RU2594832C1 - Method of removing heavy particles from air flow in axial compressor stage and device for axial stage, removing heavy particles - Google Patents

Abstract

FIELD: engines.

SUBSTANCE: method of removing heavy particles from air flow in an axial compressor stage and device for axial stage, removing heavy particles based on provision of main mass of heavy particles moving in air flow, pulse from rotating blades of impeller stages and their subsequent separation into area beyond radial size of straightening unit, that is distant from impeller at a certain distance. Device is supposed to be used in assembly of a multistage compressor as one of first of its stages, can be used both in aircraft gas turbine engines and surface transport and stationary gas turbine units.

EFFECT: reduced number of damaged blades from engines ahead of schedule, as well as reduced number of repairs of engines during operation, related to cleaning nicks on blades of compressor due to improved degree of air cleaning in axial compressor stage.

6 cl, 5 dwg

Description

The invention relates to techniques for gas turbine engine building, and in particular to methods and devices for protecting gas turbine engines (GTE) from damage to parts of their internal tract (compressor blades) from foreign objects (solid, heavy particles) coming in with the air stream ¹ . ¹ (Note: In the following we will use the terms: “foreign objects” when describing their harmful effects on the blades of a gas turbine compressor, “heavy particles” when describing the processes of inertial separation of particles.).

Known devices that use the principles of inertial separation of heavy particles, as well as reflective methods to purify the air entering the compressor, a description of such devices is given in the following patents, as well as in the description of the domestic aircraft engine PS-90A:

- RU 2045451. 03/05/1992 [1].

- US 5123240. 06.23.1992 [2].

- RU 2198311. 03.01.2011 [3].

- Engine PS-90A ′ ′ Technical Operation Manual ′ ′. 1990, edition of OJSC ′ ′ Aircraft Engine ′ ′ Perm. [four].

In the device [1], air purification in the axial stage of the compressor is performed by reflecting foreign objects to the periphery on the tilted blades of the stage straightening apparatus, according to the applicant, the number of missing particles is reduced by 2.5 times, that is, the remaining gap (slip) is 40%, which cannot be considered acceptable.

In sentences [2], [3] the problem of separation of heavy particles in the axial stage of the booster compressor is not solved at all, its solution is simply declared. A device for purifying air from foreign objects using an axial stage is used in the PS-90A domestic gas turbine engine [4], but, as the operating experience of this engine shows, the level of air purification in it is clearly insufficient. For this engine there is quite complete information, and based on a comparison of the essential features of this analogue and the claimed device, the PS-90A engine is adopted as a prototype of the proposed method and device.

The main reason for the low level of air purification in the axial stage of the compressor is that for the most part they use standard axial stages designed for air compression and not for separation of solid particles, the geometry of individual elements and the layout are used, in which it is impossible to obtain an effective cleaning. The result is that:

- a large proportion of heavy particles does not enter into interaction with rotating blades, particles are skipped and they do not receive momentum from rotating blades;

- the momentum transmitted to the particles from the rotor blades of the wheel is insufficient in magnitude and is not directed towards effective separation;

- there is no space necessary for the implementation of the separation process of the particles after they receive an impulse from the stage blades;

- The collection and removal sites of the separated heavy particles are not organized.

The technical problem to be solved by the claimed method and device is to improve the degree of air purification in the axial stage of the compressor by eliminating the above disadvantages inherent in standard axial stages. At the same time, the task is not to introduce an unacceptable deterioration in the characteristics of the stage and the whole gas turbine engine.

As a result of the solution of the problem, the expected degree of purification of air from foreign particles should satisfy the main requirement - not to pass into the subsequent stages of the compressor foreign objects that can cause its shoulder blades.

As a result, during the operation of a gas turbine engine with the proposed axial stage, the number of prematurely removed engines with damaged blades is reduced, and the number of engine repairs in operation associated with the cleaning of nicks on the compressor blades is also reduced.

The main factors contributing to the solution of the technical problem are the use in the method and device of the energy capabilities of the axial stage blades in the force action on heavy particles, and on the bulk of the particles (located in the sleeve zone), which must be moved from the center to the periphery to the greatest distance, use already known and widely used in engine building methods of profiling compressor blades and placing the blades in the grill to ensure the force impact of the shovels ok on heavy particles, using the principle of momentum transfer to heavy particles and subsequent inertial separation of particles when they move by inertia.

The problem is achieved in that in the proposed method, the bulk of the heavy particles passing with the air flow through the interscapular channels of the impeller (RK) of the stage and to be removed from the air stream, organize the kinematics of movement along the interscapular channels in such a way that they provide particles with contact interaction with the surface of the oncoming scapula of the RK in a wide range of initial conditions for the entry of particles into the interscapular canal (at the entry point, the magnitude and direction of the particle velocity). At the time of the specified contact interaction (shock and aftershock), heavy particles are given an impulse of movement in the tangential-axial direction, and, if possible, a large tangential component is put into the transmitted impulse, for which the force acting on the side of the blade on the heavy particle normal to the surface of the scapula, at the exit section from the interscapular channel, they are oriented approximately parallel to the plane of rotation of the stage of the stroke The contact interaction of particles in the annular zone of the interscapular canal, from which effective separation of particles is required (usually this is the annular coil-in zone of the canal), is achieved by using blades with a large (increased) profile bend and with a greater density of the scapular lattice.

Since the trajectories of the particles are straightforward in heavy particles (without drift by the air flow), in relative motion these particles do not flow around the surface of the scapula like air, but collide with the surface of the trough of the oncoming scapula, providing the required contact.

The kinematics of the movement of heavy particles in the interscapular channels, providing contact interaction of particles with the surface of the oncoming blade, is formed on the basis of the condition that for a wide range of initial conditions for the entry of heavy particles into the interscapular channel, the following relation is fulfilled for them - the time of the particle’s movement along the interscapular channel in the axial direction should be longer than the time the particle moves in the tangential direction along the azimuthal width of the channel, from the tip of the first blade in rotation to the shank of the second channel blade a.

The proposed method also provides that in the axial stage of the compressor, heavy particles after they exit the RK are provided with the possibility of free movement by inertia from the acquired impulse in the space that is formed between the impeller (RK) and the rectifier (SA) of the stage due to the fact that the straightening apparatus is shifted backward through the air flow at a certain distance from the RC. When heavy particles perform inertial motion in the tangential-axial direction, particles are simultaneously separated (the process of moving particles in the radial direction) from the center to the periphery, while the distance by which the SA is moved away from the RC is selected based on the condition of its sufficiency for the separation process heavy particles from the central (prankcase) zone to the annular zone adjacent to the outside of the CA rim, into which heavy particles are removed from the air flow, and the air flow is directed into the CA steps, eyes heavy particles.

The indicated axial distance between the RC and the CA is formed on the basis of the condition that the time of movement of heavy particles in the space between them in the axial direction should be longer than the time of movement of the particles in the radial direction from the radius of the RC shell zone to the radius of the outer ring of the CA. Thanks to the above method, in the axial stage, it becomes possible to carry out all the necessary processes to obtain effective air purification:

- provide a collision of the bulk of heavy particles with rotating blades of the Republic of Kazakhstan;

- give the particles an impulse of movement from the blades of the Republic of Kazakhstan with the maximum possible component in the tangential direction;

- provide axial space and the possibility of inertial separation of particles during their movement in the axial tangential direction;

- create conditions for the selection and removal of separated heavy particles.

In accordance with the above method, the axial stage of the compressor, which removes heavy particles from the air stream, consists of a blade rim of the inlet guide vane (VNA), which can be used as the SA of the previous axial stage of the compressor, a rotating impeller, which is a disk mounted on it working blades, and a stationary straightening apparatus located behind the air stream, which is a circular crown of straightening blades fixed in the external and external friction rings. The proposed axial stage performs the function of removing heavy particles from the air stream by giving the bulk of the particles a separation impulse from the rotating working blades of the Republic of Kazakhstan, performing subsequent inertial separation of them in the radial direction and removing them from the air stream.

A distinctive feature of the axial stage is that in the radial-annular zone of the flow channel of the RK stage, from which heavy particles should be effectively removed, the geometry of the blades of the RK and their position in the scapular lattice are made in such a way that the angle of bending of the midline of the profile of the blades, the density of the scapular lattice , the angle of installation of the blades in the grill have elevated values allowed by changing the characteristics of the compressor stage.

Also, in the indicated zone of the flow channel of the RK stage, the value of the outlet angle of the blade profile in the grate has a value approaching or equal to 90 °, in addition, in the axial stage of the compressor CA is located at a distance from the RK, which is equal to the axial component of the trajectory of movement of the heavy particle during its rectilinear movement in the tangential-axial direction from the Republic of Kazakhstan to going beyond the radial dimensions of the CA (beyond the radius of the outer ring of the CA).

An annular channel is formed between the SC and the CA, formed by the outer and inner shells located between the SC and the CA, while the outer shell of the annular channel from the side adjacent to the CA has a diametrical size larger than the diameter of the outer ring of the CA. Between the outer shell of the annular channel and the outer ring CA, an annular intake channel is formed, which is an input for receiving and subsequent removal of heavy particles separated in the annular channel.

Below are the characteristic values of some parameters of the geometry of the blades of the Republic of Kazakhstan and their location in the scapular lattice of the proposed axial stage:

- bending angle of the midline of the profile 45 ± 10 °;

- the density of the scapular lattice ≥1.5;

- the angle of installation of the blades in the grill ≥65 °;

- the outlet angle of the profile of the blade in the lattice 80 ° -90 °.

To a first approximation, the distance from SA to RK is determined on the basis of the assumption that the particles leave the interscapular canal of the step in the root zone of the blades (in a plane perpendicular to the radial direction) in the tangential-axial direction at an angle of approximately 45 ° to the axis, then

where L is the axial distance from CA to RK;

Rca is the radius of the outer ring of the crown CA;

Rpк is the radius of the disk of the impeller (sleeve);

K is a coefficient depending on the initial conditions for the motion of heavy particles, the geometry of the annular channel, in the typical case at Rca≥Rpк К = 0.5-1.0.

The essence of the proposed method and device is illustrated by diagrams, which depict:

in FIG. 1 - elementary stage axial compressor in accordance with the invention;

in FIG. 2 is a section along AA in FIG. one;

in FIG. 3 is a section BB in FIG. 1 along the midline of the flow channel of a typical axial stage of the compressor, typical geometry of the profile of the working blade, the interscapular channel, the trajectory of the passage of heavy particles, the triangle of the speeds of movement of heavy particles;

in FIG. 4 - section of the flow channel of the axial stage of the compressor in accordance with the proposed axial stage in the radial-circumferential zone of the channel, from which it is required to carry out effective removal of heavy particles, the profile geometry of the blade, the interscapular channel, the path of the passage of heavy particles, a triangle of the speeds of movement of heavy particles. In the same diagram, the dashed line shows the blades of a typical blade grid in accordance with FIG. 3;

in FIG. 5 is a section along BB in FIG. 2 trajectories of the separated heavy particles.

A typical axial stage of a compressor according to [5], [6] consists of a blade rim of the VNA input guide vane - pos. 1 in FIG. 1 (VNA functions are often performed by the rectifier apparatus of the previous compressor stage) of the rotating impeller of the RK, which includes the disk 2 and the working blades 3 mounted on it, located behind the RK along the air flow of the blade rim of the straightening apparatus CA - pos. 4. In a typical axial stage, the CA is located at a small axial distance from the RC, shown in FIG. 1 dashed line. In the design of the axial stage in accordance with the invention, the CA is separated from the RK at a distance L defining the separation section of the stage, consists of blades of a straightening device 4 - FIG. 1 and 2, fixed in the inner 7 and outer 9 rings. An annular channel 5 formed by the outer 6 and inner 7 shells is made between the RC and the CA, while the inner shell 7 is a continuation of the inner ring 7 of the rectifier.

The outer shell 6 of the annular channel has a diametrical dimension larger than the diameter of the outer ring CA - 9 from the side adjacent to the CA. In the radial space between them, an annular intake channel 8 is formed, which is the input for receiving and subsequent removal of heavy particles separated in the annular channel 5.

In FIG. 3 shows a cross-section (scan) of the impeller of a typical axial stage along the midline BB of the flow channel of FIG. 1, sections of the blades are shown and some elements and parameters used in the following description are indicated:

- the midline of the profile of the blade 3 with angles β1 - input, β2 - output (<90 °);

- profile bending angle - θ (~ 30 °);

- profile chord length - b;

- lattice pitch (distance between adjacent profiles) - 1;

- the density of the installation of the blades in the lattice - b / t (~ 1);

- profile installation angle - υ (~ 55 °).

In FIG. 4 shows a similar section of the blades of the impeller of the axial stage, made in accordance with the claimed invention. Blades 3 are of great importance:

- profile bending angle θ ~ 55 °;

- profile installation angle υ ~ 65 °;

- the density of installation of the blades in the lattice b / t ~ 1.5 (the lattice pitch t is reduced);

- output profile angle β2 ~ 90 °.

The above recommendations do not contradict the rules used in the practice of designing blade machines, therefore, from their application, one can not expect any unacceptable deterioration of the characteristics of the stage.

The implementation of the method of removing heavy particles from the air flow in the axial stage, made in accordance with the invention, provides, first of all, the definition of the radial-circumferential zone of the flow channel of the stage, from which it is supposed to carry out the effective removal of foreign objects. In the general case, for Rca> Rpk, such a zone is the back-up space ranging from Rpk to Rca. In the annular zone of the flow channel located at a radius greater than Rca, the requirements for the separation of heavy particles are no longer relevant. In our case, Rpк = R internal.ca (radius of the inner ring 7 CA - Fig. 1) the zone from which the removal of heavy particles is required is the entire flow channel of the stage.

Heavy particles after passing VNA - pos. 1, FIG. 1 steps enter the input of the RK pos. 1, 2 at a speed C1 of FIG. 3, the direction of which is largely determined by the VNA blades. In FIG. 3 and 4, C1 is shown with the value / C1 / </ U / (where / U / is the modulus of the speed of rotation of the blade at the point of contact with the heavy particle) and with some positive twist (in the direction of rotation of the RC). Adding with the peripheral speed of the blades U, heavy particles enter the interscapular canal with a relative speed W2. Following in this direction, the heavy particles do not rotate with the air flow along the curved paths a-a ′ and k-k ′ (Figs. 3 and 4), but move along straight-line trajectories a-a ′ ′, k-k ′ ′ until the collision with the surface of the trough of the oncoming blade or either exit the interscapular canal without coming into contact with the shoulder blade — the trajectory k-k ′ ′ ′ in FIG. 4 with the initial geometry of the blades shown by the dashed line. It is in order to prevent the passage (leakage) of particles through the interscapular channel without interacting with the surface of the blade in the proposed axial stage of the blade with a large bending angle of the profile and installed in the lattice with a smaller step (with greater density).

In a collision with the surface of the blade, the relative velocity of the particle W1 is projected onto the surface of the blade and gets a certain value less than the original. In the above construction of velocity triangles, this circumstance is not taken into account, since the angles of attack in a collision are small and it is assumed that / W2 / = / W1 /, where W2 is the particle velocity relative to the blade when it contacts the surface of the blade. Following the surface of the blade, the particle acquires a new direction in relative motion and leaves contact with the blade with a relative speed W2, with an exit angle β2 - FIG. 3, 4.

Adding to the portable rotational speed acquired as a result of interaction with the blade, the speed of the heavy particle after the end of contact with the blade has a value of C2, FIG. 3, 4. Comparing C2 in FIG. 3 and C2 in FIG. 4 shows that the first has a direction close to the axial, and a small tangential component.

Speed C2, FIG. 4, has a pronounced tangential component equal to the peripheral speed of the blade. The reasons for the small twist C2 in the initial version of the stage are the small output angle ά2, FIG. 3, and only a partial perception of peripheral velocity from the scapula, since the interaction of the particle with the scapula occurs normal to the surface of the scapular surface of the scapula, therefore, the particle acquires only a component of the peripheral speed - UN - FIG. 3. In FIG. Figure 4 shows that the output relative velocity of the particle W2 has an output angle of ά2 ~ 90 ° and a circumferential component equal to the total value of U is added to it; as a result, C2 receives the maximum possible momentum in the lateral direction and has an output angle of ά2 ~ 45 °.

The kinematics of the movement of heavy particles in the RK is shown in the velocity triangles of FIG. 3 and 4, wherein in FIG. 4, for comparison, the dashed line shows the speed C2 obtained in the initial geometry of the lattice in FIG. 3.

When forming the geometry of the interscapular channel, taking into account the kinematics of the movement of heavy particles in order to ensure (initiate) the contact interaction of particles with the surface of the scapula and to exclude the passage (slip) - non-contact passage of particles through the interscapular channel - it is necessary to fulfill the condition: the time the particles move along the interscapular channel in the axial direction should be longer than the particle’s time in tangential (circumferential) direction along the azimuthal width of the interscapular canal, from the toe of the first in rotation l patki output to follow the blade edge interblade channel. For the bulk of heavy particles, this condition can be fulfilled in a wide range of initial conditions for particles to enter the interscapular channel, however, there may be exceptions when the positive velocity swirl of the particle at input C1 has an increased value and the axial component is also large. A possible pass in this case provides the particle with an output speed C2 equivalent in magnitude and direction to the speed of the particle that had contact with the blade, i.e. such a pass is not dangerous. In this regard, the situation with a large negative swirl of the particle velocity C1 at the input is more dangerous, since in this case a large value of the relative speed W1 at the input and, as a result, at the output W2 is formed, as a result, the absolute speed C2 is obtained with a large axial component, which requires an increased length of the separation section, much larger than at the output speed with the output angle ά2 ~ 45 °.

Moving in the annular channel 5, FIG. 2, with a speed C2 in the axially tangential direction in the plane BB, FIG. 2 and 5, the heavy particle is simultaneously moving (separated) in the radial direction from the center to the periphery. If you cross the particle trajectory by a set of meridional planes d, e, f, g, h, FIG. 2 and fold them vertically in FIG. 1, then the particle trajectory (indicated by the dashed line) will be reflected in this plane by the set of points of intersection of the particle trajectory with the indicated planes.

It is important to note that the separation of the particle from the root section of the SC blade to the external radius CA (entrance to channel 8) occurs within the axial length L of the separation section, which is determined, to a first approximation, as the length of the leg d′-h ′ of the triangle Od′h ′ , Fig 2, which is a consequence of the equality of the output speed angle C2 ά2 ~ 45 °. In FIG. 5 also shows that the length of the separation section L is the axial component of the length of the particle’s trajectory separated in the plane of the root section BB of FIG. 2. In FIG. 5 it is shown that a particle moving at a speed C2, shown by a dashed trajectory obtained in a typical axial stage, on the accepted length of the separation section L does not reach Rca of the intake channel 8. A necessary condition for the separation of heavy particles in the proposed axial stage should be the condition that the distance between the RC and the SA should be formed so that the time of movement of heavy particles in the space between them (in the separation section L) in the axial direction is longer than the time of movement of cha particles in the radial direction of the radius RK privtulochnoy zone to the radius of the outer ring parser.

One of the drawbacks of the proposed axial stage is an increase in the axial size of the stage due to the presence of a separation section, however, in some widespread types of gas turbine engines, in particular fan-type gas turbine engines with retaining stages [2], [4] or when a gas turbine engine has a 2-stage compressor [3], in the layout of the engines transitional annular channels between the stages are provided. Using the length of these channels, it is possible to integrate the stage of the present invention into the compressor without increasing the initial engine length.

In this case, it is also convenient to combine the existing air intake system in the anti-surge system through an annular gap (as performed in [3], [4]) with an annular channel for receiving separated particles - 8 (Fig. 1, 2, 5). Also important in this case is the fact that the outer diameter of the stage RK in these configurations is often larger than the outer diameter of the backward displaced CA - position 10, FIG. 1, as a result of which the height (width) of the side-by-side zone of the step, from which effective cleaning of air from foreign objects is required, and the length of the separation section (distance 1, Fig. 1) can be significantly reduced.

Information sources

1. Patent RU 2045451 - 03/05/92. A device for protecting the internal circuit of a turbojet bypass engine from foreign objects.

2. Patent US 5123240 - 06/23/1992 Method and device for removing foreign objects from the internal circuit of the gas turbine engine.

3. RU 2198311 - 01/03/2001. Gas turbine unit.

4. Engine PS-90A. 1990 Technical Operation Manual. Publication of Aviadvigatel OJSC, Perm. 94-00-807RE. Book 1, section 072.3300, page 2, paragraph 2.1 (capture and release of foreign objects into the external circuit from the internal circuit).

5. Kholshchevnikov K.V. Theory and calculation of aircraft blade machines. - M.: Mechanical Engineering, 1978

6. Yu.A. Rzhavin, O.N. Emin, V.N. Karasev. Blade engines of aircraft engines. - M .: MAI-PRINT, 2008.

Claims (6)

1. The method of removing heavy particles from the air flow in the axial stage of the compressor, consisting of a blade rim of the input guide vane (VNA), a rotating impeller (RK), which is a disk with working blades mounted on it, and located behind the blade air rim straightening apparatus (CA), based on the principle of inertial separation of heavy particles in the air stream, characterized in that the bulk of the heavy particles passing with the air stream through the flow channel of the stage to be removed from the air flow, they organize the kinematics of movement along the interscapular canals of the Republic of Kazakhstan in such a way that they provide particles with contact interaction with the surface of the oncoming blade of the Republic of Kazakhstan in a wide range of initial conditions for the entry of particles into the interscapular channel at the place of entry, the magnitude and direction of the particle velocity at the time of the specified contact interaction gives the heavy particles an impulse of movement in the tangential axial direction, while investing in the transmitted momentum as much as possible This is a large tangential component, for which the force of action from the side of the blade surface on the heavy particle at the exit section from the interscapular channel is oriented approximately parallel to the plane of rotation of the PK of the stage, in addition, in the indicated axial stage of the compressor, the heavy particles after they exit the PK provide the possibility of free movement along inertia from the acquired impulse in the space that is formed between the impeller and the stage rectifier due to the fact that the rectifier is they are rearward along the air flow at a certain distance from the RC, while moving heavy particles by inertia in the tangential-axial direction, particles are simultaneously moving in the indicated space in the radial direction from the center to the periphery, while the distance by which the SA is moved away from the RC is chosen based on from the condition of its sufficiency for carrying out the process of moving heavy particles from the side-by-side zone of the Republic of Kazakhstan to the annular zone adjacent to the CA rim outside. 2. The method of removing heavy particles from the air flow in the axial stage of the compressor according to claim 1, which consists in the fact that the kinematics of the movement of heavy particles in the interscapular channels, providing contact interaction of particles with the surface of the oncoming blade, is formed on the basis of the condition that for a real range of initial the conditions for the entry of heavy particles into the interscapular channel for them fulfill the relation - the time of movement of the particle along the interscapular channel in the axial direction should be greater than the time of movement of the particle in the tangential the direction along the azimuthal width of the interscapular canal, from the toe of the first blade in rotation to the output edge of the second blade channel forming. 3. The method of removing heavy particles from the air stream in the axial stage of the compressor according to claim 1, which consists in the fact that the length of the distance between the RC and the SA is formed on the basis that the time of movement of heavy particles in the space between them in the axial direction should be longer particle movement in the radial direction from the radius of the plenum zone of the Republic of Kazakhstan to the radius of the outer ring CA. 4. The axial stage of the compressor, which removes heavy particles from the air stream, consisting of a blade rim of the inlet guide vane, a rotating impeller, which is a disk with impellers fixed to it, and a stationary straightening vane, which is a circular rim from rectifier blades fixed in the outer and inner rings, performing the function of removing heavy particles from the air stream by imparting an impulse to the bulk of the particles the movement from the rotating working blades of the Republic of Kazakhstan and the subsequent inertial separation of particles in the radial direction with their removal from the air stream, characterized in that in the radial-annular zone of the flow channel of the RK of the stage from which heavy particles must be removed effectively, the geometry of the blades of the RK and their the position in the scapular lattice is made in such a way that the angle of bending of the midline of the profile of the blades, the density of the scapular lattice, the angle of installation of the profile of the scapula in the lattice have increased values, The change in the characteristics of the compressor stage, also in the specified zone of the flow channel of the RK stage, the value of the outlet angle of the blade profile in the grate has a value approaching or equal to 90 °, in addition, in the axial stage of the compressor CA is located at a distance from the RK, which is equal to the axial component of the trajectory of movement a heavy particle during its rectilinear movement in the tangential-axial direction from the RC to going beyond the radial dimensions of the CA — beyond the radius of the outer ring of the CA; an annular channel formed between the RC and the CA the outer and inner shells located between the RC and the CA, while the outer shell of the annular channel from the side adjacent to the CA has a diametrical size larger than the diameter of the outer ring CA, between the outer shell of the annular channel and the outer ring CA is formed an annular intake channel, which is an input for receiving and subsequent removal of particles separated in the annular channel. 5. The axial stage of the compressor, which removes heavy particles from the air stream in accordance with paragraph 4, characterized in that in the radial-annular zone of the flow channel of the RK stage, from which heavy particles must be removed, the following parameters of the geometry of the blades of the RK and their location in the scapular the lattice has the following meanings:
- bending angle of the midline of the profile 35 ° ± 10 °;
- the density of the scapular lattice ≥1.5;
- angle of installation of the profile of the blade in the grill ≥65 °;
- outlet profile angle of the blade in the grill 80 ° ÷ 90 ° 6. The axial stage of the compressor that removes heavy particles from the air stream, in accordance with paragraph 4, in which the SA is separated from the RK at a distance determined by the ratio
$$L=K\sqrt{R^2\mathrm{from}\mathrm{but}-R^{2}R\mathrm{to}}$$

,
where L is the axial distance from CA to RK;
Rca is the radius of the outer ring CA;
Rpк is the radius of the disk of the impeller of the stage;
K is a coefficient depending on the initial conditions of particle motion in the separation section; in the typical case, when Rca≥Rpк, it can have values K = 0.5-1.

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