Control of the leakage flow and heat transfer characteristics at the blade tip by cavity filling

• Published in: Results in engineering 2023-12, Vol.20, p.101446, Article 101446
• Main Authors: Li, Lei, Tu, Chuanqi, Wang, Chenglong, Sun, Yongchao, Zou, Jianjun, Zhang, Jianfeng
• Format: Article
• Language: English
• Subjects: Aerodynamic performance; Cavity-filling geometry; Heat transfer; High-pressure turbine; Leakage flow
• ISSN: 2590-1230; 2590-1230
• DOI: 10.1016/j.rineng.2023.101446

In order to reduce leakage flow, cavity tips are often used in high-pressure turbines, at the cost of higher thermal load compared to flat tips. To better control the leakage flow and heat transfer at the blade tip, a cavity-filling geometry is proposed in this paper, and the effects of the filling area are also investigated by numerical simulation. The results indicate that the new geometries maintain the advantages of cavity tips in terms of aerodynamic performance. With the cavity filling area increasing, the heat transfer of the new geometries shows a trend of initially increasing and then decreasing. When the front 15% of the blade tip chord length is filled, the average heat transfer of this configuration is reduced by 3.7% compared to the cavity blade tip, and the high heat transfer area is reduced by 23.3%, at the cost of more intensive hot spots. As the cavity-filling area increases from 5% to 15%, the size of the vortexes at the cavity reduces, resulting in a rise in the leakage. Similar behaviors of the tip heat transfer and leakage flow were also found when the turbine pressure ratios varied from 3 to 7, with the cavity-filling geometry. •This study combines the advantages of the flat tip in heat transfer and the cavity tip in leakage flow by filling the high heat transfer area of the cavity.•The new geometry can effectively reduce the high heat transfer area at the tip of the cavity, and in terms of leak flow control, this structure maintains an advantage over the flat tip.•For aerodynamic performance, the new geometry can maintain the aerodynamic performance of the original cavity.•This structure exhibits broad applicability, and as the pressure ratio at the inlet and outlet of the turbine increases, both heat transfer and aerodynamic performance are enhanced.