Investigation on aerothermal characteristics of turbine blade tip clearance with large-scale and shrinkage groove
Longfei Wang, Dewei Zhang, Shuai Bi, Junkui Mao, Ziqiang Li, Chengliang Lv
Abstract
A numerical investigation was carried out on a turbine rotor featuring a large-scale tapered profile groove to assess the effectiveness in mitigating leakage flow . Five different clearance heights and six groove depths were selected for evaluation. The findings revealed that the Nusselt number ( Nu ) on the shoulder surface, sidewall, and bottom surface of large-scale groove were reduced by up to 11.2%, 33.3%, and 76%, respectively, compared to the conventional-scale groove. This indicates the efficacy of large-scale groove in suppressing leakage flow. Furthermore, the dimensionless velocity, entropy production rate loss, tip leakage, and total pressure loss coefficient at the outlet section were notably diminished, further supporting the effectiveness of the large-scale groove in mitigating leakage losses . However, it is crucial to note that the advantages of large-scale groove are optimized within a reasonable range of groove depth. Additionally, the relative leakage of the tapered grooved blade tip structure was reduced by up to 0.81% compared to the flat tip. Moreover, the Nusselt number ( Nu ) within the groove and tip shoulder surface under the large clearance scheme was significantly higher than that under the small clearance scheme, indicating that large-scale groove attenuates the impact of clearance size on tip heat transfer.