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Numerical investigations of unsteady passing wake effects on turbine blade tip aerothermal performance with different tip clearances

Bo Zhang (School of Aeronautics and Astronautics, Shanghai Jiao Tong University, Shanghai, China)
Xiaoqing Qiang (Shanghai Jiao Tong University, Shanghai, China and Department of Engineering Research Center of Gas Turbine and Civil Aero Engine, Ministry of Education of the People's Republic of China, Shanghai, China)
Shaopeng Lu (Shanghai Jiao Tong University, Shanghai, China)
Jinfang Teng (Shanghai Jiao Tong University, Shanghai, China)

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 29 August 2019

Issue publication date: 16 January 2020

Abstract

Purpose

The purpose of this paper is to numerically investigate the effect of guide vane unsteady passing wake on the rotor blade tip aerothermal performance with different tip clearances.

Design/methodology/approach

The geometry and flow conditions of the first stage of GE-E3 high-pressure turbine have been used to obtain the blade tip three-dimensional heat transfer characteristics. The first stage of GE-E3 high-pressure turbine has 46 guide vanes and 76 rotor blades, and the ratio of the vane to the blade is simplified to 38:76 to compromise the computational resources and accuracy. Namely, each computational domain comprises of one guide vane passage and two rotor blade passages. The investigations are conducted at three different tip gaps of 1.0, 1.5 and 2.0 per cent of the average blade span.

Findings

The results show that the overall discrepancy of the heat transfer coefficient between steady results and unsteady time-averaged results is quite small, but the dramatic growth of the instantaneous heat transfer coefficient along the pressure side is in excess of 20 per cent. The change of the aerothermal performance is mainly driven by turbulence-level fluctuations of the unsteady flow field within gap regions. In addition, the gap size expansion has a marginal impact on the variation ratio of tip unsteady aerothermal performances, even though it has a huge influence on the leakage flow state within the tip region.

Originality/value

This paper emphasizes the change ratio of unsteady instantaneous heat transfer characteristics and detailed the mechanism of blade tip unsteady heat transfer coefficient fluctuations, which provide some guidance for the future blade tip design and optimization.

Keywords

Citation

Zhang, B., Qiang, X., Lu, S. and Teng, J. (2020), "Numerical investigations of unsteady passing wake effects on turbine blade tip aerothermal performance with different tip clearances", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 30 No. 2, pp. 792-817. https://doi.org/10.1108/HFF-05-2019-0411

Publisher

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Emerald Publishing Limited

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