Review of tip air injection to improve stall margin in axial compressors
Introduction
In the pursuit of developing modern aircrafts that can fly faster, higher, and farther, they have to be equipped with advanced aero-engines that satisfy the requirements of a wide and safe operating range, high thrust to weight ratio, and high efficiency. However, the safe operation of aero-engines is commonly constrained by the rotating stall, which mainly occurs in axial flow compressors. As a type of aerodynamic instability, the rotating stall is considered as the most unfortunate occurrence that should be avoided at all cost in aero-engine compressors (Day [1]). Thus, numerous efforts have been exerted over the last seven decades to understand how and why the compressor stalls [[1], [2], [3]]. At the same time, a fairly consistent effort has been devoted to the development of active and passive control techniques aimed at increasing compressor stability. Hathaway [2] has summarized different passive endwall treatments, including the traditional axial slots and circumferential grooves with different geometries [[4], [5], [6], [7], [8], [9], [10]]. However, the above passive control technologies frequently entail efficiency penalty that cannot satisfy the demands of high thrust to weight ratio and high efficiency required of modern aero-engines.
Another common form of a stability-enhancing technology is the tip air injection, which injects into the blade tip region by means of high-pressure air. The earliest reported concept about this form was a 1950-patent filed by Geoffrey Wilde of Rolls-Royce Limited. It proposes aft stage bleeds that feed flow upstream of the inlet guide vane (IGV) to be injected along the casing ahead of the IGV [11]. Under this guidance, a few researchers have separately extracted the upstream reinjection and developed tip air injection [[12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24],[31], [32], [33], [34], [35], [36], [37], [38]]. Since the tip air injection has been confirmed to effectively extend the stall margin in an axial flow compressor, the studies on this type of injection are divided into two routes as follows.
The first route is the mechanism of tip air injection, which mainly focuses on the influence of injected parameters on the stall margin and its corresponding stability-enhancing mechanism [[12], [13], [14], [15], [16], [17], [18], [19], [20], [21]]. A varied selection of injected parameters generates not only a different stall margin improvement (SMI), but also lead to a different understanding of the stability-enhancing mechanism [12]. For example, a few researchers think that the tip air injection can influence the main stream flow (inlet incidence and radial loading) [13,14,20,21], whereas others assume it can only act on the tip clearance flow [[15], [16], [17]].
The second route is the application of tip air injection, which includes active control [[22], [23], [24],[31], [32], [33], [34], [35], [36], [37], [38]] and self-recirculating injection [[39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53]]. Day [22] firstly realized the active control through the use of a pulse jet over the blade tip and detection of a spike-type stall inception. This method was further validated in the Viper engine by Freeman et al. [23] and in Lazac 04 turbofan engine by Leinhos et al. [24]. However, existing results showed that the time interval from the spike-type inception to the deep stall is less than 1s for some axial compressors [22,[25], [26], [27]]; thus, a timely detection of the spike-type stall inception is a serious problem in actual applications. Consequently, with the help of the Moore–Greitzer model [28], some researchers developed the active control prediction based on the development of harmonics with different order numbers in the model [[29], [30], [31], [32], [33], [34], [35], [36]]; however, it is limited to the detection of modal-wave inception. Accordingly, recent studies have shifted to the prediction and detection of pre-stall inception and active control; the active control uses the pre-stall inception as a feedback signal [37,38]. As another application of the tip air injection, the self-recirculating injection is also a recent topic of considerable interest because existing studies indicate that it can consider stability and efficiency in the compressor [[39], [40], [41], [42], [43], [44], [45], [46], [47], [48], [49], [50], [51], [52], [53]].
This review article presents the fundamental technical problems related to the tip air injection. It focuses on the stability-enhancing mechanisms and applications of tip air injection. The stability-enhancing mechanism of the tip air injection is categorized into two parts—selection of injected parameters and response to steady/unsteady parameters. Thereafter, the realizations of active and self-recirculating injections, which were anticipated to be applied in actual aero compressor in previous decades, are presented. The prospects and problems pertaining to tip air injection are discussed in the conclusion.
Section snippets
Design of injector parameters
The idea of tip air injection for extending the stall margin of the compressor originated from the boundary layer control in delaying flow breakdown in cascade tunnels and inlets [[54], [55], [56]]. In 1960, researchers in the National Aeronautics and Space Administration (NASA) Lewis Research Center conducted experiments using casing blowing and bleeding to control the end wall boundary layer in the rotor tip region in a high-speed single-stage axial compressor [[57], [58], [59], [60], [61],
Stability-enhancing mechanism
With the aim of immediately enhancing stability in actual compressors, researchers have attempted to reveal the stability-enhancing mechanism of tip air injections. In the past, because of the different selection of injected parameters, the understanding of the stability-enhancing mechanism is divided into two explanations.
Active control
The concept of active control for extending the stall margin in compressors has been proposed in 1989 [77]. The main principles of active control include predicting the stall inception and feeding back signal to the control; thereafter, the control can drive the actuator to extend the stall margin. Two important factors have to be carefully considered. One of the two is feedback detection. The Moore-Greitzer model made a significant contribution in terms of predicting the modal-wave inception [
Self-recirculating control
The self-recirculating injection is derived from the 1950 patent filed by Geoffrey Wilde of Rolls-Royce [11] Limited. It proposes aft stage bleeds that feed flow upstream of the IGV to be injected along the casing ahead of the IGV. With this concept, some researchers have separately extracted the upstream reinjection and developed the tip air injection (e.g., Day [22], Weigl et al. [33], van Schalkwyk et al. [34], and Li et al. [38] for active tip air injection; Suder et al. [13], Kefalakis et
Discussion
The tip air injection, including the external and recirculating injections, has been confirmed to effectively extend the stall margin in axial compressors. In the past, most of the works have been performed in the laboratory, such as the typical studies by Suder et al. [13], Day [22], Weigl et al. [33], and Hathaway [39]. Inspired by the previous experience, the numerical and experimental works on the tip air injection were implemented; examples of these are the following: parameter studies of
Conclusions
A wide stall margin is one of the design targets for compressors; moreover, it is the key parameter for ensuring safe engine operation. As an effective stability-enhancing method, the tip air injection, such as steady injection, active injection, and recirculating injection, has been widely studied in the past. However, previous results showed that the stability-enhancing capability of tip air injection is uncertain. To aid in the design of an effective tip air injection system in actual
Acknowledgement
The authors are thankful for the support of the National Science Foundation of China with Project No.51676183 and No.51727810. And the Special Fund for the Member of Youth Innovation Promotion Association of CAS (2018173). The authors also acknowledge Prof. Jingyi Chen, Prof. Feng Lin, Dr. Zhiting Tong, Dr. Xi Nan and Dr. Shaojuan Geng for the insightful discussion.
References (100)
Effect of discrete endwall recirculation on the stability of a high-speed compressor rotor
Aero. Sci. Technol.
(2014)Stall inception and control in a transonic fan, Part B: stall control by discrete endwall injection
Aero. Sci. Technol.
(2015)- et al.
Role of tip injection in desensitizing the compressor to the tip clearance size
Aero. Sci. Technol.
(2016) Stall, surge, and 75 Years of research
ASME J. Turbomach.
(2016)Passive endwall treatments for enhancing stability
Tech. rep.
(2007)- et al.
Spike-type compressor stall inception, detection, and control
Annu. Rev. Fluid Mech.
(2010) - et al.
Effect of several porous casing treatments on stall limit and on overall performance of an axial flow compressor rotor
Tech. rep.
(1971) Casing Treatment for Axial Flow Compressors, PhD Thesis
(1999)- et al.
Enhancing the stability of subsonic compressors using casing grooves
- et al.
The dynamics of prestall process in an axial low-speed compressor with single circumferential casing groove
Extensive experimental study of circumferential single groove in an axial flow compressor
Study of casing treatment stall margin improvement phenomena
Tech. rep.
A study on configurations of casing treatment for axial flow compressors
Bulletin of JSME
The dual mechanisms and implementations of stability enhancement with discrete tip injection in axial flow compressor
ASME J. Turbomach.
Compressor stability enhancement using discrete tip injection
ASME J. Turbomach.
Micro air injection and its unsteady response in a low-speed axial compressor
ASME J. Turbomach.
The self-induced unsteadiness of tip leakage vortex and its effect on compressor stall inception
Numerical study on the unsteady response of tip leakage flow unsteadiness to discrete micro tip injection in a low-speed isolated compressor
Parametric study of tip injection in an axial flow compressor stage
A new design for tip injection in transonic axial compressors
Stability enhancement of a multistage compressor by air injection
ASME J.Turbomach.
The effect of injector size on compressor performance in a transonic axial compressor with discrete tip injection
Proc IMechE Part A: J Power and Energy
Active suppression of rotating stall and surge in axial compressors
ASME J. Turbomach.
Experiments in active control of stall on an aeroengine gas turbine
ASME J. Turbomach.
Experiments in active control of a twin-spool turbofan engine
Stall inception in axial compressors
ASME J. Turbomach.
Stall inception and the prospects for active control in four high speed compressors
ASME J. Turbomach.
Stall inception measurements in a high-speed multistage compressor
ASME J. Turbomach.
A theory of post-stall transients in axial compression systems: Part I-development of equations
ASME J. Eng. Gas Turbines Power
Theoretical study of sensor-actuator schemes for rotating stall control
AIAA J. Propul. Power
Dynamic control of rotating stall in axial flow compressors using aeromechanical feedback
ASME J. Turbomach.
Rotating stall control of an axial flow compressor using pulsed air injection
ASME J.Turbomach.
Active stabilization of rotating stall and surge in a transonic single stage axial compressor
ASME J. Turbomach.
Active stabilization of axial compressors with circumferential inlet distortion
ASME J. Turbomach.
Rotating stall control in a high-speed stage with inlet distortion: Part I—radial distortion
ASME J. Turbomach.
Rotating stall control in a high speed stage with inlet distortion-Part II: circumferential distortion
ASME J. Turbomach.
Online stall control with the digital signal processing method in an axial compressor
Self-adaptive stability-enhancing technology with tip air injection in an axial flow compressor
ASME J. Turbomach.
Self-recirculating casing treatment concept for enhance compressor performance
Assessment of the self-recirculating casing treatment concept to axial compressors
Numerical investigation of casing treatment mechanisms with a conservative mixed-cell approach
Recirculation casing treatment by using a vaned passage for a transonic axial-flow compressor
Proc. IMechE Part A: Journal of Power and Energy
Self-regulating casing treatment for axial compressor stability enhancement
Tip gap variation on a transonic rotor in the presence of tip blowing
Difference in the working principle of axial slot and tip blowing casing treatments
The effects on stability, performance, and tip leakage flow of recirculating casing treatment in a subsonic axial flow compressor
Coupling stability-enhancing mechanism with compact self-recirculating injection in an axial flow compressor
Proc. IMechE Part A: J. Power and Energy
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2023, Chinese Journal of AeronauticsExperimental investigation of instability inception on a transonic compressor under various radial distributions of loading
2023, Aerospace Science and TechnologyFlow mechanism of self-recirculating casing treatment in a low-reaction transonic compressor rotor
2022, Aerospace Science and TechnologyCitation Excerpt :Since tip loading is critical to compressor stability, the spanwise distribution of the diffusion factor is given in Fig. 12. Prior research has established that self-recirculating casing treatment or tip injection tends to reduce tip loading, which is regarded as a key mechanism underlying the stability enhancement [21,44]. This study, however, reaches the exact opposite conclusion: for the SRCT configuration, the diffusion factor increases in the outer 10% span, indicating a rise in tip loading.
Implementation of stability-enhancement with tip air injection in a multi-stage axial flow compressor
2021, Aerospace Science and TechnologyCitation Excerpt :Another method with application potential is tip air injection, which is derived from an early patent proposed by Rolls-Royce Limited in the 1950s [6]. Numerous researchers have actively worked to fully leverage the stability-enhancing capability of tip air injection [7–10]. Originally, tip air injection was primarily used in active control [11–14].