The Experts below are selected from a list of 13566 Experts worldwide ranked by ideXlab platform

Jan Tommy Gravdahl - One of the best experts on this subject based on the ideXlab platform.

  • drive torque actuation in active Surge control of centrifugal compressors
    Automatica, 2002
    Co-Authors: Jan Tommy Gravdahl, Olav Egeland, Svein Ove Vatland
    Abstract:

    A novel approach to active Surge control is presented for a centrifugal compressor driven by an electrical motor. The main idea of the paper is to use the drive itself for Surge control. This eliminates the need for additional actuators, and has the potential of energy efficient operation. It is shown that previous unstable operating points to the left of the Surge Line can be made globally exponentially stable by using the rotational speed of the motor as control. It is then shown that stability and exponential convergence to a set follows when the torque of the drive is considered to be the control input. The proposed method is simulated on a compressor model using an approximation of a real compression system.

  • Active Surge control of centrifugal compressors using drive torque
    Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228), 2001
    Co-Authors: Jan Tommy Gravdahl, Alv Egeland, Olav Egeland, Svein Ove Vatland
    Abstract:

    An approach to active Surge control is presented. A centrifugal compressor driven by an electrical motor is studied, and the drive itself is used for Surge control, thus eliminating the need for additional actuators. It is shown that by using the rotational speed of the motor as control, previous unstable operating points to the left of the Surge Line can be made globally exponentially stable. It is also shown that using the torque of the drive as control ensures exponential convergence. The proposed method is simulated on a compressor model using an approximation of a real compression system.

  • Centrifugal compressor Surge and speed control
    IEEE Transactions on Control Systems Technology, 1999
    Co-Authors: Jan Tommy Gravdahl, Olav Egeland
    Abstract:

    Previous work on stabilization of compressor Surge is extended to include control of the angular velocity of the compressor. A low-order centrifugal compressor model is presented, where the states are mass flow, pressure rise, and rotational speed of the spool. Energy transfer considerations are used to develop a compressor characteristic. In order to stabilize equilibria to the left of the Surge Line, a close coupled valve is used in series with the compressor. Controllers for the valve pressure drop and spool speed are derived. Semiglobal exponential stability is proved using a Lyapunov argument

Olav Egeland - One of the best experts on this subject based on the ideXlab platform.

  • drive torque actuation in active Surge control of centrifugal compressors
    Automatica, 2002
    Co-Authors: Jan Tommy Gravdahl, Olav Egeland, Svein Ove Vatland
    Abstract:

    A novel approach to active Surge control is presented for a centrifugal compressor driven by an electrical motor. The main idea of the paper is to use the drive itself for Surge control. This eliminates the need for additional actuators, and has the potential of energy efficient operation. It is shown that previous unstable operating points to the left of the Surge Line can be made globally exponentially stable by using the rotational speed of the motor as control. It is then shown that stability and exponential convergence to a set follows when the torque of the drive is considered to be the control input. The proposed method is simulated on a compressor model using an approximation of a real compression system.

  • Active Surge control of centrifugal compressors using drive torque
    Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228), 2001
    Co-Authors: Jan Tommy Gravdahl, Alv Egeland, Olav Egeland, Svein Ove Vatland
    Abstract:

    An approach to active Surge control is presented. A centrifugal compressor driven by an electrical motor is studied, and the drive itself is used for Surge control, thus eliminating the need for additional actuators. It is shown that by using the rotational speed of the motor as control, previous unstable operating points to the left of the Surge Line can be made globally exponentially stable. It is also shown that using the torque of the drive as control ensures exponential convergence. The proposed method is simulated on a compressor model using an approximation of a real compression system.

  • Centrifugal compressor Surge and speed control
    IEEE Transactions on Control Systems Technology, 1999
    Co-Authors: Jan Tommy Gravdahl, Olav Egeland
    Abstract:

    Previous work on stabilization of compressor Surge is extended to include control of the angular velocity of the compressor. A low-order centrifugal compressor model is presented, where the states are mass flow, pressure rise, and rotational speed of the spool. Energy transfer considerations are used to develop a compressor characteristic. In order to stabilize equilibria to the left of the Surge Line, a close coupled valve is used in series with the compressor. Controllers for the valve pressure drop and spool speed are derived. Semiglobal exponential stability is proved using a Lyapunov argument

Svein Ove Vatland - One of the best experts on this subject based on the ideXlab platform.

  • drive torque actuation in active Surge control of centrifugal compressors
    Automatica, 2002
    Co-Authors: Jan Tommy Gravdahl, Olav Egeland, Svein Ove Vatland
    Abstract:

    A novel approach to active Surge control is presented for a centrifugal compressor driven by an electrical motor. The main idea of the paper is to use the drive itself for Surge control. This eliminates the need for additional actuators, and has the potential of energy efficient operation. It is shown that previous unstable operating points to the left of the Surge Line can be made globally exponentially stable by using the rotational speed of the motor as control. It is then shown that stability and exponential convergence to a set follows when the torque of the drive is considered to be the control input. The proposed method is simulated on a compressor model using an approximation of a real compression system.

  • Active Surge control of centrifugal compressors using drive torque
    Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228), 2001
    Co-Authors: Jan Tommy Gravdahl, Alv Egeland, Olav Egeland, Svein Ove Vatland
    Abstract:

    An approach to active Surge control is presented. A centrifugal compressor driven by an electrical motor is studied, and the drive itself is used for Surge control, thus eliminating the need for additional actuators. It is shown that by using the rotational speed of the motor as control, previous unstable operating points to the left of the Surge Line can be made globally exponentially stable. It is also shown that using the torque of the drive as control ensures exponential convergence. The proposed method is simulated on a compressor model using an approximation of a real compression system.

R A Dougal - One of the best experts on this subject based on the ideXlab platform.

  • dynamic centrifugal compressor model for system simulation
    Journal of Power Sources, 2006
    Co-Authors: Wei Jiang, Jamil A Khan, R A Dougal
    Abstract:

    A dynamic model of a centrifugal compressor capable of system simulation in the virtual test bed (VTB) computational environment is presented. The model is based on first principles, i.e. the dynamic performance including the losses is determined from the compressor geometry and not from the experimentally determined characteristic performance curves. In this study, the compressor losses, such as incidence and friction losses, etc., are mathematically modeled for developing compressor characteristics. For easy implementation in the VTB platform, the non-Linear governing equations are discretized in resistive companion (RC) form. The developed simulation model can be applied to virtually any centrifugal compressor. By interfacing with a composite system, such as a Brayton cycle gas turbine, or a fuel cell, the compressor dynamic performance can be evaluated. The Surge Line for the compressor can also be determined from the simulation results. Furthermore, the model presented here provides a valuable tool for evaluating the system performance as a function of various operating parameters.

Christian H. Roduner - One of the best experts on this subject based on the ideXlab platform.

  • 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, 2006
    Co-Authors: H. P. Dickmann, Thomas Secall Wimmel, Jaroslaw Szwedowicz, Dietmar Filsinger, Christian H. Roduner
    Abstract:

    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.