Aerodynamic Performance of Steam Turbine Blades with Influence of Tip Seal Leakage Flow
Year: 2026
Type: article
Abstract: Tip seal leakage in shrouded steam turbines can significantly affect the aerodynamic performance of downstream blade rows. An unsteady three-dimensional numerical model of a 1.5-stage high-pressure steam turbine is established using ANSYS CFX (ANSYS2021) with the SST k–ω turbulence model. Tip seal clearances of 1.0, 1.5, and 1.9 mm are investigated using the Q-criterion and vorticity transport equation to characterize leakage-vortex evolution and its interaction with the mainstream. The results show that increasing tip seal clearance strengthens leakage flow and expands its interaction region. The expansion term exhibits a relatively stronger influence on vorticity variation near the seal teeth, whereas the vortex stretching term plays a significant role in leakage-vortex evolution near the seal inlet, outlet, and cavity. Leakage vortices interact with the rotor wake, intensifying velocity gradients and aerodynamic loss, with pronounced flow distortion near 85% rotor span. The disturbance is further transported to the downstream stator, causing marked variations in flow angle, circumferential velocity, and static pressure in the upper-span region. At 95% and 99% blade heights, pronounced differences in suction-surface static pressure occur within the forward 80% of the chord length. These findings clarify the aerodynamic consequences of tip seal leakage and its downstream effects.
Source: Processes
DOI: 10.3390/pr14172728
Authors: Lihua Cao, Dacai Li, Lei Wang, Heyong Si, Zhongbin Zhang
Institution: Northeast Electric Power University
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,896
Award: G1835712720
OpenAlex ID: W7204232690