Experimental-Based Correlations for the Characterization of Free Convection of Air Inside Isosceles Triangular Cavities With Variable Apex Angles

Abstract

The archival literature contains an abundance of correlations for the characterization of laminar-free convection in rectangular, square, and annular cavities, but unfortunately does not disclose a single correlation for triangular cavities. A prominent application of triangular cavities specialized to isosceles shapes arises in air-filled attic spaces of houses and buildings with sloped roofs and horizontal suspended ceilings. In this work, two contrasting situations are considered embodying three apex angles and several Grashof numbers: a hot base and symmetrically cold inclined sides for winter conditions, and a cold base and symmetrically hot inclined sides for summer conditions. The goal of this article is to construct two dependable correlations, one for the mean convective coefficient at the air/wall interface, and the other for the temperature variation of the ascending air along the center plane of attic spaces. The input data was taken from precise measurements available in the specialized literature.

Experimental and numerical analysis of buoyancy-induced flow in inclined triangular enclosures

“…Flack [7] obtained laser velocimetry data and theoretically predicted the velocities of flow field in a triangular enclosure that had previously been studied to elucidate heat transfer correlation. Then, experimentalbased correlations for the characterization of free convection of air in isosceles triangular enclosures with different apex angles are studied by Ridouane and Campo [8]. They obtained a correlation for Nusselt number as a function of Grashof number and aspect ratio.…”

Suppression of natural convection heat transfer coefficients in an attic shaped enclosure

“…In the authors' previous study [1] it was noted that a correlation developed by Ridouane and Campo' [2] to describe natural convection in attic style enclosures for Grashof Numbers in the range 2.9 x 10 6 to 9 x 10 6 was also valid for Grashof Numbers in the range of 10 7 to 10 9 . This served to validate the proposition of Anderson et al [9,10] that natural convection in the attic of a cold roof building could serve as an insulating medium for roof integrated solar collectors installed in a cold roof building.…”

Numerical analysis of natural convection in a prismatic enclosure

“…The main conclusion drawn in this paper was that, for identical isosceles triangular cavities engaging symmetrical and non-symmetrical assumptions, the differences in terms of mean Nusselt number were about 5%. Ridouane et al [6] generated experimental-based correlations for the reliable characterization of the center plane temperature and the mean convective coefficient in isosceles triangular cavities filled with air. The experimental data was gathered from various sources for various aspect ratios and Grashof numbers.…”