JPS59193329A - Testing device for dynamic balance of turbine rotor - Google Patents

Abstract

PURPOSE:To prevent positively grave accident, such as turbine rotor fracture due to unbalance cause by cracks by inspecting a turbine rotor blank for its intactness and further, by watching specimen turbine rotor for its cracks. CONSTITUTION:Elastic wave emitted from a specimen turbine rotor 3 is received by a transmitter-provided AE sensor 4, detecting wave signal C is received by a receiver 5, the signal is delivered into a channel frequency analyzer 8 via amplifier 6 and AD convertor 7 and it is subjected to frequency analysis together with an elastic wave detecting signal A from a memory unit 10. In a comparator 9, comparison of area of frequency distribution of signal C and (a) in the normal condition and upon finding an excess of the area difference over the predetermined value, an alarm 13 is operated with a recognition that the signal includes an abnormal signal element causing generation of cracks. By a positioner 11, an emitting position of the elastic wave is identified, and a number of revolution is detected by a revolution detector 14, and a monitor 12 watches intactness of blank of specimen turbine rotor 3 and generation of cracks, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a dynamic balance test device for a turbine rotor such as a steam turbine or a gas turbine.

[Technical background of the invention and its problems]

Generally, during operation of a steam turbine or gas turbine, a large tensile stress due to centrifugal force acts around the center hole due to the high speed rotation of the turbine rotor.

Furthermore, thermal stress is generated due to temperature changes when the turbine rotor is started and stopped and when the load fluctuates, and this acts as repetitive stress. Therefore, centrifugal stress and reversing stress act on the turbine rotor during high speed rotation,
Creep losses and fatigue damage begin to occur. As these damages accumulate, the material of the turbine rotor progresses to deteriorate, eventually causing cracks to occur. Particularly around the center hole of the turbine rotor, inclusions such as MnS, which is a type of defect that occurs during the manufacturing of the rotor material, tend to concentrate, and separation of the inclusions and the base material easily causes cracks. Once a crack occurs, damage is concentrated at the crack tip due to stress concentration at the crack tip, and the crack progresses rapidly in a short period of time, eventually leading to a serious accident such as unstable fracture of the turbine rotor. It becomes connected to.

In order to prevent serious accidents, various non-destructive tests such as ultrasonic flaw detection, magnetic particle flaw detection, and penetrant flaw detection are carried out during the manufacturing process of turbine rotors and during periodic inspections during service. Although these non-destructive tests are effective in detecting the presence or absence of defects in turbine rotor materials and the location of defects,
There is a drawback that the shape and properties of defects cannot be detected with high accuracy.

In addition, since non-destructive testing alone is insufficient to evaluate whether harmful cracks occur during operation, it is important to note that non-destructive testing alone is insufficient to evaluate whether or not harmful cracks occur during operation. Confirming that no cracks occur is absolutely necessary as a preventive maintenance measure.

Incidentally, dynamic balance tests have conventionally been carried out during the manufacture of turbine rotors or during periodic inspections during service. This uses a dynamic balance test device to measure the vibration conditions of the turbine rotor's journal section, coupling section, etc. by rotating the joint test turbine rotor at high speed to the rated speed or overspeed, and then transmitting the vibration data to the attached enter it into the computer,
The aim is to analyze the amount of dynamic unbalance and correct the unbalance in each part of the turbine rotor by adding balance weights, thereby improving the vibration value during operation of the turbine rotor. In addition, in this dynamic balance test, measures were taken to prevent brittle fracture of the turbine rotor material, such as heating the test turbine rotor above the transition temperature of the rotor material to increase its rotation.

However, such conventional gJ)) balance test equipment does not have the function of predicting and monitoring the risk that defects inherent in a test turbine rotor will develop into harmful cracks due to increased rotation.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and is a method for diagnosing the soundness of turbine rotor materials in a dynamic balance test conducted during manufacturing of the turbine rotor and periodic inspection during use, and By monitoring the occurrence of cracks in the turbine rotor under test, we have developed a dynamic balance test device for turbine rotors that can reliably prevent the occurrence of serious accidents such as unstable fracture of the turbine rotor due to cracks. The purpose is to provide

[Summary of the invention]

In order to achieve the above object, a turbine rotor dynamic balance test apparatus according to the present invention is configured as follows.

In a dynamic balance test device for a turbine rotor, which rotates a turbine rotor connected to the dynamic balance test device and tests the dynamic balance of the turbine rotor, the turbine rotor is placed at an appropriate location on the turbine rotor and rotates. An elastic wave detector detects the elastic waves of The turbine rotor is configured to include a signal processing circuit for comparing the signals, and a monitor for inputting the output signal from the signal processing circuit to monitor the health of the turbine rotor and the occurrence of cracks.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a turbine rotor dynamic balance test apparatus according to the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and reference numeral 1 in the figure indicates a dynamic balance test device, which is driven by a driving turbine 2. In FIG. A test turbine rotor 3 is connected to this dynamic balance test device 1,
It is rotated at high speed to the rated speed or overspeed in conjunction with the dynamic balance test device 1. An AE sensor with a transmitter Acousti as an elastic wave detector is installed at an appropriate location in a plurality of balance weight insertion grooves 3a formed in this test turbine rotor 3.
Multiple cEmission 5ensor 4 are installed. The AE sensor 4 with a transmitter detects elastic waves emitted from the turbine rotor 3 under test when the turbine rotor 3 rotates, and transmits the elastic wave detection signal as a radio wave of an appropriate frequency. This elastic wave detection signal is input to a signal processing circuit to be described later, where it is appropriately encoded, the signal waveform is monitored on a monitor, and a thin layer is outputted from the alarm device as appropriate.

As shown in FIG. 1, the signal processing circuit has a receiver 5 that receives a radio wave of an elastic wave detection signal transmitted from the AE sensor with transmitter 4, and this receiver 5 has an amplifier 6. ,
An analog-to-digital converter 7 (hereinafter referred to as an AD converter), a frequency analyzer 8, and a comparator 9 are connected in series. A part of the output of the AD converter 7 is input to a digital memory 10 that stores normal elastic waves emitted during normal operation of the turbine rotor 3 under test, and is also input to one terminal on the input side of the position evaluator 11. is connected so that it is input to the The elastic wave detection signal transmitted from the AE sensor 4 with a transmitter is input to the other terminal on the input side of the σ position evaluator 11, and the time difference between the elastic waves reaching each AE sensor 4 with a transmitter determines whether the turbine under test The elastic wave emission position within the rotor 3 is located. Further, the output signal of the digital memory 10 is connected to be applied to the frequency analyzer 8.

In the signal processing circuit configured in this way, the output side of the comparator 9 is connected to the input sides of the monitor 12 and the alarm 13 to monitor the waveform of the elastic wave detection signal and output an alarm as appropriate. ing. The input side of this monitor 12 is further connected to the output side of a rotation speed detector 14 that detects the rotation speed of the turbine rotor 3 under test.

Next, the operation of the above-described embodiment will be described.

When the test turbine rotor 3 rotates at high speed in conjunction with the dynamic balance test device 1 driven by the dynamic balance test of the turbine rotor, elastic waves are emitted from the test turbine rotor 3. This elastic wave is transmitted by an AE with a transmitter installed at an appropriate location.
It is detected by the sensor 4 and transmitted as an elastic wave detection signal using radio waves of an appropriate frequency. This radio-wave sexual fluid detection signal is received by the receiver 5 and then amplified by the amplifier 6, for example, signal waveforms A, B, etc. as shown in FIG.
C and is added to the AD converter 7. Waveform A in Figure 2
waveforms B and C represent elastic wave detection signals detected during normal operation of the test turbine rotor 3, and waveforms B and C represent elastic wave detection signals detected during abnormal operation of the test turbine rotor 3, respectively. A part of the normal elastic wave detection signal A is stored in the digital memory 10 and is output to the two-channel frequency analyzer 8 at any time.

The frequency analyzer 8 analyzes the frequency of the normal elastic wave detection signal A as well as the other elastic wave detection signal B or C.
As shown in the frequency distribution diagrams of I), (Ill) and σ■), the signal A is analyzed into a, the signal B into b, and the signal C into C, and sent to the comparator 9.

In the comparator 9, the area of the frequency distribution of the normal elastic wave detection signal a and the other elastic wave detection signal B or C is compared as shown in FIG. 3 (11), (Ill), and the areas of both are A difference is detected. For example, when comparing the elastic wave detection signal B (b) with the normal elastic wave detection signal A (a), Fig. 3 (II
), the two almost overlap, and there is almost no difference between them. This is because the elastic wave detection signal B (b) contains elastic waves emitted by the same mechanism as the normal elastic wave detection signal A (a), and is a normal elastic wave that does not cause cracking. It shows that it is a wave. Furthermore, another elastic wave detection signal C(c) is converted into normal elastic wave detection signal A(a).
As shown in Figure 3 (1 and 10), in the medium and high frequency ranges, the two almost overlap and the difference is just a minute difference, but in the low frequency range, the elastic wave detection signal C has a peak cpk.
, and the difference in area from the normal elastic wave detection signal a is large;
Contains abnormal signal components. When the area difference between the two signals a and c exceeds a predetermined value, the alarm 13 is activated and outputs a notification.

The elastic wave detection signals A, B, and C from the AE sensors 4 with transmitters installed at multiple locations on the test turbine rotor 3 are sent to the receiver 5 as well as to the digit positioner 11. Sent. At this point, the danger location device 11 detects the time difference between each elastic wave emitted from the test turbine rotor 3 and each transmitter + lAE Sentsu-4, and detects the emission position r'i-t of each elastic wave. Orient. The emission position of each elastic wave is appropriately displayed on the monitor 12 together with the waveform of the elastic wave. Also, the monitor 12 shows the turbine rotor 3 under test.
The rotation speed detection output of a rotation speed detector 140 that detects the rotation speed of the test turbine rotor 3 is input, and the rotation speed of the test turbine rotor 3 is also monitored at the same time. This monitor 12 can simultaneously monitor the waveform of the elastic wave, the emission position of the elastic wave, and the rotational speed of the test turbine rotor 3 at the time of emission of the elastic wave.

As a result, the health of the members of the test turbine rotor 3 and the occurrence of cracks can be monitored using the monitor 12.

〔Effect of the invention〕

As described above, the turbine rotor dynamic balance test device according to the present invention connects a test turbine rotor to the dynamic balance test device, and uses elastic waves emitted from the turbine rotor during high-speed balancing of the turbine rotor. The configuration is configured to detect the waveform of the elastic wave, the position at which the elastic wave is emitted, and the rotational speed of the test turbine rotor when the elastic wave is emitted. It is possible to monitor the soundness of the test turbine rotor material and the occurrence of cracks therein, which has the effect of reliably preventing the occurrence of serious accidents such as unstable destruction of the turbine rotor due to cracks.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an embodiment of a dynamic balance test device for a turbine rotor according to the present invention, and FIG. 2 is a waveform diagram of each elastic wave detection signal output from the amplifier.
FIG. 3 (I) ([1) (JH) It-1 is a frequency distribution diagram of each elastic wave detection signal. 1... Axial balance test rig f6.2...l! λ4 dynamic turbine, 3... Test turbine rotor, 4... A with transmitter, E sensor, 5... Receiver, 6... Amplifier, 7... AD converter, 8... Frequency analyzer, 9...
・Comparator, 10...Digital memory, 11...Position evaluator, 12...Monitor, 13...-Title indicator, 1
4...Rotation speed detector.

Claims (1)

[Scope of Claims] 1. A dynamic balance test device for a turbine rotor, which rotates a turbine rotor connected to the dynamic balance test device to test the dynamic balance of the turbine rotor. An elastic wave detector is installed at a location to detect elastic waves during rotation, and an elastic wave detection signal output from this elastic wave detector is input and converted into a digital signal. It has a signal processing circuit that analyzes the frequency and compares it with a normal elastic wave signal, and a monitor that monitors the health of the turbine rotor and the occurrence of cracks by inputting the output signal from the signal processing circuit. A turbine rotor dynamic balance test device featuring: 2. The signal processing circuit includes a receiver that receives an elastic wave detection signal from an elastic wave detector, an analog/digital converter that converts this elastic wave detection signal into a digital signal, and an output from this analog/digital converter. The method according to claim 1, further comprising a frequency analyzer for frequency-analyzing a digital signal to be transmitted, and a comparator for comparing the output signal from the frequency analyzer with a normal elastic wave signal. Dynamic balance test equipment for turbine rotors. 3. The monitor includes a position locator that locates the position of the elastic wave emitted from the arrival time difference of each elastic wave emitted when the turbine rotor rotates to the elastic wave detector, and a rotation speed detector that detects the rotation speed of the turbine rotor. Dynamic balance of the turbine rotor according to claim 1, characterized in that the dynamic balance of the turbine rotor is electrically connected to the turbine rotor and configured to display the elastic wave emission position and the rotation speed of the turbine rotor. Test equipment. 4. The dynamic balance test device for a turbine rotor according to claim 2, wherein the elastic wave detector is configured to transmit the detected elastic waves as radio waves of an appropriate frequency. 5. The dynamic balance of the turbine rotor as set forth in claim 2, wherein the comparator is electrically connected to an alarm device that outputs an appropriate alarm based on the output signal from the comparator. test equipment. 6. The frequency analyzer inputs the output signal from the digital memory that stores part of the elastic wave detection signal output from the analog/digital converter at any time, and frequency-analyzes the output signal from the digital memory. 3. The dynamic balance test device for a turbine rotor according to claim 2, wherein the device is configured to output the measured value to a comparator after the calculation is performed.