William Foiles - Academia.edu (original) (raw)

Papers by William Foiles

Research paper thumbnail of Experimental Evaluation of the Effectiveness of Online Water-Washing in Gas Turbine Compressors

Babcock and Wilcox, oil and gas with Saudi Aramco, and consulting with GE-Bently Nevada. Mr. Foil... more Babcock and Wilcox, oil and gas with Saudi Aramco, and consulting with GE-Bently Nevada. Mr. Foiles graduated from the Rotating Machinery and Controls (ROMAC) program of the University of Virginia.

Research paper thumbnail of Review: Rotor Balancing

Shock and Vibration, 1998

This article reviews the literature concerning the balancing of rotors including the origins of v... more This article reviews the literature concerning the balancing of rotors including the origins of various balancing techniques including ones that use influence coefficient, modal, unified, no phase, and no amplitude methods to balance. This survey covers the computational algorithms as well as the physical concepts involved in balancing rotating equipment.

Research paper thumbnail of Practical applications of singular value decomposition in rotordynamics

Australian Journal of Mechanical Engineering, 2005

Abstract Singular value decomposition (SVD) is used extensively in the controls community to exam... more Abstract Singular value decomposition (SVD) is used extensively in the controls community to examine the dynamic behavior of systems. SVD is one component of linear systems theory that has developed into a very mature mathematical tool for assessing systems. One objective of this paper is to illustrate the manner in which that large base of analysis can be brought to bear on both classical and emerging rotordynamics problems. This paper reviews the mathematical fundamentals of SVD and addresses its physical implications with respect to rotordynamics. To illustrate these physical concepts, simple rotor systems are examined in terms of forced response and stability margin characteristics. Additional examples are presented in which SVD is applied to more complex rotor systems for balancing, model reconciliation, and model reduction objectives.

Research paper thumbnail of Experimental Evaluation of the Effectiveness of Online Water-Washing in Gas Turbine Compressors

Journal of Engineering for Gas Turbines and Power, 2015

An investigation of the effectiveness of online combustion turbine axial compressor washing using... more An investigation of the effectiveness of online combustion turbine axial compressor washing using various purity grade waters and commercial washing detergents was performed. For this project, blade surface fouling dirt was obtained from gas turbine axial compressor blades installed at various field sites. The dirt was analyzed to determine consistency of typical blade surface fouling materials. A representative dirt formula and blade coating procedure was developed so that comparative tests could be performed using various cleaning fluids. Dirt coated blades were installed in a wind tunnel capable of simulating compressor operating conditions. A spray nozzle upstream of the blade test section was used for washing blades with five different test liquids to determine the effectiveness or advantages of any liquid. Once this testing was completed, a similar test setup was then utilized to inject a mixture of formulated fouling dirt and the various online cleaning liquids upstream of th...

Research paper thumbnail of Balancing of flexible rotors using convex optimization techniques: Optimum min-max LMI influence coefficient balancing

Journal of Vibration and Acoustics, Transactions of the ASME, 2008

In some industrial applications, influence coefficient balancing methods fail to find the optimum... more In some industrial applications, influence coefficient balancing methods fail to find the optimum vibration reduction due to the limitations of the least-squares optimization methods. Previous min-max balancing methods have not included practical constraints often encountered in industrial balancing. In this paper, the influence coefficient balancing equations, with suitable constraints on the level of the residual vibrations and the magnitude of correction weights, are cast in linear matrix inequality (LMI) forms and solved with the numerical algorithms developed in convex optimization theory. The effectiveness and flexibility of the proposed method have been illustrated by solving two numerical balancing examples with complicated requirements. It is believed that the new methods developed in this work will help in reducing the time and cost of the original equipment manufacturer or field balancing procedures by finding an optimum solution of difficult balancing problems. The resulting method is called the optimum min-max LMI balancing method.

Research paper thumbnail of Single Plane and Multi-Plane Rotor Balancing Using Only Amplitude

Both analytic and graphical means of balancing using only 1× rotor amplitude vibration data with ... more Both analytic and graphical means of balancing using only 1× rotor amplitude vibration data with no phase data are developed that allow the trial weights to have the different magnitudes. Traditional methods of amplitude only balancing require the use of trial balance weights of the same size. This new methodology uses relative influence coefficients for single plane and multi-plane balancing. An extension to least squares balancing procedures is shown. The matrix based formulation lends itself to computer implementation. 1 NOMENCLATURE ~ui response vector with trial weight i ~xi effect vector for trial weight i ~u original response vector θ angle that ~x1 makes with ~u (See Figure 1.) α angle between the first trial weight and the second β angle between the first trial weight and the third xi |~xi| ri magnitude of the i th trial weight γi angle of the i th trial weight φ angle between the original vibration vector and the vector that represents the effect of adding a trial weight a...

Research paper thumbnail of Balancing With Phase Only (Single-Plane and Multiplane)

Journal of Vibration Acoustics Stress and Reliability in Design, 1988

A balancing technique is developed which requires nothing more sophisticated in vibration instrum... more A balancing technique is developed which requires nothing more sophisticated in vibration instrumentation than a pencil or a crayon. This method of balancing is a calibration weight technique which uses only the phase information at 1X (rotative speed); no amplitude information is required. The basic technique is developed for both single-plane and multiplane balancing. The technique is applicable to both in situ and shop balancing. This paper presents both novel and historical balancing theory and practice. It is novel, to the knowledge of the authors, on balancing with phase only. The historical portions on the abundantly published balancing with amplitude only and “trial weight” calibration weight balancing are included for comparison.

Research paper thumbnail of Experimental Evaluation of the Effectiveness of Online Water-Washing in Gas Turbine Compressors

Babcock and Wilcox, oil and gas with Saudi Aramco, and consulting with GE-Bently Nevada. Mr. Foil... more Babcock and Wilcox, oil and gas with Saudi Aramco, and consulting with GE-Bently Nevada. Mr. Foiles graduated from the Rotating Machinery and Controls (ROMAC) program of the University of Virginia.

Research paper thumbnail of Review: Rotor Balancing

Shock and Vibration, 1998

This article reviews the literature concerning the balancing of rotors including the origins of v... more This article reviews the literature concerning the balancing of rotors including the origins of various balancing techniques including ones that use influence coefficient, modal, unified, no phase, and no amplitude methods to balance. This survey covers the computational algorithms as well as the physical concepts involved in balancing rotating equipment.

Research paper thumbnail of Practical applications of singular value decomposition in rotordynamics

Australian Journal of Mechanical Engineering, 2005

Abstract Singular value decomposition (SVD) is used extensively in the controls community to exam... more Abstract Singular value decomposition (SVD) is used extensively in the controls community to examine the dynamic behavior of systems. SVD is one component of linear systems theory that has developed into a very mature mathematical tool for assessing systems. One objective of this paper is to illustrate the manner in which that large base of analysis can be brought to bear on both classical and emerging rotordynamics problems. This paper reviews the mathematical fundamentals of SVD and addresses its physical implications with respect to rotordynamics. To illustrate these physical concepts, simple rotor systems are examined in terms of forced response and stability margin characteristics. Additional examples are presented in which SVD is applied to more complex rotor systems for balancing, model reconciliation, and model reduction objectives.

Research paper thumbnail of Experimental Evaluation of the Effectiveness of Online Water-Washing in Gas Turbine Compressors

Journal of Engineering for Gas Turbines and Power, 2015

An investigation of the effectiveness of online combustion turbine axial compressor washing using... more An investigation of the effectiveness of online combustion turbine axial compressor washing using various purity grade waters and commercial washing detergents was performed. For this project, blade surface fouling dirt was obtained from gas turbine axial compressor blades installed at various field sites. The dirt was analyzed to determine consistency of typical blade surface fouling materials. A representative dirt formula and blade coating procedure was developed so that comparative tests could be performed using various cleaning fluids. Dirt coated blades were installed in a wind tunnel capable of simulating compressor operating conditions. A spray nozzle upstream of the blade test section was used for washing blades with five different test liquids to determine the effectiveness or advantages of any liquid. Once this testing was completed, a similar test setup was then utilized to inject a mixture of formulated fouling dirt and the various online cleaning liquids upstream of th...

Research paper thumbnail of Balancing of flexible rotors using convex optimization techniques: Optimum min-max LMI influence coefficient balancing

Journal of Vibration and Acoustics, Transactions of the ASME, 2008

In some industrial applications, influence coefficient balancing methods fail to find the optimum... more In some industrial applications, influence coefficient balancing methods fail to find the optimum vibration reduction due to the limitations of the least-squares optimization methods. Previous min-max balancing methods have not included practical constraints often encountered in industrial balancing. In this paper, the influence coefficient balancing equations, with suitable constraints on the level of the residual vibrations and the magnitude of correction weights, are cast in linear matrix inequality (LMI) forms and solved with the numerical algorithms developed in convex optimization theory. The effectiveness and flexibility of the proposed method have been illustrated by solving two numerical balancing examples with complicated requirements. It is believed that the new methods developed in this work will help in reducing the time and cost of the original equipment manufacturer or field balancing procedures by finding an optimum solution of difficult balancing problems. The resulting method is called the optimum min-max LMI balancing method.

Research paper thumbnail of Single Plane and Multi-Plane Rotor Balancing Using Only Amplitude

Both analytic and graphical means of balancing using only 1× rotor amplitude vibration data with ... more Both analytic and graphical means of balancing using only 1× rotor amplitude vibration data with no phase data are developed that allow the trial weights to have the different magnitudes. Traditional methods of amplitude only balancing require the use of trial balance weights of the same size. This new methodology uses relative influence coefficients for single plane and multi-plane balancing. An extension to least squares balancing procedures is shown. The matrix based formulation lends itself to computer implementation. 1 NOMENCLATURE ~ui response vector with trial weight i ~xi effect vector for trial weight i ~u original response vector θ angle that ~x1 makes with ~u (See Figure 1.) α angle between the first trial weight and the second β angle between the first trial weight and the third xi |~xi| ri magnitude of the i th trial weight γi angle of the i th trial weight φ angle between the original vibration vector and the vector that represents the effect of adding a trial weight a...

Research paper thumbnail of Balancing With Phase Only (Single-Plane and Multiplane)

Journal of Vibration Acoustics Stress and Reliability in Design, 1988

A balancing technique is developed which requires nothing more sophisticated in vibration instrum... more A balancing technique is developed which requires nothing more sophisticated in vibration instrumentation than a pencil or a crayon. This method of balancing is a calibration weight technique which uses only the phase information at 1X (rotative speed); no amplitude information is required. The basic technique is developed for both single-plane and multiplane balancing. The technique is applicable to both in situ and shop balancing. This paper presents both novel and historical balancing theory and practice. It is novel, to the knowledge of the authors, on balancing with phase only. The historical portions on the abundantly published balancing with amplitude only and “trial weight” calibration weight balancing are included for comparison.