Study on effects of inlet nonuniformities on aerothermal performance of NGV pressure side with different film cooling designs

Abstract

High pressure (HP) turbine works under nonuniform inlet conditions produced mainly by modern lean burn combustors. This article employed the conjugate heat transfer method to investigate the influences of nonuniform inflow conditions and film hole arrangements on the film coolant coverage and heat transfer characteristics. The researched region is on the pressure side (PS) of the nozzle guiding vane (NGV). A scaled-up model of the GE-E3 engine HP turbine stator vane was used and the film cooling performances of four different film hole arrangement schemes on the PS were discussed. In addition, the results of four nonuniform inflow conditions, including positive/negative swirl aligned with the stator vane leading edge (case PSW-LE and NSW-LE), and positive/negative swirl aligned with the stator vane mid passage (case PSW-PA and NSW-PA), were compared with the uniform inlet condition. The results indicate that the temperature distributions of stator vane PS are dominated by the film hole arrangements and the nonuniform inlet conditions. In the positive swirl (PSW) influenced region, film cooling effectiveness can be improved if the coolant orientation is consistent with the swirl direction. The film cooling effectiveness can be improved by 12%–20% under the Leading Edge (LE) clocking position and 45% under the Passage (PA) clocking position. In contrast, the negative swirl dominates the film cooling effectiveness distribution. Under the PA clocking position, the highest film cooling effectiveness can be enhanced by 45% compared with the LE. In contrast, the design of film holes has a weak contribution to the coolant outflow direction under the negative swirl (NSW) condition. However, the film holes with negative angles can enhance the cooling effectiveness behind the 13th row holes.