turbulent channel flow. In PRB flows, the combination of buoyancy driven (Rayleigh-Bénard) with pressure driven (Poiseuille) effects produce a complex flow structure, which depends on the relative intensity of the flow parameters (i.e., the Grashof number, Gr, and the shear Reynolds number, Reτ). In liquids, however, temperature variations induce local changes of fluid properties which influence the macroscopic flow field. We present results for different absolute values of the shear Richardson numbers (Riτ=|Gr/Reτ2|) under constant temperature boundary conditions. As Riτ is increased buoyant thermal plumes are generated, which induce large scale thermal convection that increases momentum and heat transport efficiency. Analysis of friction factor (Cf) and Nusselt number (Nu) for NOB conditions shows that the effect of viscosity is negligible, whereas the effect of thermal expansion coefficient is significant. Statistics of mixing show that (i) mixing increases for increasing Riτ (and decreases for increasing Reτ) and (ii) the effect of thermal expansion coefficient on mixing increases for increasing Riτ (and decreases for increasing Reτ). A simplified phenomenological model to predict heat transfer rates in PRB flows has also been developed.

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Section: Introductionmentioning

confidence: 99%

Effect of Temperature Dependent Fluid Properties on Heat Transfer in Turbulent Mixed Convection

Zonta¹,

Soldati

2013

Journal of Heat Transfer

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“…For example, Shotorban et al [19] studied the temperature statistics in a turbulent shear flow, and both Zonta et al [20] and Arcen et al [21] studied the effect of particles on the heat transfer in a turbulent channel flow. Puragliesi et al [22] studied by a similar method Rayleigh-Bénard convection, but their work assumes one-way coupling, with the fluid unaffected by the particles.…”

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confidence: 99%

Effects of particle settling on Rayleigh-Bénard convection

Oresta

Prosperetti

2013

Phys. Rev. E

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The effect of particles falling under gravity in a weakly turbulent Rayleigh-Bénard gas flow is studied numerically. The particle Stokes number is varied between 0.01 and 1 and their temperature is held fixed at the temperature of the cold plate, of the hot plate, or the mean between these values. Mechanical, thermal and combined mechanical and thermal couplings between the particles and the fluid are studied separately. It is shown that the mechanical coupling plays a greater and greater role in the increase of the Nusselt number with increasing particle size. A rather unexpected result is an unusual kind of "reverse one-way coupling", in the sense that the fluid is found to be strongly influenced by the particles, while the particles themselves appear to be little affected by the fluid, in spite of the relative smallness of the Stokes numbers. It is shown that this result derives from the very strong constraint on the fluid behavior imposed by the vanishing of the mean fluid vertical velocity over the cross sections of the cell demanded by continuity.

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“…Particles were found to settle at the walls, depleting the RBC bulk flow of particles and forming a porous layer at the plates that eventually would cause a decrease of the heat transfer. In numerical studies particles are often prevented from getting stuck at the plates by neglecting gravity [3,12,35], by pointing gravity in the direction parallel to the walls [17,20] or by removing particles from the flow as soon as they reach one of the plates [15,23,22]. Here, the larger thermal expansion coefficient of particles alone ensures that particles eventually move away from the plates again.…”

Section: Introductionmentioning

confidence: 99%

Statistical properties of thermally expandable particles in soft-turbulence Rayleigh-Bénard convection

et al. 2019

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The dynamics of inertial particles in Rayleigh-Bénard convection, where both particles and fluid exhibit thermal expansion, is studied using direct numerical simulations (DNS). We consider the effect of particles with a thermal expansion coefficient larger than that of the fluid, causing particles to become lighter than the fluid near 1 arXiv:1907.00049v1 [cond-mat.soft] 22 Jun 2019 the hot bottom plate and heavier than the fluid near the cold top plate. Because of the opposite directions of the net Archimedes' force on particles and fluid, particles deposited at the plate now experience a relative force towards the bulk. The characteristic time for this motion towards the bulk to happen, quantified as the time particles spend inside the thermal boundary layers (BLs) at the plates, is shown to depend on the thermal response time, τ T , and the thermal expansion coefficient of particles relative to that of the fluid, K = α p /α f . In particular, the residence time is constant for small thermal response times, τ T 1, and increasing with τ T for larger thermal response times, τ T 1. Also, the thermal BL residence time is increasing with decreasing K. A one-dimensional (1D) model is developed, where particles experience thermal inertia and their motion is purely dependent on the buoyancy force. Although the values do not match one-to-one, this highly simplified 1D model does predict a regime of a constant thermal BL residence time for smaller thermal response times and a regime of increasing residence time with τ T for larger response times, thus explaining the trends in the DNS data well.

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Heat transfer in a turbulent particle-laden channel flow

Cited by 17 publications

References 32 publications

Effect of Temperature Dependent Fluid Properties on Heat Transfer in Turbulent Mixed Convection

Effect of Temperature Dependent Fluid Properties on Heat Transfer in Turbulent Mixed Convection

Effects of particle settling on Rayleigh-Bénard convection

Statistical properties of thermally expandable particles in soft-turbulence Rayleigh-Bénard convection

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