The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Michael M. Cui - One of the best experts on this subject based on the ideXlab platform.
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Unsteady flow around suction elbow and inlet guide vanes in a centrifugal compressor
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2006Co-Authors: Michael M. CuiAbstract:AbstractSuction elbow and inlet guide vanes (IGVs) are typical upstream components in front of the first-Stage Impeller in a centrifugal compressor. As 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 resulting unsteadiness affects efficiency, vibration, and noise generation of the compressor. To understand the mechanism controlling the interactions between upstream 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 included the suction elbow, IGV housing, and firstStage Impeller. HFC 134a was used as the working fluid. The thermodynamic and transport properties of the refrigerant gas were modelled by the Martin-Hou equation of state and power laws, respectively. The three-dimensional unsteady flow field was nume...
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Unsteady Flow Around Suction Elbow and Inlet Guide Vanes in a Centrifugal Compressor
Volume 5: Turbo Expo 2004 Parts A and B, 2004Co-Authors: Michael M. CuiAbstract: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.Copyright © 2004 by ASME
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Effect of Suction Elbow and Inlet Guide Vanes on Flow Field in a Centrifugal Compressor Stage
Volume 5: Turbo Expo 2002 Parts A and B, 2002Co-Authors: Michael M. CuiAbstract:Suction elbows and inlet guide vanes (IGVs) are typical upstream components in front of first-Stage Impellers in centrifugal compressors. The three-dimensional distortion induced by elbows and IGVs affects the flow field behind the IGV housing. Since the flow field in front of the Impeller is subsonic, the flow motion induced by the rotating Impeller will interact with the elbow and IGVs as well. The flow field resulting from these interactions is three-dimensional. The nature of this flow field defines design requirements of upstream components and impact overall performance of the compressor. To understand the mechanism controlling the interactions of up-steam components and optimize the compressor design for better efficiency and reliability, a numerical simulation of the flow field inside the entire first Stage of the compressor was conducted. The Stage studied includes suction elbow, IGV housing with vanes, 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 flow field was simulated with a Navier-Stokes solver using the k-e turbulence model. The overall performance parameters are obtained by integrating the field quantities. The force, torque, and arm of moment acting on the IGVs were then calculated. The results can be used to improve centrifugal compressor design to achieve higher efficiency and improve reliability. The methodology developed in the current study can be applied to centrifugal compressor design and optimization.Copyright © 2002 by ASME
Christian H. Roduner - One of the best experts on this subject based on the ideXlab platform.
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Unsteady Flow in a Turbocharger Centrifugal Compressor: Three-Dimensional Computational Fluid Dynamics Simulation and Numerical and Experimental Analysis of Impeller Blade Vibration
Journal of Turbomachinery, 2006Co-Authors: H. P. Dickmann, Thomas Secall Wimmel, Jaroslaw Szwedowicz, Dietmar Filsinger, Christian H. RodunerAbstract:Experimental investigations on a single Stage centrifugal compressor showed that mea- sured blade vibration amplitudes vary considerably along a constant speed line from choke to surge. The unsteady flow has been analyzed 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 analyzed. 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 ob- tained; 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 nonaxisymmetric components, such as the suction elbow and the discharge volute, was analyzed. The volute geometry itself had not been modeled. It turned out to be sufficient to impose a circumferentially asymmetric pressure distribu- tion 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 trans- formed into the frequency domain by Fourier decomposition. The complex modal pres- sure 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 experi- mental 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.
M. N. Labib - One of the best experts on this subject based on the ideXlab platform.
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Numerical assessment on improving multiStage centrifugal Impeller performance by changing inlet skew angle at Impeller inlet
Journal of Central South University, 2012Co-Authors: M. N. Labib, Choi Du-youl, Bahari Fajar, Tony Utomo, Chung Han-shikAbstract:MultiStage centrifugal Impellers with four different skew angles were investigated by using computational fluid dynamics. The purpose of this work is to investigate the influences of lean angle at the blade tip of the Impeller inlet. Four variations of lean angles, that is, 8°, 10°, 15° and 20°, were made at first Stage Impeller. Reynolds Average Navier Stokes equation was used in simulation together with a shear-stress transport (SST) k-w turbulence model and mixing-plane approach, respectively. Three dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required. A good performance was expected that the secondary flow can be effectively reduced in the flow passage of the Impeller without excessive increase in manufacturing cost caused by the secondary flow. The results show that secondary flow affects the main flow intricately to form vortices or having non-uniform velocity in the flow passage, which in turn results in substantial fluid energy loss not only in the Impeller but also in the guide vane downstream of Impeller. The numerical solutions were performed and allowed the optimum design and operating conditions to be obtained.
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Numerical investigation of the effect of inlet skew angle on the performance of mechanical vapor compressor
Desalination, 2012Co-Authors: M. N. Labib, Seongsoo Kim, Du-youl Choi, Tony Suryo Utomo, Hanshik Chung, Hyomin JeongAbstract:Abstract Mechanical vapor compressor is an essential component that governs the system performance and stability in the multi-effect desalination (MED) system. The importance of improving mechanical vapor compressor's compressing ability in enhancing the efficiency of multi-effect desalination (MED) system has been stressed for a long time. This study was aimed to investigate the influences of inlet skew angle of the Impeller on performance improvement. Four designs of inlet skew angles were attempted at the first Stage Impeller with 8°, 10°, 15°, and 20° respectively. Three dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required. A good performance was expected as which effectively reduce the losses caused by secondary flow in the flow passage of the Impeller. The results show detail flow pattern on decreasing the secondary flow due to incidence angle at the Impeller eye and Impeller passage. The numerical solutions were performed and allowed the better design.
Hyomin Jeong - One of the best experts on this subject based on the ideXlab platform.
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Numerical investigation of the effect of inlet skew angle on the performance of mechanical vapor compressor
Desalination, 2012Co-Authors: M. N. Labib, Seongsoo Kim, Du-youl Choi, Tony Suryo Utomo, Hanshik Chung, Hyomin JeongAbstract:Abstract Mechanical vapor compressor is an essential component that governs the system performance and stability in the multi-effect desalination (MED) system. The importance of improving mechanical vapor compressor's compressing ability in enhancing the efficiency of multi-effect desalination (MED) system has been stressed for a long time. This study was aimed to investigate the influences of inlet skew angle of the Impeller on performance improvement. Four designs of inlet skew angles were attempted at the first Stage Impeller with 8°, 10°, 15°, and 20° respectively. Three dimensional fluid flows were simplified using periodic model to reduce the computational cost and time required. A good performance was expected as which effectively reduce the losses caused by secondary flow in the flow passage of the Impeller. The results show detail flow pattern on decreasing the secondary flow due to incidence angle at the Impeller eye and Impeller passage. The numerical solutions were performed and allowed the better design.
H. P. Dickmann - One of the best experts on this subject based on the ideXlab platform.
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Unsteady Flow in a Turbocharger Centrifugal Compressor: Three-Dimensional Computational Fluid Dynamics Simulation and Numerical and Experimental Analysis of Impeller Blade Vibration
Journal of Turbomachinery, 2006Co-Authors: H. P. Dickmann, Thomas Secall Wimmel, Jaroslaw Szwedowicz, Dietmar Filsinger, Christian H. RodunerAbstract:Experimental investigations on a single Stage centrifugal compressor showed that mea- sured blade vibration amplitudes vary considerably along a constant speed line from choke to surge. The unsteady flow has been analyzed 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 analyzed. 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 ob- tained; 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 nonaxisymmetric components, such as the suction elbow and the discharge volute, was analyzed. The volute geometry itself had not been modeled. It turned out to be sufficient to impose a circumferentially asymmetric pressure distribu- tion 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 trans- formed into the frequency domain by Fourier decomposition. The complex modal pres- sure 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 experi- mental 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.