CUED Publications database

Improving intermediate pressure turbine performance by using a nonorthogonal stator

Yoon, S and Denton, J and Curtis, E and Longley, J and Pullan, G (2013) Improving intermediate pressure turbine performance by using a nonorthogonal stator. Journal of Turbomachinery, 136. ISSN 0889-504X

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Abstract

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. © 2014 by ASME.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div A > Turbomachinery
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 11:45
Last Modified: 08 Dec 2014 02:16
DOI: 10.1115/1.4023941