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Special Topic: Reducing the Secondary Flow Losses By Endwall Contouring

  • Meinhard T. SchobeiriEmail author
Chapter

Abstract

The HP-turbine, in contrast to LP-turbine, has a relatively small aspect ratio which causes major secondary flow regions close to the hub and tip. As a result, the secondary flow caused by a system of hub and tip vortices that induce drag forces resulting in an increase of secondary flow losses, as extensively discussed in [1]. Focusing on the secondary flow loss mechanisms, the fluid particles within the endwall boundary layers are exposed to a pitchwise pressure gradient in the blade channel. The particles move from the pressure side to the suction side and generate a system of vortices. These vortices induce drag forces that are the cause of the secondary flow losses. In addition, their interaction with the main flow causes angle deviation inside and outside the blade channel resulting in additional losses due to angle deviation. The nature of different flow losses is comprehensively treated in Chapter 6.

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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringTexas A&M UniversityCollege StationUSA

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