Rotor-Stator Interactions in a Four-Stage Low-Speed Axial Compressor—Part II: Unsteady Aerodynamic Forces of Rotor and Stator Blades

2004 ◽  
Vol 126 (4) ◽  
pp. 519-526 ◽  
Author(s):  
Ronald Mailach ◽  
Lutz Mu¨ller ◽  
Konrad Vogeler
Keyword(s):  
Aerodynamic Force ◽  
Axial Compressor ◽  
Stability Limit ◽  
Experimental Investigations ◽  
Low Speed ◽  
Unsteady Aerodynamic ◽  
Pressure Distributions ◽  
Third Stage ◽  
Blade Row ◽  
Stator Blade

This two-part paper presents detailed experimental investigations of unsteady aerodynamic blade row interactions in the four-stage low-speed research compressor of Dresden. In Part I of the paper the unsteady profile pressure distributions for the nominal setup of the compressor are discussed. Furthermore the effect of blade row clocking on the unsteady profile pressures is investigated. Part II deals with the unsteady aerodynamic blade forces, which are determined from the measured profile pressure distributions. A method to calculate the aerodynamic blade forces on the basis of the experimental data is presented. The resulting aerodynamic blade forces are discussed for the rotor and stator blade rows of the first stage and the third stage of the compressor. Different operating points between design point and stability limit of the compressor were chosen to investigate the influence of loading on the aerodynamic force excitation. The time traces and the frequency contents of the unsteady aerodynamic blade force are discussed. Strong periodic influences of the incoming wakes and of potential effects of downstream blade rows can be observed. The amplitude and shape of the unsteady aerodynamic blade force depend on the interaction of the superimposed influences of the blade rows.

Rotor-Stator Interactions in a Four-Stage Low-Speed Axial Compressor: Part II — Unsteady Aerodynamic Forces of Rotor and Stator Blades

2004 ◽  
Author(s):  
Ronald Mailach ◽  
Lutz Mu¨ller ◽  
Konrad Vogeler
Keyword(s):  
Aerodynamic Force ◽  
Axial Compressor ◽  
Stability Limit ◽  
Experimental Investigations ◽  
Low Speed ◽  
Unsteady Aerodynamic ◽  
Pressure Distributions ◽  
Third Stage ◽  
Blade Row ◽  
Stator Blade

This two-part paper presents detailed experimental investigations of unsteady aerodynamic blade row interactions in the four-stage Low-Speed Research Compressor of Dresden. In part I of the paper the unsteady profile pressure distributions for the nominal setup of the compressor are discussed. Furthermore the effect of blade row clocking on the unsteady profile pressures is investigated. Part II deals with the unsteady aerodynamic blade forces, which are determined from the measured profile pressure distributions. A method to calculate the aerodynamic blade forces on the basis of the experimental data is presented. The resulting aerodynamic blade forces are discussed for the rotor and stator blade rows of the first stage and the third stage of the compressor. Different operating points between design point and stability limit of the compressor were chosen to investigate the influence of loading on the aerodynamic force excitation. The time traces and the frequency contents of the unsteady aerodynamic blade force are discussed. Strong periodic influences of the incoming wakes and of potential effects of downstream blade rows can be observed. The amplitude and shape of the unsteady aerodynamic blade force depend on the interaction of the superimposed influences of the blade rows.

Rotor-Stator Interactions in a Four-Stage Low-Speed Axial Compressor—Part I: Unsteady Profile Pressures and the Effect of Clocking

2004 ◽  
Vol 126 (4) ◽  
pp. 507-518 ◽  
Author(s):  
Ronald Mailach ◽  
Konrad Vogeler
Keyword(s):  
Pressure Distribution ◽  
Axial Compressor ◽  
Leading Edge ◽  
Suction Side ◽  
Experimental Investigations ◽  
Low Speed ◽  
Unsteady Aerodynamic ◽  
Pressure Distributions ◽  
Blade Row ◽  
Pressure Changes

This two-part paper presents detailed experimental investigations of unsteady aerodynamic blade row interactions in the four-stage Low-Speed Research Compressor of Dresden. In part I of the paper the unsteady profile pressure distributions for the nominal setup of the compressor are discussed. Furthermore, the effect of blade row clocking on the unsteady profile pressures is investigated. Part II deals with the unsteady aerodynamic blade forces, which are calculated from the measured profile pressure distributions. The unsteady pressure distributions were analyzed in the first, a middle and the last compressor stage both on the rotor and stator blades. The measurements were carried out on pressure side and suction side at midspan. Several operating points were investigated. A complex behavior of the unsteady profile pressures can be observed, resulting from the superimposed influences of the wakes and the potential effects of several up- and downstream blade rows of the four-stage compressor. The profile pressure changes nearly simultaneously along the blade chord if a disturbance arrives at the leading edge or the trailing edge of the blade. Thus the unsteady profile pressure distribution is nearly independent of the convective wake propagation within the blade passage. A phase shift of the reaction of the blade to the disturbance on the pressure and suction side is observed. In addition, clocking investigations were carried out to distinguish between the different periodic influences from the surrounding blade rows. For this reason the unsteady profile pressure distribution on rotor 3 was measured, while stators 1–4 were separately traversed stepwise in the circumferential direction. Thus the wake and potential effects of the up- and downstream blade rows on the unsteady profile pressure could clearly be distinguished and quantified.

Rotor-Stator Interactions in a Four-Stage Low-Speed Axial Compressor: Part I — Unsteady Profile Pressures and the Effect of Clocking

2004 ◽  
Author(s):  
Ronald Mailach ◽  
Konrad Vogeler
Keyword(s):  
Pressure Distribution ◽  
Axial Compressor ◽  
Leading Edge ◽  
Suction Side ◽  
Experimental Investigations ◽  
Complex Behaviour ◽  
Low Speed ◽  
Unsteady Aerodynamic ◽  
Pressure Distributions ◽  
Blade Row

This two-part paper presents detailed experimental investigations of unsteady aerodynamic blade row interactions in the four-stage Low-Speed Research Compressor of Dresden. In part I of the paper the unsteady profile pressure distributions for the nominal setup of the compressor are discussed. Furthermore the effect of blade row clocking on the unsteady profile pressures is investigated. Part II deals with the unsteady aerodynamic blade forces, which are calculated from the measured profile pressure distributions. The unsteady pressure distributions were analysed in the first, a middle and the last compressor stage both on the rotor and stator blades. The measurements were carried out on pressure side and suction side at midspan. Several operating points were investigated. A complex behaviour of the unsteady profile pressures can be observed, resulting from the superimposed influences of the wakes and the potential effects of several up- and downstream blade rows of the four-stage compressor. The profile pressure changes nearly simultaneously along the blade chord if a disturbance arrives at the leading edge or the trailing edge of the blade. Thus the unsteady profile pressure distribution is nearly independent of the convective wake propagation within the blade passage. A phase shift of the reaction of the blade to the disturbance on the pressure and suction side is observed. In addition clocking investigations were carried out to distinguish between the different periodic influences from the surrounding blade rows. For this reason the unsteady profile pressure distribution on rotor 3 was measured, while stator 1–4 were separately traversed stepwise in the circumferential direction. Thus the wake and potential effects of the up- and downstream blade rows on the unsteady profile pressure could clearly be distinguished and quantified.

scholarly journals The Turbine Regime of a Rear Axial Compressor Stage

1990 ◽  
Author(s):  
Václav Cyrus
Keyword(s):  
Aspect Ratio ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Compressor Stage ◽  
Flow Mechanism ◽  
Three Dimensional Flow ◽  
Low Speed ◽  
Dimensional Flow ◽  
Blade Row ◽  
Stator Blade

A detailed investigation of three-dimensional flow has been carried out in a low speed rear axial compressor stage with aspect ratio of 1 at the extreme off-design condition-turbine regime. Measurements were performed by means of both stationery and rotating pressure probes. The mechanism of flow in the rotor and stator blade row in the turbine regime is analysed. Comparison is made with flow mechanism at the design condition.

Effects of inlet radial distortion on the type of stall precursor in low-speed axial compressor

2016 ◽  
Vol 232 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Ali Arshad ◽  
Qiushi Li ◽  
Simin Li ◽  
Tianyu Pan
Keyword(s):  
Pressure Fluctuations ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Experimental Investigations ◽  
Inlet Flow ◽  
Blade Loading ◽  
Stall Inception ◽  
Low Speed ◽  
Modal Type ◽  
Stall Precursor

Experimental investigations of the effect of inlet blade loading on the rotating stall inception process are carried out on a single-stage low-speed axial compressor. Temporal pressure signals from the six high response pressure transducers are used for the analysis. Pressure variations at the hub are especially recorded during the stall inception process. Inlet blade loading is altered by installing metallic meshed distortion screens at the rotor upstream. Three sets of experiments are performed for the comparison of results, i.e. uniform inlet flow, tip, and hub distortions, respectively. Regardless of the type of distortion introduced to the inflow, the compressor undergoes a performance drop, which is more severe in the hub distortion case. Under the uniform inlet flow condition, stall inception is caused by the modal type disturbance while the stall precursor switched to spike type due to the highly loaded blade tip. In the presence of high blade loading at the hub, spike disappeared and the compressor once again witnessed a modal type disturbance. Hub pressure fluctuations are observed throughout the process when the stall is caused by a modal wave while no disturbance is noticed at the hub in spike type stall inception. It is believed that the hub flow separation contributes to the modal type of stall inception phenomenon. Results are also supported by the recently developed signal processing techniques for the stall inception study.

A Comparison Between the Design Point and Near-Stall Performance of an Axial Compressor

1990 ◽  
Vol 112 (1) ◽  
pp. 109-115 ◽  
Author(s):  
N. M. McDougall
Keyword(s):  
Rotor Blade ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Tip Clearance ◽  
Tip Clearance Flow ◽  
Design Point ◽  
Blade Row ◽  
Clearance Flow ◽  
Stator Blade

Detailed measurements have been made within an axial compressor operating both at design point and near stall. Rotor tip clearance was found to control the performance of the machine by influencing the flow within the rotor blade passages. This was not found to be the case in the stator blade row, where hub clearance was introduced beneath the blade tips. Although the passage flow was observed to be altered dramatically, no significant changes were apparent in the overall pressure rise or stall point. Small tip clearances in the rotor blade row resulted in the formation of corner separations at the hub, where the blade loading was highest. More representative clearances resulted in blockage at the tip due to the increased tip clearance flow. The effects that have been observed emphasize both the three-dimensional nature of the flow within compressor blade passages, and the importance of the flow in the endwall regions in determining the overall compressor performance.

scholarly journals A Three Dimensional Computational Study of Windage Heating Within an Axial Compressor Stator Well

1998 ◽  
Author(s):  
H. K. Ozturk ◽  
P. R. N. Childs ◽  
A. B. Turner ◽  
J. M. Hannis ◽  
J. R. Turner
Keyword(s):  
Flow Rate ◽  
Computational Study ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Labyrinth Seal ◽  
Leakage Flows ◽  
Temperature Boundary ◽  
Blade Row ◽  
Stator Blade ◽  
Tip Leakage Flows

Shrouded stator blades are sometimes used to prevent vibration problems, but more often they are used to eliminate blade over-tip leakage flows. A trench or recess referred to as a stator well must be provided in the rotor drum assembly in order to accommodate the stator shroud. This paper presents a computational study of the flow and windage generation within an axial compressor stator well. Windage heating levels for a three dimensional compressible solution of flow through a geometry comprising upstream and downstream stator well cavities, labyrinth seal and the stator blade row are quantified. The potential for hot fluid ejected from the upstream stator well seal into the mainstream annulus, migrating through the blade row and being re-ingested at the downstream stator well seal for further windage heating has been studied using a layered temperature boundary condition at entry to the stator row. The possible reconfiguration of detailed stator well geometry has been explored to identify options for controlling flow rate and reducing windage levels, other than controlling clearances, yielding a 9% reduction in flow rate and a 9% reduction in windage heating.

A Comparison Between the Design Point and Near Stall Performance of an Axial Compressor

1989 ◽  
Author(s):  
N. M. McDougall
Keyword(s):  
Rotor Blade ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Tip Clearance ◽  
Tip Clearance Flow ◽  
Design Point ◽  
Blade Row ◽  
Clearance Flow ◽  
Stator Blade

Detailed measurements have been made within an axial compressor operating both at design point and near stall. Rotor tip clearance was found to control the performance of the machine by influencing the flow within the rotor blade passages. This was not found to be the case in the stator blade row, where hub clearance was introduced beneath the blade tips. Although the passage flow was observed to be altered dramatically, no significant changes were apparent in the overall pressure rise or stall point. Small tip clearances in the rotor blade row resulted in the formation of corner separations at the hub, where the blade loading was highest. More representative clearances resulted in blockage at the tip due to the increased tip clearance flow. The effects which have been observed emphasize both the three dimensional nature of the flow within compressor blade passages, and the importance of the flow in the endwall regions in determining the overall compressor performance.

The Potential of Rotor and Stator Clocking in a 2.5-Stage Low-Speed Axial Compressor

2012 ◽  
Author(s):  
J. Städing ◽  
J. Friedrichs ◽  
T. Waitz ◽  
C. Dobriloff ◽  
B. Becker ◽  
...  
Keyword(s):  
Axial Compressor ◽  
Axial Flow ◽  
Pressure Rise ◽  
Boundary Layer Transition ◽  
Experimental Investigations ◽  
Layer Transition ◽  
Low Speed ◽  
Beneficial Effects ◽  
Pass Through ◽  
Flow Compressor

Detailed experimental investigations have been conducted to gain profound knowledge of airfoil clocking mechanisms in axial compressors. Clocking, the circumferential indexing of adjacent rotor or stator rows with equal blade counts, is known as a potential means to modify the flow field in multistage turbo-machinery and increase overall efficiencies of both turbines and compressors. These beneficial effects on turbomachine performance are due to wake-airfoil interactions and primarily depend on the alignment of a downstream blade or vane row with upstream wake trajectories that are generated in the same frame of reference. The present survey describes and discusses the experimental research on Rotor and Stator Clocking effects in a low-speed 2.5-stage axial flow compressor. For both Rotor and Stator Clocking, variations of Stage 2 performance have been found that are sinusoidal in trend over the clocking angle and originate from a significant change in static pressure rise across the clocked blade rows. Time-averaged measurements basically suggest the highest pressure gain, if the upstream wakes pass through mid-passage of the downstream blade row. In case of Rotor Clocking, this may even lead to a variation in compressor operating range. The fundamental aerodynamic mechanism responsible for the clocking effect can be attributed to a shift of the suction-sided boundary layer transition over the clocking angle. Regarding overall Stage 2 performance, the investigations show that Full Clocking, i.e. the combination of Rotor and Stator Clocking, nearly doubles the potential of single row indexing.

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