Evolution of convective plumes adjacent to localized heat sources of various shapes

Kondrashov, А. N.; Sboev, I.; Dunaev, P.

doi:10.1016/j.ijheatmasstransfer.2016.07.065

Cited by 28 publications

(7 citation statements)

References 26 publications

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“…Many experimental, numerical and theoretical studies (List 1982; Vincent, Yuen & Munqer 2012) of plumes have been performed due to their significance in fundamental research and engineering applications. Additionally, a plume may be influenced by the size (Guha & Sengupta 2016), shape (Kondrashov, Sboev & Dunaev 2016, 2017) and heating method (Mellado 2012) of the source. Thus, the plume from a point, line or surface heat source is typically considered in many studies due to their simplicity of geometry (Rotem & Claassen 1969; Fay 1973; Hunt & Bremer 2011).…”

Section: Introductionmentioning

confidence: 99%

Experiment of a thermal plume on an open cylinder

Zhang,

Nie,

2023

J. Fluid Mech.

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In this study, we performed a set of experiments of the thermal plume on an open cylinder heated from below and a simple scaling analysis. The flow structure of the plume was visualized using the shadowgraph technique, and the temperature at specific points was measured using a thermistor. Transient plumes in a developing stage, an equilibrating stage and a fully developed stage were described. The new scaling laws of the stem radius and the velocity of the rising plume were presented, which are different from those on a two-dimensional heated plate due to the cylindrical effect and agree with experimental results. In the fully developed stage, there is a transition route of the plume from a steady to chaotic state with an increase in the Rayleigh number, which involves a series of bifurcations. A reverse bifurcation from a periodic (Ra = 1.17 × 106) back to a steady (Ra = 1.30 × 106) state has been observed in the experiment, which is referred to as the period bubbling bifurcation. Thus, the present experimental results validate the previous numerical results presented by Zhang et al. (Phys. Fluids, vol. 33 (6), 2021, 064110). The bifurcation diagram, spectral analysis and attractor are used to characterize the transitional plume. In addition, the heat and mass transfer have also been quantified.

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Section: Introductionmentioning

confidence: 99%

Experiment of a thermal plume on an open cylinder

Zhang,

Nie,

2023

J. Fluid Mech.

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“…In the last decades, a significant number of papers have been published in specialized literature concerning the problem under consideration [1][2][3][4]. An excellent review on thermogravitational convection in enclosures for engineering applications was presented by Baïri et al [5].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Surface Radiation on the Passive Cooling of a Heat-Generating Element

2019

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Low-power electronic devices are suitably cooled by thermogravitational convection and radiation. The use of modern methods of computational mechanics makes it possible to develop efficient passive cooling systems. The present work deals with the numerical study of radiative-convective heat transfer in enclosure with a heat-generating source such as an electronic chip. The governing unsteady Reynolds-averaged Navier-Stokes (URANS) equations were solved using the finite difference method. Numerical results for the stream function-vorticity formulation are shown in the form of isotherm and streamline plots and average Nusselt numbers. The influence of the relevant parameters such as the Ostrogradsky number, surface emissivity, and the Rayleigh number on fluid flow characteristics and thermal transmission are investigated in detail. The comparative assessment clearly emphasizes the effect of surface radiation on the overall energy balance and leads to change the mean temperature inside the heat generating element. The results of the present study can be applied to the design of passive cooling systems.

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“…8 In this case, not all the heat sources can convert into the space cooling load, because only the portion of those entering the occupied zone should be considered. 9 The different heat source distributions, which means the different intensities, 10,11 locations, 12 centralization/decentralization conditions, 13,14 shapes, 11,15 ratios of radiation to convection, 16 heights 17 or aspect ratios 18 of the heat sources, have a crucial influence on the indoor air temperature distribution and airflow field. Accordingly, the space cooling load oriented to the occupied zone could be greatly affected by the heat source distribution, which has been reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

The influence of heat source distribution on the space cooling load oriented to local thermal requirements

Liang

Melikov

2019

Indoor and Built Environment

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Existing studies have shown that the space cooling load oriented to local thermal requirements is significantly influenced by different heat source distributions. However, numerical methods have been mainly used in the analysis based on a fixed airflow field and ignoring the thermal plume. Here, an experiment in a chamber with mixing ventilation was conducted. The heat sources were simulated by metal barrels and an oil-filled radiator, 13 types of heat source distributions were designed and the local cooling load (LCL) was used as the evaluation index. The results show that (1) the LCL is equal to the total amount of heat sources at the steady state in a room with mixing ventilation only if the heat sources are also distributed uniformly; (2) the LCL decreases with a decrease in the intensity of heat sources, achieving a decrease rate of 47.4%–70.8% in the experiment with different intensities; (3) the LCL is 9.2%–22.3% lower than the total amount of heat sources when these are located near the exhaust diffuser or far away from the target zone; (4) owing to its smaller surface area, the LCL with an oil-filled radiator is 7% lower than that with five metal barrels.

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Evolution of convective plumes adjacent to localized heat sources of various shapes

Cited by 28 publications

References 26 publications

Experiment of a thermal plume on an open cylinder

Experiment of a thermal plume on an open cylinder

The Influence of Surface Radiation on the Passive Cooling of a Heat-Generating Element

The influence of heat source distribution on the space cooling load oriented to local thermal requirements

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