Natural Convection Heat Transfer Between Bodies and Their Spherical Enclosure

1983 ◽  
Vol 105 (3) ◽  
pp. 440-446 ◽  
Author(s):  
R. E. Powe ◽  
R. O. Warrington

The natural convective heat transfer phenomena which occur between a body and its spherical enclosure have been experimentally investigated. Bodies of several different shapes were employed, so the results should have broad applicability. New temperature field and heat transfer results, in the form of natural convection from cubical inner bodies to a spherical enclosure, have been combined with previously available enclosure data. By considering all of the data combined, trends in the behavior of the convective heat transfer phenomena have been established, thus enabling a much more reliable analysis of enclosed body problems than is now possible. A very general heat transfer correlation has been developed which predicts the natural convection heat transfer from spheres (concentric and eccentric), cylinders, and cubes to a spherical enclosure with an average deviation of less than 12 percent. Although these results are strictly valid only for a spherical outer body, they should give a preliminary indication of expected behavior for other shapes.

1979 ◽  
Vol 101 (4) ◽  
pp. 655-659 ◽  
Author(s):  
B. A. Meyer ◽  
J. W. Mitchell ◽  
M. M. El-Wakil

Local and average heat transfer coefficients for natural convection between parallel plates separated by slats to create enclosures of moderate aspect ratio have been experimentally determined using an interferometric technique. The effects of Rayleigh number, tilt and slat angle, and aspect ratio on the Nusselt number have been determined. The Rayleigh number range tested was up to 7 × 104, and the aspect ratio (ratio of enclosure length to plate spacing) varied between 0.25 and 4. The angles of tilt of the enclosure with respect to the horizontal were 45, 60 and 90 deg. Slat angles of 45, 60, 90 and 135 deg were studied. The results obtained in a previous investigation [1] for aspect ratios of 9 to 36 are included to show continuity. The results indicate that the convective heat transfer is a strong function of the aspect ratio for aspect ratios less than 4. For aspect ratios in the range of 0.5 to 4, spacers between the plates increase, rather than decrease, natural convection heat transfer compared to that for long enclosures. Slat angles less than 90 deg (i.e., oriented downward) reduce convective heat transfer.


2021 ◽  
Author(s):  
L. Di Liddo ◽  
D. Naylor

A numerical and experimental study, in the preliminary stages, has been conducted examining the effect of swirling flow on the natural convective heat transfer rate from a flat, horizontal, heated, upward facing, isothermal circular disk surrounded by insulation.


1981 ◽  
Vol 103 (1) ◽  
pp. 103-107 ◽  
Author(s):  
R. O. Warrington ◽  
Gordon Crupper

Natural convection heat transfer from a fixed array of four isothermal, heated cylinders to an isothermal, cooled cubical enclosure was experimentally investigated for both a horizontal and vertical position of the array. Included in this study are heat transfer, flow visualization, and temperature profile results for Prandtl numbers in the range of .7 to 3.1 × 104 and Rayleigh numbers, based on gap width, in the range of 6.3 × 105 to 6.9 × 108. Several geometric effects were observed. The vertical configuration convected less heat than the horizontal while a rotation about the vertical axis for each of these configurations had negligible effect on the overall heat transfer. The heat transfer results were correlated and compared with previous enclosure results. The heat transfer correlations fit the data with an average deviation of less than 10 percent.


2021 ◽  
Author(s):  
L. Di Liddo ◽  
D. Naylor

A numerical and experimental study, in the preliminary stages, has been conducted examining the effect of swirling flow on the natural convective heat transfer rate from a flat, horizontal, heated, upward facing, isothermal circular disk surrounded by insulation.


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