scholarly journals The Concept of Monitoring Blades of Rotor Machines with the Identification of their Vibration Frequency

2017 ◽  
Vol 44 (1) ◽  
pp. 389-412
Author(s):  
Edward Rokicki ◽  
Paweł Lindstedt ◽  
Jerzy Manerowski ◽  
Jarosław Spychała
Keyword(s):  
Vibration Frequency ◽  
Direct Determination ◽  
Technical Condition ◽  
Parameter Analysis ◽  
Diagnostic Model ◽  
Blade Vibration ◽  
Blade Tip ◽  
Instantaneous Speed ◽  
Amplitude Amplification

Abstract The paper presents the basis of a new method for monitoring the technical condition of rotating blades during their operation. Utilizing the measurement of blade tip instantaneous speed under subsequent sensors, enables direct determination of the blade vibration frequency. The method utilizes a diagnostic model in the form of amplitude amplification W2ij and phase shift φij of a diagnostic signal y(t) resulting from the operation of the blade and the signal from its environment, when the blade tip passes under a cascade of blade tip instantaneous speed sensors. The adopted diagnostic model, indirectly takes into account the current surrounding of a blade without the need to measure it [12, 14]. Evaluation of the blade technical condition in real time and static analysis shall be performed on the basis of the vibration process parameter analysis. The suggested method may play an important role in the diagnostics of rotor machine blades during their operation.

The Influence of Diagnostic Signal Measurement Period on Blades Technical Condition Images Determined from Phase Shift Difference

2013 ◽  
Vol 199 ◽  
pp. 67-72 ◽  
Author(s):  
Rafał Grądzki
Keyword(s):  
Phase Shift ◽  
Damage Detection ◽  
Technical Condition ◽  
New Method ◽  
Diagnostic Model ◽  
Inductive Sensor ◽  
Blade Tip ◽  
Space Range ◽  
Measurement Period

In the article, new method of monitoring of rotor machine blades technical condition is presented. This method is based on diagnostic model φT12T01 [ which uses phase shift difference of signal fragments resulting from blade operation y (t) during blade recession from sensor and during approach of blade tip towards the sensor as well as signal of its environment x (t) described using proper distribution. The assumed diagnostic model also indirectly includes actual blade environment x (t) without necessity of its measurement [3,. Contactless inductive sensor constantly measures the signal of operating blade transition below the sensor. However, several difficulties with determination of last sample of blade receding from the sensor with first sample of blade approaching the sensor exist. Additionally the problem occurs with measurement of space between blades. So far, the case was solved by use 90% of this space range (in order to eliminate the overlapping of adjacent blades signals). Hence the problem of assessment of measurement period breadth on obtained models (images) of blades. The possibility of blade damage detection by analysis of less than 90% signal course was tested.

scholarly journals An expert system aided method of the blade vibration sources identification with blade-tip timing (BTT) signal decomposition

2018 ◽  
Vol 48 (1) ◽  
pp. 341-358
Author(s):  
Henryk Borowczyk ◽  
Edward Rokicki ◽  
Jarosław Spychała
Keyword(s):  
Expert System ◽  
Turbine Blade ◽  
Signal Decomposition ◽  
Diagnostic Model ◽  
Discrete Wavelet ◽  
Blade Vibration ◽  
Sources Identification ◽  
System Use ◽  
Frequency Components ◽  
Blade Tip

Abstract An expert system aided method of the blade-tip signal decomposition to the turbine blade vibration sources identification is presented. The method utilises a multi-valued diagnostic model based on the discrete wavelet transform. Proposed algorithm consists of four stages: signal decomposition into low- and high-frequency components (approximations and details), approximations and details parameterization, multi-valued encoding of parameters obtained at the second stage, an expert system use of the turbine blade vibration sources identification.

The Direct Determination of I131 in Heterogeneous Fecal Specimens

1961 ◽  
Vol 41 (4) ◽  
pp. 380-384 ◽  
Author(s):  
Arthur F. Dratz ◽  
James C. Coberly
Keyword(s):  
Direct Determination

A New Method for Direct Determination of the Recoilless Fraction with Application to Magnetic Nanoparticles

2002 ◽  
Vol 721 ◽  
Author(s):  
Monica Sorescu
Keyword(s):  
Room Temperature ◽  
Average Particle Size ◽  
Direct Determination ◽  
Average Particle ◽  
Lattice Method ◽  
Recoilless Fraction ◽  
Single Room ◽  
Magnetite Particles ◽  
Physical Mixtures

AbstractWe propose a two-lattice method for direct determination of the recoilless fraction using a single room-temperature transmission Mössbauer measurement. The method is first demonstrated for the case of iron and metallic glass two-foil system and is next generalized for the case of physical mixtures of two powders. We further apply this method to determine the recoilless fraction of hematite and magnetite particles. Finally, we provide direct measurement of the recoilless fraction in nanohematite and nanomagnetite with an average particle size of 19 nm.

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