Effects of Rotation at Different Channel Orientations on the Flow Field inside a Trailing Edge Internal Cooling Channel

Matteo Pascotto,Pietro Giannattasio,Alessandro Armellini,Claudio Mucignat,Luca Casarsa

doi:10.1155/2013/765142

Matteo Pascotto, Pietro Giannattasio + Show 3 more

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https://doi.org/10.1155/2013/765142

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Abstract

The flow field inside a cooling channel for the trailing edge of gas turbine blades has been numerically investigated with the aim to highlight the effects of channel rotation and orientation. A commercial 3D RANS solver including a SST turbulence model has been used to compute the isothermal steady air flow inside both static and rotating passages. Simulations were performed at a Reynolds number equal to 20000, a rotation number (Ro) of 0, 0.23, and 0.46, and channel orientations ofγ=0∘, 22.5°, and 45°, extending previous results towards new engine-like working conditions. The numerical results have been carefully validated against experimental data obtained by the same authors for conditionsγ=0∘and Ro = 0, 0.23. Rotation effects are shown to alter significantly the flow field inside both inlet and trailing edge regions. These effects are attenuated by an increase of the channel orientation fromγ=0∘to 45°.

Highlights

It is a matter of fact that the adoption of proper cooling techniques is a key factor in the development of high performance and reliable gas turbine engines, since the hot gas temperature can be far above the melting point of the material used to manufacture the engine components
According to the analysis proposed in Armellini et al [28], the velocity uncertainty must be increased by 1% of Ub for the data acquired under rotation
The slight flow imbalance towards the trailing edge (TE) side of the channel (y < 0) because of the blockage effect of the redirecting wall at the leading edge is well captured for rotation number (Ro) = 0 (Figure 4(a)), as well as the strong flow imbalance towards the leading edge side (y > 0) for Ro = 0.23 (Figure 4(c))

Summary

Introduction

It is a matter of fact that the adoption of proper cooling techniques is a key factor in the development of high performance and reliable gas turbine engines, since the hot gas temperature can be far above the melting point of the material used to manufacture the engine components. Focusing the attention on the internal cooling of gas turbine blades, the experimental research conducted on laboratory scaled models has played a great role in the engines development, while more recently, the availability of powerful computational tools has allowed a deeper insight into the performance of cooling channels characterized by various cross-section shapes (squared, rectangular, and triangular) and layouts (single pass, double pass). In this regard, significant examples concerning the simulation of cooling channels for nozzle blades, in static conditions, are represented by the works of Ooi et al [1], Lohasz et al [2], Luo et al [3], Viswanathan and Tafti [4], and Spring et al [5]. When the blade thickness is reduced further on, cutting material from the TE region (cut-back) can be a solution to ensure the thermal protection of thin TEs by a shield of coolant

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