Effect of various pin-fin diameters on cooling performance of turbine blade internal passage

The effect of different diameters of pin-fin array was analyzed to control the cooling performance of internal passage of the gas turbine. Numerical simulations were conducted to determine the flow and thermal characteristics of two different diameter of pin-fin array effect. A staggered pin-fin array with same pin-fin diameter, 1.2x pin-fin array with 20% large pin-fin diameter at the bottom 2 array, and 1.4x pin-fin array with 40% large pin-fin diameter at the bottom 2 array were compared. The results showed that higher velocity was observed in large pin-fin array cases and different local heat transfer distributions were observed near large pin-fin arrays. Furthermore, the heat transfer distributions on the endwall increased. The friction factor increased owing to the installation of larger pin-fin, and thermal performance factor was increased to 0.4% in 1.2x pin-fin array. Therefore, installation of larger diameter pin-fin will be helpful in controlling the cooling performance of pin-fin array internal passage of gas turbine blades.