Experimental and numerical investigation of forced convective characteristics of arrays of channel mounted obstacles

An experimental investigation of the forced convective heat transfer of ind ividual and arrays of multiple two-dimensional obstacles is reported The ai rflow rate was varied from 800 less than or equal to Re-Dh less than or equ al to 13000. The effects upon the Nusselt numbers and obstacle temperature differences of parametric changes in the Reynolds number, channel height, a rray configuration, and input heat flux are established. The input heat flu xes to the obstacles ranged from 950 less than or equal to q(11) less than or equal to 20200 W/m(2), which significantly extends beyond that seen in t he open literature for forced convective air cooling of simulated electroni c components. Comparisons of the obstacle mean Nusselt numbers are,made wit h a two-dimensional laminar numerical model employing the Navier-Stokes equ ations. A set of correlations characterizing the heat transfer from the pro truding heat sources within the channel is obtained. It was found that the obstacle temperature, the critical measure for electronic device failure, m ust be shown along with the corresponding Nusselt number to fully character ize the thermal state of the heated obstacle as the ratio definition of the Nusselt number can obscure large fer,temperature increases. The results fi nd that the proper placement of geometrically dissimilar obstacles, such as a taller obstacle, can be used to passively enhance the heat transfer in i ts vicinity. This effect would be dependent upon the flow rate and geometri es in order to control the reattachment zones and their subsequent convecti ve augmentation. The experimental results are found to be in goon agreement with the results from the numerical simulation. Finally, a set of pertinen t correlations for the arrays of channel mounted obstacles is given.