Advanced Design and Validation of Gas Turbine Blade Tip Clearance Control Systems PartⅠ: Design and Single Rig Test

The number of companies capable of manufacturing large gas turbines for power generation is limited to five globally due to the high technical requirements and complexity involved. Large gas turbines operate at high temperatures and pressures, subjecting turbine components to extreme thermal and mechanical stress. The development of these turbines involves significant research in new materials, performance testing under high-temperature and high-pressure conditions, and design optimization to enhance efficiency. The tip clearance between the turbine blade and the stator affects the efficiency of the gas turbine, as gas leakage through this gap can reduce performance. Various techniques have been developed to optimize tip clearance, typically involving cooling mechanisms. This paper introduces two advanced turbine tip clearance control systems developed by Doosan Enerbility to improve gas turbine performance. One system controls the tip clearance using a screw pitch structure, while the other uses air pressure piston to control the tip clearance. The performance and reliability of these systems were validated through single rig tests, and the most suitable materials and types were selected based on the test results. The selected system will undergo further verification in full rig tests. Part Ⅰ of this study covers the design concepts and single rig test results of the two systems, while Part Ⅱ will discuss the full rig test results and further improvements.