Session: 31-13 Flow Control

Paper Number: 121845

121845 - Numerical Study on the Effect of Back Cavity on the Aerodynamic Behavior of a Non-Axisymmetric Casing Treatment for Transonic Axial Compressors 

For decades, aeronautic engineers have studied the potential of Casing Treatments (CT) to improve the aerodynamic operability of compressors. In 2022, Yoon and Cargill in GT2022-80461 did a good synthesis of this passive control technology and its use in aeronautic propulsion engines. Among the different type of casing treatments, one of the most promising one is made of a row of circumferentially discrete axial slot (or ASCT). While some authors use designs that keep the slots separated (GT2011-45364, GT2023-101620), other chooses to add a circumferential back cavity that link the slots outside the compressor main flow path (GT2014-26298, GT2020-14955). Both concepts have shown good results on separate compressors but comparisons of the two concepts on the same modern transonic compressor are lacking.

This study proposes to increase the knowledge of the mechanisms underlying the efficiency of ASCT by doing a back-to-back comparison of two CT designs that differ(s) only by the presence or the absence of the back cavity. First, this paper presents the effect of the cavity on the global operability and efficiency of the compressor. Then, the paper does a detailed analysis of the fluid exchanges between the slots and the main flow path for the two CTs.

The results show that the presence of the cavity reduces the amplitude of the velocity fluctuations and allows for a more uniform redistribution of the recirculated mass flow. While both designs show a good capacity to improve operability, the design with cavity is less intrusive on the rotor performances while the design without cavity allows for a slight increase in rotor global mass flow.

Presenting Author: Simon Martin Safran SA

Presenting Author Biography: Design Engineer for Safran Aircraft Engines from 2013 to 2018 on aeroelasticity of Fan blades
Research Engineer for Safran Tech (Safran SA) from 2018 on compressor operability

Authors:

Simon Martin Safran SA
Benoit Rodriguez Safran SA