Effect of Sloped Trench Casing Treatment on Performance and Stability of Axial Compressors

2021 ◽  
Author(s):  
Jiexuan Hou ◽  
Yangwei Liu
Keyword(s):  
Casing Treatment ◽  
Axial Compressors

scholarly journals Alleviation of spike stall in axial compressors utilizing grooved casing treatment

2015 ◽  
Vol 28 (3) ◽  
pp. 649-658 ◽  
Author(s):  
Reza Taghavi-Zenouz ◽  
Sarallah Abbasi
Keyword(s):  
Casing Treatment ◽  
Axial Compressors

Influence of Casing Treatment on the Operating Range of Axial Compressors

1982 ◽  
Author(s):  
J. Paulon ◽  
D. Dehondt
Keyword(s):  
Axial Flow ◽  
Outer Wall ◽  
Groove Depth ◽  
Experimental Investigations ◽  
Casing Treatment ◽  
Axial Compressors ◽  
Operating Range ◽  
Geometric Configurations ◽  
Surge Margin ◽  
Casing Treatments

Experimental investigations brought to light the possibilities of broadening the operating range of axial flow compressors by means of outer wall casing treatments such as grooves, honeycombs or cavities. The industrial use of these techniques is however limited by uncertainties on the effectiveness of these treatments as, while they are very beneficial in some cases, they deteriorate the performance of the machine in some others. A theoretical investigation has been conducted on the flow field in cavities most commonly used, and laws for determining the groove depth have been established which account for the surge margin improvement obtained in some cases and make it possible to dismiss inefficient geometric configurations. A comparison between theory and experiment is presented, based on test results published in the literature and on an experimentation on two industrial compressors.

Experimental Study on the Influence of Casing Treatment on Near-Stall Unsteady Behavior of a Mixed-Flow Compressor

2019 ◽  
Author(s):  
Juan Du ◽  
Felix Kauth ◽  
Jichao Li ◽  
Qianfeng Zhang ◽  
Joerg R. Seume
Keyword(s):  
Stability Limit ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Surprising Result ◽  
Mixed Flow ◽  
Stall Inception ◽  
Casing Treatment ◽  
Axial Compressors ◽  
Flow Compressor ◽  
Unsteady Behavior

Abstract This paper aims at experimentally demonstrating the effects of axial slot casing treatment and tip gap variation on compressor performance, unsteady tip clearance flow, and stall inception features in a highly-loaded mixed-flow compressor at partspeed. Two tip gaps (0.32% and 0.64% of rotor blade chord at mid-span) were tested at three rotational speeds. A semicircular axial slot casing treatment improves compressor stability. The experimental results show that this casing treatment significantly moves the stability limit at partial speeds towards lower mass flow for both tip gaps, compared to the reference case without casing treatment. In the case of the compressor with casing treatment, efficiency increases for the large tip gap and decreases for the small tip gap. Dynamic pressure transducers installed in the casing upstream and along the rotor tip chord direction are used to detect the unsteady behavior of tip region flow and stall inception signals of the compressor. The characteristic frequency in the tip region decreases, and the oscillating amplitude first decreases and then increases during the throttling process, regardless of tip gap size or casing treatment. For axial compressors, by contrast, the observation in previous work has been an increase of the oscillating amplitude with decreasing flow coefficient. This is a surprising result of our work. Neither experiment nor CFD so far was able to explain why the trend in this mixed-flow compressor is different from the trend expected from axial compressors. The compressor stalls through the spike stall inception both with and without casing treatment. This observation also differs from recent studies on axial compressors, which demonstrated that casing treatments could change the type of stall inception. The unstable disturbance indicating initial stall inception initially appears in the blade tip region from blade mid-chord to trailing edge, and then propagates upstream towards the leading edge. This disturbance might be generated by the reversed flow separation near mid-chord.

scholarly journals Flow Control by Slot Position and Noise Baffle in a Self-Recirculation Casing Treatment on an Axial Fan-Rotor

2017 ◽  
Vol 2017 ◽  
pp. 1-18
Author(s):  
Xiangjun Li ◽  
Stephen Spence ◽  
Hua Chen ◽  
Wuli Chu ◽  
Lee Gibson
Keyword(s):  
Flow Control ◽  
Incoming Flow ◽  
Axial Fan ◽  
Treatment Needs ◽  
Optimum Length ◽  
Casing Treatment ◽  
Axial Compressors ◽  
Recirculating Flow ◽  
Optimization Study ◽  
Baseline Case

To address the situations where the casing treatment needs to be used to stabilize axial compressors through strong recirculation, this paper initiated a CFD study to investigate how the flow could be suitably controlled in the casing treatment to minimize the efficiency penalty and increase the flow range. A counter-swirl self-recirculation casing treatment was first designed on a low speed axial fan rotor as a baseline case. Then three different slot positions and the influence of including the noise baffle were numerically studied. Based on the understanding of their coeffects, the shorter noise baffle was considered and it was found that the highest efficiency was achieved in the case of the upstream slot when the length of baffle was suitably adjusted to balance the incoming flow and recirculation. The largest flow range was achieved by locating the slot at the most downstream position and using a 50% length baffle since it suitably controlled the recirculating flow and relieved the separation at the low-span region. An optimization study showed that the optimum length of the baffle for efficiency was always larger than for the flow range. Both of the two optimum values reduce as the slot moves downstream.

Effect of Sloped Trench Casing Treatment on Performance and Stability of Axial Compressors

2020 ◽  
Author(s):  
Hou Jiexuan ◽  
Liu Yangwei
Keyword(s):  
Working Environment ◽  
Leakage Flow ◽  
Compressor Cascade ◽  
Tip Leakage Flow ◽  
Tip Leakage Vortex ◽  
Casing Treatment ◽  
Axial Compressors ◽  
Tip Leakage ◽  
Inflow Condition ◽  
The Stability

Abstract Numerical simulations are carried out to investigate the effect of the sloped trench casing treatment on the performance and stability of a compressor cascade, an isolated rotor, and a single compressor stage. The research objects alter from a simplified flow model to an actual compressor working environment. Firstly, a detailed study of how the sloped trench casing treatment effects the tip leakage flow structure, especially the tip leakage vortex of a compressor cascade, is presented. Results show that the strength of the tip leakage vortex is weakened as the sloped trench casing treatment transforms the structure of the tip leakage vortex. Then the simulation results of the isolated rotor and the single stage are studied. For both cases, the effect of the sloped trench casing treatment on the tip leakage flow is analogous to that of the cascade case. For the isolated rotor, the improvement on the performance is not obvious. While under the stage environment, different from the traditional casing treatment, both the performance and the stability of the compressor are advanced, by getting the tip leakage vortex under control and letting the downstream stator working under a better inflow condition.

Numerical Investigation of a Single Circumferential Groove Casing Treatment on Three Different Compressor Rotors

2011 ◽  
Author(s):  
F. Heinichen ◽  
V. Gu¨mmer ◽  
H.-P. Schiffer
Keyword(s):  
Aerodynamic Performance ◽  
Tip Clearance ◽  
Shock Interaction ◽  
Casing Treatment ◽  
Axial Compressors ◽  
Transonic Compressor ◽  
Circumferential Groove ◽  
Number Of Publications ◽  
Tip Clearance Vortex ◽  
Casing Treatments

In axial compressors, casing treatments represent a passive method to increase the working range without the need to modify the blade geometry. The majority of the open literature on the topic considers one or several casing treatment variants on the same compressor. The question how one casing treatment and its basic mechanisms can be transferred to a different compressor is only covered in a small number of publications. This paper tries to fill this gap by applying a single circumferential groove type casing treatment to three different transonic compressor rotors. It is demonstrated numerically that the casing treatment is able to improve the aerodynamic performance of all three rotors. Detailed investigation of the flow field near the rotor tip shows that the single circumferential groove works by influencing the interaction between the tip clearance vortex and the shock. Hence, this type of casing treatment can be generalized to transonic rotors with a stall mechanism that is based on tip clearance vortex-shock interaction.

scholarly journals Momentum Transportation Analysis in Axial-slot Casing Treatment for Axial Compressors

2019 ◽  
Author(s):  
Junda Feng ◽  
◽  
Mingmin Zhu ◽  
Jinfang Teng ◽  
Xiaoqing Qiang
Keyword(s):  
Casing Treatment ◽  
Axial Compressors

Numerical Study on Effects of Axial-Slot Casing Treatment on Peak Efficiency of Axial Compressors

2016 ◽  
Author(s):  
Ning Ma ◽  
Xi Nan ◽  
Feng Lin
Keyword(s):  
Numerical Study ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Peak Efficiency ◽  
Leakage Loss ◽  
Casing Treatment ◽  
Axial Compressors ◽  
Tip Leakage ◽  
Transonic Compressor ◽  
Casing Treatments

Axial compressors can obtain substantial improvement on stall margin by using axial-slot casing treatments. However, this type of casing treatment usually yields large peak efficiency penalty due to the interaction between the slots and rotor tip region where the tip leakage flow plays an important role. Therefore, as a main factor that influences the peak efficiency, the tip leakage loss was examined in this paper with a variety of slot geometries. Unsteady numerical simulations were performed on both low speed and transonic compressors with axial skewed slot casing treatments with different geometric parameters. In addition, an equation which can be applied to evaluate the tip leakage loss under casing treatment cases was derived from Denton’s leakage mixing model. The leakage loss can be expressed in terms of the cube of the tip leakage flow rate. Combined with the simulation results, the effects of the number, depth and width of the slots on both the leakage loss and peak efficiency deficit were investigated. For the transonic compressor, the impacts of shock wave and its interaction with the tip leakage flow /vortex were assessed as well. Lastly, two axial-slot casing treatments with an isosceles-trapezoid shaped opening were designed to reduce the loss in the rotor tip region. It was shown that the newly designed axial-slot casing treatments were capable of improving the peak efficiency of both compressors.

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