JPS60111093A - Surging preventing apparatus for axial-flow compressor - Google Patents

Abstract

PURPOSE:To prevent surging by increasing the opening degree of a blowing valve for adjusting discharge pressure when the calculated pressure ratio of a compressor which is calculated by a calculating means is larger than the limit pressure ratio memorized in a memory apparatus and performing the control so that the pressure ratio remains within the limit pressure ratio. CONSTITUTION:Each output of an inlet-pressure detector 16, inlet-temperature detector 17, discharge-pressure detector 11, and the revolution number detector 18 for a rotor 9 is introduced into a calculator 13, and the compression ratio and the corrected speed of a compressor are calculated. In a memory apparatus 14, the relation between the corrected number of revolution and the limit pressure ratio of the compressor are memorized through a preparatory test carried- out beforehand. The pressure ratio at the operation point of the compressor which is outputted from the calculator 13 and the limit pressure ration in the memory apparatus 14 are compared, and when the pressure ratio reaches a limit pressure ratio, a blowing valve 10 is opened by a blowing valve controller 15 and the intrusion into a surging region can be suppressed.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an axial flow compressor, and particularly to surging, etc.
This invention relates to a surging prevention IF and device for an axial flow compressor suitable for cases where it is necessary to avoid operation of the compressor in the unstable fJJ region.

[Background of the invention]

In recent years, with the rise in temperature of gas turbines, the l'
The pressure ratio of 1/2 flow compressors is increasing, and as a result, some models with a per-stage pressure ratio of t, 3 to 1.5 have appeared [7]. As a result, the stable operating range becomes narrower, which may lead to problems in the startability and controllability of the gas turbine. 1st
The figure shows the general characteristics of a typical 4nfr flow compressed fluid pressure. 1st
In t4, the song%! 1. + 2...4 shows the characteristics of flow rate and discharge pressure when the compressor rotation speed is constant, and the dotted line shows the surging line in 7 ways; However, in the left side area, surging, rotational stall, etc. occur, so the compressor cannot operate stably.In such an unstable area of the compressor, pressure fluctuations inside the compressor rapidly increase, causing blade vibration and shaft vibration. In extreme cases, this can even lead to wing damage.

Therefore, when the compressor is used by changing its operating point, a surging prevention control device for the compressor is required to monitor and control the compressor to prevent it from entering such an unstable region. FIG. 2 shows the configuration of a conventional axial flow compressor equipped with a surging prevention device. The axial flow compressor is composed of a plurality of rows of stator blades 7 attached to the inside of a casing 6 and a rotor 9 that rotates with a row of rotor blades 8 provided between the rows of stator blades. In the configuration shown in FIG. 2, a compressor characteristic map determined in advance through a preliminary test is stored in the storage device 14. Outputs from the compressor discharge pressure detector 11 and flow rate detector 12 are led to an arithmetic unit 13. The output from the arithmetic device 13 is guided to the blow-off valve control device]5, and the operating point of the compressor is stored in the memory device 14.
A comparison is made to determine whether the compressor is in the stable region or the unstable region on the compressor characteristic map stored in the compressor characteristic map. When the operating point of the compressor is changed and used, when the compressor operating point reaches the unstable region from the stable region of the compressor, the blow-off valve 10 is opened and controlled so as to remain within the stable operating region. surging area/
It is possible to 11- block the intrusion of \.

As mentioned above, in the conventional Australian and Torzink Defense I] two devices,
It is necessary to use a compressed flow rate detector. The flow rate meter used in a normal compressor is -7:IIf'i1 From the viewpoint of accuracy, the flow rate is 11. Pipe part (usually ``Nihanryuagake-'')
(20 to 30 times the length of the pipe diameter). For this reason, there is a drawback that the piping of the compressor becomes long and the piping cost increases.

[Purpose of the invention]

This invention was made based on the above-mentioned item Jj.

The purpose of this invention is to provide a surging prevention device for an axial flow compressor that can perform inexpensive and reliable control. Instead of the conventional method of determining the flow rate based on discharge pressure, we focused on the fact that by determining the flow rate using corrected rotational speed and pressure ratio, it is possible to stop the surging region with high accuracy without installing long piping for measuring compressor meteors. The characteristic diagram of a normal axial flow compressor is shown in Fig. 3. In Fig. 3, unlike Fig. 1 described above, the vertical axis shows the pressure ratio π of the compressor, and the horizontal axis shows the pressure ratio π of the compressor. (Use the corrected number of revolutions for the corrected flow rate d parameter and the number of revolutions)
Ru. Definition formulas for the pressure ratio π, the corrected flow rate G, and the corrected rotational speed are as follows.

π= P d / P s ... (1) Q = ,
"T" s / P s G == (2) n = n
/, 1 loaf...(3) Here Pd: Compressor discharge pressure (kg/m2ab5) PS: ++ Inlet pressure (I
I) Ts: II Inlet humidity (I<) G: 〃 Flow rate n: 〃 Rotation speed In general, the characteristics of a compressor are affected by the compressor's calyx force and inlet temperature, but as mentioned above, the pressure ratio, correction If the characteristics are organized using the flow rate and corrected rotational speed as parameters, the influence of the compressor inlet condition can be corrected.

In other words, if we organize it in a map like the one shown in Figure 3, π furnace crystal 452 1 + When the ratio is read and the horizontal axis is plotted with the corrected rotational speed n, it is expressed as shown in Fig. 4. In Fig. 4, there is a stable region below the surge line and an unstable region above it.

If the characteristics shown in FIG. 4 are measured in advance, it is possible to determine whether the rotational speed of the trickle compressor is in the stable operating region or unstable operating region from the pressure ratio. As described above, the present invention provides a surging prevention device that determines whether a compressor is stable or unstable based on the corrected rotational speed and pressure ratio of the compressor.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in more detail with reference to FIG. The Jl+ flow compressor has a plurality of stator blade rows 7 installed inside a casing 6 and a rotor blade row 8 between these stator blade rows.
It consists of a rotor 9 that rotates with a rotor 9. At the inlet of the compressor, there is a compressor inlet pressure detector 16, an inlet temperature detector 17, and a compressor discharge pressure detector 1j, and on the rotor there is a rotation speed detector 1 for detecting the rotation speed of the compressor rotor.
8 is provided. In addition, an inlet pressure detector J6, an inlet temperature detector 17, a discharge pressure detector 11, a rotation speed detector 1
The output of 8 is led to the calculation device 13, and the pressure ratio of the compressor,
Calculate the corrected rotation speed. The storage device 14 stores the relationship between the corrected rotational speed of the compressor and the critical pressure ratio based on a preliminary test conducted in advance. Comparing the operating point pressure ratio of the compressor output from the calculation device 13 with the limit pressure ratio of the storage device 14, and when the pressure ratio reaches the limit pressure ratio, the blow-off valve is opened by the blow-off valve control device 15, It is possible to strike out into the surging area.

〔Effect of the invention〕

To summarize, this invention differs from conventional surging prevention devices in that instead of determining the compressor operating point based on the flow rate and discharge pressure, the compressor operating point is determined based on the pressure ratio and corrected rotation speed. conduct. Therefore, there is no need for a long flow pipe downstream of the compressor, and an inexpensive and highly accurate surging prevention device 4 for an axial flow compressor can be provided.

[Brief explanation of the drawing]

1, 3, and 4 are schematic diagrams of a characteristic device for an axial flow compressor, and FIG. 5 is a schematic diagram of a surging prevention device of the present invention. 6...Sing, 7. Stator blade row, 8. Moving blade row, 9..
・Rotor, 10... Air discharge valve, 11... Discharge pressure 4 is 1 output, 13... Arithmetic device, 14. Storage device, 15. Discharge, 41 Control device, 16... Input [1 Pressure @t? ,vessel,
17 people: 1 temperature detector, 18... time number detector. Agent: Patent attorney-1, Gao Akimeng \, (, Figure 1; i-l (. Round 111' zz lower VJ 4 mouths]

Claims (1)

[Claims] Input pressure detector for detecting the pressure of the compressor, a population temperature detector for detecting the inlet temperature, a discharge pressure detector for detecting the compressor discharge pressure, a compression a rotation speed detector for detecting the rotation speed of the machine rotor and the inlet pressure detector;
[1] Calculate the pressure ratio and corrected rotation speed of the compressor using the outputs from the temperature detector, discharge pressure detector, and rotation speed detector? t; [Sun device, 9 years old and the above pressure Ii! A storage device that stores the machine's critical pressure ratio, and fi! Compare the pressure ratio calculated by the calculation device f with the limit pressure ratio stored in the device, and when the calculated pressure ratio is greater than the limit pressure ratio, adjust the opening degree of the blowoff valve. A surging prevention equipment for an axial flow compressor, further comprising a blow-off valve control device for controlling the pressure ratio of the compressor to remain within the limit pressure ratio.