3D Unsteady Flow and Forces in Centrifugal Impellers With Circumferential Distortion of the Outlet Static Pressure

Fatsis, A.; Pierret, Stéphane; Braembussche, R. A. Van den

doi:10.1115/95-gt-033

Cited by 13 publications

(14 citation statements)

References 7 publications

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“…Relevant studies have showed that the airflow near the volute tongue would appear strong non-uniformity in off-design mass flow condition [4] . Therefore, two typical off-design flow conditions are adopted in this paper.…”

Section: Static Pressure Distribution In the Volutementioning

confidence: 99%

“…It affects the distribution of the pressure and the velocity at the circumferential direction inside the volute. For the vaneless diffuser, these distortions have great influence on the flow field at impeller outlet [3] , which propagates reversely against the mainstream to the leading edge of the impeller [4] , thus, the non-axisymmetric flow is formed in the centrifugal compressor. Additionally, the aerodynamic performance and the operating stability of the compressor can also be reduced due to the effect of the volute on the impeller [5] .…”

Section: Introductionmentioning

confidence: 99%

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Non-axisymmetric flow characteristics in centrifugal compressor

et al. 2015

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The flow field distribution in centrifugal compressor is significantly affected by the non-axisymmetric geometry structure of the volute. The experimental and numerical simulation methods were adopted in this work to study the compressor flow field distribution with different flow conditions. The results show that the pressure distribution in volute is characterized by the circumferential non-uniform phenomenon and the pressure fluctuation on the high static pressure zone propagates reversely to upstream, which results in the non-axisymmetric flow inside the compressor. The non-uniform level of pressure distribution in large flow condition is higher than that in small flow condition, its effect on the upstream flow field is also stronger. Additionally, the non-uniform circumferential pressure distribution in volute brings the non-axisymmetric flow at impeller outlet. In different flow conditions, the circumferential variation of the absolute flow angle at impeller outlet is also different. Meanwhile, the non-axisymmetric flow characteristics in internal impeller can be also reflected by the distribution of the mass flow. The high static pressure region of the volute corresponds to the decrease of mass flow in upstream blade channel, while the low static pressure zone of the volute corresponds to the increase of the mass flow. In small flow condition, the mass flow difference in the blade channel is bigger than that in the large flow condition.

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Section: Static Pressure Distribution In the Volutementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Non-axisymmetric flow characteristics in centrifugal compressor

et al. 2015

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“…This prediction agrees better with the measurements but the remaining discrepancy suggests (and this will be confirmed later) that separation already starts in the volute. (Fatsis et al 1997) and can not be predicted by the simple impeller response model used in the present calculations. However this discrepancy has no large effect on the circumferential pressure distortion which is a major result of these calculations.…”

Section: -Psmentioning

confidence: 60%

“…In the context of the present approach a simple 1D quasi-steady model is proposed. The alternative is an 3D unsteady impeller flow prediction with prescribed outlet pressure distortion (Fatsis et al 1997).…”

Section: R111111111111mentioning

confidence: 99%

Improved Model for the Design and Analysis of Centrifugal Compressor Volutes

Braembussche

Ayder

Hagelstein³

et al. 1998

Volume 1: Turbomachinery

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This paper describes a new model for the analysis of the flow in volutes of centrifugal compressors. It explicitly takes into account the vortical structure of the now that has been observed during detailed 3D flow measurements. It makes use of an impeller and diffuser response model to predict the non-uniformity of the volute inlet flow due, to the circumferential variation of the pressure at the volute inlet, and is therefore applicable also at off-design operation of the volute. Predicted total pressure loss and static pressure rise coefficients at design and off-design operation have been compared with experimental data for different volute geometries but only one test case is presented here. Good agreement in terms of losses and pressure rise is observed at most operating points and confirms the validity of the impeller and diffuser response model.

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“…There is no doubt that, in a near future, new suitable models, issued probably from unsteady three-dimensional calculations using Euler (Fatsis, 1995), or Navier-Stokes solvers (Dawes, 1994), will be efficiently established. But these problems are not readily solved, and a lot of research is still needed.…”

Section: Introductionmentioning

confidence: 99%

Experience in Full Load Testing Natural Gas Centrifugal Compressors for Rotordynamics Improvements

Gelin

Pugnet

Bolusset

et al. 1996

Volume 5: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation;

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During full load shop tests under natural gas, two multistage centrifugal compressors exhibited subsynchronous vibrations. Both of them are low flow, high pressure, high rotational speed compressors, and are fitted with tilting pad bearings, and dry gas seals. A rotating stall problem was firstly eliminated by a modification of the diffuser geometry. Then, aerodynamic excitations caused the rotors to operate at their stability limit, and high vibration levels were observed at the first natural frequency. A complete rotordynamics analysis was performed in order to model precisely all the fluid-structure interactions. Modifications of the rotor designs were implemented, consisting in optimizing conveniently the bearing pads, replacing the toothed labyrinth seals of the balance pistons by damping honeycomb seals, fitting them with improved shunt hole systems. In addition, the dry gas seals were found to have been damaged, due to thermal effects, and further modifications were implemented to eliminate this problem. Final full load tests demonstrated a satisfactory behaviour of both centrifugal compressors.

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3D Unsteady Flow and Forces in Centrifugal Impellers With Circumferential Distortion of the Outlet Static Pressure

Cited by 13 publications

References 7 publications

Non-axisymmetric flow characteristics in centrifugal compressor

Non-axisymmetric flow characteristics in centrifugal compressor

Improved Model for the Design and Analysis of Centrifugal Compressor Volutes

Experience in Full Load Testing Natural Gas Centrifugal Compressors for Rotordynamics Improvements

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