Considerations for Using 3-D Pneumatic Probes in High-Speed Axial Compressors

2003 ◽  
Vol 125 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Simon Coldrick ◽  
Paul Ivey ◽  
Roger Wells
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Pressure Probe ◽  
Probe Type ◽  
Calibration Data ◽  
Axial Compressors ◽  
Close Proximity ◽  
Multistage Axial Compressor ◽  
Preparatory Work

This paper describes preparatory work towards three-dimensional flowfield measurements downstream of the rotor in an industrial, multistage, axial compressor, using a pneumatic pressure probe. The probe is of the steady-state four-hole cobra probe type. The design manufacture and calibration of the probe is described. CFD calculations have been undertaken in order to assess the feasibility of using such a probe in the high-speed compressor environment where space is limited. This includes effects of mounting the probe in close proximity to the downstream stator blades and whether it is necessary to adjust the calibration data to compensate for these effects.

Considerations for Using 3D Pneumatic Probes in High Speed Axial Compressors

2002 ◽  
Author(s):  
Simon Coldrick ◽  
Paul Ivey ◽  
Roger Wells
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Pressure Probe ◽  
Probe Type ◽  
Calibration Data ◽  
Axial Compressors ◽  
Close Proximity ◽  
Multistage Axial Compressor ◽  
Preparatory Work

This paper describes preparatory work towards three dimensional flowfield measurements downstream of the rotor in an industrial, multistage, axial compressor, using a pneumatic pressure probe. The probe is of the steady state four hole cobra probe type. The design manufacture and calibration of the probe is described. CFD calculations have been undertaken in order to assess the feasability of using such a probe in the high speed compressor environment where space is limited. This includes effects of mounting the probe in close proximity to the downstream stator blades and whether it is necessary to adjust the calibration data to compensate for these effects.

Influence of different loads on the stresses of multistage axial compressor rotors

2016 ◽  
Vol 231 (5) ◽  
pp. 787-798 ◽  
Author(s):  
Xinqian Zheng ◽  
Chuang Ding ◽  
Yangjun Zhang
Keyword(s):  
Thermal Load ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Load ◽  
Design Phase ◽  
Total Stress ◽  
Axial Compressors ◽  
Centrifugal Load ◽  
Last Stage ◽  
Multistage Axial Compressor

Multistage axial compressors are widely used in the gas turbine engines. The strength of rotors is one of the key factors for the reliability of multistage axial compressors. The stresses of rotors at real working conditions can be caused by the centrifugal load, thermal load, and aerodynamic load. It is important to figure out the roles and the mechanism of the three kinds of loads in the stresses generating process. In this paper, the stresses of rotors in a typical five-stage axial compressor are calculated with different kinds of loads by solid–fluid coupling method. The results show that the proportion of the stress caused by centrifugal load is more than 80% of the total stress, which is dominant. The maximum proportion of the stress caused by thermal load is about 20% of the total stress at the front stages. However, the influence of thermal load is quite different from the first stage to the last stage. It is surprising that thermal load can decrease the stresses of the last stage rotor, which is mainly because of the variation of radial temperature gradient at disks for different stages. The proportion of the stress caused by aerodynamic load is usually less than 4%, and it tends to make the stresses at the suction side of the blades lower and enlarge it at the pressure side. According to the above results, centrifugal load is necessary of consideration at the conceptual design phase for the multistage axial compressor rotors. At preliminary three-dimensional design phase, centrifugal load and thermal load should be considered together. At optimized three-dimensional design phase, aerodynamic load cannot be neglected and all the three loads should be considered.

Viscous Throughflow Modeling for Multistage Compressor Design

1993 ◽  
Vol 115 (2) ◽  
pp. 296-304 ◽  
Author(s):  
M. A. Howard ◽  
S. J. Gallimore
Keyword(s):  
Shear Force ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Design System ◽  
Flow Angle ◽  
Axial Compressors ◽  
Dynamic Head ◽  
Viscous Shear ◽  
Compressor Design

An existing throughflow method for axial compressors, which accounts for the effects of spanwise mixing using a turbulent diffusion model, has been extended to include the viscous shear force on the endwall. The use of a shear force, consistent with a no-slip condition, on the annulus walls in the throughflow calculations allows realistic predictions of the velocity and flow angle profiles near the endwalls. The annulus wall boundary layers are therefore incorporated directly into the throughflow prediction. This eliminates the need for empirical blockage factors or independent annulus boundary layer calculations. The axisymmetric prediction can be further refined by specifying realistic spanwise variations of loss coefficient and deviation to model the three-dimensional endwall effects. The resulting throughflow calculation gives realistic predictions of flow properties across the whole span of a compressor. This is confirmed by comparison with measured data from both low and high-speed multistage machines. The viscous throughflow method has been incorporated into an axial compressor design system. The method predicts the meridional velocity defects in the endwall region and consequently blading can be designed that allows for the increased incidence, and low dynamic head, near the annulus walls.

Viscous Throughflow Modelling for Multi-Stage Compressor Design

1992 ◽  
Author(s):  
M. A. Howard ◽  
S. J. Gallimore
Keyword(s):  
Shear Force ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Design System ◽  
Flow Angle ◽  
Axial Compressors ◽  
Multi Stage ◽  
Viscous Shear ◽  
Compressor Design

An existing throughflow method for axial compressors, which accounts for the effects of spanwise mixing using a turbulent diffusion model, has been extended to include the viscous shear force on the endwall. The use of a shear force, consistent with a no-slip condition, on the annulus walls in the throughflow calculations allows realistic predictions of the velocity and flow angle profiles near the endwalls. The annulus wall boundary layers are therefore incorporated directly in the throughflow prediction. This eliminates the need for empirical blockage factors or independent annulus boundary layer calculations. The axisymmetric prediction can be further refined by specifying realistic spanwise variations of loss coefficient and deviation to model the three-dimensional endwall effects. The resulting throughflow calculation gives realistic predictions of flow properties across the whole span of a compressor. This is confirmed by comparison with measured data from both low and high speed multi-stage machines. The viscous throughflow method has been incorporated into an axial compressor design system. The method predicts the meridional velocity defects in the endwall region and consequently blading can be designed which allows for the increased incidence, and low dynamic head, near to the annulus walls.

scholarly journals Physics of Airfoil Clocking in a High-Speed Axial Compressor

1998 ◽  
Author(s):  
Daniel J. Dorney ◽  
Om P. Sharma ◽  
Karen L. Gundy-Burlet
Keyword(s):  
Relative Motion ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Unsteady Aerodynamics ◽  
Navier Stokes ◽  
Jet Engines ◽  
Axial Compressors ◽  
Multi Stage ◽  
Significant Performance

Axial compressors have inherently unsteady flow fields because of relative motion between rotor and stator airfoils. This relative motion leads to viscous and inviscid (potential) interactions between blade rows. As the number of stages increases in a turbomachine, the buildup of convected wakes can lead to progressively more complex wake/wake and wake/airfoil interactions. Variations in the relative circumferential positions of stators or rotors can change these interactions, leading to different unsteady forcing functions on airfoils and different compressor efficiencies. In addition, as the Mach number increases the interaction between blade rows can be intensified due to potential effects. In the current study an unsteady, quasi-three-dimensional Navier-Stokes analysis has been used to investigate the unsteady aerodynamics of stator clocking in a 1-1/2 stage compressor, typical of back stages used in high-pressure compressors of advanced commercial jet engines. The effects of turbulence have been modeled with both algebraic and two-equation models. The results presented include steady and unsteady surface pressures, efficiencies, boundary layer quantities and turbulence quantities. The main contribution of the current work has been to show that airfoil clocking can produce significant performance variations at the Mach numbers associated with an engine operating environment. In addition, the growth of turbulence has been quantified to aid in the development of models for the multi-stage steady analyses used in design systems.

The Design, Development and Evaluation of 3D Aerofoils for High Speed Axial Compressors: Part 2 — Simulation and Comparison With Experiment

2005 ◽  
Author(s):  
G. Woollatt ◽  
D. Lippett ◽  
P. C. Ivey ◽  
P. Timmis ◽  
B. A. Charnley
Keyword(s):  
Collaborative Design ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Loss Reduction ◽  
Test Results ◽  
Design Development ◽  
Axial Compressors ◽  
Quantitative Basis ◽  
End Wall

The focus of this paper is to report on measurements from and simulation of Cranfield University’s 3-stage high-speed axial compressor test rig. This newly built rig is supported by European Commission funding and has tested a set of conventionally stacked 2D rotor and stator blades (Reference 1). The results were used to evaluate and to assess the performance of several commercially available CFD codes leading to the collaborative design of an advanced three-dimensional blade set. The philosophy behind the advanced design is described. The datum test results show that the state of the art, highly loaded, datum compressor is well matched with limited potential for loss reduction. A comparison is made between the measured results and a series of numerical analyses using the various CFD codes. Although the codes showed reasonable qualitative agreement with each other and the measured data, there were significant differences in the predicted performance of the datum build. Further the codes were unable to grade candidate redesigns consistently on a quantitative basis and therefore increased the difficulty of selecting suitable ‘3d’ features. Generic studies involving sweep, lean and recambering are used to evolve a design philosophy for the advanced three-dimensional design. Over cambering of the end-wall sections, coupled with a suitable stack of the blades, enables the blade count to be reduced. In the presence of a clearance combinations of sweep and lean are used to modify the loading in the clearance gap, thereby influencing the associated losses. The application of three-dimensional features redistributes the flow. The opportunity is therefore taken to rematch the sections based on the predicted results of the CFD codes. The above philosophy is used in the redesign of the datum compressor. Overall characteristics and exit traverse results from the test of the advanced build are compared to those from the datum build.

Three-Dimensional Flows and Loss Reduction in Axial Compressors

1987 ◽  
Vol 109 (3) ◽  
pp. 354-361 ◽  
Author(s):  
Y. Dong ◽  
S. J. Gallimore ◽  
H. P. Hodson
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Flow ◽  
Tracer Gas ◽  
Suction Surface ◽  
Axial Compressors ◽  
Small Clearance ◽  
Oil Flow ◽  
Stator Blade ◽  
Flow Compressor

Measurements have been performed in a low-speed high-reaction single-stage axial compressor. Data obtained within and downstream of the rotor, when correlated with the results of other investigations, provide a link between the existence of suction surface–hub corner separations, their associated loss mechanisms, and blade loading. Within the stator, it has been shown that introducing a small clearance between the stator blade and the stationary hub increases the efficiency of the stator compared to the case with no clearance. Oil flow visualizaton indicated that the leakage reduced the extensive suction surface–hub corner separation that would otherwise exist. A tracer gas experiment showed that the large radial shifts of the surface streamlines indicated by the oil flow technique were only present close to the blade. The investigation demonstrates the possible advantages of including hub clearance in axial flow compressor stator blade rows.

Wake Recovery Performance Benefit in a High-Speed Axial Compressor

2002 ◽  
Vol 124 (2) ◽  
pp. 275-284 ◽  
Author(s):  
Dale E. Van Zante ◽  
John J. Adamczyk ◽  
Anthony J. Strazisar ◽  
Theodore H. Okiishi
Keyword(s):  
High Speed ◽  
Axial Compressor ◽  
Decay Process ◽  
Operating Conditions ◽  
Rotor Wake ◽  
Stage Design ◽  
Axial Compressors ◽  
Laser Anemometer ◽  
Stretching Process ◽  
Actual Loss

Rotor wakes are an important source of loss in axial compressors. The decay rate of a rotor wake is largely due to both mixing (results in loss) and stretching (no loss accrual). Thus, the actual loss associated with rotor wake decay will vary in proportion to the amounts of mixing and stretching involved. This wake stretching process, referred to by Smith (1996) as recovery, is reversible and for a 2-D rotor wake leads to an inviscid reduction of the velocity deficit of the wake. It will be shown that for the rotor/stator spacing typical of core compressors, wake stretching is the dominant wake decay process within the stator with viscous mixing playing only a secondary role. A model for the rotor wake decay process is developed and used to quantify the viscous dissipation effects relative to those of inviscid wake stretching. The model is verified using laser anemometer measurements acquired in the wake of a transonic rotor operated alone and in a stage configuration at near peak efficiency and near stall operating conditions. Results from the wake decay model exhibit good agreement with the experimental data. Data from the model and laser anemometer measurements indicate that rotor wake straining (stretching) is the primary decay process in the stator passage. Some implications of these results on compressor stage design are discussed.

Inverse Design of 3D Compressor Blades With Adjoint Method

2003 ◽  
Author(s):  
June Chung ◽  
Jeonghwan Shim ◽  
Ki D. Lee
Keyword(s):  
High Speed ◽  
Adjoint Method ◽  
Design Method ◽  
Computational Cost ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Internal Flow ◽  
Adjoint System ◽  
Inverse Design ◽  
Compressor Blades

A three-dimensional (3D) CFD-based design method for high-speed axial compressor blades is being developed based on the discrete adjoint method. An adjoint code is built corresponding to RVC3D, a 3D turbomachinery Navier-Stokes analysis code developed at NASA Glenn. A validation study with the Euler equations indicates that the adjoint sensitivities are sensitive to the choice of boundary conditions for the adjoint variables in internal flow problems and constraints may be needed on internal boundaries to capture proper physics of the adjoint system. The design method is demonstrated with inverse design based on Euler physics, and the results indicate that the adjoint design method produces efficient 3D designs by drastically reducing the computational cost.

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