Flow Control of Rotating Stall in a Radial Vaneless Diffuser

Tsurusaki, Hiromu; Kinoshita, Takahiro

doi:10.1115/1.1351174

Cited by 20 publications

(6 citation statements)

References 7 publications

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“…Tsujimoto et al [10], who investigated vaneless diffuser rotating stall based on a two-dimensional inviscid flow analysis, have also found that the flows in the vaneless diffuser have a two-dimensional, inviscid, and rotational flow instability. Besides these models, the experimental results of Tsurusaki and Kinoshita [19] also suggested that the instability of the main flow contributes to the onset of rotating stall in vaneless diffuser, which is in agreement with the two models.…”

Section: Discussionsupporting

confidence: 78%

Two‐Dimensional Rotating Stall Analysis in a Wide Vaneless Diffuser

Ljevar

Lange

Steenhoven

2006

International Journal of Rotating Machinery

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We report a numerical study on the vaneless diffuser core flow instability in centrifugal compressors. The analysis is performed for the purpose of better understanding of the rotating stall flow mechanism in radial vaneless diffusers. Since the analysis is restricted to the two-dimensional core flow, the effect of the wall boundary layers is neglected. A commercial code with the standard incompressible viscous flow solver is applied to model the vaneless diffuser core flow in the plane parallel to the diffuser walls. At the diffuser inlet, rotating jet-wake velocity pattern is prescribed and at the diffuser outlet constant static pressure is assumed. Under these circumstances, two-dimensional rotating flow instability similar to rotating stall is found to exist. Performed parameter analysis reveals that this instability is strongly influenced by the diffuser geometry and the inlet and outlet flow conditions.

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Section: Discussionsupporting

confidence: 78%

Two‐Dimensional Rotating Stall Analysis in a Wide Vaneless Diffuser

Ljevar

Lange

Steenhoven

2006

International Journal of Rotating Machinery

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“…Mailach et al 16 studied the effect of tip clearance on rotating stall and explained that the reversed flow in the tip clearance at the leading edge enters the neighboring blade channel around the trailing edge due to self-induced instability. [17][18][19][20][21][22] Pullan et al 21 studied the mechanism of rotating stall at low speed and found a separated vortex extending to the neighboring channel which causes stall of the fan.…”

Section: Introductionmentioning

confidence: 99%

Flow instability in a volute-free centrifugal fan subjected to non-axisymmetric pre-swirl flow from upstream bended inflow tube

Liu

Yang

He³

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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The characteristics of internal flow and performance of a centrifugal fan is greatly dependent on the inflow pattern. As the fan is subjected to incoming flow from an upstream tube, the size and geometry of the tube affect the three-dimensional motion of local flow and possibly degrades the aerodynamic performance of the fan. In this work, we performed a numerical investigation on the internal flow in a centrifugal fan subjected to incoming flow from an upstream bended inflow tube of various radii using the steady and unsteady Reynolds-averaged Navier-Stokes (RANS and URANS) simulation approaches. The effects of the non-axisymmetric pre-swirl flow generated due to the curvature of the bended inflow tube are demonstrated by analyzing the internal flow characteristics of the fan, including the spatial distributions and temporal variations of pressure field and streamlines, pressure fluctuations in the upstream tube, the inflow and outflow sections of the impeller, and the circumferential distributions of velocity and pressure in the impeller. The numerical results reveal that as the inflow tube is curved with larger curvature (smaller radius of the bended section), the pre-swirl inflow is strong and deteriorates the static pressure rise and static pressure efficiency of the centrifugal fan more remarkably, and the circumferential non-uniformity of pressure and velocity distributions appears inside of the channels of the fan. As the radius of the bended section increases, the instability of the internal flow gets more pronounced, as represented by the stronger pressure fluctuations at the inflow and outflow sections. The prediction capabilities of RANS and URANS approaches are also analyzed based on the numerical data and we found that the latter is more reliable in predicting the performance of the fan.

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“…Kurokawa et al [31] have shown that customized radial grooves completely suppressed rotating stall in a vaneless diffuser, however, the implementation resulted in an overall loss of pressure in the diffuser. Alternatively, low-speed blowing has been found to be effective in controlling flow separation in a vaneless diffuser, but resulted in a loss of impellerdiffuser combination performance [32].…”

Section: Introductionmentioning

confidence: 99%

Implementing Rotating Stall Control in a Radial Diffuser Using Microjet Arrays

Gavin

Fernandez

Sellappan

et al. 2018

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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This study is part of our effort to implement and refine microjet-based flow control in realistic and challenging applications. Our goal is to reduce/eliminate rotating stall in the radial diffuser of a production compressor used in commercial heating, ventilation, and air conditioning (HVAC) systems, using microjet arrays. We systematically characterize the flow using pressure and velocity field measurements. At low load conditions, the flow is clearly stalled over a range of RPM where the presence of two rotating stall cells was documented. Circular microjet arrays were integrated in the diffuser and the flow response to actuation was examined. The array closest to the initiation of stall cells was most effective in reattaching the flow. Control led to a very significant increase in the stall margin, reducing the minimum operational mass flow rate to 14% of the design flow rate, half of the original 28% flow rate before microjet control was implemented. The results will show that the parameters found be most effective in the simple configurations proved to be near-optimal for the present surge control application in a much more complex geometry. This provides us confidence that the lessons learned from prior studies can be extended to more complex configurations.

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Flow Control of Rotating Stall in a Radial Vaneless Diffuser

Cited by 20 publications

References 7 publications

Two‐Dimensional Rotating Stall Analysis in a Wide Vaneless Diffuser

Two‐Dimensional Rotating Stall Analysis in a Wide Vaneless Diffuser

Flow instability in a volute-free centrifugal fan subjected to non-axisymmetric pre-swirl flow from upstream bended inflow tube

Implementing Rotating Stall Control in a Radial Diffuser Using Microjet Arrays

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