The present study investigated experimentally the heat transfer from a heat source simulating an electronic
chip mounted on a printed circuit board placed downstream of a guide fence on the lower wall
of the flow passage with two different aspect ratios (H/W = 0.3 and 1). The channel height to the heat
source height ratios (H/B) are of 10 and 3. The effect of the guide fence height (b) and the spacing between
the guide fence and the heat source (S) were investigated. The guide fence was orientated such that guide
fence extension point was varied from the midpoint of the front face of the heat source to the endpoint of
the side face at 5000 6 ReL 6 30,000. The results for the heat source without guide fence displayed noticeable
difference when compared with the flow over smooth plate placed on the lower wall of the flow passage.
An enhancement in the convective heat transfer coefficient up to 20% is obtained when decreasing
the flow passage height to the heat source height ratio from 10 to 3. Also, higher Nusselt number is
located at the front face and the vertical sides of the heat source compared with that of the top surface.
Nusselt number increases with the increase in both Reynolds number and the guide fence height while
the effect of spacing between the guide fence and the heat source depending on the guide fence height.
Correlations for the average Nusselt number were obtained utilizing the present measurements within
the investigated range of the different parameters.