RU1816986C - Method of vibration testing of gas-turbine engines - Google Patents

Abstract

Usage: diagnosis of gas turbine installations, testing of aircraft gas turbine engines. SUMMARY OF THE INVENTION: The engine is started and throttle from minimum to maximum speeds. The vibration signal and rotor speed are measured and recorded at the nominal and limit settings of the fuel control equipment. From the deviations of the vibration signal from the reference signal in transient conditions for the characteristic rotational speeds of the rotor, the technical state of the engine, 1 sludge, is determined.

Description

The invention relates to the field of diagnostics of power plants and can mainly be used in the operation and testing of aircraft gas turbine engines (GTE) in determining their technical condition.

The aim of the invention is to increase the reliability of engine failure detection. Tests of gas turbine engines showed that the proposed technical solution makes it possible to achieve a reliable diagnosis of engines by vibration parameters during operation not lower than 0.99. whereas conventional methods give a range of confidence (depending on specific conditions) from 0.35 to 0.95.

The invention takes advantage of the effect of a change in the level of adjustment of the control characteristics of the fuel supply control system in the combustion chamber on the change in diagnostic parameters

vibration during the occurrence and development of malfunctions. To this end, the diagnosed engine is tested at predetermined transient conditions at the maximum (according to the technical specifications) settings of the fuel control equipment (minimum permissible excess fuel, ensuring the engine start time within the standard specifications, and the maximum excess fuel allowed for throwing the gas temperature behind the turbine).

In this case, the most complete combination of disturbing influences (gas and hydrodynamic loads from interacting parts and assemblies of the engine flow part and its units, changes in damping, etc.), generating oscillations with certain frequencies and exhibiting a technical condition, takes place. ny with maximum completeness.

The invention uses the fact that when a malfunction occurs and develops

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GTE the largest increase in vibration is observed at points that are multiples of the resonant frequencies, with the extreme settings of the fuel control equipment. The type and degree of development, malfunctions are estimated by increasing the amplitude values of the level of the vibration signal by the frequency of rotation due to the appearance of additional harmonics from the developing malfunction. By classifying deviations of changes in the amplitude envelope of the vibration signal by the rotational speed, one can judge about the early signs of a large group of malfunctions of the flow part and engine assemblies, which with other methods of vibration diagnostics are not manifested until the failure of the aggregates or engine assemblies.

The inventive method consists of the following interdependent operations:

Claims (4)

1. The transient mode of operation of the engine is set with the measurement and registration of the vibration signal and rotor speed at the initial (nominal) setting of the fuel control equipment. 2. The operations of claim 1 are performed when tuning the fuel of the control equipment to the minimum allowable excess fuel. 3. The operations of claim 1 are carried out when tuning the fuel control equipment to the maximum allowable excess fuel. 4. According to the deviations of the vibrosignal in the floodlight x transition mode according to p. 2 and 3 from the initial (reference) one, for the characteristic rotor speeds, the technical condition of the gas turbine engine is determined. An essential feature of the invention, which distinguishes the claimed solution from the prototype and ensures the achievement of the goal, is the introduction into the process of diagnosing (according to recorded parameters of the vibration signal and rotor speed) adjustments of the ACS of the engine to the minimum and maximum allowable excess fuel at specified transient conditions. This method covers such groups of malfunctions as damage to parts of the engine flow part, destruction of compressor or turbine blades, destruction of bearings of rotor bearings, misalignment of shafts and drive units, malfunction of the engine ACS, etc. The possibility of achieving a positive effect in the practice of the invention is determined by the fact that the adjustment of the engine ACS within the limits of the technical specifications is widely used in operation to increase the reliability and efficiency of the operation of the gas turbine engine. Standard procedures are used to implement the method. regulating and testing the engine under operating organization conditions. The drawing shows examples of the manifestation of engine malfunction in transient mode when adjusting automation 0 to the minimum (a) and maximum (b) excess fuel, as well as at the initial (nominal) position of the control elements (c). The invention is illustrated by the following example. Diagnostics of aircraft dual-circuit turbojet engines (GRGD) is carried out during their operation as part of the aircraft power plant (LA) power plant, which consists of two engines. The vibration velocity and rotational speed of the high-pressure compressor (HPC) rotor are measured during engine start-up. Parametric Information 5 after the conversion, the on-board computer display is displayed on the screen for comparison with the reference values or is recorded on the on-board recorder for subsequent analysis on the computer of the ground processing device of the Ray type with data output to the plotter. During repeated tests of gas turbine engines, it was found that serviceable engines have the same character of vibration 5 at a given transient mode, which allows one to obtain stable standards characterizing a healthy state with respect to this parameter. . The left side of figure 1 is shown in 0 figurative representation of information (against a contrasting background) standards of good condition in the transition mode of starting the engine in the following sequence: for minimum (a), maximum 5 (b) and nominal (c) excess fuel. The upper curves (n) characterize the changes in the rotational speed of the HPC rotor, and the lower (B) curves show the envelope of the vibration signal. On the upper curves, characteristic kinks in In the region of reduced rotational speeds, n is 35% (point 1) and n is 70% (point 2) of the maximum value. The first of these is associated with switching fuel automation from a start-up machine to a pick-up machine, 5, the second - with switching to a centrifugal speed controller when entering the idle mode. The indicated bends correspond to the characteristic changes of the lower curves (B) shown in the drawing. In this case, a violation of the correspondence between the inflection points of the rotation frequency line (p) and the position of the emissions in the vibration signal record (B), as well as a change in the amplitude of the vibration signal at these points, are effective signs of engine malfunctions (rotor imbalance due to damage to the blades, destruction of parts thrust bearings, etc.). However, with a relatively short start-up process (in the case of tuning to large excess fuel), these signs have a fuzzy manifestation. The reason is that with a high intensity of vibration processes, the signals of individual faults are difficult to distinguish in the general vibration background. The implementation of the transition mode with a minimum excess of fuel allows to increase the time of the start-up process and thereby extend the curve of the envelope of the vibration signal, which provides a clearer manifestation of these diagnostic features. At the same time, on a serviceable engine, when the adjusting characteristics of fuel automation are changed to minimum and maximum fuel burns, the average level of vibrations of the signal at characteristic points is maintained. In the event of engine malfunction and development, the amplitudes (at these points) change vibration signal with minimum and maximum excess fuel; at the same time with a minimal excess of fuel, the extreme values of the vibration signal are shifted relative to the indicated characteristic points, as shown in the drawing, to the right .. An example of the manifestation of a faulty vibration state of a turbojet engine (rotor imbalance associated with damage to a turbine blade) for cases of minimum, maximum, and nominal excess fuel at start-up is shown on the right side of the drawing. For r mul a isret n and The method of vibration diagnostics of gas turbine engines by measuring and recording the values of the vibration signal and the rotational speed of the engine rotor in transient conditions, comparing the measured and reference values of the vibration signal for the characteristic frequencies of rotation and determining the technical condition of the engine by deviating the measured value of the vibration signal from the reference, characterized in that, for the purpose increase the reliability of fault detection, measure and record the values of the vibration signal and speed when adjusting t fuel equipment for minimum and maximum excess fuel. a) Minimum fuel surplus 6) Maximum fuel surplus