Effect of shape and distribution of pin-fins on the flow and heat transfer characteristics in the rectangular cooling channel

Pin-fin arrays play a very important role in heat transfer enhancement for turbine blade trailing edge. To find a configuration with better heat transfer effect and lower flow resistance, the flow and heat transfer characteristics of several rectangular channels with staggered pin-fins of different shapes (circular, elliptic, oblong, teardrop, lancet and NACA) are studied numerically and then the effects of the spanwise and streamwise spacing of the teardrop and NACA pin-fins are investigated and compared with circular pin-fins. Reynolds number varies from 5 × 10³ to 3 × 10⁴. The ratio of streamwise spacing to diameter (X/D) varies from 2.5 to 5, and the ratio of spanwise spacing to diameter (S/D) varies from 2 to 4. It is found that the teardrop and NACA pin-fins are relatively better than the other four pin-fins, and the NACA and teardrop pin-fins at S/D = 3 and X/D = 2.5 have the better flow and heat transfer performance in comparison with circular pin-fins. Moreover, the NACA pin-fins deserve more attentions and work for its potential application in the trailing edge cooling of the actual turbine blades because it is easier to machine based on its reliable profile equation.