Casing-groove optimisation for stall margin in a transonic compressor rotor

Abstract

Purpose

This paper aims to understand the aerodynamic blockage related to near casing flow in a transonic axial compressor using numerical simulations and to design an optimum casing groove for stall margin improvement using a surrogate optimisation technique.

Design/methodology/approach

A blockage parameter (Ψ) is introduced to quantify blockage across the blade domain. A surrogate optimisation technique is then used to find the optimum casing groove design that minimises blockage at an axial location where the blockage is maximum at near stall conditions.

Findings

An optimised casing groove that improves the stall margin by about 1% can be found through optimisation of the blockage parameter (Ψ).

Originality/value

Optimising for stall margin is rather lengthy and computationally expensive, as the stall margin of a compressor will only be known once a complete compressor map is constructed. This study shows that the cost of the optimisation can be reduced by using a suitably defined blockage parameter as the optimising parameter.

Citation

Mustaffa, A.F. and Kanjirakkad, V. (2021), "Casing-groove optimisation for stall margin in a transonic compressor rotor", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 31 No. 2, pp. 694-717. https://doi.org/10.1108/HFF-09-2019-0675