An Experimental Study of Vane Clocking Effects on Embedded Compressor Stage Performance

Key, Nicole L.; Lawless, Patrick B.; Fleeter, Sanford

doi:10.1115/1.3072714

Cited by 28 publications

(14 citation statements)

References 21 publications

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“…There is a clear increase in vane clocking effectiveness beginning somewhere between the high-design and high-loading conditions, after which the clocking effects decline. These trends support the previous vane clocking studies conducted in this compressor, where vane clocking effects were strongest at a high-loading condition [15], but no measurable changes in stall margin aer associated with vane clocking [1]. …”

Section: Overall Stator 2 Total Pressure Losssupporting

confidence: 89%

“…Clocking effects at the design point and a high-loading case have been interrogated in detail previously in this facility, and both conditions are known to have measurable and different influences on stator 2 loss [15]. Rather than monotonically increasing as the compressor is loaded to stall, clocking effects decrease as the compressor is loaded to stall, and previous work has shown that the stalling mass flow for different clocking configurations were nearly the same and within the uncertainty of the flow rate measurements [1].…”

Section: Experimental Approachmentioning

confidence: 99%

“…Key et al [15] measured a change in stage efficiency with clocking in the embedded stage of an intermediate-speed three-stage compressor. This vane clocking study included both the design point and a high-loading condition.…”

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confidence: 99%

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Vane Clocking Effects on Stator Loss for Different Compressor Loading Conditions

Smith

Key

2015

Journal of Propulsion and Power

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Vane clocking is the relative circumferential indexing of adjacent vane rows with similar vane counts, and it affects discrete frequency noise, forced response, and stage performance in axial compressors. The objective of this paper is to investigate vane clocking effects on stator 2 loss for many loading conditions in a three-stage axial compressor. Although previous studies have focused on two or three operating conditions, this is the first to investigate vane clocking effects over many loading conditions. Detailed circumferential traverses of stagnation pressure were acquired for six clocking configurations at six different loading conditions: a low-loading condition, two conditions near design point, two high-loading conditions, and a near-stall condition. Stator 2 wake widths and depths were similar for different clocking configurations at low loadings, but the high-loading cases exhibited larger changes associated with vane clocking, especially near the stator hub. This resulted in different radial total pressure profile shapes for different clocking configurations that, coupled with flow visualization, showed that vane clocking modulates the hub corner separation for the high-loading operating condition. For design-loading and low-loading conditions, the differences in area-averaged stator 2 loss coefficients with vane clocking were small, but changes in loss increased at the high-loading condition and resulted in a 20.6% difference in loss coefficient between the minimum and maximum clocking cases, with local changes near the hub as much as 46.6%. The effect of clocking on vane loss lessened as the stall boundary was approached. Nomenclature CL = clocking configuration N c = corrected rotational speed P = static pressure P o = total pressure R = rotor S = stator Y p = total pressure loss coefficient Subscripts inlet = compressor inlet LE = leading edge MP = midpassage 1-8 = axial stations

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Section: Overall Stator 2 Total Pressure Losssupporting

confidence: 89%

Section: Experimental Approachmentioning

confidence: 99%

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Vane Clocking Effects on Stator Loss for Different Compressor Loading Conditions

Smith

Key

2015

Journal of Propulsion and Power

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“…A probe configuration with five radial probes (P0) on three instrumented stators around the annulus is schematically shown in Figure 1. The time-mean flow field in a multi-stage axial compressor at design operating conditions is circumferentially non-uniform [4], [7], [12]. The flow field is affected by the wakes from the upstream stator rows and the potential fields of the adjacent stationary components.…”

Section: Introductionmentioning

confidence: 99%

Reducing Instrumentation Errors Caused by Circumferential Flow-Field Variations in Multistage Axial Compressors

Chilla

Pullan

Gallimore

2020

Journal of Turbomachinery

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The effects of blade row interactions on stator-mounted instrumentation in axial compressors are investigated using unsteady numerical calculations. The test compressor is an 8-stage machine representative of an aero-engine core compressor. For the unsteady calculations, a 180deg sector (half-annulus) model of the compressor is used. It is shown that the time-mean flow field in the stator leading edge planes is circumferentially non-uniform. The circumferential variations in stagnation pressure and stagnation temperature respectively reach 4.2% and 1.1% of the local mean. Using spatial wave number analysis, the incoming wakes from the upstream stator rows are identified as the dominant source of the circumferential variations in the front and middle of the compressor, while towards the rear of the compressor, the upstream influence of the eight struts in the exit duct becomes dominant. Based on three circumferential probes, the sampling errors for stagnation pressure and stagnation temperature are calculated as a function of the probe locations. Optimization of the probe locations shows that the sampling error can be reduced by up to 77% by circumferentially redistributing the individual probes. The reductions in the sampling errors translate to reductions in the uncertainties of the overall compressor efficiency and inlet flow capacity by up to 50%. Recognizing that data from large-scale unsteady calculations is rarely available in the instrumentation phase for a new test rig or engine, a method for approximating the circumferential variations with single harmonics is presented. The construction of the harmonics ...

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“…6 The experiment in embedded stage of the Purdue Three-Stage Compressor Facility indicated that in the embedded Stage 2 the overall efficiency change induced by the vane clocking was 0.27 points. 7 In addition, the compound-lean stators were adopted in a low speed repeating compressor stage to investigate the strengthened clocking effect, and a maximum efficiency increase of 1.22 points at design condition was obtained. 8 Vane clocking has also been demonstrated to have an effect on the unsteady blade loading.…”

Section: Introductionmentioning

confidence: 99%

An experimental investigation of the vane clocking effects on the centrifugal compressor time-averaged performance

Wuqi

Zhang

et al. 2013

Proceedings of the Institution of Mechanical Engineers, Part A:

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The clocking effect, known as a potential means to improve the aerodynamic performance of the turbomachinery, has been investigated widely in the multistage axial turbomachinery, but little reported on the radial turbomachinery. In the present paper, an experimental investigation was made on the vane clocking effect between the inlet guide vanes and the vaned diffuser in a medium-speed centrifugal compressor. The measured data show that the vane clocking has an effect on the aerodynamic performance of the researched centrifugal compressor stage. At the design point, the maximum efficiency variation is about 0.52 points and the maximum total pressure ratio variation is 0.004. When the inlet guide vane’s stagger angle was adjusted to −45°, the vane clocking effect is strengthened. The maximum efficiency and total pressure ratio variation for the design point, respectively, are 0.67 points and 0.006, and for the low flow rate point even, respectively, increases to 0.90 points and 0.007. The wake characteristics show that the maximum efficiency variation always arises at a similar clocking configuration, in which the upstream inlet guide vanes wake was detected to impinge on the diffuser blade leading edge. In addition, the profile pressure distribution on the diffuser blade was measured in detail and the blade loading analysis shows that there is no measureable variation for the vane clocking effect on the steady diffuser blade loading.

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An Experimental Study of Vane Clocking Effects on Embedded Compressor Stage Performance

Cited by 28 publications

References 21 publications

Vane Clocking Effects on Stator Loss for Different Compressor Loading Conditions

Vane Clocking Effects on Stator Loss for Different Compressor Loading Conditions

Reducing Instrumentation Errors Caused by Circumferential Flow-Field Variations in Multistage Axial Compressors

An experimental investigation of the vane clocking effects on the centrifugal compressor time-averaged performance

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