scholarly journals Closure to “Discussion of ‘Detailed Flow Measurements in a Centrifugal Compressor Vaneless Diffuser’” (1994, ASME J. Turbomach., 116, pp. 460–461)

1994 ◽  
Vol 116 (3) ◽  
pp. 461-461
Author(s):  
A. Pinarbasi ◽  
M. W. Johnson
Keyword(s):  
Centrifugal Compressor ◽  
Vaneless Diffuser ◽  
Flow Measurements

Off-Design Flow Measurements in a Centrifugal Compressor Vaneless Diffuser

1995 ◽  
Vol 117 (4) ◽  
pp. 602-608 ◽  
Author(s):  
A. Pinarbasi ◽  
M. W. Johnson
Keyword(s):  
Flow Rate ◽  
Centrifugal Compressor ◽  
Secondary Flows ◽  
Design Flow ◽  
Vaneless Diffuser ◽  
Flow Measurements ◽  
Vaned Diffuser ◽  
Flow Angle ◽  
Flow Rates ◽  
Study Results

Detailed measurements have been taken of the three-dimensional velocity field within the vaneless diffuser of a backswept low speed centrifugal compressor using hot-wire anemometry. A 16 percent below and an 11 percent above design flow rate were used in the present study. Results at both flow rates show how the blade wake mixes out more rapidly than the passage wake. Strong secondary flows inherited from the impeller at the higher flow rate delay the mixing out of the circumferential velocity variations, but at both flow rates these circumferential variations are negligible at the last measurement station. The measured tangential/radial flow angle is used to recommend optimum values for the vaneless space and vane angle for design of a vaned diffuser.

Detailed Flow Measurements in a Centrifugal Compressor Vaneless Diffuser

1994 ◽  
Vol 116 (3) ◽  
pp. 453-460 ◽  
Author(s):  
A. Pinarbasi ◽  
M. W. Johnson
Keyword(s):  
Centrifugal Compressor ◽  
Turbulent Mixing ◽  
Phase Lock Loop ◽  
Wake Flow ◽  
Hot Wire ◽  
Velocity Measurements ◽  
Vaneless Diffuser ◽  
Flow Measurements ◽  
Loop Technique ◽  
Made In

Hot-wire anemometer measurements have been made in the vaneless diffuser of a 1-m-dia low-speed backswept centrifugal compressor using a phase lock loop technique. Radial, tangential, and axial velocity measurements have been made on eight measurement planes through the diffuser. The flow field at the diffuser entry clearly shows the impeller jet-wake flow pattern and the blade wakes. The passage wake is located on the shroud side of the diffuser and mixes out slowly as the flow moves through the diffuser. The blade wakes, on the other hand, distort and mix out rapidly in the diffuser. Contours of turbulent kinetic energy are also presented on each of the measurement stations, from which the regions of turbulent mixing can be deduced.

Experimental and Numerical Investigation of the Flow in a Vaneless Diffuser of a Centrifugal Compressor Stage. Part 2: Numerical Investigation

2005 ◽  
Vol 219 (10) ◽  
pp. 1061-1068 ◽  
Author(s):  
T Sato ◽  
J M Oh ◽  
A Engeda
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
High Flow ◽  
Flow Coefficient ◽  
Compressor Stage ◽  
Vaneless Diffuser ◽  
Flow Measurements ◽  
Centrifugal Compressor Stage ◽  
Improved Performance ◽  
Very High

As user demands grew for improved performance and more reliable equipment and as compressor vendors sought improved analytical and design methodologies, the application of computational fluid dynamics (CFD) in the industrial world became a necessity. Fortunately, large increases in available, economic computing power together with development of improved computational methods now provide the industrial designer with much improved analytic capability. As CFD algorithms and software have continued to be developed and refined, it remains essential that validation studies be conducted in order to ensure that the results are both sufficiently accurate and can be obtained in a robust and predictable manner. Part I of this paper presented detailed flow measurements in a vaneless diffuser of a centrifugal compressor stage with a very high flow coefficient radial impeller, where measurements were carried out in the vaneless diffuser at seven radial positions downstream of the radial impeller designed for a very high flow coefficient of ϕ = 0.2. This paper, Part II, attempts to verify and validate the results numerically.

Detailed Flow Measurements in a Centrifugal Compressor Vaneless Diffuser

1993 ◽  
Author(s):  
Ali Pinarbasi ◽  
Mark W. Johnson
Keyword(s):  
Centrifugal Compressor ◽  
Turbulent Mixing ◽  
Phase Lock Loop ◽  
Wake Flow ◽  
Hot Wire ◽  
Velocity Measurements ◽  
Vaneless Diffuser ◽  
Flow Measurements ◽  
Loop Technique ◽  
Made In

Hot wire anemometer measurements have been made in the vaneless diffuser of a 1 metre diameter low speed backswept centrifugal compressor using a phase lock loop technique. Radial, tangential and axial velocity measurements have been made on eight measurement planes through the diffuser. The flow field at the diffuser entry clearly shows the impeller jet-wake flow pattern and the blade wakes. The passage wake is located on the shroud side of the diffuser and mixes out slowly as the flow moves through the diffuser. The blade wakes, on the other hand, distort and mix out rapidly in the diffuser. Contours of turbulent kinetic energy are also presented on each of the measurement stations, from which the regions of turbulent mixing can be deduced.

scholarly journals Detailed Off Design Flow Measurements in a Centrifugal Compressor Vaned Diffuser

1997 ◽  
Author(s):  
Ali Pinarbasi ◽  
Mark W. Johnson
Keyword(s):  
Centrifugal Compressor ◽  
Flow Characteristic ◽  
Design Flow ◽  
Wake Flow ◽  
Centrifugal Impeller ◽  
Hot Wire ◽  
Vaneless Diffuser ◽  
Mean Velocity ◽  
Flow Measurements ◽  
Vaned Diffuser

Three component hot wire measurements in the vaneless space and vane region of a low speed centrifugal compressor vaned diffuser are presented. These comprise mean velocity and turbulence level distributions for a below and above design flow rate for three vane-to-vane locations at each of five radial measurement stations. The flow entering the diffuser closely resembles the classic jet-wake flow characteristic of centrifugal impeller discharges. A strong upstream influence of the diffuser vanes is observed which results in significant variations in flow quantities between the vane-to-vane locations. The circumferential variations due to the passage and blade wakes rapidly mix out in the vaneless space, although some variations are still discernible in the vaned region. Comparison with results in a vaneless diffuser suggest that the presence of the vanes accelerates this mixing out process.

Clearance Effects on the Evolution of the Flow in the Vaneless Diffuser of a Centrifugal Compressor at Part Load Condition

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Matthias Schleer ◽  
Reza S. Abhari
Keyword(s):  
Flow Structure ◽  
Centrifugal Compressor ◽  
Load Condition ◽  
Tip Clearance ◽  
Small Scale ◽  
Vaneless Diffuser ◽  
Data Set ◽  
Flow Measurements ◽  
Part Load ◽  
Clearance Flow

This work reports on flow measurements taken within the vaneless diffuser of a scaled-up model of a small-scale, highly loaded unshrouded compressor with large relative tip clearance. The aims are to describe and to analyze the influence of the clearance flow on the flow structure at the impeller exit in part load operation. The kind of compressor described herein is widely used in distributed power applications and automotive turbocharging. It demands further enhancement of the operation range, as well as a high head rise and an improved efficiency. Therefore, the understanding of flow features and their interaction is crucial. The interaction and mixing of the flow pattern downstream of the impeller are shown using spatially and temporally resolved 3D-velocity data. The measurements have been obtained by using a 3D laser Doppler anemometry system throughout the vaneless parallel wall diffuser. This unique data set provides insight into the development of the flow within the diffuser and allows conclusions on the mixing and migration of the three-dimensional pattern. The flow structure in part load condition is strongly affected by the flow across the large relative tip gap. Due to the large relative tip clearance, a low momentum zone is formed as an additional pattern at the shroud. This clearance flow is highly vortical and interacts with the channel wake structure but remains stable throughout the vaneless diffuser. At the pressure side hub corner, a jet structure is formed, which interacts rapidly with the blade wake. This flow behavior does not comply with the classical jet-wake pattern. It is proposed that in a centrifugal compressor with large relative tip clearance, a modified flow model that includes tip leakage is more appropriate to describe the flow structure at part load condition.

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