Experimental Investigation of Forced Response Impeller Blade Vibration in a Centrifugal Compressor With Variable Inlet Guide Vanes: Part 2—Forcing Function and FSI Computations

2011 ◽  
Author(s):  
Armin Zemp ◽  
Reza S. Abhari ◽  
Matthias Schleer
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Compressor ◽  
Guide Vane ◽  
Forced Response ◽  
Inlet Guide Vane ◽  
Compressor Stage ◽  
Blade Vibration ◽  
Impeller Blade ◽  
Inlet Guide Vanes ◽  
Vane Angle

As the second part of a two-part paper, this paper presents an experimental investigation of forced response impeller blade vibrations in a centrifugal compressor stage caused by variable inlet guide vanes. Although it is common practice to experimentally test the forced response blade vibration behavior of new impeller designs in terms of strain gauge or tip-timing measurements, the impact of the unsteady blade pressure distribution acting as an unsteady load on the blade surfaces is still not known. A centrifugal compressor impeller was therefore instrumented with dynamic strain gauges and fast-response pressure transducers to measure the forcing of the impeller blades for different compressor operating points and various inlet guide vane angle settings. The results showed a decrease in the excitation amplitudes for reduced mass flow rates of the compressor stage. The inlet guide vane angle setting affected the convection speed of the distortion pattern along the blade surface. An increase in the negative inlet guide vane angle caused higher excitation amplitudes especially in the inducer part of the blade. However, the largest negative inlet guide vane setting caused the smallest excitation amplitudes as this setup introduced the smallest amount of inlet distortion to the inlet flow field. A series of unidirectional fluid structure interaction calculations was performed to show the limitations and requirements of today’s numerical tools.

Experimental Investigation of Forced Response Impeller Blade Vibration in a Centrifugal Compressor With Variable Inlet Guide Vanes: Part 1—Blade Damping

2011 ◽  
Author(s):  
Armin Zemp ◽  
Reza S. Abhari ◽  
Beat Ribi
Keyword(s):  
Centrifugal Compressor ◽  
Guide Vane ◽  
Operating Conditions ◽  
Inlet Pressure ◽  
Dynamic Strain ◽  
Inlet Guide Vane ◽  
Guide Vanes ◽  
Aerodynamic Damping ◽  
Inlet Guide Vanes ◽  
Vane Angle

Forming the first part of a two-part paper, the quantification of the resonant response levels and the damping quantities for a centrifugal compressor impeller with variable inlet guide vanes under engine representative operating conditions is detailed in this work. The motivation for the investigation is the lack of experimental data that are needed to improve and validate computational tools used during the design phase. Measurements were performed during resonant blade vibrations with the inlet pressure, the inlet guide vane angle and the operating point as the varying parameters. The flow non-uniformity introduced into the inlet flow field was measured with an aerodynamic probe. These measurements showed an increase in flow distortion for increased guide vane angles. The response amplitudes were acquired with dynamic strain gauges. A curve-fit method was applied to estimate the critical damping ratios. The results showed a linear correlation of the aerodynamic damping with the inlet pressure. The mode dependent material damping was therefore derived using a linear extrapolation to vacuum conditions of the inlet pressure dependent overall damping. The resonant blade dynamics could be captured with a single degree of freedom model. The aerodynamic damping and the maximum strain response were found to significantly depend on the inlet guide vane angle setting and on the throttle setting of the compressor.

Triaxial Gas Turbine Performance Analysis for Variable Power Turbine Inlet Guide Vane Control Law Optimization

2018 ◽  
Author(s):  
Tao Wang ◽  
Yong-sheng Tian ◽  
Zhao Yin ◽  
Qing Gao ◽  
Chun-qing Tan
Keyword(s):  
Gas Turbine ◽  
Working Conditions ◽  
Guide Vane ◽  
Inlet Guide Vane ◽  
Control Law ◽  
Inlet Guide Vanes ◽  
Turbine Performance ◽  
Turbine Inlet ◽  
Power Turbine ◽  
Vane Angle

This paper proposes an inlet guide vane control law optimization technique for improving the off-design working condition thermal efficiency of triaxial gas turbine. Gas turbine dynamic and steady component-level simulation models are established in MATLAB/SIMULINK via Newton-Raphson algorithm based on component characteristic maps. After validating the models against experimental data and Gasturb software, they are applied to determine the effects of guide vane angle on gas turbine performance parameters. High Efficiency Mode (HEM) is utilized to adjust the power turbine inlet guide vanes to enhance the gas turbine efficiency and decrease the specific fuel consumption under off-design working conditions on account of the above gas turbine overall performance analysis results. The optimal angles of power turbine inlet guide vanes for various working conditions are acquired based on the steady gas turbine model as-established. HEM enhances the gas turbine’s thermal efficiency without exceeding its temperature or rotational speed constraints. The Radial Basis Function (RBF), a three-layer, feedforward neural network, is employed to fit the optimal guide vane angles and establish the corresponding relationship between the angles and various working conditions by system identification. The control strategy and gas turbine dynamic simulation model are tested in MATLAB/SIMULINK to verify their effects on gas turbine performance. The guide vane angle is found to significantly influence the gas turbine operating parameters, and HEM to effectively optimize gas turbine performance even within unpredictable atmospheric environment and working conditions.

Variable Inlet Guide Vane Effect on Centrifugal Compressor Performance in Wet Gas Flow

2016 ◽  
Author(s):  
Levi André B. Vigdal ◽  
Lars E. Bakken
Keyword(s):  
Centrifugal Compressor ◽  
Guide Vane ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Compressor Stage ◽  
Guide Vanes ◽  
Wet Gas ◽  
Compressor Performance

The introduction of variable inlet guide vanes (VIGVs) upfront of a compressor stage affects performance and permits tuning for off-design conditions. This is of great interest for emerging technology related to subsea compression. Unprocessed gas from the wellhead will contain liquid condensate, which affects the operational condition of the compressor. To investigate the effect of guide vanes on volume flow and pressure ratio in a wet gas compressor, VIGVs are implemented upfront of a centrifugal compressor stage to control the inlet flow direction. The guide vane geometry and test rig setup have previous been presented. This paper documents how changing the VIGV setting affects compressor performance under dry and wet operating conditions. The reduced performance effect and operating range at increased liquid content are of specific interest. Also documented is the change in the VIGV effect relative to the setting angle.

scholarly journals An Analysis of Spatial Nonuniformity of the Flow at the Entrance Section of the Axial-Radial Impeller of a Centrifugal Compressor Stage Working on Regulation Modes

2019 ◽  
pp. 30-40
Author(s):  
A.D. Vanyashov ◽  
V.V. Karabanova
Keyword(s):  
Centrifugal Compressor ◽  
Guide Vane ◽  
Inlet Guide Vane ◽  
Compressor Stage ◽  
Turning Angle ◽  
Centrifugal Compressor Stage ◽  
Entrance Section ◽  
Spatial Nonuniformity ◽  
Optimum Diameter ◽  
Significant Difference

The article presents an analysis of the experimental data on testing a centrifugal compressor stage on regulation modes by changing the rotational speed of the rotor and the turning angle of the blades in the inlet guide vane unit. The distribution of the angles of attack at the entrance section of the impeller in relation to the blade height is obtained. It is established that a significant difference in the angles of attack from the plug to the periphery influences the polytropic efficiency of the compressor stage. Recommendations are given on the improvement of the mechanism of regulation by the inlet guide vane unit and on the choice of the optimum diameter for the entrance part of the driving impeller blades.

Unsteady Flow in a Turbocharger Centrifugal Compressor: 3D-CFD-Simulation and Numerical and Experimental Analysis of Impeller Blade Vibration

2005 ◽  
Author(s):  
Hans-Peter Dickmann ◽  
Thomas Secall Wimmel ◽  
Jaroslaw Szwedowicz ◽  
Dietmar Filsinger ◽  
Christian H. Roduner
Keyword(s):  
Unsteady Flow ◽  
Pressure Distribution ◽  
Centrifugal Compressor ◽  
Cfd Simulation ◽  
Forced Response ◽  
Experimental Investigations ◽  
Excitation Mechanism ◽  
Blade Vibration ◽  
Impeller Blade ◽  
Vibration Behavior

Experimental investigations on a single stage centrifugal compressor showed that measured blade vibration amplitudes vary considerably along a constant speed line from choke to surge. The unsteady flow has been analysed to obtain detailed insight into the excitation mechanism. Therefore, a turbocharger compressor stage impeller has been modeled and simulated by means of Computational Fluid Dynamics (CFD). Two operating points at off-design conditions were analysed. One was close to choke and the second one close to the surge line. Transient CFD was employed, since only then a meaningful prediction of the blade excitation, caused by the unsteady flow situation, can be expected. Actually, it was observed that close to surge a steady state solution could not be obtained; only transient CFD could deliver a converged solution. The CFD results show the effect of the interaction between the inducer casing bleed system and the main flow. Additionally, the effect of the non-axisymmetric components, such as the suction elbow and the discharge volute, was analysed. The volute geometry itself had not been modeled. It turned out to be sufficient to impose a circumferentially asymmetric pressure distribution at the exit of the vaned diffuser to simulate the volute. Volute and suction elbow impose a circumferentially asymmetric flow field, which induces blade excitation. To understand the excitation mechanism, which causes the measured vibration behavior of the impeller, the time dependent pressure distribution on the impeller blades was transformed into the frequency domain by Fourier decomposition. The complex modal pressure data were imposed on the structure that was modeled by Finite Element Methods (FEM). Following state-of-the-art calculations to analyze the free vibration behavior of the impeller, forced response calculations were carried out. Comparisons with the experimental results demonstrate that this employed methodology is capable of predicting the impeller’s vibration behavior under real engine conditions. Integrating the procedure into the design of centrifugal compressors will enhance the quality of the design process.

scholarly journals The influence of blade profile shape of inlet guide vane on performance map of centrifugal compressor stage

2020 ◽  
Vol 4 (4) ◽  
pp. 41-48
Author(s):  
V. V. Karabanova ◽  
◽  
A. D. Vanyashov ◽  
V. L. Yusha ◽  
◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Guide Vane ◽  
Inlet Guide Vane ◽  
Compressor Stage ◽  
Rotor Speed ◽  
Blade Profile ◽  
Centrifugal Compressor Stage ◽  
Profile Shape ◽  
Performance Map ◽  
Lower Loss

The object of the study is a centrifugal compressor stage with an inlet guide vane. The performance map of the stage are investigated in the modes of combined regulation by changing the rotor speed and changing the swirl of the flow in front of the impeller by turning the blades of the inlet guide vane. Two variants of the design of the profile of the blades of the inlet guide vane are considered and the method of turning the blades by performance map. As a result of the study, it is found that a profile with a fixed inlet part at large swept angles has a lower loss coefficient, which contributes to an increase in the efficiency of the stage. The effect of regulation to achieve the set point in terms of pressure and flow for the re-profile stage is achieved at lower speeds

A Practical Approximate Method to Predict Adjusting Performance of a Centrifugal Compressor Stage With Inlet Guide Vane

2011 ◽  
Author(s):  
Changsheng Liu ◽  
Jiajian Tan ◽  
Datong Qi ◽  
Xuejun Wang ◽  
Guoliang Qin
Keyword(s):  
Centrifugal Compressor ◽  
Guide Vane ◽  
Prediction Method ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Compressor Stage ◽  
Performance Curve ◽  
Centrifugal Compressor Stage ◽  
Basic Model ◽  
Curve Family

This paper has proposed a method for predicting an adjusting performance curve family of a centrifugal compressor stage with the inlet guide vane (IGV). The method can be separated into two steps. In the first step, a centrifugal compressor model stage is selected as a basic model stage to build the basis of prediction. Both the ordinary performance curve of the model stage without IGV and the adjusting performance curve family of the model stage at various setting angles of the IGV are obtained by experiments. Then, using the ordinary performance curve as a criterion, a non-dimensional mathematical relationship is set up between the ordinary performance curve and each curve in the adjusting performance curve family. In the second step, based on the relationship established above, a prediction is made for the adjusting performance curve family of another centrifugal compressor stage with an IGV. For this prediction, two conditions must be satisfied: 1) The adjustment must be done using the IGV of the same type as used in the first step; 2) The ordinary performance curve of the predicted model stage must have been obtained experimentally. By applying the method, a prediction was carried out for the IGV adjusting performance curve family of a centrifugal compressor stage. Comparison between the predicted results and experimental results shows that although there is relatively great discrepancy between the basic model stage and the predicted stage under the mechanical geometric construction and operating conditions, the two results agree well in most of the areas of the adjusting performance curve family. There are only greater errors of predicted results in areas of large IGV setting angle. Although the current method has some deficiencies, it still possesses some strength featuring simplicity, convenience and reliability, thus providing a practical approximate prediction method available for the centrifugal compressor manufacturers that have the model stage database, but lack the APCF for the model stages with IGV.

Unsteady Flow Around Suction Elbow and Inlet Guide Vanes in a Centrifugal Compressor

2004 ◽  
Author(s):  
Michael M. Cui
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Centrifugal Compressor ◽  
Guide Vane ◽  
Power Laws ◽  
Working Fluid ◽  
Inlet Guide Vane ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Compressor Design

A suction elbow and inlet guide vanes (IGVs) are typical upstream components in the front of the first-stage impeller in a centrifugal compressor. Since the flow field in the front of the impeller is subsonic, the flow motion induced by the rotating impeller interacts with the elbow and IGVs. These interactions induce turbulent unsteady flows inside compressors. The resulted unsteadiness affects efficiency, vibration, and noise generation of the compressor. To understand the mechanism controlling the interactions between up-steam components and to optimize the compressor design for better efficiency and reliability, the turbulent unsteady flow inside the first-stage of the compressor was simulated. The model includes the suction elbow, inlet guide vane housing, and first-stage impeller. HFC 134a was used as the working fluid. The thermodynamic and transport properties of the refrigerant gas were modeled by the Martin-Hou equation of state and power laws, respectively. The three-dimensional unsteady flow field was numerically simulated. The overall performance parameters were obtained by integrating the field quantities. The force, torque, and the arm of moments acting on the IGVs are then calculated. The results can be used to improve centrifugal compressor design to achieve higher efficiency and improve reliability.

Redesign of a Compressor Stage for a High-Performance Electric Supercharger in a Heavily Downsized Engine

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Peng Wang ◽  
Mehrdad Zangeneh ◽  
Bryn Richards ◽  
Kevin Gray ◽  
James Tran ◽  
...  
Keyword(s):  
Design Method ◽  
Pressure Ratio ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Surge Margin ◽  
Stable Operating ◽  
Inverse Design Method ◽  
Ported Shroud

Engine downsizing is a modern solution for the reduction of CO2 emissions from internal combustion engines. This technology has been gaining increasing attention from industry. In order to enable a downsized engine to operate properly at low speed conditions, it is essential to have a compressor stage with very good surge margin. The ported shroud, also known as the casing treatment, is a conventional way used in turbochargers to widen the working range. However, the ported shroud works effectively only at pressure ratios higher than 3:1. At lower pressure ratio, its advantages for surge margin enhancements are very limited. The variable inlet guide vanes are also a solution to this problem. By adjusting the setting angles of variable inlet guide vanes, it is possible to shift the compressor map toward the smaller flow rates. However, this would also undermine the stage efficiency, require extra space for installing the inlet guide vanes, and add costs. The best solution is therefore to improve the design of impeller blade itself to attain high aerodynamic performances and wide operating ranges. This paper reports a recent study of using inverse design method for the redesign of a centrifugal compressor stage used in an electric supercharger, including the impeller blade and volute. The main requirements were to substantially increase the stable operating range of the compressor in order to meet the demands of the downsized engine. The three-dimensional (3D) inverse design method was used to optimize the impeller geometry and achieve higher efficiency and stable operating range. The predicted performance map shows great advantages when compared with the existing design. To validate the computational fluid dynamics (CFD) results, this new compressor stage has also been prototyped and tested. It will be shown that the CFD predictions have very good agreement with experiments and the redesigned compressor stage has improved the pressure ratio, aerodynamic efficiency, choke, and surge margins considerably.

scholarly journals Influence of blade geometry on secondary flow development in a transonic centrifugal compressor

2018 ◽  
Vol 2 ◽  
pp. I1RSJ3 ◽  
Author(s):  
Moritz Mosdzien ◽  
Martin Enneking ◽  
Alexander Hehn ◽  
Daniel Grates ◽  
Peter Jeschke
Keyword(s):  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Large Scale ◽  
Optimization Methods ◽  
Experimental Investigations ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Flow Development ◽  
Transonic Centrifugal Compressor ◽  
Increasing Demand

Due to the increasing demand for higher efficiencies of centrifugal compressors, numerical optimization methods are becoming more and more relevant in the design process. To identify the beneficial features of a numerical optimized compressor design, this paper analyses the influence of arbitrary blade surfaces on the loss generation in a transonic centrifugal compressor. The paper therefore focuses on an analysis of the secondary flow development within the impeller blade passages. To do this, steady simulations were performed on both a baseline and an optimized blade design. Two distinct design features of the optimized compressor stage were identified, which lead to a more homogenous impeller exit flow and thus to an increase in total-to-static efficiency of 1.76% points: the positive lean in the near-tip region and the positive blade curvature in the rear part of the optimized impeller. Furthermore, through extensive experimental investigations conducted on a large scale test rig it has been possible to prove the particular impeller outflow characteristics of the baseline compressor stage.

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