Intermediate pressure (IP) turbines in high bypass ratio civil aeroengines are characterized by a significant increase in radius and a low aspect ratio stator. Conventional aerodynamic designs for the IP turbine stator have had leading and trailing edges orthogonal to the hub and casing end walls. The IP turbine rotor, however, is stacked radially due to stress limits. These choices inevitably lead to a substantial gap between the IP stator and rotor at the outer diameter in a duct that is generally diffusing the flow due to the increasing radius. In this low Mach number study, the IP stator is redesigned, incorporating compound sweep so that the leading and trailing edges are no longer orthogonal to the end walls. Computational investigations showed that the nonorthogonal stator reduces the flow diffusion between the stator and rotor, which yields two benefits: The stator trailing edge velocity was reduced, as was the boundary layer growth on the casing end wall within the gap. Experimental measurements confirm that the turbine with the nonorthogonal stator has an increased efficiency by 0.49%, while also increasing the work output by 4.6%, at the design point.
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February 2014
Research-Article
Improving Intermediate Pressure Turbine Performance by Using a Nonorthogonal Stator
Sungho Yoon,
Sungho Yoon
1
e-mail: sungho.yoon@cantab.net
1Currently, GE Global Research Center, Munich, Germany.
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Graham Pullan
Cambridge University,
Cambridge,
Graham Pullan
Whittle Laboratory
,Cambridge University,
Cambridge,
UK
Search for other works by this author on:
Sungho Yoon
e-mail: sungho.yoon@cantab.net
Graham Pullan
Whittle Laboratory
,Cambridge University,
Cambridge,
UK
1Currently, GE Global Research Center, Munich, Germany.
Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the Journal of Turbomachinery. Manuscript received February 2, 2013; final manuscript received February 9, 2013; published online September 26, 2013. Editor: David Wisler.
J. Turbomach. Feb 2014, 136(2): 021012 (8 pages)
Published Online: September 26, 2013
Article history
Received:
February 2, 2013
Revision Received:
February 9, 2013
Citation
Yoon, S., Denton, J., Curtis, E., Longley, J., and Pullan, G. (September 26, 2013). "Improving Intermediate Pressure Turbine Performance by Using a Nonorthogonal Stator." ASME. J. Turbomach. February 2014; 136(2): 021012. https://doi.org/10.1115/1.4023941
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