Calculation of the unsteady aerodynamic parameters of a rotating cascade of oscillating blades in incompressible flow

Kurzin, V. B.; Tolstukha, A. S.

doi:10.1007/s10697-005-0041-4

Cited by 3 publications

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“…Figure 2 shows the amplitudes of vibrations averaged over the period T = 100 sec, which were obtained not long before the accident (A x , A y , and A z are the amplitudes of vibrations in the directions from north to south, from east to west, and along the turbine axis, respectively). Forced vibrations with frequencies (9) can be seen at Ω 0 = 2.38 Hz and Ω v = 0.5-1.5 Hz. The level of these vibrations is rather high, obviously, because their frequencies are close to the frequencies of natural hydroacoustic oscillations (8).…”

Section: Comparison Of Theoretical and Experimental Resultsmentioning

confidence: 98%

“…In non-separated flow around the blades, the classical flutter of turbomachine cascades is known to arise at Strouhal numbers much lower than in separated flow regimes. An approximate solution of the corresponding problem of an unsteady flow of a cascade with an arbitrary geometry can be constructed within the framework of the incompressible fluid model, for instance, by the method developed in [9]. The classical flutter is almost impossible in the case of vibrations of a cascade with one degree of freedom; therefore, the probability of emergence of instability of hydroacoustic oscillations in these regimes is rather low.…”

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confidence: 99%

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Mechanism of emergence of intense vibrations of turbines on the Sayano-Shushensk hydro power plant

Kurzin

Селезнев

2010

J Appl Mech Tech Phy

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ON THE SAYANO-SHUSHENSK HYDRO POWER PLANT UDC 621.51:534 V. B. Kurzin and V. S. Seleznev It is demonstrated that the level of vibrations of turbines on the Sayano-Shushensk hydro power plant is enhanced by the capability of a compressible fluid to perform its own hydroacoustic oscillations (which can be unstable) in the turbine duct. Based on the previously obtained results of solving the problem of natural hydroacoustic oscillations in the turbine duct and some ideas about turbine interaction with an unsteady compressible fluid flow, results of full-scale studies of turbine vibrations and seismic monitoring of the dam of the Sayano-Shushensk hydro power plant before and during the accident are analyzed.Introduction. Various possible reasons were given after the accident on the Sayano-Shushensk hydro power plant (HPP), which happened on August 17, 2009. These reasons were analyzed in much detail in [1]. Some versions of the accident are based on the assumption that the turbine was subjected to a certain pulsed high-power action (something like a hydraulic hammer), which exceeded the safety margin of the structure. These versions, however, do not agree with the results of seismic monitoring of the dam of the Sayano-Shushensk HPP before and during the accident. The main reason for the accident is assumed to be the fatigue failure of the fixtures of the turbine cover of the power-generating unit No. 2, which was induced by the high level of turbine vibrations in the standard operation mode. This fact was established by the technical commission investigating the reasons for the accident.The elevated level of turbine vibrations on the Sayano-Shushensk HPP (as compared with vibrations obtained for its model) was observed in full-scale tests performed back in 1988. It was shown [2, 3] that emergence of such vibrations is caused by the effect of water compressibility on turbine interaction with the unsteady flow, which was ignored in design of the Sayano-Shushensk HPP. The study of this problem was continued in [4,5]. Based on results of these studies, certain restrictions were imposed on operation of power-generating units of the Sayano-Shushensk HPP. It should be noted, however, that the hydrodynamic problem in [4,5] (results of these studies were used as a basis for the version described in [1]) was considered in a linear formulation and in a quasi-steady approximation. It is convenient to use the solution of this problem in such a formulation for engineering calculations, but the solution is rather rough and does not explain some qualitative features observed in experiments. In addition, there is a mistake in [4,5].In the present work, based on the theory of cascades in an unsteady flow [6-8] and on the laws of aeroacoustics, we study the qualitative effect of nonlinearity and reduced frequency of vibrations on turbine interaction with an unsteady compressible fluid flow, which was partly taken into account in [2, 3], but skipped in [4,5]. Using the data obtained, we analyze the results of full-scale studies of turbi...

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Section: Comparison Of Theoretical and Experimental Resultsmentioning

confidence: 98%

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confidence: 99%

Mechanism of emergence of intense vibrations of turbines on the Sayano-Shushensk hydro power plant

Kurzin

Селезнев

2010

J Appl Mech Tech Phy

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“…In fact, there exit some literatures to study the problems in the transient stability of the non‐linear MUHGSs. Such problems involve the structure optimisation [23], fault diagnosis [24], system parameter setting [25] and the analysis of start‐up opening laws [] etc. However, the fact is that the researcher faces great challenges due to the complex non‐linearity of the MUHGS, such as, the non‐linear effect of surge tanks, the water hammer in penstocks and the shafting vibration.…”

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confidence: 99%

Evaluation of parametric effect on transient stability of a multi‐unit hydroelectric generating system

Yang

Chen

2021

IET Renewable Power Gen

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Transient stability of a multi‐unit hydroelectric generating system significantly influences the safety operation of power stations. The uncertainty of operating parameter is one of the important factors to influence the system stability during the transient process. For this reason, the target of this paper aims to explore the optimised operating parameter in order to enhance the stability of a multi‐unit hydroelectric generating system. To overcome the limitations of existing methods in literature, a new high‐dimensional, complex and non‐linear dynamic model of the multi‐unit hydroelectric generating system that combines the conventional hydro‐turbine governing system and the shaft system is established. Then, the dynamic behaviour of the proposed system targeting the transient process is exhaustingly investigated with the change of the critical parameters. The calm interval of critical parameters is also determined in order to improve the transient stability of the system. The obtained results not only enrich the theoretical knowledge of transient dynamics but also ensure the safety operation of hydropower stations. Meanwhile, the presented research method, high‐dimensional non‐linear dynamic model and the interesting findings in transient process can promote the development of the theory of non‐linear dynamics.

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“…Starting from a series of papers [26][27][28][29] as well as [30,31], several 3-D aeroelastic codes have been developed by different researchers during the last decade [32][33][34][35][36][37]. Most of them are based on the energy method, though there are some employing time-domain and eigenfrequency calculations.…”

Section: Introductionmentioning

confidence: 99%

Experimental Validation of Numerical Blade Flutter Prediction

Vedeneev

Kolotnikov

Макаров³

2015

Journal of Propulsion and Power

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Blade flutter of modern gas-turbine engines is one of the main issues that engine designers have to face. The most used numerical method that is employed for flutter prediction is the energy method. Although a lot of papers are devoted to the analysis of different blade wheels, this method was rarely validated by experiments. Typical mesh size, time step, and various modeling approaches that guarantee reliable flutter prediction are not commonly known, whereas some examples show that predictions obtained through nonvalidated codes can be inaccurate. In this paper, we describe our implementation of the energy method. Analysis of convergence and sensitivity to various modeling abstractions are carefully investigated. Numerical results are verified by compressor and full engine flutter test data. It is shown that the prediction of flutter onset is rather reliable so that the modeling approaches presented in this paper can be used by other researchers for the flutter analysis of industrial compressor blades. Nomenclature f = natural frequency m = number of nodal diameters N = number of blades n = rotor speed W = work done by the unsteady pressure over one cycle of blade oscillation α = inlet angle of attack φ = 2π m∕N, interblade phase shift ω = 2πf, circular frequency

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Calculation of the unsteady aerodynamic parameters of a rotating cascade of oscillating blades in incompressible flow

Cited by 3 publications

References 1 publication

Mechanism of emergence of intense vibrations of turbines on the Sayano-Shushensk hydro power plant

Mechanism of emergence of intense vibrations of turbines on the Sayano-Shushensk hydro power plant

Evaluation of parametric effect on transient stability of a multi‐unit hydroelectric generating system

Experimental Validation of Numerical Blade Flutter Prediction

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