LIU Yan, LIU Pan-nian, JIANG Wo-han, et al. Experiment on clearance leakage flow and aerodynamic performance in shrouded turbine cascade[J]. 2013, 28(10).
LIU Yan, LIU Pan-nian, JIANG Wo-han, et al. Experiment on clearance leakage flow and aerodynamic performance in shrouded turbine cascade[J]. 2013, 28(10).DOI:
Flow structure at the exit of turbine cascades and aerodynamic performance were studied experimentally in a low speed wind tunnel for unshrouded and shrouded blades with a turning angle of 108.1°. The secondary structure
distribution of flow angles and total pressure loss coefficient on exit planes were investigated under various working conditions
including different clearances between the blade and the casing and different angles of incidence. Experimental results show that
compared with the unshrouded turbine cascades
the shroud can effectively control tip clearance leakage flow and reduce aerodynamic loss of cascade. With the growing clearance between the shroud and casing
the amount of leaked fluid increases. Consequently the mixing loss induced by the leaked fluid becomes larger. For the cascade studied hereto
the clearance should be less than 1% span of the blade. Variation of angle of incidence influences three-dimensional vortex structures and their intensity in cascade passages. Also it clearly affects static pressure distribution on the suction surface of the blade. Proper and positive angle of incidence helps improve the flow field
thus enhancing aerodynamics performance for cascades with large turning angles.