Natural convection heat transfer within multi-layer domes

Abstract

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1016/S0017-9310(00)00195-2International Journal of Heat and Mass Transfer, 44, 10, pp. 1973-1981, 2001 Natural convection heat transfer within multi-layer domes Laouadi, A.; Atif, M. R. Natural convection heat transfer within multilayer domes Laouadi, A.; Atif, M. R.A version of this paper is published in / Une version de ce document se trouve dans : International Journal of Heat and Mass Transfer, v. 44, no. 10, May 2001, pp. 1973-1981 www.nrc.ca/irc/ircpubs on natural convection heat transfer within these layers. This information is required for the evaluation of the dome thermal performance (e.g., the U-factor). NRCC-43954 Natural Convection Heat Transfer within Multi-layer DomesThis paper presents a numerical study on heat transfer by laminar natural convection within multi-layer domes with uniform spacing heated from the outside. The flow and temperature fields within the domed enclosure were obtained using the control volume approach combined with the fully implicit scheme. Correlations for the heat transfer as a function of the dome shape and the gap spacing between the layers were developed under steady state conditions. The results showed that the convection heat transfer for fully hemispheric domes (half of spheres) may reach more than 13% higher than that for low profile domes (hemispherical caps) for small gap spacings (gap spacingto-radius ratio δ < 0.1) and more than 100% for large gap spacings (δ > 0.3). The critical gap spacing that yields the maximum heat transfer was quantified for each dome shape.2

A three‐dimensional Cartesian cut cell method for incompressible viscous flow with irregular domains

“…The values of N u i , N u o and N u ave .N u ave D .N u i C N u o /=2/ obtained by the present simulations, together with the N u values for the same Ra reported by Garg [25] and Laouadi and Atif [26] and the N u values obtained by Equation (57), are listed in Table IV. The N u values obtained by Garg [25] and Laouadi and Atif [26] correspond well with those obtained in the present simulations, To analyze the flow pattern versus Ra number, the three-dimensional temperature fields (a quarter of the concentric spheres are removed to illustrate the interior temperature) and streamlines in the cross-section of the computation domain on the y-´plane for Ra=420, 10,500, and 250,000 are shown in Figures 12 and 13, respectively. The natural convection for Ra=420 is extremely weak and the heat transfer is dominated by pure conduction.…”

“…The values of Nu i , Nu o and obtained by the present simulations, together with the Nu values for the same Ra reported by Garg and Laouadi and Atif and the Nu values obtained by Equation , are listed in Table . The Nu values obtained by Garg and Laouadi and Atif correspond well with those obtained in the present simulations, with a maximum relative error of 3.1%. Equation tends to underestimate the Nu values, with a maximum error of 13.77% with respect to the Nu values of the present simulations.…”

“…Natural convection between two isothermal concentric spheres (a heated inner sphere and a cooled outer sphere, as shown in Figure ) in the enclosed annulus is of vital importance in various applications such as nuclear reactor design, aircraft cabin insulation, cooling of electronic equipment and thermal storage systems. Various numerical and experimental studies on natural convection between concentric spheres have been presented . Spherical coordinate‐based body‐fitted grids have been used to decompose the computational domain in most reported numerical simulations.…”

Thermal blob convection in spherical shells

“…We would expect therefore that some type of convectively driven flow will be established, acting to transport heat from the outer sphere to the inner. This simple system is thus well suited to studying natural convection and heat transfer, with many of the key results directly transferable to engineering and industrial applications [1][2][3].…”

Natural Convection Heat Transfer between Two Concentric and Eccentric Oblate Hemi Spheroids with Different Elliptical Ratios (Dept.M)

“…delivered general Nu -R" correlations. A aumencal siudy on the herll tfllllsfer by laminar natural eonvcctlon within multi-layer domes with unifonn spacing heated from the outside was done by (6]. The flow and tmlper1Iture fields .... Ithin the domed enclosure were obailled Correlations ror the heat ITIl/1S ret as a function of the dome shape: and gap SPicing among the layers were developed.…”