SU666454A1 - Method of monitoring turbomachine stage working blade state - Google Patents

Description

Preallp (t: from the recorded signal.

Fig. 1 shows the variation of the amplitude of the torque at the resonance of the blades of the rotor stage of the axial compressor of the GTK-10-2 t-nitrogen turbine unit with the third rotor harmonic of various degrees of calm, where it is on the abscissa axis. The values of the ratio of the frequency of the disturbing force to the natural frequency, and along the ordinate axis the amplitude of the torque; in fig. 2 - the spectrum of the instantaneous angular velocity of rotation of the rotor (resonance with the third rotor harmonic), where the numbers of rotor harmonics are plotted on the abscissa, and the amplitudes of these harmonics are plotted on the ordinate; FIG. 3 - amplitude-frequency characteristics of the blade and the instantaneous angular velocity of the rotor at the resonance of the fifth stage of the rotor of an axial compressor of the GTK-1O & instant angular velocity; and the amplitude of oscillations of the blades of the fifth degree; in fig. 4 is a block diagram of an apparatus for implementing the described method.

Considering a controlled object, such as a turbomachine blade, as an oscillatory system with damping proportional to speed, for each stage of the turbine and compressor we obtain a torque on the rotor of the turbomachine.

7: ff - -; where Lk is the coefficient depending on the material, the geometrical dimensions of the blade, and the aero impact force acting on it;

 - the ratio of the frequency of the disturbing force to the frequency of the blade;

And) is the circular frequency of rotation of the rotor;

IJo is the proper circular frequency of the scapula;

S - log, 1rify aikKfjfMGHT decay;

and - phase shift by the heaving of force and Bb 3BanHbiNf oscillation;

Z is the number of tread blades;

t - time

Torque B1. torsional vibrations of the rotor of the turbomachine, forming a complex signal of the angular velocity of rotation. The sinusoids of this spectrum pass through the valon wire (channel) independently of each other and, therefore, in the yrvioeoft speed spectrum there are all harmonic components caused by rotor harmonics of torque (l).

The intense torsional vibrations of the shafting, the magnitude of the change in the angular velocity of which can be registered, are caused by the torque at the resonant, oscillations of the blades. In this case, the maximum value of the amplitude of the moment is determined only by the resonant rotor harmonic and the expression

HHTV).

BUT

t

M

)

(Jw)

-W

t

where t is the order of the rotor harmonic (integer), corresponding to the resonance of the blades at cif - i.

G-,

13 All the remaining rotor harmonics of torque, and consequently, ANGULAR speed, are inevitable measurement noise. The expression graph ($} is shown in Fig. 1 with a logarithmic decrement of

: 0.3.

Claims (2)

When measuring the instantaneous angular velocity with a sensor, to obtain an amplified signal, the rotation frequency of the rotor of the turbomachine is set, the entire frequency of which fntu is close to the natural frequency of oscillation of the blade of the controlled stage. The recorded signal enters the harmonic analyzer, where spectral analysis of the instantaneous angular velocity is performed, which consists in extracting simple harmonic components. The instantaneous angular velocity spectrum is shown in FIG. 2. The determination of the amplitude of the resonant oscillations of the blade by the selected rotary harmonic of the angular velocity is based on the fact that the amplitude of oscillation of the blade at a controlled step is connected with: r-: 1 | gp nl.chkonp motion SOOGNOPKINSM. and - rft gtso - amplitude and co-juban th shoulder blade; f - f) OTOf) naH i-; if) Mof {MKT yiviOBOfl mo ler1n () OTOfia; F is a pereootochny funkts, which is definitely for each type of turbo; 1Sh (shy produced experimentally or pkk-chutm. Pa. Fig. 3 shows the amplitude of the oscillations of the blades and the angular velocity of the rotor when the value of the logarithmic decrement S is 0.3. The device contains a rotor 1 (see Fig. 4) on which sensor 2 is mounted, connected to generator 3 and amplifier 4 connected to demodulator 5 connected to a harmonic analyzer 6 connected to level recorder 7. When the rotor rotates 1 with an angular velocity varying by law resonant oscillations of the blades, the voltage removed from sensor 2 has the form of an amplitude-modulated signal with a carrier frequency equal to the frequency of the sensor supply voltage and an envelope that reproduces the law of variation of the instantaneous angular speed. Generator 3 serves to supply the primary winding of sensor 2 with sinusoidal current the set frequency, the amplifier 4 is for amplification, and the demodulator 5 is for selecting 1 and the envelope.The signal from the demodulator enters the harmonic analyzer 6, where a harmonic harmonic analysis of the envelope is performed. Dedicated garmic nicknames fikspyry tc on; 1entto samopisi. ypovF 7. Application of the described method in the conditions of operation will allow to establish between {mont terms of the rotors of the tour of bomashchina according to their 4: 1 condition, which is two or more times the volume | x; assembly works by eliminating the bulkhead of the units that are P good technical condition, as well as to prevent possible damage to the blades, and, consequently, the entire rotor of the turbomachine. The method of controlling the state of the working blades of a turbomachine stage by registering instantaneous angular velocity of rotation of the rotor with a fixed sensor, processing the received signal and then selecting the magnitude of the amplitude of vibration of the blades, characterized in that, in order to extend the range of application of the method under the conditions of operation, the registration of the instantaneous angular speeds are produced at the frequency of rotation {and of the rotor, the multiplicity of which corresponds to the natural frequency of the blades of the controlled stage, and The amplitude of the vibrations of the blades takes the magnitude of the amplitude of the resonant harmonic extracted from the resistor) signal. Sources of INFOOM.1TS11I, p; p (into account in the examination.can 1.Patent CUiA sV; Uin4803, class 73-71.4, 1972. 2. Avtorskoelsgvo number 236826, CL. G 01 L 1 l / OO, 1960.