Investigation on the influence of the film hole diameters on the cooling performance of the film and vortex composite cooling under rotating conditions

Abstract

This article numerically explores the effects of the film hole diameter on the performance of the film and vortex composite cooling. The vortex cooling structure is set in the leading edge of a GE E3 airfoil, connecting with the mainstream flow by the film holes and the blade material to achieve mass transfer and heat transfer, respectively. Five cooling structures with the film diameter d equal to 0.12 mm, 0.20 mm, 0.28 mm, 0.36 mm, and 0.44 mm are involved. Simulations are carried out under the rotating speed of 0 rpm, 1000 rpm, 2000 rpm, 2500 rpm, and 3000 rpm for all structures. The dimensionless temperature θ of the blade leading edge surface is defined to evaluate the cooling performance. The higher θ represents the lower temperature. Results show the different rotational effects on the different structures. First, the value of θ increases with the increasing film hole diameter under the same rotating speed. The value of θ in the case of 0.44 mm is around 5 times that in the case of 0.12 mm. Second, the peak value of θ is observed under the rotating speed higher than 2500 rpm when d is lower than 0.28 mm. While the peak value of θ is observed under 1000 rpm when d is higher or equal to 0.28 mm. The peak value of θ represents an increase of 11.23% and 2.76%, as compared to the lowest value of θ when d is equal to 0.12 mm and 0.44 mm, respectively. Because the dominating cooling methods are different in the cases with different film hole diameters.

Keywords:

• Conjugate heat transfer
• film cooling
• gas turbine
• vortex cooling

Additional information

Funding

This work was supported by the National Science and Technology Major Project under Grant [2017-I-0009-0010].