scholarly journals IGV-Rotor Interactions in a 4-Stage Axial Compressor

1998 ◽  
Author(s):  
O. Puetz ◽  
J. Eikelmann ◽  
H. Stoff
Keyword(s):  
Flow Field ◽  
Total Pressure ◽  
Guide Vane ◽  
Axial Compressor ◽  
Suction Side ◽  
Fast Response ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Mean Values ◽  
Swirl Angle

Detailed experiments have been made in a 4-stage axial compressor of industrial design. The exit flow field of the rotor of the first stage was measured by hot-wire anemometry and fast-response pressure probes under design operating conditions. Tandem inlet guide vanes (IGV) are situated upstream of the first rotor. Flow field results are presented for total pressure, massflux and swirl angle over a closely-spaced grid of probe locations in radial and circumferential directions in the absolute and rotating frame of reference. The tandem inlet guide vane row and stage 1 vane row are positioned peripherally for various settings (clocking). Depending on the peripherical position of IGV and stator 1 the mean values for one rotor pitch varies by 1.5% for mass flow, 1.3° for swirl angle and 8.7% for total pressure. Loss in total pressure at the rotor exit is a minimum, when the IGV row wakes enter the downstream rotor passage at about 1/4 pitch from the suction-side. Blade and vane channels have similar pitchwise spacing.

Experimental and Numerical Examinations of a Transonic Compressor-Stage With Casing Treatment

2013 ◽  
Author(s):  
D. Schönweitz ◽  
M. Voges ◽  
G. Goinis ◽  
G. Enders ◽  
E. Johann
Keyword(s):  
Flow Field ◽  
Total Pressure ◽  
Guide Vane ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Tip Leakage Vortex ◽  
Casing Treatment ◽  
Tip Leakage ◽  
Transonic Compressor

The flow in the blade tip vicinity of the transonic first stage of a multi-stage axial flow compressor with variable inlet guide vane (IGV) and casing treatment (CT) above the rotor is investigated experimentally and numerically with focus on the effects of the CT on flow structures and compressor performance. For the experimental part of this study, conventional performance instrumentation is used to estimate the operating condition of the compressor. Radial distributions of total temperature and total pressure are taken at the leading edges of the stators for comparison with simulations as well as for adjusting the operating conditions of the compressor. The velocity field in the rear part of the first-rotor is determined with Particle Image Velocimetry (PIV) at 90% and 96% radial height using two periscope light sheet probes. The employed PIV setup allows a spatial resolution of 0.7 mm × 0.7mm and thus a similar resolution as the spatial discretization in the simulation. For the numerical part of the study, time-accurate simulations are conducted for the same operating conditions as during experiments. Additional simulations of the same configuration with smooth casing are conducted in order to estimate the effect of the CT on the flow. The examination of PIV measurements and corresponding simulations exposes complex vortical structures originating from the interaction of the rotor bow shock with the IGV trailing edge, CT, IGV wake and the tip leakage vortex. The associated induced velocities together with the general passage flow form a complex flow field with significantly altered blockage compared to a common flow field in the tip vicinity. Position and trajectory of the tip leakage vortex are deduced from interactions between tip leakage vortex and IGV wake / CT. The detailed comparison of the tip region of simulations with and without CT shows that the CT influences pressure rise and flow parameters in a wide radial range due to a radial redistribution of the flow. Correspondingly, a rotor with CT can achieve an increased total pressure rise compared to a rotor with smooth casing, with only minor effects on the efficiency.

A New Loss and Deviation Model for Axial Compressor Inlet Guide Vanes

2013 ◽  
Author(s):  
Milan Banjac ◽  
Milan V. Petrovic ◽  
Alexander Wiedermann
Keyword(s):  
Guide Vane ◽  
Thickness Distribution ◽  
Axial Compressor ◽  
Algebraic Model ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Viscous Effects ◽  
Through Flow ◽  
Trailing Vortices ◽  
Compressor Inlet

This paper describes a new universal algebraic model for the estimation of flow deflection and losses in axial compressor inlet guide vane devices. The model deals with nominal flow and far-off-design operating conditions in connection with large stagger angle adjustments. The first part of the model considers deflection and losses in 2D cascades, taking into account the main cascade geometry parameters and operating conditions, such as Mach number and stagger adjustment. The second part of the model deals with additional deviation and losses due to secondary flow caused by the endwall viscous effects and by the trailing vortices. The model is developed for NACA65 airfoils, NACA63-A4K6 airfoils and airfoils having an NACA65 thickness distribution on a circular-arc camber line. It is suitable for application in 1D or 2D through-flow calculations for design and analysis cases. The development of the method is based on systematic CFD flow calculations for various cascade geometries and operating parameters. The comparison of correlation results with experimental data for several test cases shows good agreement.

A New Loss and Deviation Model for Axial Compressor Inlet Guide Vanes

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Milan Banjac ◽  
Milan V. Petrovic ◽  
Alexander Wiedermann
Keyword(s):  
Guide Vane ◽  
Thickness Distribution ◽  
Axial Compressor ◽  
Algebraic Model ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Viscous Effects ◽  
Through Flow ◽  
Trailing Vortices ◽  
Compressor Inlet

This paper describes a new universal algebraic model for the estimation of flow deflection and losses in axial compressor inlet guide vane devices. The model deals with nominal flow and far-off-design operating conditions in connection with large stagger angle adjustments. The first part of the model considers deflection and losses in 2D cascades, taking into account the main cascade geometry parameters and operating conditions, such as Mach number and stagger adjustment. The second part of the model deals with additional deviation and losses due to secondary flow caused by the end wall viscous effects and by the trailing vortices. The model is developed for NACA65 airfoils, NACA63-A4K6 airfoils, and airfoils having an NACA65 thickness distribution on a circular-arc camber line. It is suitable for application in 1D or 2D through-flow calculations for design and analysis cases. The development of the method is based on systematic computational fluid dynamics (CFD) flow calculations for various cascade geometries and operating parameters. The comparison of correlation results with experimental data for several test cases shows good agreement.

Unsteady Flow Field and Coarse Droplet Measurements in the Last Stage of a Low Pressure Steam Turbine With Supersonic Airfoils Near the Blade Tip

2016 ◽  
Author(s):  
Ilias Bosdas ◽  
Michel Mansour ◽  
Anestis I. Kalfas ◽  
Reza S. Abhari ◽  
Shigeki Senoo
Keyword(s):  
Flow Field ◽  
Steam Turbine ◽  
Leading Edge ◽  
Suction Side ◽  
Fast Response ◽  
Operating Conditions ◽  
Electricity Production ◽  
Test Facility ◽  
Steam Turbines ◽  
Last Stage

The largest share of electricity production worldwide belongs to steam turbines. However, the increase of renewable energy production has led steam turbines to operate under part load conditions and increase in size. As a consequence long rotor blades will generate a relative supersonic flow field at the inlet of the last rotor. This paper presents a unique experiment work that focuses at the top 30% of stator exit in the last stage of an LP steam turbine test facility with coarse droplets and high wetness mass fraction under different operating conditions. The measurements were performed with two novel fast response probes. A fast response probe for three dimensional flow field wet steam measurements and an optical backscatter probe for coarse water droplet measurements ranging from 30 up to 110μm in diameter. This study has shown that the attached bow shock at the rotor leading edge is the main source of inter blade row interactions between the stator and rotor of the last stage. In addition, the measurements showed that coarse droplets are present in the entire stator pitch with larger droplets located at the vicinity of the stator’s suction side. Unsteady droplet measurements showed that the coarse water droplets are modulated with the downstream rotor blade-passing period. This set of time-resolved data will be used for in-house CFD code development and validation.

Effect of Clocking on the Unsteady Rotor Blade Loading in a 1.5-Stage Low-Speed Axial Compressor

2007 ◽  
Author(s):  
Huixia Jia ◽  
Konrad Vogeler
Keyword(s):  
Guide Vane ◽  
Pressure Fluctuations ◽  
Suction Side ◽  
Rotor Blades ◽  
Inlet Guide Vane ◽  
Mean Values ◽  
Design Point ◽  
Low Speed ◽  
Unsteady Pressure ◽  
Pressure Distributions

This paper presents the effect of clocking on the unsteady loading of the rotor blades in the first stage with an inlet guide vane row (IGV) of the Dresden Low-Speed Research Compressor (LSRC). The unsteady flow field of the Dresden LSRC at 10 IGV clocking positions for the design point was investigated using a 3D time-accurate viscous solver. The time-averaged pressure distributions on the pressure side (PS) and the suction side (SS) of the rotor blades at midspan (MS) are presented for different clocking positions. The effect of the clocking on the time-averaged Root Mean Square-value (RMS) of the unsteady pressure fluctuations of the rotor blades at MS is investigated. The unsteady pressure fluctuations on the PS and the SS of the rotor blades at MS for different clocking positions are presented and discussed. The unsteady blade pressure forces on the rotor blades, which are calculated from the profile pressure distributions, are presented and analysed for different clocking positions. The maximal fluctuation amplitude of the unsteady pressure forces on the rotor blades, which fluctuate around the nearly identical mean values for different clocking positions, can be reduced about 60 percent with the IGV clocking for the design point in the investigated configuration. The effect of the clocking on the time-resolved inlet- and outlet flow fields of the rotor blades is investigated and discussed.

Steady and Unsteady Flow Field in a Multistage Low-Speed Axial Compressor: A Test Case

2008 ◽  
Author(s):  
Mario Ku¨nzelmann ◽  
Ralf Mu¨ller ◽  
Ronald Mailach ◽  
Konrad Vogeler
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Laser Doppler Anemometry ◽  
Guide Vane ◽  
Axial Compressor ◽  
Inlet Guide Vane ◽  
Test Case ◽  
Data Set ◽  
Low Speed ◽  
Blade Row

This paper introduces a new test case for compressor aerodynamics. The dataset is provided for the Dresden four-stage Low-Speed Research Compressor (LSRC), which was put into operation in 1995. The compressor consists of four identical stages, which are preceded by an inlet guide vane. The data set will be provided for the reference blading of the compressor with cantilevered stator vanes. This blading was developed on the basis of the profiles of a middle stage of a high-pressure compressor of a jet engine. This paper makes available the blading geometry as well as a variety of flow field measurement results. This includes the compressor map, selected pressure distributions and other results of flow field measurements with conventional techniques (e.g. Pitot probes, 5-hole probes). Furthermore different aspects of blade row interactions were addressed in this compressor within recent years. The periodical unsteady flow field within a selected rotor blade row was investigated using Laser-Doppler-Anemometry. Further results on the unsteady profile pressures and profile boundary layers will be provided. Supplementary, numerical results will be compared to the experiments. Results are available for several stages of the compressor and different operating points. With this test case a unique database for the aerodynamics in a multistage axial compressor will be provided that can be used for the validation of numerical codes.

Aerodynamic Optimization of a Two-Part Variable Inlet Guide Vane in a Highly Loaded Low Pressure Compressor

2018 ◽  
Author(s):  
Stefan Hemmert-Pottmann ◽  
William Gouézou ◽  
Eberhard Nicke
Keyword(s):  
Design Optimization ◽  
Total Pressure ◽  
Guide Vane ◽  
Low Pressure ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Wide Range ◽  
Variable Inlet Guide Vane ◽  
Operating Points ◽  
Pressure Compressor

Continuous reduction of fuel consumption for a wide range of operating conditions leads to a high efficiency demand for all engine parts of modern jet engines and especially the compressor. To meet these requirements a two-part Variable Inlet Guide Vane (VIGV), composed of a fixed strut and a variable flap, can be used. Besides the aerodynamic aspects, the VIGV strut is a substantial part for the structural integrity of the compressor. The aerodynamic design optimization of such a VIGV, located upstream of the first rotor of a 2.5 stage low pressure compressor, under the conditions of three different operating points is presented in this paper. In a previous study the shape of the axial gap between strut and flap was optimized without changing the envelope of both parts [1]. The new design tool SplitBlade, developed at the DLR, enables the creation of an axial gap and has been integrated in the design process of the in-house optimization tool AutoOpti. The target of the optimization was to decrease the total pressure loss coefficients for all three operating points. The design optimization presented in this paper is more complex by allowing the VIGV blade geometry to change. The basic dimensions of the VIGV such as the axial chord and the maximum profile thickness are still frozen. In total, 88 parameters are free to change in the optimization process. Additionally to the main target of loss reduction, the circumferential outflow angles are restricted to maintain the deflection of the blade and therewith the required rotor inflow conditions to ensure the operability of the entire compressor in the whole working range. The final result is a two-part VIGV with an axial gap, which is optimized in terms of total pressure losses in three operating points. Compared to a reference geometry without an axial gap, the losses are almost equal at nominal speed, and about one to two percentage points higher in the two part speed operating points.

Flow Evolution in a One and a Half Axial Steam Turbine Stage Under Different Operating Conditions

2015 ◽  
Author(s):  
Berardo Paradiso ◽  
Alessandro Mora ◽  
Vincenzo Dossena ◽  
Giacomo Gatti ◽  
Andrea Nesti ◽  
...  
Keyword(s):  
Flow Field ◽  
Steam Turbine ◽  
Mass Flow ◽  
Rotational Speed ◽  
Cfd Simulation ◽  
Guide Vane ◽  
Operating Conditions ◽  
Design Stage ◽  
Inlet Guide Vane ◽  
Turbine Stage

In order to investigate in detail the performance of steam turbine stages the Low Speed Test Rig at Politecnico di Milano has been adapted. The setup consists of a one and an half turbine stage with an inlet guide vane. Two kind of experimental approaches are planned in the project: the first, denominated “performance”, has been carried out by the OGTL department of GE Oil&Gas Florence while, at the same time, Politecnico di Milano performed detailed inter-stage measurements with steady probes and time resolved high response pressure probes. An axial steam turbine stage was tested under several operating conditions in terms of rotational speed, mass flow and inlet angle with the aim to provide the functional curves of the machine together with detailed flow-field measurements. In this paper, a detailed description of the inter-stage flow-field is presented for the most relevant operating condition. Then, a comparison between three different points at the same rotational speed (but different mass flow) is proposed. Finally, the effects of different axial gaps on the overall performance of the stage are discussed. In particular, two different vane-rotor axial gaps have been tested by traversing pressure and temperature probes in three different axial planes. The first measurement plane is located at the first stator exit with the aim to provide details of the inlet swirl angle and 3D flow-field generated by the IGV. In the second plane, located at the rotor exit, the effect of different load conditions on the rotor performance and average flow-field is discussed. Finally, the measurements obtained in the third plane, placed at the second stator exit, are afterwards compared with the one obtained in the first plane, in order to evidence the influence of an unsteady inlet flow-field on the stator behaviour. The aim of the work is to provide very detailed aerodynamic measurements; this large amount of data will be used to validate the results of the CFD simulation carried out in the design stage. In this paper the preliminary findings of the steady flow-field will be presented as the basis for further analysis.

Aerodynamic Investigations of an Advanced VIGV Design of Adjustable Geometry for Very High Flow Turning

2015 ◽  
Author(s):  
David Händel ◽  
Reinhard Niehuis ◽  
Jan Klausmann
Keyword(s):  
Pressure Loss ◽  
Total Pressure ◽  
High Speed ◽  
Guide Vane ◽  
Operating Conditions ◽  
Total Pressure Loss ◽  
Inlet Guide Vane ◽  
Basic Design ◽  
Low Loss ◽  
Symmetric Profile

On the basis of experimental results the new design of a Variable Inlet Guide Vane (VIGV), as can be used for the control and regulation in multishaft compressors, is presented. Main goal of this investigation is a significant increase of the operating range and a reduction of the total pressure loss compared to a currently used basic design. For both designs 2D-cascades were build for detailed measurements in the High-Speed Cascade Wind Tunnel at the Institute of Jet Propulsion at the Universität der Bundeswehr München. The basic design exhibits a symmetric profile with only one segment. In contrast to that the new VIGV design consists of two symmetric vane segments which are arranged pivotable to each other. This provides the advantage of a symmetric profile for a fully opened VIGV associated with a low-loss level. For guidance of the flow, both vane segments can be rotated. Hence, the turning of the flow is split onto two segments. This avoids a huge flow separation on the suction side for high turning angles (Δβ > 30°) which is linked with a strong and abrupt loss increase. Due to the design, the new VIGV exhibits a gap between the two vane segments. Results with opened and sealed gap are presented and discussed. Using a sealing between the segments, a reduction of the profile loss could be detected for all investigated operating conditions. Even without a sealing in the gap, the “low-loss working range” is significantly increased. In addition, it is depicted that the presented results are valid for varying inflow velocities. This broadens the usability of the outcomes. Concluding, it is shown that all aims are achieved. Using the new VIGV design with sealing the low-loss working range can almost be doubled (Δβ > 55°) and the total pressure loss decreases in every working condition compared to the basic design.

Studies on Downstream Stator With Rotor Re-Staggering and Forward Sweeping in a Subsonic Axial Compressor Stage

2011 ◽  
Author(s):  
P. V. Ramakrishna ◽  
M. Govardhan
Keyword(s):  
Flow Field ◽  
Computational Model ◽  
Flow Rate ◽  
Total Pressure ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Axial Distance ◽  
Compressor Stage ◽  
Numerical Work ◽  
Stagger Angle

The present numerical work studies the flow field in subsonic axial compressor stator passages for: (a) preceding rotor sweep (b) preceding rotor re-staggering (three stagger angle changes: 0°, +3° and +5°); and (c) stator sweeping (two 20° forward sweep schemes). The following are the motives for the study: at the off-design conditions, compressor rotors are re-staggered to alleviate the stage mismatching by adjusting the rows to the operating flow incidence. Fundamental to this is the understanding of the effects of rotor re-staggering on the downstream component. Secondly, sweeping the rotor stages alters the axial distance between the successive rotor-stator stages and necessitates that the stator vanes must also be swept. To the best of the author’s knowledge, stator sweeping to suit such scenarios has not been reported. The computational model for the study utilizes well resolved hexahedral grids. A commercial CFD package ANSYS® CFX 11.0 was used with standard k-ω turbulence model for the simulations. CFD results were well validated with experiments. The following observations were made: (1) When the rotor passage is closed by re-staggering, with the same mass flow rate and the same stator passage area, stators were subjected to negative incidences. (2) Effect of stator sweeping on the upstream rotor flow field is insignificant. Comparison of total pressure rise carried by the downstream stators suggests that an appropriate redesign of stator is essential to match with the swept rotors. (3) While sweeping the stator is not recommended, axial sweeping is preferable over true sweeping when it is necessary.

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