Paweł Majewski

Rotor Blades Condition Monitoring Method Based on the Elimination of the Environment Signal

Rotor Blades Condition Monitoring Method Based on the Elimination of the Environment Signal The paper presents fundamentals of a new method for monitoring of technical condition demonstrated by blades of rotor machines during operation thereof. The method involves the diagnostic model expressed as a quotient of the amplitude amplification for the diagnostic signal y(t) that results from the blade impact and the signal x(t) produced by the blade surrounding when the blade tip approaches the sensor, divided by the amplitude amplification of these signals when the blade tip has already passed the sensor position and moves away. The adopted diagnostic model takes account for current surrounding of the blade x(t) with no need of measurements of its parameters [12, 14, 15]. Thus, the model is sensitive to alterations of the technical condition demonstrated by the blade but very little vulnerable to variations in the blade surroundings. Consequently, the proposed method may be able to play an important role for diagnostics of rotor blades during operation thereof.

Application of Blade-Tip Sensors to Blade-Vibration Monitoring in Gas Turbines

Non-contact blade vibration measurement in turbomachinery is performed during development phase to verify design quality of bladed disk and its structural integrity (Zielinski & Ziller, 2005). The method, referred as blade tip-timing (BTT) or Non-contact Stress Measurement System (NSMS) is applied by mostly all manufacturers as a complement of strain gauges, traditionally used to measure stress levels and blade vibration parameters (Roberts, 2007). Measurement results are usually presented in the function of rotational speed in Campbell diagram, showing vibration modes excited by particular engine orders. Operational stress levels and accumulated fatigue cycles should not exceed material endurance limits. High Cycle Fatigue, occurring at low stress and high vibration frequency is a common reason for blade damage in turbomachinery. HCF has been identified as factor limiting development of more efficient blade designs, affecting safe operation of turbomachinery and causing considerable losses (Nicholas, 2006). US Air Forces initiated HCF Science and technology program in late 1990’s, which launched and supported multidisciplinary efforts for HCF mitigation, continued recently as Engine Prognosis Program. Development of tiptiming instrumentation both for supporting design of fatigue-resistant components and also for online blade crack detection has been one of research priorities and provided new sensors and advanced data analysis methods. NSMS technologies are also developed and successfully applied in power industry (Ross, 2007). Nowadays Blade Tip-Timing using optical sensors is considered as mature technology able to replace strain gauges in development process of fans or compressors (Rushard, 2010; Courtney, 2011). Current research activities concentrate on turbines, which are more demanding environment for tip-timing instrumentation due to high temperature, contamination and lower amplitude of vibration. Development of alternative tip sensors is considered as another priority. Optical sensors despite providing the highest available resolution, require cleaning and ensure quite limited life, which makes them unusable in embedded systems for blade health monitoring. This chapter describes development and application of inductive, eddy-current and microwave tip-timing sensors for gas-turbine blades, carried out in ITWL in last five years. Other sensors’ applications, like measurement of tip-clearance, blade twist and disk

Analysis of Middle Bearing Failure in Rotor Jet Engine Using Tip-Timing and Tip-Clearance Technique

The reported problem is the failure of the middle bearing in an aircraft rotor engine. Tip-timing and tip-clearance and variance analyses are carried out on a compressor rotor blade in the seventh stage above the middle bearing. The experimental analyses concern both an aircraft engine with a middle bearing in good working order and an engine with a damaged middle bearing. A numerical analysis of the seventh stage blade free vibration are conducted to explain the experimental results. This appears to be an effective method of predicting middle bearing failure. The blade vibration variance increases when there is bearing failure.© 2014 ASME

Detection Damage in Bearing System of Jet Engine Using the Vibroacoustic Method

Abstract The article discusses typical, operational systems for monitoring vibrations of jet engines, which constitute the propulsion of combat aircraft of the Armed Forces of the Republic of Poland. After that, the paper presents the stage of installing vibration measuring sensors in the direct area of one of the jet engine bearings, which is a support system for its rotor. The article discusses results of carried out analyses of data gathered during tests of the engine in the conditions a jet engine test bed. Results of detecting damages to the bear-ing, using sensors built in the direct area will be presented.

A Laboratory System to Testing Characteristics Wind Turbine at Low Speeds of Wind

The article presents design solutions air generator systems, measurement of air velocity and software of acquisition and control. It also provides the results obtained during the calibration of the test tunnel developed at Air Force Institute of Technology.

The Use of the Vibroacoustic Method for Monitoring the Technical Condition of Aero Engines with Extended Time between Overhauls

The article presents some aspects of several years of work on the use of the vibroacoustic method (Non-Destructive Testing) for assessing a turboprop engine from a trainer aircraft. The functioning engine does not have an operating system for measuring vibration, and therefore the current levels of vibrations and its changes in trends are not known. In order to extend its service life, performing a number of works was required. On the basis of assessing the current state of the engine, opportunities for further exploitation were identified thus developing methodology for evaluating technical condition regarding the whole population. The paper shortly describes the object and equivalent tests on the engine. The article focuses on the methods prepared for extending life between overhauls required for turboprop engines and discusses the results received during their implementation.

Vibration Reduction System Using Magnetic Suspension Technology

Abstract The article presents considerations concerning the construction of vibration reduction system using magnetic suspension technology. Presents the results of simulation, numerical and experimental the bearingless electric motor, for which successfully used this type of solution. Positive results of research and testing have become the basis for the development of the concept of building this type of active vibration reduction system , at the same time acting as a support for a technical object, which is a jet engine. Bearing failures are manifested by loss or distortion of their mass, which leads to a total destruction of the roller bearing, and thus reflected in the security. The article presents the concept of building active magnetic suspension to eliminate the bearing system of classical rolling bearing and replace it with magnetic bearing.

Ocena Stanu Technicznego Łopatki Maszyny Wirnikowej w Procesie Użytkowania z Eliminacją Sygnału Otoczenia

Ocena Stanu Technicznego Łopatki Maszyny Wirnikowej w Procesie Użytkowania z Eliminacją Sygnału Otoczenia W artykule przedstawiono podstawy nowej metody monitorowania stanu technicznego łopatek maszyn wirnikowych podczas ich użytkowania. Metoda wykorzystuje model diagnostyczny w postaci ilorazu wzmocnienia amplitudowego sygnału diagnostycznego y(t) wynikającego z działania łopatki i sygnału x(t) jej otoczenia podczas zbliżania się wierzchołka łopatki do czujnika i wzmocnienia amplitudowego tych sygnałów podczas oddalania się wierzchołka łopatki od czujnika Przyjęty model diagnostyczny pośrednio uwzględnia aktualne otoczenie łopatki x(t) bez konieczności jego pomiaru [12, 14, 15]. Zatem jest on czuły na zmiany stanu technicznego łopatki, a mało wrażliwy na zmianę otoczenia. Proponowana metoda może odegrać istotną rolę w diagnostyce łopatek wirnikowych podczas ich użytkowania.