RU140781U1 - GTE AXIAL TURBINE WITH REDUCED NOISE - Google Patents

Abstract

An axial turbine turbine engine with a reduced noise level, containing a group or groups of crowns of the type "stator - rotor - stator" and / or "rotor - stator - rotor" of the compressor and / or turbine type, characterized in that the numbers of blades of all the crowns are equal or multiple and their mutual circumferential location is determined by the distance in the circumferential direction from the output edges of the previous crown to the input edges of the next, equal to, where Δ is the value of the axial clearance, γ is the installation angle of the previous profile.

Description

The utility model relates to axial turbomachines used in gas turbine engines, stationary power plants, compressors and pumps. It is intended to reduce pressure pulsations in the flow, which arise due to the hydrodynamic interaction of the rotor and stator and cause the generation of radiated noise and vibration of the blades.

A number of works on the creation of turbomachines with low noise levels are known. For example, European patent EP 0756667 B1, where the relative circumferential arrangement of two crowns of a turbomachine, for example stators, between which there is a third crown, for example a rotor, is determined from the condition that the input edges of the stator vanes located downstream of the rotor are in the vortex wake zone behind the blades of the stator located in front of the rotor upstream. The position of the vortex traces corresponding to this mode of operation of the turbomachine is determined by the calculation of the flow.

From Russian publications, work can be cited as an example. F.M. Muravchenko, V.M. Lapotko, Yu.P. Kukhtin, S.B. Reznik, A.I. The parrot. Evaluation of the acoustic interaction of the crowns of a turbine of a D-18T engine fan. // Bulletin of engine building. 2006. No. 1, S. 8-13. The authors of which, on the basis of a calculation and experimental study of the low-pressure turbine of the D-18T engine, propose a method for reducing noise, which consists in installing the blades of the second working blade ring with a shift of 0.5 steps relative to the step along the input edges of the blades of the first working ring.

An analogue of the proposed model can be a device for implementing the method of suppressing acoustic noise resulting from the interaction between the rotor and the stator in a gas turbine engine (patent RU No. 2246632, IPC F04D 5/14, F04D 29/66 dp 10.03.2006) .

Disadvantages: the use of a 0.5-pitch turn of the second blade of the second wheel relative to similar blades of the first wheel is of a private nature and cannot be used in a wide range of design features of the crowns of modern and promising turbines. Moreover, at certain angles of installation of the profiles of the blades of the first impeller, the blades of the second fall with this approach to their mutual orientation into the most “disadvantageous” positions from the position of noise generation, i.e. noise in this case will be maximum.

As a prototype of the proposed utility model, one should consider an axial turbomachine (turbine) with a reduced level of pressure pulsations, exciting vibrations of the blades and emitted noise (patent RU 2280169, IPC F02C 7/045, dp 02.20.2005). This axial turbomachine contains a group or groups of crowns of the type “fixed crown - rotating crown - fixed crown” and / or ”rotating crown - fixed crown - rotating crown” of the compressor and / or turbine type, and differs in that the number of blades of the extreme crowns in each group or in separate groups are equal or multiple and their mutual circumferential location is determined by the value of the parameter v = v ∗. The choice of the optimal value of the parameter v = v ∗ corresponding to the minimum or close to it level of pulsations of the aerodynamic load on the blades of the second crown can be determined by the formulas:

;

;

,

, T=θ/ω,

,

, T = θ / ω,

- единичный вектор внешней нормали к поверхности σ; P - давление потока в точке поверхности σ.where t is time; v ∗ is the value of the parameter v providing the minimum value of δ _F ; v is a dimensionless parameter that uniquely determines the mutual circumferential arrangement of the extreme rims; θ is the total angular period of the extreme rims in the group; ω is the angular velocity of rotation of the middle rim relative to the extreme rims in the group; σ is the surface of the scapula of the middle rim in the group;

is the unit vector of the external normal to the surface σ; P is the flow pressure at the surface point σ.

These turbomachine designs and approaches to actively reducing turbine noise have a number of significant drawbacks.

The prototype and analogue does not take into account a significant effect on the trace unevenness, which is the main source of noise in the grating, such parameters as the angle of installation of the profile, the width of the grating, the maximum curvature of the profile and the magnitude of the axial clearance. Without taking these parameters into account, it is possible not only not to obtain the effect of reducing aerodynamic noise, but, on the contrary, to strengthen it due to the location of the second stage crown blades in the zones of greatest trace irregularities and flow turbulization, which will cause an increase in aerodynamic noise.

To eliminate these drawbacks, a utility model of a gas turbine axial turbine with a low noise level is proposed.

The advantage of the proposed utility model is, firstly, in achieving lower levels of aerodynamic noise and, secondly, in universality - i.e. Applicability to any range of geometrical features of stator and rotor crowns of axial turbomachines.

The technical result is expressed in the reduction of the aerodynamic noise of a turbine stage.

The technical result is achieved by the fact that in a gas turbine axial turbine with a reduced noise level containing a group or groups of crowns of the type “stator - rotor - stator” and / or “rotor - stator - rotor” of compressor and / or turbine type the number of blades of all crowns is equal to or are multiples and their mutual circumferential location is determined by the distance in the circumferential direction from the output edges of the previous crown to the input edges of the subsequent one, equal to

where Δ _o is the value of the axial clearance, γ is the installation angle of the previous profile.

A diagram of the proposed utility model is shown in FIG.

(Δ_o - величина осевого зазора, γ - угол установки предыдущего профиля).The turbine stage consists of stator (1) and rotor (2) crowns. The blades of the stator grating are installed at an angle y to the front of the grating. The blades of the subsequent crown are located as follows: the input edges of the blades of the working grid are separated from the output edges of the stator lattice by a distance equal to

(Δ _o is the value of the axial clearance, γ is the installation angle of the previous profile).

, где Δ_о - величина осевого зазора, γ - угол установки предыдущего профиля. При этом числа лопаток всех венцов равны или кратны.In developing the proposed utility model, we used the results of experimental aerodynamic and acoustic studies of plane models of turbine stages, based on which the influence of the geometric parameters of the gratings on the noise generated by the interaction of the blade crowns was taken into account. It is proposed to install the blades of the second crown relative to the first (and / or third relative to the first and / or second) in the circumferential direction with a distance along the output edge at a distance

where Δ _about - the value of the axial clearance, γ is the installation angle of the previous profile. In this case, the number of blades of all the crowns are equal or multiple.

When the turbine is operating and flowing through the scapular crowns of the tract gas, trailing marks (3) go off, which are strongly swirling secondary streams that cause subsequent unevenness of the parameters in the outlet cross-section of the grating and, accordingly, the inlet cross-section into the working grating. Trace uneven flow of the working fluid is the cause of noise generation.

The design of the proposed model achieves an effect in which, under the conditions of any geometry of the gratings, marginal marks will fall on the input edges of the blades, which helps to reduce the aerodynamic noise of the stage.

Claims (1)

An axial turbine turbine engine with a reduced noise level, containing a group or groups of crowns of the type "stator - rotor - stator" and / or "rotor - stator - rotor" of the compressor and / or turbine type, characterized in that the number of blades of all the crowns are equal or multiple and their mutual circumferential location is determined by the distance in the circumferential direction from the output edges of the previous crown to the input edges of the next, equal

, where Δ _o is the value of the axial clearance, γ is the installation angle of the previous profile.

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