RU2229616C1 - Gas-turbine engine reheat unit - Google Patents

Abstract

FIELD: mechanical engineering; gas-turbine engines. SUBSTANCE: proposed reheat unit of gas-turbine engine contains prechamber with ring flame stabilizers installed in housing and arranged at outlet of diffuser formed by its housing and fairing of turbine rear support. Oscillations suppressor installed before prechamber is made in form of row of acoustic waveguides communicating peripheral zones of unit gas space with central zone at fairing. Length of acoustic waveguides is found from equation

Description

The invention relates to aircraft engine construction, and in particular to the design of the afterburner of a gas turbine engine.

Known afterburner chamber of a gas turbine engine, comprising a housing and a frontal device mounted therein with ring flame stabilizers and an anti-vibration screen mounted on the housing (1).

Its disadvantage is the damping of pressure fluctuations in a narrow frequency range.

There is a known afterburner chamber of a gas turbine engine, comprising a front-mounted device with annular flame stabilizers arranged coaxially to a vibration absorber made in the form of a hollow fairing of the turbine back support with perforation in it in the form of two sections in front and in the plane of the front device, forming an annular with the camera body diffuser (2).

Such a device for absorbing vibrational energy is difficult to manufacture and has a significant mass.

The objective of the invention is to simplify the design and reduce the mass of the afterburner.

To achieve this, in the afterburner of the gas turbine engine, which contains a front-mounted device with ring flame stabilizers located at the outlet of the diffuser formed by its body and the cowling of the turbine's back support, a front-mounted vibration suppression device made in the form of a series of acoustic waveguides communicating the peripheral zones of the gas cavity of the chamber with a central zone near the fairing, while the length of the acoustic waveguides is determined from ootnosheniya

where λ is the wavelength of the radial oscillation mode.

In addition, acoustic waveguides are located in the transverse plane and are made of at least three pipelines.

What is new here is that in front of the frontal device, a device for suppressing vibrations is installed, made in the form of a series of acoustic waveguides that communicate the peripheral zones of the gas cavity of the chamber with a central zone at the fairing, while the length of the acoustic waveguides is determined from the relation

where λ is the wavelength of the radial oscillation mode.

Acoustic waveguides are located in the transverse plane and are made of at least three pipelines.

After calculating the length of the acoustic waveguides, we get the opportunity to make a device for suppressing vibrations by interference of acoustic waves during vibrational combustion and, thus, ensure the operation of the afterburner with regular vibrations in it over the entire range of operating modes. The device required for this is simpler and with less weight.

This provides the objective of the invention is to simplify the design and reduce the mass of the afterburner.

Figure 1 presents a longitudinal section of the afterburner; figure 2 is a transverse section of the camera along aa with acoustic waveguides.

The afterburner contains a front-mounted device 2 in the housing 1 with annular flame stabilizers 3 located at the outlet of the diffuser 4 formed by the housing 1 and the cowling 5 of the rear support 6 of the turbine 7. In front of the front-mounted device 2, an oscillation suppression device 8 is made in the form of a series acoustic waveguides 9, communicating the peripheral zones 10 of the gas cavity of the chamber 11 with the central zone 12 at the fairing 5. The acoustic waveguides 9 are made of pipelines 13. Moreover, 14 is the length of the diffuser 4 along the longitudinal axis and, 15 is the calculated length of the acoustic waveguides 9 along the arc.

During the operation of the afterburner during the onset of vibrational combustion, periodic fluctuations in pressure and velocity occur with one of the modes of radial chamber vibrations. In this case, the gas makes periodic movement along a certain path in the radial direction of the afterburner 11 itself and along the acoustic waveguides 9 (pipelines) installed in it in a certain way. For any mode of radial chamber vibrations, the length of the corresponding pipeline 15 is approximately one and a half times the wavelength of the oscillations along axis 14 and, as a result, at the exit from the pipeline 15, the waves interact in the opposite phase, cancel each other out due to interference of acoustic waves during vibrational combustion, and thus provide effective suppression of acoustic vibrations in a wide range of operating modes of the afterburner.

Sources of information

1. Skubachevsky G.S. Aircraft gas turbine engines. - Design and calculation of parts, 1969, p.445.

2. RF patent No. 2117806, F 02 K 3/10, 1995.

Claims (2)

1. The afterburner of a gas turbine engine, comprising a front-mounted device with annular flame stabilizers installed in the housing, located at the outlet of the diffuser formed by its body and the cowl of the rear turbine support, characterized in that a front vibration suppression device is installed in the form of a series acoustic waveguides communicating the peripheral zones of the gas cavity of the chamber with the central zone at the fairing, while the length of the acoustic waveguides is determined from the ratio

where λ is the wavelength of the radial oscillation mode. 2. The afterburner according to claim 1, characterized in that the acoustic waveguides are located in the transverse plane and are made of at least three pipelines.

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