This paper presents a study of the three-dimensional flow field within the blade rows of a high-pressure axial flow steam turbine stage. Half-delta wings were fixed to a rotating hub to simulate an upstream rotor passage vortex. The flow field is investigated in a low-speed research turbine using pneumatic and hot-wire probes downstream of the blade row. The paper examines the impact of the delta wing vortex transport on the performance of the downstream blade row. Steady and unsteady numerical simulations were performed using structured three-dimensional Navier-Stokes solver to further understand the flow field. The loss measurements at the exit of the stator blade showed an increase in stagnation pressure loss due to the delta wing vortex transport. The increase in loss was 21% of the datum stator loss, demonstrating the importance of this vortex interaction. The transport of the stator viscous flow through the rotor blade row is also described. The rotor exit flow was affected by the interaction between the enhanced stator passage vortex and the rotor blade row. Flow underturning near the hub and overturning towards the midspan was observed, contrary to the classical model of overturning near the hub and underturning towards the midspan. The unsteady numerical simulation results were further analyzed to identify the entropy producing regions in the unsteady flow field.
Vortex Transport and Blade Interactions in High Pressure Turbines
Contributed by the International Gas Turbine Institute and presented at the International Gas Turbine and Aeroengine Congress and Exhibition, Atlanta, GA, June 16–19, 2003. Manuscript received by the IGTI December 2002; final revision March 2003. Paper No. 2003-GT-38389. Review Chair: H. R. Simmons.
Chaluvadi , V. S. P., Kalfas , A. I., and Hodson, H. P. (September 3, 2004). "Vortex Transport and Blade Interactions in High Pressure Turbines ." ASME. J. Turbomach. July 2004; 126(3): 395–405. https://doi.org/10.1115/1.1773849
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