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Bleed Valve

The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform

Richard M Murray – 1st expert on this subject based on the ideXlab platform

  • Feedback stabilization of bifurcations in multivariable nonlinear systems—Part I: equilibrium bifurcations
    International Journal of Robust and Nonlinear Control, 2007
    Co-Authors: Yong Wang, Richard M Murray

    Abstract:

    Under certain non-degeneracy conditions, necessary and sufficient conditions for stabilizability are obtained for multi-input nonlinear systems possessing a simple equilibrium bifurcation with the critical mode being linearly uncontrollable. Stabilizability is defined as the existence of a sufficiently smooth state feedback such that the bifurcation of the closed-loop system is a supercritical pitchfork bifurcation, which is equivalent to local asymptotic stability of the system at the bifurcation point. Stabilizability is reduced to the existence of solutions to a third order algebraic inequality, coupled with a quadratic algebraic equation, with the unknowns being the feedback gains. Explicit conditions for the existence of solutions to the algebraic equation and the inequality are derived. Part of the sufficient conditions are equivalent to the rank conditions of augmented matrices. Conditions under which there exists a stabilizing linear feedback law are also derived. The theoretical results are applied to active control of rotating stall in axial compressors using Bleed Valve as actuator. Copyright © 2006 John Wiley & Sons, Ltd.

  • Feedback stabilization of bifurcations in multivariable nonlinear systems—Part II: Hopf bifurcations
    International Journal of Robust and Nonlinear Control, 2007
    Co-Authors: Yong Wang, Richard M Murray

    Abstract:

    In this paper we derive necessary and sufficient conditions of stabilizability for multi-input nonlinear systems possessing a Hopf bifurcation with the critical mode being linearly uncontrollable, under the non-degeneracy assumption that stability can be determined by the third order term in the normal form of the dynamics on the centre manifold. Stabilizability is defined as the existence of a sufficiently smooth state feedback such that the Hopf bifurcation of the closed-loop system is supercritical, which is equivalent to local asymptotic stability of the system at the bifurcation point. We prove that under the non-degeneracy conditions, stabilizability is equivalent to the existence of solutions to a third order algebraic inequality of the feedback gains. Explicit conditions for the existence of solutions to the algebraic inequality are derived, and the stabilizing feedback laws are constructed. Part of the sufficient conditions are equivalent to the rank conditions of an augmented matrix which is a generalization of the Popov–Belevitch–Hautus (PBH) rank test of controllability for linear time invariant (LTI) systems. We also apply our theory to feedback control of rotating stall in axial compression systems using Bleed Valve as actuators. Copyright © 2006 John Wiley & Sons, Ltd.

  • Bleed Valve rate requirements evaluation in rotating stall control on axial compressors
    Journal of Propulsion and Power, 2000
    Co-Authors: S Yeung, Yong Wang, Richard M Murray

    Abstract:

    The actuator rate requirements are evaluated for control of rotating stall using a Bleed Valve and to provide tools for predicting these requirements. Modie cation of both the stable and unstable parts of the compressor characteristic via addition of continuous air injection serves to reducetherequirement of a Bleed Valve used forthe purpose of rotating stall stabilization. Analytical tools based on low-order models (2‐3 states)and simulation tools based on a reduced-ordermodel (37states)aredescribed. ABleedactuatorratelimitstudy ispresentedto compare the actuator requirements predicted by theory, simulation, and experiment using a single-stage, low-speed, axial compressor.Thecomparisonsshowthatthepredictionsobtainedfrom theory andsimulationssharethesametrend as the experiments, with increasing accuracy as the complexity of the underlying model increases. Some insights on the design of Bleed ‐compressor pair are given.

Yong Wang – 2nd expert on this subject based on the ideXlab platform

  • Effects of actuator limits in bifurcation control with applications to active control of fluid instabilities in turbomachinery
    , 2020
    Co-Authors: Yong Wang

    Abstract:

    Feedback stabilization is one of the most dominant issues in modern control theory. The validity of linear control design is based on the assumption that the system is stabilizable. With rapid broadening of control applications to complex systems during the past two decades, the attainability of linear stabilizability sometimes has to compromise with system constraints and affordability of distributed actuation. The goal of this thesis is to tackle some of the problems in control of nonequilibrium behavior and to apply the theory to active control of fluid instabilities in gas turbine engines.

    We consider two of the simplest nontrivial scenarios in local smooth feedback stabilization: the steady-state case, when the linearly unstabilizable eigenvalue is zero; and the Hopf case, when the unstabilizable eigenvalues are a pair of pure imaginary numbers. Under certain nondegeneracy conditions, we give explicit algebraic conditions for stabilizability. And when the system is stabilizable, the stabilizing feedback can be explicitly constructed.

    The problem of local smooth feedback stabilization for systems with critical unstabilizable modes is closely related to bifurcation control. Under certain nondegeneracy conditions, a steady-state/Hopf bifurcation can be turned into a supercritical pitchfork/Hopf bifurcation if and only if the system is locally stabilizable at the bifurcation point. Algebraic necessary and sufficient conditions are derived under which the criticality of a simple steady-state or Hopf bifurcation can be changed to supercritical by a smooth feedback. The effects of magnitude saturation, bandwidth, and rate limits are important issues in control engineering. We give qualitative estimates of the region of attraction to the stabilized bifurcating equilibrium/periodic orbits under these constraints.

    We apply the above theoretical results to the Moore-Greitzer model in active control of rotating stall and surge in gas turbine engines. Though linear stabilizability can be achieved using distributed actuation, it limits the practical usefulness due to considerations of affordability and reliability. On the other hand, simple but practically promising actuation schemes such as outlet Bleed Valves, a couple of air injectors, and magnetic bearings will make the system loss of linear stabilizability, thus the control design becomes a challenging task. The above mentioned results in bifurcation stabilization can be applied to these cases. We analyze the effects of magnitude and rate saturations in active stall and surge control using Bleed Valves and magnetic bearings using the Moore-Greitzer model. The analytical formulas for Bleed Valve actuation give good qualitative predictions when compared with experiments. Our conclusion is that these constraints are serious limiting factors in stall control and must be addressed in practical implementation to the aircraft engines.

  • Feedback stabilization of bifurcations in multivariable nonlinear systems—Part I: equilibrium bifurcations
    International Journal of Robust and Nonlinear Control, 2007
    Co-Authors: Yong Wang, Richard M Murray

    Abstract:

    Under certain non-degeneracy conditions, necessary and sufficient conditions for stabilizability are obtained for multi-input nonlinear systems possessing a simple equilibrium bifurcation with the critical mode being linearly uncontrollable. Stabilizability is defined as the existence of a sufficiently smooth state feedback such that the bifurcation of the closed-loop system is a supercritical pitchfork bifurcation, which is equivalent to local asymptotic stability of the system at the bifurcation point. Stabilizability is reduced to the existence of solutions to a third order algebraic inequality, coupled with a quadratic algebraic equation, with the unknowns being the feedback gains. Explicit conditions for the existence of solutions to the algebraic equation and the inequality are derived. Part of the sufficient conditions are equivalent to the rank conditions of augmented matrices. Conditions under which there exists a stabilizing linear feedback law are also derived. The theoretical results are applied to active control of rotating stall in axial compressors using Bleed Valve as actuator. Copyright © 2006 John Wiley & Sons, Ltd.

  • Feedback stabilization of bifurcations in multivariable nonlinear systems—Part II: Hopf bifurcations
    International Journal of Robust and Nonlinear Control, 2007
    Co-Authors: Yong Wang, Richard M Murray

    Abstract:

    In this paper we derive necessary and sufficient conditions of stabilizability for multi-input nonlinear systems possessing a Hopf bifurcation with the critical mode being linearly uncontrollable, under the non-degeneracy assumption that stability can be determined by the third order term in the normal form of the dynamics on the centre manifold. Stabilizability is defined as the existence of a sufficiently smooth state feedback such that the Hopf bifurcation of the closed-loop system is supercritical, which is equivalent to local asymptotic stability of the system at the bifurcation point. We prove that under the non-degeneracy conditions, stabilizability is equivalent to the existence of solutions to a third order algebraic inequality of the feedback gains. Explicit conditions for the existence of solutions to the algebraic inequality are derived, and the stabilizing feedback laws are constructed. Part of the sufficient conditions are equivalent to the rank conditions of an augmented matrix which is a generalization of the Popov–Belevitch–Hautus (PBH) rank test of controllability for linear time invariant (LTI) systems. We also apply our theory to feedback control of rotating stall in axial compression systems using Bleed Valve as actuators. Copyright © 2006 John Wiley & Sons, Ltd.

B. Sloof – 3rd expert on this subject based on the ideXlab platform

  • Evaluation of Gas Turbine Outboard Bleed Air on Overall Engine Efficiency and CO2e Emission in Natural Gas Compressor Stations
    Journal of Engineering for Gas Turbines and Power-transactions of The Asme, 2013
    Co-Authors: K. K. Botros, D. Rogers, H. Golshan, B. Sloof

    Abstract:

    Gas turbine (GT) engines employed in natural gas compressor stations operate in different modes depending on the power, turbine inlet temperature, and shaft speeds. These modes apply different sequencing of Bleed Valve opening on the air compressor side of the engine. Improper selection of the GT and the driven centrifugal gas compressor operating conditions can lead to larger Bleed losses due to wider Bleed Valve openings. The Bleed loss inevitably manifests itself in the form of higher overall heat rate of the GT and greater engine emission. It is, therefore, imperative to determine and understand the engine and process conditions that drive the GT to operate in these different modes. The ultimate objective is to operate the engine away from the inefficient modes by adjusting the driven gas compressor parameters as well as the overall station operating conditions (i.e., load sharing, control set points, etc.). This paper describes a methodology to couple the operating conditions of the gas compressor to the modes of GT Bleed Valve opening (and the subsequent air Bleed rates) leading to identification of the operating parameters for optimal performance (i.e., best overall efficiency and minimum CO2e emission). A predictive tool is developed to quantify the overall efficiency loss as a result of the different Bleed opening modes and map out the condition on the gas compressor characteristics. One year’s worth of operating data taken from two different compressor stations on TransCanada Pipelines’ Alberta system were used to demonstrate the methodology. The first station employs a GE-LM1600 gas turbine driving a Cooper Rolls-RFBB-30 centrifugal compressor. The second station employs a GE-LM-2500+ gas turbine driving NP PCL-800/N compressor. The analysis conclusively indicates that there are operating regions on the gas compressor maps where losses due to Bleed Valves are reduced and, hence, CO2 emissions are lowered, which presents an opportunity for operation optimization.

  • Evaluation of GT Outboard Bleed Air on Overall Engine Efficiency and CO2e Emission in Natural Gas Compressor Stations
    Volume 5B: Oil and Gas Applications; Steam Turbines, 2013
    Co-Authors: K. K. Botros, D. Rogers, H. Golshan, B. Sloof

    Abstract:

    Gas turbine (GT) engines employed in natural gas compressor stations operate in different modes depending on the power, turbine inlet temperature and shaft speeds. These modes apply different sequencing of Bleed Valve opening on the air compressor side of the engine. Improper selection of the GT and the driven centrifugal gas compressor operating conditions can lead to larger Bleed losses due to wider Bleed Valve openings. The Bleed loss inevitably manifests itself in the form of higher overall heat rate of the GT and greater engine emission. It is therefore imperative to determine and understand the engine and process conditions that drive the GT to operate in these different modes. The ultimate objective is to operate the engine away from the inefficient modes by adjusting the driven gas compressor parameters as well as the overall station operating conditions (i.e. load sharing, control set points, etc.). This paper describes a methodology to couple the operating conditions of the gas compressor to the modes of GT Bleed Valve opening (and the subsequent air Bleed rates) leading to identification of the operating parameters for optimal performance (i.e., best overall efficiency and minimum CO2e emission). A predictive tool is developed to quantify the overall efficiency loss as a result of the different Bleed opening modes, and map out the condition on the gas compressor characteristics. One year’s worth of operating data taken from two different compressor stations on TransCanada Pipelines’ Alberta system were used to demonstrate the methodology. The first station employs GE-LM1600 gas turbine driving a Cooper Rolls-RFBB-30 centrifugal compressor. The second station employs GE-LM-2500+ gas turbine driving NP PCL-800/N compressor. The analysis conclusively indicates that there are operating regions on the gas compressor maps where losses due to Bleed Valves are reduced and hence CO2 emissions are lowered, which presents an opportunity for operation optimization.Copyright © 2013 by ASME

  • Natural Gas Compressor Operation Optimization to Minimize Gas Turbine Outboard Bleed Air
    Volume 1: Upstream Pipelines; Project Management; Design and Construction; Environment; Facilities Integrity Management; Operations and Maintenance; P, 2012
    Co-Authors: K. K. Botros, H. Golshan, B. Sloof, Z. Samoylove, D. Rogers

    Abstract:

    Gas turbine (GT) engines employed in natural gas compressor stations operate in different modes depending on the power, turbine inlet temperature and shaft speeds. These modes apply different sequencing of Bleed Valve opening on the air compressor side of the engine. Improper selection of the GT and the driven booster compressor operating conditions can lead to larger Bleed losses due to wider Bleed Valve openings. The Bleed loss inevitably manifests itself in the form of higher overall heat rate of the GT and greater engine emission. It is therefore imperative to determine and understand the engine and process conditions that drive the GT to operate in these different modes. The ultimate objective is to operate the engine away from the inefficient modes by adjusting the driven booster compressor parameter as well as the overall station operating conditions (i.e. load sharing, control set points, etc.). This paper describes a methodology to couple the operating conditions of the booster compressor to the modes of GT Bleed Valve opening (and the subsequent air Bleed rates) leading to identification of the operating parameters for optimal performance (i.e., best overall efficiency and minimum CO2e emission). A predictive tool is developed to quantify the overall efficiency loss as a result of the different Bleed opening modes, and map out the condition on the gas compressor characteristics. One year’s worth of operating data taken from an existing compressor station on TransCanada Pipelines’ Alberta system was used to demonstrate the methodology. This station employs GE-LM1600 gas turbine driving a Cooper Rolls-RFBB-30 centrifugal compressor. The results from the analysis conclusively indicate that there are operating regions on the gas compressor map where losses due to Bleed Valves are reduced and hence lower CO2 emissions, which presents an opportunity for operation optimization.Copyright © 2012 by ASME