The effect of instability flow for two-dimensional natural convection in a square enclosure with different arrays of two inner cylinders

Cho, Hyun Woo; Seo, Young Min; Mun, Gi Su; Ha, Man Yeong; Park, Yong Gap

doi:10.1016/j.ijheatmasstransfer.2017.06.080

Cited by 24 publications

(10 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The magnetohydrodynamics natural convection in closed cavities has been considered in various studies, namely in the case of two, 25,26 three, 27 and four heating blocks 28 . Other than the square shape of the heating blocks, several works have considered different geometrical shapes, such as rectangular, 5,11,29–31 triangular, 32 circular, 33–35 elliptical, 36 and hexagonal 37 …”

Section: Introductionmentioning

confidence: 99%

Natural convection coupled to surface radiation in an air‐filled square cavity containing two heat‐generating bodies

et al. 2022

View full text Add to dashboard Cite

The present numerical study focuses on the cooling by natural convection and surface radiation of two electronic components generating two different and uniform volumetric powers. These components are modeled by two square bodies placed inside a closed square cavity with a cold straight wall. Two configurations are analyzed based on the position of the two heat‐generating bodies. In the first one (horizontal position configuration), the two bodies are located at the same height of the cavity, while they are placed at different heights in the second case (vertical position configuration). The effects of two Rayleigh numbers (0 ≤ ( Ra 1 , Ra 2 ) ≤ 10 6 $0\le ({{Ra}}_{1},{{Ra}}_{2})\le {10}^{6}$), the conductivity ratio (0.01 ≤ K ≤ 100 $0.01\le K\le 100$), and the emissivity (0 ≤ ε ≤ 1 $0\le \varepsilon \le 1$) on the heat transfer characteristics and the flow structure are analyzed. The data is displayed as streamlines, isotherms, velocity, and maximum temperature profiles, and local heat transfer on the active wall. The obtained results indicate that the choice of the appropriate configuration depends mainly on the deviation between the two Rayleigh numbers. Furthermore, the maximum temperature of a specific block decreases as the quantity of heat generated by the other block rises. We can also see that the maximum temperature of the two blocks decreases by about 50 % $50 \% $ with the increase in the emissivity (from 0 $0$ to 1 $1$) or the conductivity ratio (from 0.1 $0.1$ to 1 $1$).

show abstract

Section: Introductionmentioning

confidence: 99%

Natural convection coupled to surface radiation in an air‐filled square cavity containing two heat‐generating bodies

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The combination of the conditions of the enclosure and the internal bodies provides various reach topics. Thus, numerous studies have dealt with the natural convection for the internal bodies in the enclosure by considering the individual condition or combined conditions such as the thermal boundary [1][2][3][4][5], the shape [3,4,[6][7][8][9], 3D effect [2,[10][11][12], the size [8,9,11,[13][14][15][16][17][18][19][20][21][22], the number of the internal bodies [23], the concentric and eccentric internal body [12,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40], Rayleigh number…”

Section: Introductionmentioning

confidence: 99%

Classification of Flow Modes for Natural Convection in a Square Enclosure with an Eccentric Circular Cylinder

Yoon¹,

Shim²

2021

Energies

View full text Add to dashboard Cite

The present study investigated the natural convection for a hot circular cylinder embedded in a cold square enclosure. The numerical simulations are performed to solve a two-dimensional steady natural convection for three Rayleigh numbers of 103, 104 and 105 at a fixed Prandtl number of 0.7. This study considered the wide range of the inner cylinder positions to identify the eccentric effect of the cylinder on flow and thermal structures. The present study classifies the flow structures according to the cylinder position. Finally, the present study provides the map for the flow structures at each Rayleigh number (Ra). The Ra = 103 and 104 form the four modes of the flow structures. These modes are classified by mainly the large circulation and inner vortices. When Ra = 105, one mode that existed at Ra = 103 and 104, disappears in the map of the flow structures. The new three modes appear, resulting in total six modes of flow structures at Ra = 105. New modes at Ra = 105 are characterized by the top side secondary vortices. The corresponding isotherms are presented to explain the bifurcation of the flow structure.

show abstract

“…The spacing between the cylinders gives rise to a greater Nusselt number in cases of aiding and opposing buoyancy, but in the case of forced convection, the Nusselt number is higher at tight spacings. Cho et al [39] analyzed the two-dimensional natural convection in a square enclosure with different arrays of two cylinders at Rayleigh number Ra = 10 3 -10 6 . Flow and thermal patterns are represented for different arrangements of cylinders and for varied spacing between the cylinders.…”

Section: Introductionmentioning

confidence: 99%

“…In summary, it is clear that there is a considerable amount of work [1,4,[33][34][35][36][37][38][39][40] which has been done to find the flow characteristics of Newtonian fluid flow across arrays of cylinders subjected to different range of conditions; along with this there has been a development in finding the thermal characteristics of the flow, although most of the studies which depict thermal characteristics have only been analyzed for low values of Prandtl number. Many investigations [1, 12-20, 24-27, 29, 31, 33-35] have been done on laminar viscous flow past periodic arrays of cylinders.…”

Section: Introductionmentioning

confidence: 99%

Analysis of laminar flow across a triangular periodic array of heated cylinders

Asif

Dhiman

2018

J Braz. Soc. Mech. Sci. Eng.

View full text Add to dashboard Cite

The laminar flow and heat transfer across a triangular periodic array of heated cylinders are simulated computationally and analyzed. The study has been carried out at Reynolds number 10-100 for fluid volume fraction ranging from 0.7 to 0.99 and Prandtl number ranging from 0.7 to 50. The size of the wake region increases continuously with an increase in the Reynolds number for all values of fluid volume fraction. The recirculation bubble from the rear of a cylinder is reaching the front of the next cylinder in the same column of the periodic array for low values of free volume fraction, but this is not the case with the highest free volume fraction, i.e., 0.99. At high Reynolds number, the flow is separating early on the cylinder surfaces. The wake size at higher Reynolds number 75 and 100 for the lowest free volume fraction 0.7 is more in comparison with the wake size at free volume fraction 0.99, which is explained by plotting the location of flow separation against Reynolds number for both the extreme values of free volume fractions, i.e., 0.7 and 0.99. The isovorticity contours are concentrated in the vicinity of the cylinders on increasing the Reynolds number irrespective of free volume fraction and then convected downstream. On increasing free volume fraction, the friction and pressure drags in the array decrease. The increase in Reynolds number also results in the decrease in the values of the individual (friction and pressure drag coefficients) as well as total drag coefficients for all values of free volume fraction. At high values of Reynolds number, the emergence of carbuncle or thermal spike on isotherm near the cylinder's surface is observed where the value of the local Nusselt number is observed low. The heat transfer improves and the Nusselt number increases as the Reynolds number and/ or Prandtl number increases. On the contrary, heat transfer decreases as free volume fraction increases.

show abstract

The effect of instability flow for two-dimensional natural convection in a square enclosure with different arrays of two inner cylinders

Cited by 24 publications

References 28 publications

Natural convection coupled to surface radiation in an air‐filled square cavity containing two heat‐generating bodies

Natural convection coupled to surface radiation in an air‐filled square cavity containing two heat‐generating bodies

Classification of Flow Modes for Natural Convection in a Square Enclosure with an Eccentric Circular Cylinder

Analysis of laminar flow across a triangular periodic array of heated cylinders

Contact Info

Product

Resources

About