A simplified approach for control of rotating stall. II - Experimental results

Badmus, O. O.; Chowdhury, Shajjad; Eveker, K. M.; Nett, C. N.; Rivera, Carlos Mallén

doi:10.2514/6.1993-2234

Cited by 14 publications

(13 citation statements)

References 3 publications

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“…In contrast, a modal wave occupies length scales comparable to the annulus circumference and travels at slower speeds. Several other researchers have also used this approach to explore the stall inception mechanism under clean [6][7][8] and distorted inflow conditions [2,[9][10][11][12]. Nie et al [3] demonstrated the effects of dynamic inlet flow distortion on a low-speed singlestage axial flow compressor.…”

Section: Introductionmentioning

confidence: 97%

“…As per this approach, the axisymmetric equilibrium is stable as long as it lies within the stable flow range. Further, this control approach was experimentally validated on a single-stage low-speed axial compressor [11]. Anderson et al [12] used vortex generators for the secondary flow control at the engine face under circumferential inflow distortion.…”

Section: Introductionmentioning

confidence: 99%

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Stall inception and its control in an axial flow fan under dynamic inflow distortion

Salunkhe

Pradeep

2009

Proceedings of the Institution of Mechanical Engineers, Part A:

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The present experimental study demonstrates the effects of clean and distorted inflow conditions on the performance and nature of stall inception in a single stage axial flow fan. A 90 • distortion screen located upstream of the rotor leading edge was rotated up to 40 per cent of the rotor speed in the clockwise (co-rotation) and counterclockwise (counter-rotation) directions to generate dynamic inflow distortion. It was observed that the stall margin deteriorated substantially under co-rotating inflow distortion as compared to counter-rotating inflow distortion. The degradation in stall margin was about 15 per cent and 1.98 per cent under co-and counterrotating inflow distortions, respectively. Tip injection was used as a means of enhancing the fan performance under distorted inflow. With tip injection under co-rotating inflow distortion, about 2.8 per cent improvement in stall margin was observed. The improvement in stall margin under counter-rotating inflow distortion with tip injection was 2.98 per cent. The unsteady static pressure traces show clear differences in the nature of stall inception under co-and counterrotating inflow distortions. The stall inception occurs through long-length-scale disturbances under co-rotating inflow distortion, while the mode of stall inception under clean flow and counter-rotating inflow distortions was through short-length-scale disturbances. The nature of stall inception under dynamic inflow distortion with tip injection remains the same as without tip injection.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Stall inception and its control in an axial flow fan under dynamic inflow distortion

Salunkhe

Pradeep

2009

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…A common type of sensor is an array of hot-wire anemometers, perhaps in a "cross" arrangement, (2) and (3) are installed between the inlet guide vanes and the first stage of the compressor. With actuators (I), (2), and one of (3) it is possible to produce a "traveling wave" input because they can be activated individually. This requires each vane to have its own motor or each air inlet to have its own valve, a costly, complicated, and failure prone setup.…”

Section: An Altemative Compressor Model Is Developed In [141mentioning

confidence: 99%

“…The cycle starts at (1) where the flow becomes unstable. It then goes very fast (approximately represented by the straight line) to the negative flow characteristic at (2) and descends this until the flow is approximately zero (3). Then it proceeds very fast to the normal characteristic at (4) where it starts to climb to point (1).…”

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Rotating stall and surge control: a survey

Jager

Proceedings of 1995 34th IEEE Conference on Decision and Control

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The AbstractThe paper presents an analysis of the current state of the art in the control of aero-or hydrodynamic instabilities in turbomachines. It describes the flow phenomena associated with rotating stall and surge, discusses methods devised to prevent these instabilities to occur, but concentrates mainly on the active control (stabilization) of the unstable flows. It appears that lately significant progress has been made in this area. It seems to foster to a more mature state, although several problems deserve further consideration. The consequences of this state of the art for several interested parties, researchers, developers, manufacturers, and users, are stipulated. The MotivationThere are two main types of continuous flow compressors: the axial compressor, where the flow leaves the compressor in the direction parallel to the rotational axis, and the centrifugal compressor, where the flow leaves the compressor in the direction perpendicular to the rotational axis. Rotating stall, surge, and other flow instabilities occur in turbomachinery, in particular in axial and radial compressors, and limit its efficiency and effectiveness, and by that its usefulness. Preventing these instabilities to occur would benefit the large community of users of turbomachines where these phenomena are important in employing this equipment. The PhenomenaRotating stall is an instability phenomenon, local to the compressor, in which a Circumferentially uniform flow pattem is disturbed. A local region or local regions appear where the flow is stagnant: the flow stalls. The regions propagate in the same direction as the blades (i.e., regions of stall rotate around the annular flow path), at a fraction of the rotor speed. This speed is often between one fifth and half of the wheel speed, at least for fully developed stall, initial rotating stall cells move faster [9]. The part of the area of the annular flow path the stalled regions occupy may also grow exponentially with time, until a certain size is reached. This depends on the slope of the pressure/flow characteristic for constant speed in the compressor performance map, in the sequel called compressor Characteristic or speed lines, and compressor map, respectively, see Fig. 1. 4The essential differences between rotating stall and surge are that the average flow in pure rotating stall is steady in time, but the flow has a circumferentially nonuniform mass deficit, while in pure surge the flow is unsteady but circumferentially uniform. Because it is steady, rotating stall may be local to the compressor or to parts of the compressor. Due to its unsteadiness, surge involves the entire compression system. So, the phenomena can be regarded as distinct. On the other hand, both phenomena are natural oscillatory modes of the compression system, with surge corresponding to the lowest (zero) order mode, and thus they are related [30,36].Discussions are still ongoing if rotating stall is important for centrifugal compressors, and perhaps also single stage axial compressors, or if only sur...

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1995

Applied Nonlinear Dynamics

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A simplified approach for control of rotating stall. II - Experimental results

Cited by 14 publications

References 3 publications

Stall inception and its control in an axial flow fan under dynamic inflow distortion

Stall inception and its control in an axial flow fan under dynamic inflow distortion

Rotating stall and surge control: a survey

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