Experimental investigation of the effects of orientation angle on heat transfer performance of pin-finned surfaces in natural convection

Natural convection heat transfer in air from a pin-finned surface is investigated experimentally by considering the effect of radiation heat transfer. The plate was oriented as the pin arrays facing either downwards or upwards from vertical axis with different angles and the experiments were performed for different values of heater power input. From the results of the experiments it is observed that the pin fins increase the heat transfer considerably when compared to the unpinned surface. The upfacing pins are more enhancing heat transfer than the downfacing pins and the enhancement is decreasing with increasing orientation angle from the vertical axis.

Research highlights
► Effect of orientation in free convection heat transfer from a pin-finned surface.
► The upfacing pins are more enhancing heat transfer than the downfacing pins.
► Radiation view factor is calculated by a modular analysis.
► The radiation is comparable to free convection as not to be neglected.
► The radiative part is 25–40% and increases for low heat transfer rates.