scholarly journals Blade Row Interaction Effects on the Performance of a Moderately Loaded NASA Transonic Compressor Stage

2002 ◽  
Author(s):  
Dale E. Van Zante ◽  
Wai-Ming To ◽  
Jen-Ping Chen
Keyword(s):  
Experimental Data ◽  
Velocity Field ◽  
Interaction Effects ◽  
Operating Conditions ◽  
Laser Doppler Velocimeter ◽  
Compressor Stage ◽  
Peak Efficiency ◽  
Transonic Compressor ◽  
Blade Row ◽  
Blade Row Interaction

Blade row interaction effects on loss generation in compressors have received increased attention as compressor work-per-stage and blade loading have increased. Two dimensional Laser Doppler Velocimeter measurements of the velocity field in a NASA transonic compressor stage show the magnitude of interactions in the velocity field at the peak efficiency and near stall operating conditions. The experimental data are presented along with an assessment of the velocity field interactions. In the present study the experimental data are used to confirm the fidelity of a three-dimensional, time-accurate, Navier Stokes calculation of the stage using the MSU-TURBO code at the peak efficiency and near stall operating conditions. The simulations are used to quantify the loss generation associated with interaction phenomena. At the design point the stator pressure field has minimal effect of the rotor performance. The rotor wakes do have an impact on loss production in the stator passage at both operating conditions. A method for determining the potential importance of blade row interactions on performance is presented.

The Unsteady Loss in One-Stage Transonic Compressor Under Peak Efficiency and Near Stall Conditions

2008 ◽  
Author(s):  
Yutao Sun ◽  
Yu-Xin Ren ◽  
Song Fu ◽  
Aspi R. Wadia
Keyword(s):  
Operating Conditions ◽  
Flow Structures ◽  
Surface Boundary ◽  
Peak Efficiency ◽  
Suction Surface ◽  
Loss Mechanism ◽  
Transonic Compressor ◽  
Thermodynamic Irreversibility ◽  
Unsteady Rans ◽  
Blade Row Interaction

The loss mechanism due to the blade row interaction effects in a compressor is an important and interesting problem. In the present paper, the loss in a compressor stage under both peak efficiency (PE) and near stall (NS) operating conditions is studied numerically by solving the 3D unsteady RANS equations. The loss is measured in terms of the thermodynamic irreversibility. In order to examine the relationship between loss and flow structures, an intensive parameter called the intensity of irreversibility is derived. The relative importance of various flow structures in loss production has been identified by the orders of the intensity of irreversibility. An audit of the irreversibility has been carried out, which shows the importance of suction surface boundary layers and the tip leakages in loss generation. Under the NS conditions, the tip leakages are the most important sources of loss production. The unsteady evolution of irreversibility in the rotor and stator passage is also analyzed.

Study of Steady State and Transient Blade Row CFD Methods in a Moderately Loaded NASA Transonic High-Speed Axial Compressor Stage

2013 ◽  
Author(s):  
Mohammed Abdullah Qizar ◽  
Mahmoud L. Mansour ◽  
Shraman Goswami
Keyword(s):  
Steady State ◽  
High Speed ◽  
Transient Flow ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Computational Time ◽  
Laser Doppler Velocimeter ◽  
Compressor Stage ◽  
Steady Stage ◽  
Blade Row

The effect of blade row interaction and hub leakage flow on the performance of moderately loaded NASA transonic hybrid compressor stage (Rotor 35 / Stator 37) is investigated through three-dimensional steady state and time-accurate, Navier Stokes calculations of the stage using the ANSYS CFX code at peak efficiency and near stall operating conditions. Understanding unsteady flow phenomena in compressor stages requires the use of time-accurate CFD simulations. Due to the inherent differences in blade counts between adjacent blade rows, the flow conditions at any given instant in adjacent blade rows differ. Depending on the blade counts, it may be necessary to model the entire annulus of the stage; however, this requires considerable computational time and memory resources. Several methods for modeling the transient flow in turbo machinery stages which require a minimal number of blade passages per row, and therefore reduced computational demands, have been presented in the literature. Recently, some of these methods have become available in commercial CFD solvers. The paper describes the steady and the unsteady CFD approaches used for investigating the ability to predict the measured performance of the NASA transonic axial stage design known as the hybrid stage, which consists of the axial Rotor35 and the axial stator 37. The steady approach employs the mixing-plane while the unsteady approaches are URANS with one based on full annulus simulation for the stage and the second enables simulations for the stage using reduced computational model, with a single passage from each blade row based on the time-tilting or the time-transformation technique. The above methods are evaluated and compared in terms of computational efficiency and comparison is made to steady stage simulations. Comparisons to overall performance data and two-dimensional Laser Doppler Velocimeter measurements of the velocity field are used to assess the predictive capabilities of the methods. Computed flow features are examined, and compared with reported measurements. This paper presents validation and calibration of methods used for determining blade row interactions and the respective predictive capabilities against the full annulus and the experimental test data.

Evaluation of Experimental Data From a Highly Loaded Transonic Compressor Stage to Determine Loss Sources

2015 ◽  
Author(s):  
David P. Lurie ◽  
Andrew Breeze-Stringfellow
Keyword(s):  
Experimental Data ◽  
Compressor Stage ◽  
Peak Efficiency ◽  
Two Stage ◽  
Transonic Compressor ◽  
Pressure Surface ◽  
Point Tracking ◽  
Pile Up ◽  
Compressor Design ◽  
Highly Loaded

An advanced GE compressor design with high reaction and stage loading, demonstrated front stage efficiencies significantly lower than predicted by CFD calculations. The source of the efficiency miss has proven difficult to pinpoint with conventional inter-stage instrumentation. A test was performed in the NASA Glenn W7 facility with the compressor operating as both a single stage and a two stage machine allowing for the acquisition of detailed traverses at each station throughout the compressor. This paper presents the data from this test and the GE interpretation of what the data implies, concentrating particularly on one operating point, the stage one peak efficiency point. Tracking of the calculated fluid entropy between the exit of the rotor and the exit of the stator leads to the conclusion that there is significant entropy increase in the freestream fluid outside the stator wakes and this loss is believed to be attributable to mixing loss in the rotor wakes. The loss due to wake mixing is largest, and may indeed be amplified, where the rotor wakes pile up on the pressure surface of the stator.

scholarly journals Navier-Stokes and Potential Calculations of Axial Spacing Effect on Vortical and Potential Disturbances and Gust Response in an Axial Compressor

1995 ◽  
Author(s):  
Meng-Hsuan Chung ◽  
Andrew M. Wo
Keyword(s):  
Lower Order ◽  
Spacing Effect ◽  
Axial Compressor ◽  
Interaction Effects ◽  
Moving Frame ◽  
Navier Stokes ◽  
Blade Row ◽  
Vortical Disturbance ◽  
Blade Row Interaction ◽  
Gust Response

The effect of blade row axial spacing on vortical and potential disturbances and gust response is studied for a compressor stator/rotor configuration near design and at high loadings using 2D incompressible Navier-Stokes and potential codes, both written for multistage calculations. First, vortical and potential disturbances downstream of the isolated stator in the moving frame are defined; these disturbances exclude blade row interaction effects. Then, vortical and potential disturbances for the stator/rotor configuration are calculated for axial gaps of 10%, 20%, and 30% chord. Results show that the potential disturbance is uncoupled; the potential disturbance calculated from the isolated stator configuration is a good approximation for that from the stator/rotor configuration for all three axial gaps. The vortical disturbance depends strongly on blade row interactions. Low order modes of vortical disturbance are of substantial magnitude and decay much more slowly downstream than do those of potential disturbance. Vortical disturbance decays linearly with increasing mode except very close to the stator trailing edge. For a small axial gap, lower order modes of both vortical and potential disturbances must be included to determine the rotor gust response.

Effects of Off-Design Operating Conditions on the Blade Row Interaction in a HP Turbine Stage

2007 ◽  
Author(s):  
G. Persico ◽  
P. Gaetani ◽  
C. Osnaghi
Keyword(s):  
Flow Field ◽  
Strong Dependence ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Pressure Probe ◽  
Turbine Stage ◽  
Mixing Rate ◽  
Aerodynamic Pressure ◽  
Blade Row ◽  
Blade Row Interaction

An extensive experimental analysis on the subject of the unsteady periodic flow in a highly subsonic HP turbine stage has been carried out at the Laboratorio di Fluidodinamica delle Macchine (LFM) of the Politecnico di Milano (Italy). In this paper the blade row interaction is progressively enforced by increasing the stator and rotor blade loading and by reducing the stator-rotor axial gap from 100% (very large to smooth the rotor inlet unsteadiness) to 35% (design configuration) of the stator axial chord. The time-averaged three-dimensional flow field in the stator-rotor gap was investigated by means of a conventional five-hole probe for the nominal (0°) and an highly positive (+22°) stator incidences. The evolution of the viscous flow structures downstream of the stator is presented to characterize the rotor incoming flow. The blade row interaction was evaluated on the basis of unsteady aerodynamic measurements at the rotor exit, performed with a fast-response aerodynamic pressure probe. Results show a strong dependence of the time-averaged and phase-resolved flow field and of the stage performance on the stator incidence. The structure of the vortex-blade interaction changes significantly as the magnitude of the rotor inlet vortices increases, and very different residual traces of the stator secondary flows are found downstream of the rotor. On the contrary, the increase of rotor loading enhances the unsteadiness in the rotor secondary flows but has a little effect on the vortex-vortex interaction. For the large axial gap, a reduction of stator-related effects at the rotor exit is encountered when the stator incidence is increased as a result of the different mixing rate within the cascade gap.

Interaction Effects in a Transonic Turbine Stage

2000 ◽  
Author(s):  
J. W. Barter ◽  
P. H. Vitt ◽  
J. P. Chen
Keyword(s):  
Analytical Techniques ◽  
Interaction Effects ◽  
Phase Lag ◽  
Turbine Stage ◽  
Reflected Waves ◽  
Blade Row ◽  
Transonic Turbine ◽  
Unsteady Loading ◽  
Unsteady Pressure Measurements ◽  
Blade Row Interaction

A 3D, viscous, time-accurate code has been used to predict the time-dependent flowfield in a transonic turbine stage. Two analytical techniques are used to understand the unsteady physics. One technique takes into account interaction effects associated with reflected waves bouncing between blade rows while the other neglects them. Both techniques model the exact blade counts using phase-lag boundary conditions. The analytical techniques are validated by comparing to unsteady pressure measurements which have been made on the vane and blade surfaces at midspan. The analytical results are then used to understand the importance of interaction effects when the blade rows are close-coupled and when they are more widely spaced. The results show that interaction effects must be taken into account in order to accurately predict the unsteady loading on the upstream blade row. However, for the downstream blade row, interaction effects are second order and do not routinely need to be taken into account in the design process.

scholarly journals Effects of Stator Indexing on Performance in a Low Speed Multistage Axial Compressor

1997 ◽  
Author(s):  
Wendy S. Barankiewicz ◽  
Michael D. Hathaway
Keyword(s):  
Peak Pressure ◽  
Axial Compressor ◽  
Loss Coefficient ◽  
Operating Conditions ◽  
Nasa Lewis Research ◽  
Performance Measurements ◽  
Peak Efficiency ◽  
Blade Row ◽  
The Impact ◽  
Multistage Axial Compressor

The results of an experimental investigation to determine the impact of stator row indexing or clocking on multistage axial compressor performance are presented. Testing was conducted in the NASA Lewis Research Center’s Four-Stage Axial Compressor Facility. The impact of stator row indexing on both the overall and stator 3 blade element performance is presented for both the peak efficiency and peak pressure operating conditions. The change in overall performance due to stator indexing is 0.2% for both operating conditions. Indexing resulted in a 5% change in stator 3 mass averaged loss coefficient at the peak efficiency condition and a 10% change at the peak pressure condition. Since the mass-averaged stator 3 loss coefficient is on the order of 7%, the changes in loss coefficient due to indexing are on the order of 0.35–0.7%. These changes are considered to be small and are of the same order of magnitude as the passage-to-passage differences in loss coefficient due to manufacturing and assembly tolerances in the test compressor. The effects of stator-stator wake interactions are also shown and indicate that for rows with unequal blade counts it may be necessary to survey across more than one blade row pitch for accurate blade row performance measurements.

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