Numerical study on heat transfer performance of a new-proposed pin-fin in an internal channel

This paper numerically investigated the flow and heat transfer characteristics in a rectangular channel with pin-fin arrays. The channel simulates a wide aspect ratio (W/E=3) internal cooling passage of gas turbine blade. The pin-fin applied in the simulation is a new-proposed geometry which consists of a cylinder body with a fixed ratio of diameter to channel height, D₀/E=1/4, and a rounded tip. Each case corresponds to a specific pin-fin array geometry of detachment spacing C between the pin-tip and endwall. In the rig studied, 18 rows of pin-fins are in staggered arrangement along the streamwise direction. The investigation on pin-fin performance has been made mainly into two aspects. One is the effect of diameter of the rounded tip Dh on heat transfer performance and pressure loss in the system, while the other is the effect of detachment C. All the cases have been performed with the range of the Reynolds numbers from 15, 000 to 25, 000. The SST k - w turbulence model is employed for all the computational analysis. Results reveal that the presence of rounded-tip pin-fin with a detachment effectively promotes the wall-flow interactions and enhances heat transfer on endwalls. The rounded tip diameter has a slight effect on heat transfer and pressure drop in the channel. In the study range, relatively higher detachment promotes higher heat transfer coefficient. In general, the new-proposed pin-fin geometry induces greater heat transfer enhancement and yields relatively lower pressure drop.