Blading Vibration and Failures in Gas Turbines: Part C — Detection and Troubleshooting

1995 ◽  
Author(s):  
Cyrus B. Meher-Homji
Keyword(s):  
Gas Turbines ◽  
Failure Modes ◽  
Measurement Techniques ◽  
Indirect Measurement ◽  
Qualitative Information ◽  
Part C ◽  
Microstructure Changes ◽  
Direct Measurements ◽  
Blade Failure

Blade failures account for as many as 42% of failures in gas turbines. This paper covers approaches to detect and avoid blade failures by direct and indirect measurement techniques. Direct measurements involve the use of special sensors or methods that measure blading vibration or condition. Indirect techniques do not quantitatively measure blade conditions but provide qualitative information that help in avoiding blade problems. Metallurgical tests of hot section blades to determine microstructure changes are also covered. A blade failure troubleshooting chart is furnished to assist users in diagnosing common failure modes.

Direct and Indirect Vibro-Acoustic Measurements for Road Noise NVH Predictions

2005 ◽  
Author(s):  
Alessandro Zanarini ◽  
Filip De Coninck ◽  
Krzysztof Mendrok ◽  
Paul Sas
Keyword(s):  
Complex Structure ◽  
Indirect Measurement ◽  
Acoustic Measurements ◽  
Road Noise ◽  
Indirect Measurements ◽  
Direct Measurements ◽  
Path Direction ◽  
Vehicle Technologies ◽  
Structure Measurement ◽  
Reverse Path

This paper describes vibro-acoustic direct and indirect measurements for road noise NVH predictions from a complete car. Attention is devoted to the dynamic response of the structure and interior pressure field toward tire patch displacement inputs. The direct measurements exploited the Team Corporation CUBE™ high frequency 6 degree-of-freedom (DOF) shaker recently installed at the KULeuven Vehicle Technologies Laboratory; the input was provided directly at the tire contact patch, while the responses were measured as accelerations and pressures on the structure. In the indirect measurements a low-mid frequency volume velocity source (LMFVVS) was used to acoustically excite the structure in the reverse path direction from the inside of the interior car cavity, while accelerations on the car and forces/torques where acquired by a 6-DOF dynamometer at the tire patch. From both types of excitations Frequency Response Functions (FRF) were calculated in the frequency range [0–500 Hz]. The non-linearity of the full car system was investigated with different direct and indirect measurement tests, in order to assess the feasibility of the reciprocity principle in such a complex structure. Measurement set-ups, results and comparisons are described and discussed in detail.

Association Between Scapular Posture and Two Different Pectoralis Minor Length Tests in Adolescents

2021 ◽  
pp. 1-6
Author(s):  
Leyla Eraslan ◽  
Gulcan Harput ◽  
Damla Deniz ◽  
Taha Yildiz ◽  
Burak Ulusoy ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Direct Measurement ◽  
Crucial Role ◽  
Indirect Measurement ◽  
Rank Test ◽  
Postural Asymmetry ◽  
Limited Knowledge ◽  
Pectoralis Minor ◽  
Direct Measurements ◽  
Length Measurements

Postural asymmetry due to the alterations in scapular posture is typically considered to be associated with injury. Pectoralis minor (PM) has played a crucial role in scapular posture, but limited knowledge exists that shows the possible effect of PM length on static scapular positioning in adolescents. The aim of this study was to investigate the association between static scapular positioning and two different PM length measurements in adolescents. Pearson rank test demonstrated that direct measurements of the PM length significantly and strongly inversely correlated to scapular anterior tilting (p = .01; r = −.592)and significantly and moderately inversely correlated to scapular internal rotation (p = .013; r = −.465) and scapular downward rotation (p = .028; r = −.416). However, indirect measurement of the PM length was not related to scapular posture. No significant correlation was found between direct and indirect PM length measurements. Direct measurement of PM length presents more information regarding alterations of the static scapular positioning.

Support Vibration Diagnostics and Limits in Gas Turbines

2016 ◽  
Author(s):  
Marcin Bielecki ◽  
Salvatore Costagliola ◽  
Piotr Gebalski
Keyword(s):  
Gas Turbine ◽  
Test Data ◽  
Gas Turbines ◽  
Failure Modes ◽  
Real Life ◽  
Reliability Function ◽  
Vibration Diagnostics ◽  
Real Life Data ◽  
Industrial Gas Turbines ◽  
Harmful Effects

The paper deliberates vibration limits for non-rotating parts in application to industrial gas turbines. As a rule such limits follow ISO 10816-4 or API616, although in field operation it is not well known relationship between these limits and failure modes. In many situations, the reliability function is not well-defined, and more comprehensive methods of determining the harmful effects of support vibrations are desirable. In the first part, the undertaken approach and the results are illustrated based on the field and theoretical experience of the authors about the failure modes related to alarm level of vibrations. Here several failure modes and diagnostics observations are illustrated with the examples of real-life data. In the second part, a statistical approach based on correlation of support vs. shaft vibrations (velocity / displacement) is demonstrated in order to assess the risk of the bearing rub. The test data for few gas turbine models produced by General Electric Oil & Gas are statistically evaluated and allow to draw an experimentally based transfer function between vibrations recorded by non-contact and seismic probes. Then the vibration limit with objectives like bearing rub is scrutinized with aid of probabilistic tools. In the third part, the attention is given to a few examples of the support vibrations — among other gas turbine with rotors supported on flexible pedestals and baseplate. Here there is determined a transfer coefficient between baseplate and bearing vibrations for specific foundation configurations. Based on the test data screening as well as analysis and case studies thereof, the conclusions about more specific vibration limits in relation to the failure modes are drawn.

Some Aspects of Operated Blades HCF Analysis: Rejuvenation and Life Estimation

2018 ◽  
Author(s):  
Sergey A. Ivanov ◽  
Maxim G. Guralnik ◽  
Alexander I. Rybnikov
Keyword(s):  
Shot Peening ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Life Extension ◽  
Ultrasonic Shot Peening ◽  
Industrial Gas Turbines ◽  
Hcf Strength ◽  
Blade Failure ◽  
Metal Properties ◽  
The Cost

The lifecycle of modern industrial gas turbines can reach hundred thousand hours and usually the turbine blades need to be replaced. The use of super alloys and application of advanced coatings makes the cost of turbine lifecycle rather high. The methods for blade rejuvenation and life extension are based on the analysis of the main defects which can considerably reduce blade strength. The effect of long operation and typical defects in turbine blades has been studied in correlation with HCF. The decrease of blades HCF under the effect of operation has been considered as the result of influence of mechanical and thermal factors. The influence of FOD on the blade HCF strength is studied. Some random defects in turbine blades which resulted in HCF decreasing and blade failure are considered. The rejuvenation heat treatment for the blades of ZhS6K and EI893 and its positive effect on metal properties is demonstrated. The ultrasonic shot peening for operated blades have been considered. It is demonstrated that HCF strength of blades after shot peening is about 25–30% higher. Relaxation of compressing stresses in operation is shown as not essential. The remaining life of operated blades can be estimated using the correlation of endurance limit and run time.

Inlet Fogging of Gas Turbine Engines: Part B — Fog Droplet Sizing Analysis, Nozzle Types, Measurement and Testing

2002 ◽  
Author(s):  
Mustapha Chaker ◽  
Cyrus B. Meher-Homji ◽  
Thomas Mee
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Measurement Techniques ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Size Measurement ◽  
The Past ◽  
Testing Method ◽  
Measurement And Testing ◽  
Experimental And Theoretical Studies

The inlet fogging of gas turbine engines for power augmentation has seen increasing application over the past decade yet not a single technical paper treating the physics and engineering of the fogging process, droplet size measurement, droplet kinetics, or the duct behavior of droplets, from a gas turbine perspective, is available. This paper provides the results of extensive experimental and theoretical studies conducted over several years, coupled with practical aspects learned in the implementation of nearly 500 inlet fogging systems on gas turbines ranging in power from 5 to 250 MW. Part B of the paper treats the practical aspects of fog nozzle droplet sizing, measurement and testing presenting the information from a gas turbine fogging perspective. This paper describes the different measurement techniques available, covers design aspects of nozzles, provides experimental data on different nozzles and provides recommendations for a standardized nozzle testing method for gas turbine inlet air fogging.

scholarly journals Remote Measurements of Horizontal Eddy Diffusivity

2005 ◽  
Vol 22 (9) ◽  
pp. 1373-1380 ◽  
Author(s):  
Darek J. Bogucki ◽  
Burton H. Jones ◽  
Mary-Elena Carr
Keyword(s):  
Numerical Models ◽  
Measurement Techniques ◽  
Rapid Assessment ◽  
Digital Camera ◽  
Eddy Diffusivity ◽  
Direct Measurements ◽  
Remote Measurements ◽  
Rgb Images ◽  
Speed Fluctuations

Abstract The rate of horizontal diffusivity or lateral dispersion is key to understanding the dispersion of tracers and contaminants in the ocean, and it is an elusive, yet crucial, parameter in numerical models of circulation. However, the difficulty of parameterizing horizontal mixing is exacerbated in the shallow coastal ocean, which points to the need for more direct measurements. Here, a novel and inexpensive approach to remotely measure the rate of horizontal diffusivity is proposed. Current shipboard measurement techniques require repeated surveys and are thus time consuming and labor intensive. Furthermore, intensive in situ sampling is generally impractical for routine coastal management or for rapid assessment in the case of emergencies. A remote approach is particularly useful in shallow coastal regions or those with complex bathymetry. A time series of images from a dye-release experiment was obtained with a standard three-megapixel digital camera from a helicopter that hovered over the study area. The red–green–blue (RGB) images were then 1) analyzed to distinguish the dye from the ambient color of the water and adjacent land features, 2) orthorectified, and 3) analyzed to obtain advection and diffusion rates of the thin subsurface dye layer. A horizontal current of the order of 6 cm s−1 was found. The estimated horizontal eddy diffusivity rate for scales of O(10 m) in the harbor was 0.1 m2 s−1. The dye diffusivity and advection rate that are calculated from the images are consistent with independent calculations based on in situ measurements of current speed fluctuations.

Using Diagnostics and Prognostics to Minimize the Cost of Ownership of Gas Turbines

2006 ◽  
Author(s):  
Hans R. DePold ◽  
Jason Siegel
Keyword(s):  
Value Chain ◽  
Gas Turbines ◽  
Failure Modes ◽  
Parametric Design ◽  
Health Management ◽  
System Component ◽  
Value Chain Analysis ◽  
Gas Generator ◽  
Material Condition ◽  
Cost Of Ownership

In general, health management technologies observe features associated with anomalous system behavior and relate these features to useful information about the system’s condition. In the case of prognostics, this information is then related to the expected condition at some future time. The ability to estimate the time to conditional or to mechanical failure is of great benefit in health management systems. Inherently probabilistic in nature, prognostics can be applied to system/component failure modes governed by material condition and by functional loss. Like diagnostic algorithms, prognostic algorithms tend to be generic in design but specific in application. Today, elements of turbine gas generator condition based maintenance, module and part life analysis, and soft removal times play essential roles in sustaining safe operations and effective equipment maintenance. When intelligently combined with value chain analysis they provide the decision support system needed to undertake the maintenance actions which minimize total cost of ownership. The methodologies and mathematical constructs for performing optimization require the system designer to clearly define a useful cost or objective function, which when minimized mathematically produces the parametric design combination that we call optimized. In the specific cases where parametric constraints exist, our optimized system typically will be found along those boundary conditions.

Carrier-Level Packaging and Reliability of a MEMS-Based Safety and Arming Device

2001 ◽  
Vol 682 ◽  
Author(s):  
Michael Deeds ◽  
Kevin Cochran ◽  
Rajesh Swaminathan ◽  
Peter Sandborn
Keyword(s):  
Failure Modes ◽  
Measurement Techniques ◽  
Accelerated Aging ◽  
Mems Devices ◽  
Mems Switches ◽  
Environmental Conditioning ◽  
Dog Bone ◽  
Ic Packaging ◽  
Bone Structures ◽  
The Impact

ABSTRACTPackaging of MEMS devices introduces new challenges to the package architecture. MEMS systems include interfaces, processes, and materials foreign to the IC packaging industry. To build reliable MEMS systems, failure modes must be identified and understood. In addition, measurement techniques must be developed to interrogate critical aspects of the package.The present work addresses the architecture of the carrier-level packaging for a MEMS-based Safety and Arming device (S&A). The impact of moisture on packaged MEMS systems and test structures are investigated through an environmental conditioning program that includes thermal cycling and accelerated aging. MEMS switches are packaged in hermetic, non-hermetic, and ventilated configurations to facilitate in-situ monitoring of device health. A MEMS humidity sensor is included in these packages to allow interrogation of package environment characteristics.Mechanical MEMS test structures are put through the same environmental conditions as the MEMS switches. These structures provide additional data on the failure modes of the packaged switches. Push test structures provide cumulative data on friction, stiction, and material properties and dog bone structures isolate material property influences.

scholarly journals Desktop Failure Analysis on a Microcomputer Using Weibull, Lognormal and Renewal Data

1989 ◽  
Author(s):  
J. L. Byers
Keyword(s):  
Life Cycle ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Life Cycle Cost ◽  
Failure Modes ◽  
Probability Distributions ◽  
Typical Case ◽  
Central Computer ◽  
User Friendly ◽  
Lognormal Probability

Gas turbine components and parts are widely known to have many failure modes for which the failures correlate in either the Weibull or Lognormal probability distributions. This paper describes a typical case which is handled by the new computer programs now being used by the U. S. Navy. These programs have brought the capability to make such analyses directly to the designer or analysts desk instead of having to be sent off to a central computer to wait in line. The programs are interactive with the user and extremely user friendly. Uses are expanding to cover almost every area in the life cycle of gas turbines where it would be beneficial to forecast future failures. This makes the programs useful to managers, logisticians, life cycle cost analysts, and a host of others. Wide applicability of the methods assures usage outside of the gas turbine field.

scholarly journals Inventory of pollutant emissions into the atmosphere from gas turbine installations of gas pumping units

2021 ◽  
pp. 58-70
Author(s):  
Oleksandr Zaporozhets ◽  
Sergii Karpenko ◽  
Sergii Puzik ◽  
Bogdan Sagaidak
Keyword(s):  
Air Pollution ◽  
Computer Simulation ◽  
Air Quality ◽  
Gas Turbines ◽  
Subsequent Development ◽  
Air Pollutant ◽  
Pollutant Emissions ◽  
Emission Sources ◽  
Direct Measurements ◽  
Adverse Weather

Development of a single method for inventory of pollutant emissions from installations based on the elaboration of existing methods for calculation of air pollution is an important scientific and practical task in the field of environmental safety. The main purpose of the study is to test and compare models of stationary emission sources and to assess air quality based on them. In the inventory of pollutant emissions, the following materials are used: direct measurements, which are based on direct instrumental measurements, and calculated measurements or combinations thereof. According to the direct measurements of NOx and CO emissions from the operation of gas turbines at the Valley compressor station with a nominal capacity of 1 to 50 MW, we found that: the actual emissions of NO and CO increase with the average load on the installation and the time of introduction into operation and date of issue and the actual values of the maximum allowable concentration of NOx (from 100.13 to 467 mg / m) and CO (from 16.08 to 444.88 mg / m) do not exceed the permissible levels of NO-500 mg / m and CO-250 mg / m according to the instructional documents. Comparison of these calculation methods showed the same results, which confirms the need for their systematization with the subsequent development of a single methodology. The distance of 106 m, where the maximum concentration of pollution in adverse weather conditions is expected, was obtained by the calculation method of determining the surface concentration of NOx and CO emissions from the installation. To assess the effectiveness of the methods for inventory of pollutant emissions into the atmosphere from gas turbines, we have developed a scheme of relationship between the object being assessed for efficiency and the object being serviced. Particularly noteworthy are the results and analysis of direct measurements of NOx and CO emissions, as well as the developed scheme for linking the inventory process for pollutant emissions into the atmosphere from installations. The actual concentration of pollutants can be estimated by measuring the background, although in this case it is impossible to exclude the influence of other neighboring and remote emission sources on the results of the air pollution assessment. Depending on the specific task, the results of computer simulation for given parameters of the external environment can also be used to assess the actual, retrospective or prospective conditions. Future conditions can be modeled only with the help of computer simulation. The method of air pollutant concentration calculation for emissions of enterprises does not consider all possible features of emission sources and, in terms of passive stationary sources and cold emissions, the algorithm needs to be clarified and the justifications in the paper indicate ways to make these improvements. Inventory is the first stage in the strategy of air quality regulation, as it provides information for the development, justification and decision-making in regulating the activities of gas turbines to reduce adverse effects on the environment and public health.

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