Westinghouse Electric Corporation

Siemens Westinghouse Power Corporation

Electric Power Research Institute Incorporated

Northrop Grumman Systems Corporation

Ronald T Harrold

Zal N Sanjana

Franklin T Emery

Emil M Fort

Allan I Bennett

Richard D Holm

Herbert E Pietsch

Lawrence Lee Ross

Brian D Ottinger

Lawrence E Ottenberg

A method of monitoring the condition of a thermal barrier coating on a turbine blade or vane during operation of the turbine is provided. The method includes providing a means for receiving acoustic output of the blade or vane during operation of the turbine and monitoring the acoustic output over time, to determine the condition of the thermal barrier coating on the blade or vane. The acoustic output arises from a force on the blade or vane, such as that due to impact of particles, a pulse of gas pressure or constant gas flow. An apparatus employing the above method for monitoring the condition of the thermal barrier coating during operation of the turbine, is also provided.

Monitoring thermal barrier coating deterioration via acoustic response to gas flow, pressure and impact

A pressure sensor () for a harsh environment such as the combustion chamber () of a gas turbine engine (). The pressure sensor includes an acoustic waveguide () having a sensing portion () exposed to the combustion gas in the combustion chamber. Modulations in an acoustic signal passing through the acoustic waveguide are sensed and correlated to pressure fluctuations in the combustion gas. The sensing portion of the waveguide includes a core acoustic waveguide element () covered by a coating material (). The coating material not only protects the core from the harsh environment, but it also improves the efficiency of the transfer of energy from the combustion gas into the waveguide because it provides a stepped transition from the acoustic impedance of the gas to the acoustic impedance of the core material. The protective coating may have a plurality of layers () and/or it may include a graded material () having an acoustic impedance value that varies across its depth.

Apparatus for sensing pressure fluctuations in a hostile environment

A method and apparatus for monitoring the condition of the thermal barrier coating on turbine blades and vanes is provided. The coating is monitored with ultraviolet sensors which can detect ultraviolet radiation emitted from electrical discharges and glow coronas at the surface of the blades and vanes. Such electrical glow discharges and coronas are the result of friction electricity found at the surface of blades and vanes, and are also due to the high pressure, temperature and velocity conditions within the turbine. As the thermal barrier coating deteriorates, the electrical discharges and glow coronas and associated UV emissions decrease in magnitude or have other characteristic changes, thus permitting monitoring of the corona to detect changes in the coating over time.

Ultraviolet sensing of the condition of the vanes and blades of gas turbines in service

A foreign object impact sensor for use with combustion turbines utilizes a passive acoustic waveguide within the turbine to receive acoustic signals from foreign object impact. The magnitude of these signals is displayed and or stored using a lighted display or other suitable indicating device. The information is also recorded and stored, so that a spectrum signature can be obtained from Fourier analysis.

Acoustic monitoring of foreign objects in combustion turbines during operation

A method and apparatus for monitoring the condition of a thermal barrier coating on the vanes and blades of a combustion turbine relies on a piezoelectric or electrostrictive effect, or tribo-charging generated within the coating. Gas flowing through the turbine will apply pressure to the vanes and blades, resulting in a strain on the blades and vanes, and causing friction as it passes the vanes and blades. An electric current is generated between the coating and vane or blade, either by a pressure-induced piezoelectric effect, a strain-induced electrostrictive effect, or friction-induced tribo-charging. This current causes a radio frequency signal, which can be detected by a high temperature antenna as the blade passes the antenna. One blade may be intentionally designed to produce a signal different from the remaining blades, thereby becoming a marking blade. After amplification and filtering, the radio signals may be analyzed and stored. Changes in the signals produced may indicate a deterioration of the coating. Counting the number of signals from the marking blade can determine the specific blade or vane requiring service.

Condition monitoring of turbine blades and vanes in service

A system for online monitoring the condition of a thermal barrier coating on the vanes and/or blades of a combustion turbine, or other forms of component deterioration affecting the acoustic properties of the vanes and/or blades. The system begins with a signal generator for transmitting a signal to an acoustic transmitter, and then to an acoustic waveguide secured within the turbine, adjacent to a vane. Acoustic waves passing through the vane's coating will have a certain magnitude and velocity when passing through an intact coating, which will change as the coating deteriorates. Additional variation of the acoustic wave will occur due to pressure pulses from passing blades, with the magnitude of the pressure pulses increasing as the blade's coating deteriorates. The acoustic waves are then received by a second acoustic waveguide. The resulting signal will be converted from an acoustic signal to an electrical signal by an acoustic receiver, and will pass through a filter to remove the lower frequency signals of the turbine from the higher frequency signals to be analyzed. The remaining higher frequency signals are sent to a computer, permitting the variations in the acoustic waves to be analyzed. A second embodiment relies solely on pressure pulses from passing blades to generate acoustic signals within the vanes.

Acoustic waveguide sensing the condition of components within gas turbines

A non-reflecting, wave-absorbing structure absorbs sound, radio and radiation wave. The non-reflecting, wave-absorbing structure combines an outer non-reflecting wave structure and a wave-absorbing portion. The outer non-reflecting wave structure allows for the transmission of the wave therethrough without appreciable reflection and the wave-absorbing material absorbs substantially all of the transmitted wave. In the case the wave to be absorbed in a sound wave, the wave-absorbing material is preferably an epoxy in a chemical state of gelatinization which is prevented from reaching a state of cure.

Sound, radio and radiation wave-absorbing, non-reflecting structure and

A device is disclosed which allows an object to be tuned to an incoming sound wave magnitude and wavelength, such that the sound wave will alternatively be passed therethrough without detectable reflection or be completely reflected. The apparatus is intended to be mounted within a hollow object and adjust the perceived distance between the exterior walls of that object to mimic a single thick wall. A signal processing means is supplied which detects the sound wave magnitude and wavelength impinging on the wall facing the sound wave source. The wavelength is passed to the signal processing means, which transmits a complimentary signal to the second wall of the hollow object. The complimentary signal allows the hollow object to resonate as a whole as if it were a solid of a thickness much different from its actual thickness, allowing the sound wave to pass undisturbed therethrough or be reflected therefrom.

Method and apparatus for selective transmission and reflection of sound

System and method for detecting arcing faults in a dynamoelectric machine by monitoring the neutral lead of the machine for a radio frequency voltage produced by arcing, providing a warning signal in response to a change in the radio frequency voltage, and providing a shutdown signal in response to a radio frequency voltage greater than a predetermined level. An RF voltage coupler is capacitively coupled ot the neutrla lead, and a radio frequency monitor connected to the voltage coupler detects peaks in the RF voltage.

System and method for detecting arcing in dynamoelectric machines

System and method of detecting arcing faults in dynamoelectric machines by monitoring the voltage on the neutral grounding lead to detect RF voltages produced by arcing in the machine. The voltage is monitored by an RF voltage coupler and an RF monitor having a high impedance input amplifier. In one embodiment, the voltage coupler is clamped onto the neutral lead, and in another it is connected electrically in series with it.

System and method for arc detection in dynamoelectric machines

Disclosed is a method of monitoring physical and chemical changes in a host material which passes from a liquid state to a solid state. A waveguide is embedded in the host material while it is in the liquid or uncured state, the waveguide extending outside of the host material. A sound wave is sent through the waveguide and is monitored after it has passed through the host material. An article is also disclosed of a container having a liquid sealing exit means for waveguide, a waveguide which passes through the liquid sealing exit means into the container, a solidifiable liquid in the container at a level above the liquid sealing exit means, means outside the container for sending an acoustic wave through the waveguide into the container, and means outside the container for monitoring the acoustic wave after it has passed through said waveguide into the container.

Acoustic waveguide monitoring

Disclosed is an apparatus which is resistant to electrical breakdown consisting of a chamber containing electrodes separated by dielectric gas supersaturated with the vapor from a dielectric liquid.

Supersaturated vapor dielectrics

A vapor-cooled power transformer characterized by a transformer within a sealed housing, and means for applying ultrasonic vibrations to a dielectric liquid within the housing in order to vaporize the fluid and to apply it to the exposed surfaces of the transformer.

Ultrasonic fluid-atomizing cooled power transformer

A dielectric fluid composition with high electrical strength characterized by a gas mixed with the vapor from a first fluid having a high vapor pressure at a low temperature and the vapor from a second fluid having a low vapor pressure at a low temperature to effect a mixture having a higher electrical strength than any component thereof over a temperature range from about -20.degree. C. to -40.degree. C. to about +120.degree. C. to +140.degree. C., with the vapor pressure of the mixture at the highest temperature being about one to two atmospheres. Also, the mixing of low and high cost liquids to obtain a low cost liquid with a vapor with an electrical strength equivalent or better than the best vapor over a wide temperature range.

Dielectric gas-vapor and vapor-vapor mixtures

A dielectric fluid composition with high electrical strength characterized by a first fluid selected from the group consisting of electronegative gases, such as SF.sub.6, CCl.sub.2 F.sub.2, C.sub.2 F.sub.6, CF.sub.3 Cl, and CF.sub.4, and mixtures thereof; or from another group consisting of electropositive gases, such as N.sub.2 and CO.sub.2, and mixtures thereof; or from mixtures of the two groups; and a second fluid from a group of atomized liquids, which may be chlorinated liquid, such as, C.sub.2 Cl.sub.4 (tetrachloroethylene); and fluorocarbon liquids, such as, C.sub.8 F.sub.16 O (perfluorodibutyl ether), and mixtures thereof.

Growing community of inventors

Murrysville, PA, United States of America

Ronald T Harrold