Session: 13-05 External and Internal Flow Heat Transfer II

Paper Number: 81569

81569 - Effects of the Ribbed-Squealer Tip on the Blade Tip Aerothermal Performance in a High Pressure Gas Turbine Cascade 

In modern gas turbines, High-temperature gas gives rise to the heat load dramatically to the tip region, inducing the leakage flow through the blade tip gap by the lateral pressure difference. Squealer tip, as an efficient technique, has been widely utilized to reduce the tip leakage flow and the heat load. In order to enhance efficiency of squealer tip, the present research proposed kinds of ribbed-squealer tip. Ribs along the axial direction and the circumferential direction are inserted inside the conventional squealer tip. The effects of different squealer tips on the blade tip leakage flow and heat transfer characteristic were numerically investigated. Three-dimensional (3D) Reynolds-Averaged Navier-Stokes (RANS) equations and standard  turbulence model were solved to conduct the simulations. The numerical results indicated that the inserted ribs truncated the cavity vortex flow from the leading edge to the trailing edge inside the tip cavity, leading to a decrease of the heat load on the blade tip. The case with the inserted ribs perpendicular to the mainstream direction obtains the smallest heat transfer coefficient among all simulated cases. Which is 20.93% lower than that of the conventional squealer tip. From the perspective of leakage flow rate comparison, the inserted ribs can effectively control leakage flow within 0-18% streamwise region. An aero-labyrinth sealing effect is formed by the staggered ribs within 0-30% stream-wise region. In addition, the staggered ribs achieve the best performance in minimizing the tip leakage flow within the 0-10% stream-wise region.

Presenting Author: Huarong Li Northwestern Polytechnical University

Presenting Author Biography: LI Hua-rong<br/>&#160;<br/>Age:27<br/>&#160;<br/>Research:Aero-thermodynamics of Turbomachinery<br/>&#160;<br/>Institution:Engineering Thermophysics, School of&#160; Power and Energy Northwestern Polytechnical University

Authors:

Kun Du Northwestern Polytechnical University
Huarong Li Northwestern Polytechnical University
Na Hui Northwestern Polytechnical University
Yuanyuan Gao Northwestern Polytechnical University
Cunliang Liu Northwestern Polytechnical University