Micro Air Injection and Its Unsteady Response in a Low-Speed Axial Compressor

Nie, Chaoqun; Xu, Gang; Cheng, Xiaobin; Chen, Jingyi

doi:10.1115/gt2002-30361

Cited by 25 publications

(30 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Nie et al [22] performed air injection upstream of the first rotor to control rotating stall in a three-stage axial flow compressor. They carried out a parametric study by varying injected mass flow, axial distance of the injector from the rotor leading edge, radial penetration of the injector, and injection skew angle.…”

Section: Introductionmentioning

confidence: 99%

“…A parametric study has been carried out by varying the axial distance of the injector from the rotor leading edge, jet-to-free-stream velocity ratio, injection pitch and skew angles, and number of injectors. The range of these parameters was chosen on the basis of the past literature [21,22,32] as well as considering the geometric characteristics of the present axial flow fan. A pulsed injection study was also carried out to investigate the possibility of further improvement in stall margin.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Tip injection as a means for rotating stall control in an axial flow fan

Salunkhe

Reddy

Pradeep

2008

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

The present experimental investigation is aimed at studying the effect of tip injection on the performance and flow characteristics in the tip region of an axial flow fan under uniform and distorted inflow conditions. A detailed parametric study was carried out by varying injection parameters such as pitch and skew angles, jet-to-free-stream velocity ratio, number of injectors, and the axial location of the injectors. The configuration with six injectors, jet-to-freestream velocity ratio of 3.5, 0 • pitch angle, and injector skew angle of −15 • (in an orientation opposing the direction of rotor rotation) resulted in the highest stall margin improvement of ∼9.4 per cent. This study was further extended to determine the effects of circumferential and combined circumferential and radial inflow distortion on fan performance and the effectiveness of tip injection under these conditions. A preliminary study of the effect of pulsed injection was also carried out at different pulsing frequencies in order to optimize injection flowrates. Interestingly, pulsed injection resulted in less stall margin improvement when compared with continuous injection. These results have been supported by flow behaviour studies carried out in the tip region using a seven-hole probe. A qualitative study was carried out using unsteady pressure transducers, and it revealed that the trailing edge of the distortion screen acts as a source of disturbances.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tip injection as a means for rotating stall control in an axial flow fan

Salunkhe

Reddy

Pradeep

2008

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

show abstract

“…Despite much efforts and achievements on mass injection upstream of the tip of axial compressor, several topics should still be very interesting. (1) For a low-speed compressor, experimental results showed that the injected flow of only 0.05% of the compressor main flow is able to lower the mass flow rate at stall for up to 5.8% [10]. However, the effectiveness of steady micro-air injection and its effects on the performance of a high-speed compressor need detailed examination.…”

Section: Introductionmentioning

confidence: 99%

“…Based on the above-mentioned argument, a new approach, steady microair injection, was proposed to improve the stability of a lowspeed axial-flow compressor in [10]. Despite much efforts and achievements on mass injection upstream of the tip of axial compressor, several topics should still be very interesting.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Investigations of Steady Micro‐Tip Injection on a Subsonic Axial‐Flow Compressor Rotor

Chu

Zhu

et al. 2006

International Journal of Rotating Machinery

View full text Add to dashboard Cite

Steady tip injection has been demonstrated to be an effective means of extending the stable operating range of a tip-critical compressor. This study presents a state-of-the-art design for the tip injection through the casing with flush-mounted inclined holes and the effectiveness of steady micro-air injection to enhance stability in a subsonic axial-flow compressor rotor using an external-air supply. For the tested rotor, experimental results demonstrate that at 53% design speed, the stalling mass flow can be reduced by 7.69% using an injected mass flow equivalent to 0.064% of the annulus flow. Time-dependent CFD simulations were conducted to identify the physical mechanic that accounts for the beneficial effects of the steady micro-air injection on the performance and stability of the compressor. Detailed analyses of the flow visualization at the tip have exposed the different tip flow topologies between the cases without tip injection and with tip injection. It was found that the primary stall margin enhancement afforded by the steady micro-air injection is a result of the tip-clearance flow manipulation. The repositioning of the tip-clearance vortex further towards the trailing edge of the blade passage and delaying the movement of incoming/tip-clearance flow interface to the leading edge plane are the physical mechanisms responsible for extending the compressor stall margin.

show abstract

“…Suder et al [50] proposed a discrete tip injection technique, and Nie et al [51] and Lin et al [52] based their proposal on microair injection. Whilst requiring significant power to drive the associated control system actuation, these control techniques result in 5 to 10 per cent improvement in compressor stall margin.…”

Section: Active: Air Injectionmentioning

confidence: 99%

A Critical Review of Stall Control Techniques in Industrial Fans

Bianchi

Corsini

Sheard³

et al. 2013

ISRN Mechanical Engineering

View full text Add to dashboard Cite

This paper reviews modelling and interpretation advances of industrial fan stall phenomena, related stall detection methods, and control technologies. Competing theories have helped engineers refine fan stability and control technology. With the development of these theories, three major issues have emerged. In this paper, we first consider the interplay between aerodynamic perturbations and instability inception. An understanding of the key physical phenomena that occurs with stall inception is critical to alleviate stall by design or through active or passive control methods. We then review the use of passive and active control strategies to improve fan stability. Whilst historically compressor design engineers have used passive control techniques, recent technologies have prompted them to install high-response stall detection and control systems that provide industrial fan designers with new insight into how they may detect and control stall. Finally, the paper reviews the methods and prospects for early stall detection to complement control systems with a warning capability. Engineers may use an effective real-time stall warning system to extend a fan's operating range by allowing it to operate safely at a reduced stall margin. This may also enable the fan to operate in service at a more efficient point on its characteristic.

show abstract

Micro Air Injection and Its Unsteady Response in a Low-Speed Axial Compressor

Cited by 25 publications

References 10 publications

Tip injection as a means for rotating stall control in an axial flow fan

Tip injection as a means for rotating stall control in an axial flow fan

Numerical and Experimental Investigations of Steady Micro‐Tip Injection on a Subsonic Axial‐Flow Compressor Rotor

A Critical Review of Stall Control Techniques in Industrial Fans

Contact Info

Product

Resources

About