Multi-field coupling analysis on the film-cooling with transverse and arched trenches

Abstract

In this study, the properties of the flat-plate film-cooling with transverse and arched trenches are investigated. The conjugate temperature field and thermal stress field were both predicted by the multi-field coupling method. In addition, the transverse trench configuration was investigated and compared as the benchmark case. The results show that the blockage effect formed by the arched trench is helpful to improve the coolant lateral coverage and thus the cooling performance. Meanwhile, the thermal stress concentration may be stronger due to the higher temperature gradient for the arched trench configuration. The distance between the downstream trench edges and the holes is of great importance to the cooling performance. The closer this distance, the more conductive to the blockage effect and the lateral coverage, which is helpful to improve the cooling performance. The distance between the upstream trench edges and the holes shows less impact on the cooling performance. Compared with the non-trench film cooling, the trenched models can form higher temperature gradient, so the thermal expansion near the film hole is more different from that in other region, which tend to form stronger stress concentration near the film hole. Compared with the transverse trench, the arched trench can deliver the coolant jet from the center line to the lateral side, which is helpful to form laterally coverage in the downstream region, especially under the higher blowing ratio. So the arched trench can form lower temperature gradient and relative uniform thermal expansion, which is helpful to decrease the stress concentration around the cooling hole.

Keywords

• film-cooling
• flat-plate
• trench
• multi-field coupling (mfc)
• thermal-stress