Heat Transfer and of Flow Structure of a Turbine Blade's Air-cooled Leading Edge Considering Different Hole Shapes and Additional Flow Angles

A numerical study is conducted to elucidate the impact of hole shapes and additional flow angles on the flow structure of the coolant and temperature field in the leading edge area of the gas turbine rotor. Four typical hole shapes are considered for the GE-E3 blade. The impact of the additional flow angle (E) within each hole shape on the temperature field is investigated. The results indicate that for the leading edge area and suction surface, the fan-shaped hole case performs best in decreasing temperatures, with a decrease of about 43K. This is mainly due to the fact that the fan-shaped hole has the maximum expansion in hole spanwise direction. For the pressure surface, the console hole case performs best in decreasing temperatures, with a maximum reduction of about 47.2 K. The influence of E on the surface temperature at leading edge area varied between the different hole shapes. For the cylinder hole and console hole, the E= -20 degrees case has the lowest area-averaged temperature. Because both the fan-shaped hole and the 7-7-7 shaped hole are expansion holes, the pattern of variation of the leading edge area temperature with increasing E is similar for the fan-shaped hole case and 7-7-7 shaped hole case. The E=20 degrees case shows the lowest spanwise-averaged temperature near the hole outlet, and the E= -20 degrees case shows the lowest spanwise-averaged temperature further downstream.