Numerical analysis of secondary flow loss reduction in axial turbine blades using a combined endwall fence and casing groove method


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Yildirim E., Kavurmacioglu L.

JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY, vol.38, no.1, pp.357-369, 2022 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 38 Issue: 1
  • Publication Date: 2022
  • Doi Number: 10.17341/gazimmfd.686234
  • Journal Name: JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Art Source, Compendex, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.357-369
  • Keywords: Secondary flow, axial turbine, secondary flow loss, fence, groove, CASCADE
  • Istanbul Technical University Affiliated: Yes

Abstract

Highly three-dimensional and complex flow structure on hub and tip region of blades in axial turbines leads to significant amount of aerodynamic losses. In this study, it is numerically investigated a method which is combined with two different methods used in literature independently to reduce secondary flow related aerodynamic losses in axial gas turbine blades. First method is endwall fencing which is used mostly for hub region and the other one is casing groove that is applied to stall problem in tip region of compressor blades. The main objective of the study is to specify the rate of decreasing secondary flows related losses by implementing fences of different geometries and casing groove treatment. In this sense firstly, solution geometry is formed by using a real blade shape. After that, five different fence geometries are implemented to geometry. After it is obtained solutions with fences, they are added two different casing groove geometries to the solution domain together with each fences. To evaluate losses, it is utilized mass averaged total pressure loss coefficient which is based on normalized total pressure differences at inlet and outlet of blades. As a result, it is seen that fences individually and both methods together, the loss coefficients are reduced. The most reduction is obtained 2.0x1.7 mm fence with 5.2x1.7 mm groove together and 3 % reduction in total pressure loss coefficient was obtained.