Modeling natural convection heat transfer from perforated plates

Staggered pattern perforations are introduced to isolated isothermal plates, vertical parallel isothermal plates, and vertical rectangular isothermal fins under natural convection conditions. The performance of perforations was evaluated theoretically based on existing correlations by considering effects of ratios of open area, inclined angles, and other geometric parameters. It was found that staggered pattern perforations can increase the total heat transfer rate for isolated isothermal plates and vertical parallel plates, with low ratios of plate height to wall-to-wall spacing (H/s), by a factor of 1.07 to 1.21, while only by a factor of 1.03 to 1.07 for vertical rectangular isothermal fins, and the magnitude of enhancement is proportional to the ratio of open area. However, staggered pattern perforations are detrimental to heat transfer enhancement of vertical parallel plates with large H/s ratios.