EXPERIMENTAL INVESTIGATION OF SWEEPING JET FILM COOLING IN A TRANSONIC TURBINE CASCADE

The sweeping jet (SJ) film cooling hole has shown promising cooling performance compared to the standard shaped hole in low-speed conditions. The present work demonstrates the first attempt of sweeping jet film cooling at an engine relevant Mach umber. An experimental investigation was conducted to study the sweeping jet film cooling on a nozzle guide vane suction surface. well-established additive manufacturing technique commonly own as Stereolithography (SLA) was unitized to design a transonic, engine representative vane geometry in which a row of holes was used on the vane suction surface. Experiments were performed in a linear transonic cascade at an exit Mach number 0.8 and blowing ratios of BR = 0.25-2.23. The measurement of eat transfer was conducted with the transient IR method and the convective heat transfer coefficient (HTC) and adiabatic film cooling effectiveness were estimated using a dual linear regression technique (DLRT). Aerodynamic loss measurements ere also performed with a total pressure Kiel probe at 0.25C(ax) downstream of the exit plane of the vane cascade. Experiments ere also conducted for a baseline shaped hole (777-hole) for a direct comparison. Results showed that the SJ hole has a wider coolant spreading in the lateral direction near the hole exit due 7 its sweeping action that improves the overall cooling performance particularly at high blowing ratios (BR>1). Aerodynamic loss measurement suggested that the SJ hole has a comparable total pressure loss to the 777-shaped hole.