Effect of Multi-hole Configuration on Film Cooling Effectiveness

A numerical study is performed to investigate the effects of shaped multi-hole on film cooling effectiveness over a flat plate. Hence a single cylindrical film cooling hole with 11.1 mm diameter is replaced with the shaped multi-hole (14 holes with 2.97 mm diameter) while maintaining constant blowing ratio. Numerical simulations are performed at a fixed density ratio of 1.6, length-to-diameter of 4 and an inclined angle of 35o. Two configurations of hook and fan shapes are considered for multihole. The control-volume method with a semi-implicit method for pressure linked equations-consistent algorithm has been used to solve the steady-state Reynolds-averaged Navier–Stokes equations. The k-ε model is applied for modeling the turbulent flow and heat transfer field. It is found that replacing a single hole with the shaped multi-hole leads to a considerable increase in the film cooling effectiveness in both axial and lateral directions. Results of the present study show that for blowing ratio of 0.6, the hook shape and fan shape configurations of multi-hole, provide a higher area-averaged film cooling effectiveness by 48% and 58.2% more than the single hole respectively.