Application and Design of Multi-Impingement Cooling Channel in Turbine Blade Trail Edge

The numerical simulations are used to conduct the comparative study of pin-fins cooling channel and multi-impingement cooling channel on the heat transfer and flow, and to design the multi-impingement channel through the parameters of impinging distance and impingement-jet-plate thickness. The Reynolds number ranges from 1e4 to 6e4. The dimensionless impinging distance is 0.60, 1.68, 2.76, respectively, and the dimensionless impinging-jet-thickness is 0.5, 1.0, 1.5, respectively. The endwall surface, pin-fins surface, impinging-jet-plate surface are the three object surfaces to investigate the channel heat transfer performance. The heat transfer coefficient $h$ and augmentation factor $Nu/N{u_0}$ are selected to measure the surface heat transfer, and the friction coefficient $f$ is chosen to evaluate the channel flow characteristics. The impinging-jet-plate surface owns higher heat transfer coefficient and larger area than pin-fins surface, which are the main reasons to improve the heat transfer performance of multi-impingement cooling channel. Reducing the impinging distance can improve the endwall surface heat transfer obviously and enhance impingement plate surface heat transfer to some extent, decreasing the thickness of impinging-jet-plate can significantly increase its own heat transfer coefficient, which both all increase the cooling air flow loss.