Influence of Inlet Flow Conditions and Geometries of Centrifugal Vaneless Diffusers on Critical Flow Angle for Reverse Flow

Senoo, Yasutoshi; Kinoshita, Yoshifumi

doi:10.1115/1.3448577

Cited by 89 publications

(85 citation statements)

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“…It is quite possible that the sudden contraction at diffuser inlet creates a diffuser inlet flow distortion. The theory [15] predicts a 3 to 7 deg change in critical flow angle due to inlet distortion.…”

Section: Discussionmentioning

confidence: 99%

Discussion: “Rotating Stall Induced in Vaneless Diffusers of Very Low Specific Speed Centrifugal Blowers” (Kinoshita, Y., and Senoo, Y., 1985, ASME J. Eng. Gas Turbines Power, 107, pp. 514–519)

Braembussche

1985

Journal of Engineering for Gas Turbines and Power

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Section: Discussionmentioning

confidence: 99%

Discussion: “Rotating Stall Induced in Vaneless Diffusers of Very Low Specific Speed Centrifugal Blowers” (Kinoshita, Y., and Senoo, Y., 1985, ASME J. Eng. Gas Turbines Power, 107, pp. 514–519)

Braembussche

1985

Journal of Engineering for Gas Turbines and Power

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“…Even so, if the flow rate is reduced too far, the radial velocity component in the boundary layer on the wall is not sufficient to withstand the radial pressure gradient, and an inward cross-flow occurs near the wall. 21), 22) If the cross-flow exceeds a limit, the flow as a whole becomes unsteady 23) and it is the lower limit of the flow rate for the compressor. Low-solidity cascade diffusers.…”

Section: )mentioning

confidence: 99%

Researches on fluid dynamics of centrifugal compressors

Senoo

2005

Proceedings of the Japan Academy. Ser. B: Physical and Biologic

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Introduction. Centrifugal compressors are widely used for distributing city gas, for transporting natural gas through long pipelines, for liquidizing natural gas, for pressurizing gas at various kinds of chemical plants. Also, they are indispensable as turbo-superchargers for reciprocating engines to increase output power dramatically. In many of these cases, demand for flow rate at high pressure varies during operation at a fixed shaft speed.As complex configurations of turbo-machines make it difficult to analyze the behavior of fluid flow through them theoretically, a lot of empirical descriptions have been used for design. If better understanding on flow in turbo-machines makes it possible to design machines with better efficiency, a considerable amount of energy resources will be saved throughout the world.Basic problems on turbo-machine. As opposed to reciprocating compressors, which are popular as high pressure-ratio and low capacity compressors, turbo-compressors are compact for the capacity and quiet without vibration, as they continuously pressurize fluid by means of high-speed rotating impeller. Consequently they are widely used and especially for large capacity applications in industry turbo-compressors are exclusively adopted.In steady flow, fluid flows toward a zone of low pressure, being accelerated by favorable pressure gradient, but in a diverging passage flow increases the pressure by reducing the velocity. In cases of centrifugal compressors in Fig. 1, this principle is directly applicable only to the diffuser. Flow through a rotating impeller is not steady unless it is observe in the rotating system. That is, if relative velocity in an impeller is reduced, static pressure increases. Using this principle the pressure of flow through a compressor increases pressure both in the impeller and in the diffuser by reducing the relative velocity successively.In cases of axial compressors where diameter of impeller and diffuser remains constant from the inlet to the exit, phenomena induced by rotating impeller and by stationary diffuser are identical to those in cases of centrifugal compressors except that the flow remains on a cylindrical surface.Inlet geometry of vanes. Specifically, in the case of a rotating impeller, straight axial or radial flow toward a rotating impeller is recognized as diagonally incoming flow relative to the impeller. Therefore, at the inlet all the vanes of the impeller should be oriented toward the direction of incoming flow relative to the impeller. Furthermore, the vanes must be curved smoothly toward axial or radial direction so that passages between vanes become wider downstream. Consequently fluid increases pressure while it flows Proc. Japan Acad., 81, Ser. B (2005) Abstract: Turbo-machines (e.g. compressors, blowers and pumps) obtain energy transfer from their rotating impellers to fluid flowing through them, and they are used for a wide range of purposes obtaining pressurized fluid flow. The author created theoretical models to clearly describe the complicated flow...

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“…Where S is the cross sectional area which is equal to Its length L can be estimated by equation (5). It is depending only on the value of the absolute flow angle α at diffuser inlet and is thus increasing with the flow rate decrease (figure 9).…”

Section: Effect Of Rotating Stall On the Diffuser Performancementioning

confidence: 99%

“…(1) Theoretical analysis, which includes three dimensional analysis (Jansen [3], Senoo et al [4,5], Frigne [6], Dou et al [7]) and two dimensional analysis (Tsujimoto [8], Moore [9] and Abdelhamid et al [10]). For two dimensional analysis, it was suggested the 2D core flow instability might be responsible for rotating stall.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study and Theoretical Analysis of the Rotating Stall in a Vaneless Diffuser of Radial Flow Pump

Heng

Ouarzazi

2016

IOP Conf. Ser.: Earth Environ. Sci.

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This paper reports an experimental and theoretical study of rotating stall in a vaneless diffuser which is coupled with a radial impeller. The experiments were conducted at 22 flow rates for two rotating speed: 1200rpm and 1800rpm. The measurements have consisted of: i/ unsteady pressure measurements delivered by two microphones flush mounted on the vaneless diffuser, ii/ 9 steady pressure taps mounted in one radial line on the diffuser to measure the pressure recovery in the vaneless diffuser. The stability of each stall mode was also studied by a 2D linear analysis; and the theoretical prediction was compared to experimental observations. The capabilities and limits of such an approach to predict the development of rotating stall have been evaluated. A non-dimensional analysis of the pressure losses at outlet was conducted to evaluate the effect of the instability development on the performance of the diffuser. It has shown that the arising of rotating stall has a positive effect on the diffuser performance.

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Influence of Inlet Flow Conditions and Geometries of Centrifugal Vaneless Diffusers on Critical Flow Angle for Reverse Flow

Cited by 89 publications

References 0 publications

Discussion: “Rotating Stall Induced in Vaneless Diffusers of Very Low Specific Speed Centrifugal Blowers” (Kinoshita, Y., and Senoo, Y., 1985, ASME J. Eng. Gas Turbines Power, 107, pp. 514–519)

Discussion: “Rotating Stall Induced in Vaneless Diffusers of Very Low Specific Speed Centrifugal Blowers” (Kinoshita, Y., and Senoo, Y., 1985, ASME J. Eng. Gas Turbines Power, 107, pp. 514–519)

Researches on fluid dynamics of centrifugal compressors

Experimental Study and Theoretical Analysis of the Rotating Stall in a Vaneless Diffuser of Radial Flow Pump

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