Nusselt number for the natural convection and surface thermal radiation in a square tilted open cavity

Hinojosa, J.; Cabanillas, R.E.; Álvarez, G.; Estrada, C.E.

doi:10.1016/j.icheatmasstransfer.2005.05.007

Cited by 78 publications

(25 citation statements)

References 24 publications

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“…Hinojosa et al [15] conducted a numerical analysis of both natural convection and radiation heat transfer in a titled 2D open cavity. They observed that cavity receiver inclination angle significantly influences the convective Nusselt number and not the radiation Nusselt number.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional analysis and numerical optimization of combined natural convection and radiation heat loss in solar cavity receiver with plate fins insert

Ngo

Bello‐Ochende

Meyer

2015

Energy Conversion and Management

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The numerical study and optimization of combined laminar natural convection and surface radiation heat transfer in solar cavity receiver with plate fins is presented in this paper. Minimizing heat loss in cavity receivers is seen as an effective way to enhance the thermal performance and the use of plate fins has been proposed as a low cost means to minimize heat loss. Firstly, the influence of operating temperature, emissivity of the surface, orientation and the geometric parameters on the total heat loss from the receiver was investigated. It was observed that convective heat loss is largely affected by the angle of inclination of the receiver, the presence of fins and the number of fins in the receiver. As for the radiation heat loss it was observed that it is mainly influenced by the properties of the cavity receiver surface. The radiation heat loss was found to be constant at all the angles of the receiver. Significant reduction in natural convection heat loss from the cavity receiver was accomplished by using the plate fins whereas radiation heat loss was marginally reduced by about 5%. Secondly, the optimization was conducted to obtain the optimal fin geometry and lastly, the overall thermal efficiency of the receiver was presented at different operating temperatures. The overall cavity efficiency marginally increased by approximately 2% with the insertion of fin plates although the convective heat loss was suppressed by about 20%. This is due to the fact that radiation heat loss dominates at high operating temperatures compared to convective heat loss.

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Section: Introductionmentioning

confidence: 99%

Three-dimensional analysis and numerical optimization of combined natural convection and radiation heat loss in solar cavity receiver with plate fins insert

Ngo

Bello‐Ochende

Meyer

2015

Energy Conversion and Management

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“…Sequential determination of flow field followed by the thermal field (a) Collision step (Eqs. (32) and (33)). …”

Section: Numerical Algorithmmentioning

confidence: 94%

“…The numerical investigation of laminar natural convection (10 3 ≤Ra≤10 6 ) in shallow rectangular cavity (1≤AR≤0.125) has also been carried out by Polat and Bilgen [31]. Similarly, Hinojosa et al [32] have numerically elucidated the effect of Rayleigh number (10 4 ≤Ra≤10 7 ) on the natural convective heat transfer and surface thermal radiation in a tilted (0 o ≤φ≤180 o ) open ended square cavity. They reported substantial change in the convective Nusselt number with the inclination angle, however, radiative Nusselt number shown negligible dependence on the inclination angle.…”

Section: Introductionmentioning

confidence: 99%

Lattice Boltzmann analysis of effect of heating location and Rayleigh number on natural convection in partially heated open ended cavity

Gangawane

Bharti

Kumar

2015

Korean J. Chem. Eng.

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Natural convection characteristics of a partially heated open ended square cavity have been investigated numerically by using an in-house computational flow solver based on the passive scalar thermal lattice Boltzmann method (PS-TLBM) with D2Q9 (two-dimensional and nine-velocity link) lattice model. The partial part of left wall of the cavity is heated isothermally at either of the three different (bottom, middle and top) locations for the fixed heating length as half of characteristic length (H/2) while the right wall is open to the ambient conditions. The other parts of the cavity are thermally isolated. In particular, the influences of partial heating locations and Rayleigh number (10 3 ≤ Ra≤10 6 ) in the laminar zone on the local and global natural convection characteristics (such as streamline, vorticity and isotherm contours; centerline variations of velocity and temperature; and local and average Nusselt numbers) have been presented and discussed for the fixed value of the Prandtl number (Pr=0.71). The streamline patterns show qualitatively similar nature for all the three heating cases and Rayleigh numbers, except the change in the recirculation zone which is found to be largest for middle heating case. Isotherm patterns are shifted towards a partially heated wall on increasing Rayleigh number and/or shifting of heating location from bottom to top. Both the local and average Nusselt numbers, as anticipated, shown proportional increase with Rayleigh number. The cavity with middle heating location shown higher heat transfer rate than that for the top and bottom heating cases. Finally, the functional dependence of the average Nusselt number on flow governing parameters is also presented as a closure relationship for the best possible utilization in engineering practices and design.

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“…The solution of elliptic partial differential equations of natural convection flow in open cavities is found to be highly sensitive to the boundary conditions at the entry and exit [11][12][13][14][15][16][17]. In the present work, the derivative of tangential velocity is set at zero and the longitudinal velocity is obtained by the mass balance at the boundary cells [12].…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…Thinking essentially of actual engineering applications, such as food and grain storage, building construction elements, internal fluid motion could interact with ambient environment through openings or infiltrations, i.e., partial enclosures. In past decades, single component natural convection in partial enclosures has been investigated broadly, including inclination, port size, heating boundary conditions, fluid properties, coupling with radiation, etc [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Combined heat and moisture convective transport in a partial enclosure with multiple free ports

Tang¹,

Liu²,

Zhao³

et al. 2010

Applied Thermal Engineering

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a b s t r a c tCombined heat and moisture transport in an enclosure with free ports has been investigated numerically. Enclosed moist air interacts with the surrounding air through these free-vented ports. The governing conservation equations were solved numerically using a control volume-based finite difference technique. Appropriate velocity boundary conditions at each ports are imposed to achieve overall mass conservation across this system. Air, heat and moisture transport structures are visualized respectively by streamlines, heatlines and masslines. Effects of buoyancy ratio, thermal Rayleigh number on convective heat/moisture transfer rate and flow rate across each free-vented port are discussed. Particularly, Numerical results demonstrate that the convective heat and moisture transport patterns and transport rates on horizontal ports greatly depend on properties of porous medium, while the air exchange rate on vertical port is almost unaffected by the buoyancy ratios for most situations.

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Nusselt number for the natural convection and surface thermal radiation in a square tilted open cavity

Cited by 78 publications

References 24 publications

Three-dimensional analysis and numerical optimization of combined natural convection and radiation heat loss in solar cavity receiver with plate fins insert

Three-dimensional analysis and numerical optimization of combined natural convection and radiation heat loss in solar cavity receiver with plate fins insert

Lattice Boltzmann analysis of effect of heating location and Rayleigh number on natural convection in partially heated open ended cavity

Combined heat and moisture convective transport in a partial enclosure with multiple free ports

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