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Computational and experimental analysis the state of stress of turbine blade
Damborský, Petr ; Jaroslav, Kovařík (referee) ; Malenovský, Eduard (advisor)
This diploma thesis deals with dynamic analysis of the steam turbine blade. This blade is part of the last row of low pressure level of steam turbine. Computational analysis has been performed in first part using FEM and software ANSYS. A Transient analysis has been used to solve forced vibrations. Main goal is to obtain a behavior of main stresses and its directions as a function of loading of the blade in the crack initiation area. Second part deals contain a an experiment. Experiment has been set up to perform a modal analysis which is necessary to obtain a fundamental numbers. Then the vibration of the blade has been performed. To perform this experiment same edge conditions as which has been used during the computational analysis. Goal is the same as in the first part – obtain a behavior of main stresses and its directions as a function of loading of the blade in the crack initiation area. The comparison of results obtained during experimental analysis and computational analysis has been performed in the last part of the thesis. Also the question if any geometrical nonlinearities appeared during analyses is answered.
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Properties of friction connections for blade dampers
Půst, Ladislav ; Pešek, Luděk ; Radolfová, Alena
Experimental laboratory equipment for direct measurement of friction forces was designed and realized. It is based on stiff prescribed relative motion. After connecting with measuring apparatus, a series of friction characteristic measurements with various combination of friction surfaces (blade material 7N, 671, wolfram carbide, chromium carbide) were carried out. Three levels of normal forces at several frequencies of relative motion were applied at each combination. The evaluation was focused particularly on ascertaining the dry friction coefficients. The analytic expressions for various relation strips “friction force - velocity” of relative motions were derived. These expressions can be applied at evaluation of experimental data or/and at numerical solution of machine dynamic problems. Nonlinear models of friction processes were linearized by the equivalent linearizing method.
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Evaluation of measurements with the system VDS-UT on 5th Jan. 2010 at TG2 ETE, Z 1450/10
Procházka, Pavel ; Čertík, P.
The report presents results of the measurements with the contactless vibrodiagnostic system VDS-UT on the third stages of the low-pressure parts NT1 and NT3 of the turbine TG2 at the power plant Temelín during a short shut-down of the second block from the 5th to 6th Jan 2010. Observed phenomena of the blades with higher amplitudes of vibrations are discussed. Vibrations of blades in the monitored period are compared with the long-term measurements in November 1st-11th 2009 as well as with the turbine start-up on 15th July 2009.
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Operational measurement of blade vibrations with the system VDS-UT at TG2 ETE, Z 1449/10
Procházka, Pavel ; Vaněk, František
The results of the analysis of long-term measurements of blade vibrations of third stages of rotors NT1 and NT3 of the turbine TG2 ETE are summarized in the report. Data belonging to the period from 1st to 11th Nov. 2009, when the turbine worked without interruption at full power, were analysed in greater detail for both rotors. Trends of blade vibrations were observed and the maximum and minimum amplitudes of the time differences of all blades were assessed. Extended analysis of data from several periods in 2009, when the turbine TG2 was approaching the operational speed and power, are discussed and presented. In the conclusion, comprehensively discussed results of the analyses of all periods are presented and further development of the vibrodiagnostic system is suggested for understanding phenomena taking place under the turbine TG2 ETE operation.
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Design, realization and test operation of the vibrodiagnostic system VDS-UT at TG2 ETE system, Z1448/10
Procházka, Pavel ; Vaněk, František
The results of the development and realization of the contactless vibrodiagnostic system VDS-UT for monitoring of blade vibrations of the third blade row in the steam turbine TG2 at the power plant Temelín are described. The report deals with the concept and mathematical model of a system based on the method of time differences. The results of the development of magneto-resistive pick-ups sensing the position of the rotor and blades are summarized. The principle methods of data evaluation are discussed, which became the basis for the elaboration of programs for data analysis and on-line display of instantaneous information about the vibration of turbine blades. The results of measurements obtained by starting-up the turbine TG2 after a downtime are involved and analysed.
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Contactless Operational Identification of Turbine Blade Stress and Vibration
Procházka, Pavel ; Vaněk, František
The study deals with the contactless vibrodiagnostic system used for identification of steam turbine blade stress and vibration. The tip-timing method based on the evaluation of time differences of blade passages in different rotor revolutions is described and the results of the development of a new contactless magnetoresistive sensor are presented. A new approach to the identification of blade stress and vibration based on the analysis of the amplitude differences of impulse blade signals is applied.
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Dynamic analysis of turbine blade M4
Hendrych, Pavel ; Pešek, Luděk ; Vaněk, František
This contribution is aimed at the numerical dynamic analysis of steam turbine low-pressure blade M4 both in steady state and under rotation. The verification of the free-free numerical model based on the modal analysis was carried out. The numerical model was developed as a three-dimensional finite element model. The Cambell diagram was calculated with respect to stress stiffening and spin softening effects.
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