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A. Baïri E. Zarco-Pernia J.-M. García de María J.-G. Bauzin N. Alilat N. Laraqi F. Gutiérrez 《Heat and Mass Transfer》2011,47(5):589-595
In the present study Nu-Ra-α correlations are proposed to calculate the steady-state natural convection heat transfer taking place in 2D air-filled cavities
of parallelogrammic section. The thermal conditions and the dimensions of the enclosures permit to cover a large range of
Rayleigh numbers, 1.7 × 103 ≤ Ra ≤ 3.0 × 109, suitable for diverse engineering applications. The two active walls of the cavities are kept vertical and isothermal at
hot and cold temperatures T
h
and T
c
respectively. Separated by a horizontal distance H, they have the same height H and are connected by a closed adiabatic channel whose upper and lower walls can be inclined at an angle α with respect to the horizontal, varying between −60° to +60°. That gives rise to a conducting or insulating cavity, in the
convective sense of the term (diode cavity). A computational model based on the finite volume method is used to solve the
governing equations. The large number of treated configurations led to propose Nu-Ra-α correlations for large ranges of Ra and α which can be applied to many engineering areas. The results of this numerical study have been successfully compared with
calculated and measured available data. 相似文献
2.
In this work, we analyse the influence of the sample shape on the experimental determination of the thermal diffusivity of
materials used in several engineering fields. By means of a simple method we obtain good estimations of the overall thermal
diffusivity for homogeneous or inhomogeneous materials. The method is based on the combination of simple temperature measurements
with the analytical solution of the 3D differential Fourier’s equation applied to cartesian geometry. The classical transient
analytical solution based on the separation of space and time variables is adapted to particular thermal boundary conditions.
By associating these solutions with the measurements obtained on a simple experimental bench, the thermal characterization
of materials can be achieved with a satisfactory precision. The present 3D study attempts to complete previous works dealing
with cartesian and cylindrical 1D and 2D models. Based on the same procedure, it sheds further light on the fast multidimensional
surface phenomena of heat exchange. Although we conclude that the 3D model does not provide the directional values typical
of anisotropic materials, our results revealed that thermal diffusivity can be useful in other respects, being advantageous
in the overall thermal characterization needed for sizing certain systems. 相似文献
3.
Journal of Thermal Analysis and Calorimetry - The present work deals with thermal regulation of a spherical electronic device used in naval navigation techniques. Cooling is achieved by means of... 相似文献
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