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Dual-system Magnetoresistive Sensor of Turbine Blades Vibration
Procházka, Pavel ; Vaněk, František ; Hodboď, Robert
The paper is focused on new methods of non-contact sensing vibrations and deflections of rotating machine parts, especially blades of steam turbines. Special attention is paid to the methods and magnetoresistive sensors developed in the Institute of Thermomechanics for non-contact measurements of characteristics of rotating blades inside steam turbines under operation. Principles of non-contact sensors based on measuring deflections are described and compared, including new types of magnetoresisitive sensors.
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Research of pressure pulsations and vibrations at the turbine 1000 MW
Procházka, Pavel ; Vaněk, František ; Sadílek, J. ; Hodboď, Robert
Experimental research of pressure pulsation with simultaneous measurements of stator and blade vibrations in the L – 1 stage was conducted at the turbine 1000 MW of the nuclear power plant Temelín in 2012. The aim of this work was to find out links and possible sources of increased vibrations of the blades of the 3rd rotor stage during the turbine start-up. The applied methods and used appliances are described in the paper. Observed phenomena are analyzed with focus on the causes of blade vibrations.
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Research of pressure pulsations and vibration in the turbine 1,000 MW
Procházka, Pavel ; Vaněk, František ; Sadílek, J.
The paper describes the methods and equipment used in experimental research of pressure pulsations with simultaneous measurement of vibration of the stator and blades of the third moving wheel in the turbine 1,000 MW at the nuclear power plant Temelín in 2012. The aim of this work was to find links and possible sources of blade vibration during the turbine start-up. The observed phenomena are analyzed, focusing on the causes of blade vibrations in the stage L-1.
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A computationally efficient and accurate numerical representation of thermodynamic properties of steam condensing steam flow in steam turbines
Hrubý, Jan
Mathematical modeling of the non-equilibrium condensing transonic steam flow in the complex 3D geometry of a steam turbine is a demanding problem both concerning the physical concepts and the required computational power. Available accurate formulations of steam properties IAPWS-95 and IAPWS-IF97 require much computation time. For this reason, the modelers often accept the unrealistic ideal-gas behavior. Here we present a computation scheme based on a piecewise, thermodynamically consistent representation of the IAPWS-95 formulation. Density and internal energy are chosen as independent variables to avoid variable transformations and iterations. On the contrary to the previous Tabular Taylor Series Expansion Method, the pressure and temperature are continuous functions of the independent variables, which is a desirable property for the solution of the differential equations of the mass, energy, and momentum conservation for both phases.
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Nonequilibrium condensation processes in steam turbines in the light of new measurements of heterogeneous particles
Hrubý, Jan ; Kolovratník, M. ; Ždímal, Vladimír ; Bartoš, Ondřej ; Moravec, Pavel ; Jiříček, I.
In a steam turbine, droplets are formed either homogeneously or via heterogeneous nucleation on pre-existing heterogeneous particles. In a pioneering work, the present team developed a system to measure the number and size of heterogeneous particles down to diameter of 3 nm. This work reports on measurements at Power Plant Prunéřov II. For the first time, the data is at higher parameters (0.27 MPa, 250°C), and the diffusion battery was used to determine the size distribuition of the particles, showing count-mean diameter of about 13 nm.
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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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