Conjugate heat transfer simulations of pulsed film cooling on an entire turbine vane

- Pulsed film cooling effects on leading edge, pressure side and suction side are compared.
- Pulsed film cooling with high blowing ratios on suction side deteriorates heat transfer.
- Pulsed film cooling with high blowing ratios on pressure side improves heat transfer.
- The effects of pulsing frequency on pressure side and suction side are opposite.

This paper presents a numerical investigation on pulsed film cooling using conjugate heat transfer with an entire NASA C3X vane model, which has nine rows of film hole: five in leading edge region, two at suction side and two at pressure side. Square and sinusoidal waves are considered to pulse the cooling air. The normalized Nusselt number distributions over the vane surface are calculated and discussed at three blowing ratios (BR = 0.78, 1.17 and 1.56) and four Strouhal numbers (St = 0.0029, 0.0058, 0.0116 and 0.0232). Based on the entire turbine vane and conjugate heat transfer algorithm, the present simulations exhibit three interesting phenomena: (1) At suction side, normalized Nusselt number increases with BR for pulsed flow, indicating pulsing film cooling with high BRs should not be used. (2) At pressure side, when BR increases, normalized Nusselt number of the pulsed flow becomes smaller than that of the steady flow, indicating pulsed film cooling with high BRs is more suitable. (3) In leading edge region, normalized Nusselt number decreases with an increasing of Strouhal number from 0.0029 to 0.0116, but then increases at St = 0.0232 for both pulsed flow types. This phenomenon indicates the importance of choosing an appropriate pulsing frequency.