Investigating Endwall-Blade Fillet Radius Variation to Reduce Secondary Flow Losses

Hawes, Craig; Williams, Richard; Ingram, Grant

Abstract

In turbomachinery the joint between a turbine blade and the endwall often involves a fillet. Previous studies show that this fillet significantly influences the secondary flows despite regularly being omitted from simulation and testing, specifically that a uniform fillet radius of 16% axial chord increased endwall losses by 10%. It was proposed that a variable radius fillet could reduce secondary flows and the associated endwall losses. This paper describes a computational study to determine what variable radius fillet is required for optimal performance in the cascade. The variable radius fillet ranges from 0.5% to 16% of axial chord and was found using a genetic algorithm optimisation. Although this is a computational study the design offers physically plausible mechanisms by which the extra losses introduced by fillets may be reduced. This paper also suggests a generalised rule of fillet radius variation to minimise endwall losses. A large radius is required on the leading edge that reduces slowly along the pressure side but rapidly on the suction side such that the smallest permitted radius is applied to the suction side. A medium radius is required at the trailing edge.

Citation

Hawes, C., Williams, R., & Ingram, G. (2015). Investigating Endwall-Blade Fillet Radius Variation to Reduce Secondary Flow Losses. In Proceedings of 11th European Conference on Turbomachinery Fluid dynamics & Thermodynamics ETC11, March 23-27, 2015, Madrid, Spain (ETC2015-089)

• Conference Name: 11th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics.
• Conference Location: Madrid, Spain
• Start Date: Mar 23, 2015
• End Date: Mar 27, 2015
• Acceptance Date: Mar 23, 2015
• Publication Date: Mar 27, 2015
• Deposit Date: Feb 3, 2016
• Publicly Available Date: Mar 11, 2016
• Pages: ETC2015-089
• Series ISSN: 2410-4833
• Book Title: Proceedings of 11th European Conference on Turbomachinery Fluid dynamics & Thermodynamics ETC11, March 23-27, 2015, Madrid, Spain.
• Publisher URL: http://www.etc11.eu/program-at-the-glance/etc11-download-papers/