Rectangular enclosures horizontal

The above discussion was concerned with enclosures in which the heated and cooled walls were at aft angle to the horizontal. In the present section, the concern is with rectangular enclosures in which the hot and cold walls are horizontal and in which the hot wall is at the bottom, see [68] to [83]. The flow situation being considered is therefore as shown in Fig. 8.32. 

Mass How Rate ttirougn ttie Space beLV, een Plates 519 9-5 Natural Convection Inside Enclosures 521 effective Thermal Conductivity 522 Horizontal Rectangular Enclosures 523 Inclined Rectangular Enclosures 523 Vertical Rectangular Enclosures 524 Concentric Cylinders 524 Concentric Spheres 525 Combined Natural Convection and Radiation 525... 

Enclosures arc frequently encountered in practice, and heal transfer through them is of practical interest. Heat transfer in enclosed spaces is complicated by the fact that the fluid in the enclosure, in general, does not remain stationary. In a vertical enclosure, the fluid adjacent to the hotter surface rises and the fluid adjacent to the cooler one falls, setting off a rolationary motion within the enclosure that enhances heat transfer through the enclo.surc. Typical flow patterns in vertical and horizontal rectangular enclosures are shown in Figs. 9-21 and 9-22. 

In a horizontal rectangular enclosure with the hotter plate at tlie top. heat transfer is by pure conduction and Nu = 1, When the hotter plate is at the bottom, the Niisselt niltnber is... 

Let us now analyze the more complex shielding application of Figure 7.12(a), which illustrates a rectangular enclosure partitioned by two equal horizontal PEC walls. In the front plane, there is a centered (20 x 5) cm horizontal aperture. The dimensions are a = b = 60 cm, d = 120 cm, / = 70 cm, w = 2 cm, and the excitation is launched by a vertical coaxially fed monopole. Due to the nonstandard operators of (3.43), the domain is discretized into the coarse grid of30 x 60 x 30 cells with Ax = Ay = Az = 2 cm and At = 30.567 ps. In the area of the aperture, spatial derivatives are computed by the fictitious-point technique of Section 2.4.5, whereas the DRP schemes of Section 2.5.3 are also utilized. Figure 7.12(b) displays the shielding efficiency defined as the ratio of the electric field amplitude evaluated in front of... 

Hideo, I. Yanlai, Z. Akihiko, H. Naoto, H. Numerical simulation of natural convection of latent heat phase-change-material microcapsulate slurry packed in a horizontal rectangular enclosure heated from below and cooled from above. Heat Mass Transfer 43 (2007) 459-470. 

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