RU2770976C1 - Cooled nozzle blade of high-pressure turbine of turbojet engine with replaceable nose for bench tests - Google Patents

Abstract

FIELD: aircraft engine construction.

SUBSTANCE: invention relates to the field of aircraft engine construction, in particular to bench tests of a gas generator of an aircraft engine or a full-size aircraft engine; it is designed to measure parameters of working fluid behind a combustion chamber (at an inlet to a high-pressure turbine). In a cooled nozzle blade, a hollow perforated pen is made prefabricated, containing a blade and a replaceable insert, wherein the blade is made with two cavities with individual cooling systems, and the replaceable insert acts as an inlet edge of the blade with a ledge relatively to a blade profile, while it is made with an internal cavity and a built-in deflector with an individual cooling system, and a bracket is installed on the outer part of the replaceable insert. In addition, a rectangular groove is additionally made on the outer shelf of the blade with the possibility of installing the outer part of the replaceable insert into it, repeating its shape, and a blind centering hole is made on the inner shelf of the blade with the possibility of fixing a cylindrical protruding element located on the bottom of the replaceable insert in it. Additionally, the inlet edge of the replaceable insert contains at least five diffusers with the possibility of installing sensors in them and at least five outlet channels of sensor connection conductors.

EFFECT: invention provides an increase in the reliability and manufacturability of a cooled nozzle blade of a high-pressure turbine of a turbojet engine with a replaceable nose for bench tests, used in the preparation.

1 cl, 3 dwg

Description

The invention, which is a two-component cooled nozzle blade of a high-pressure turbine, relates to the field of aircraft engine building, in particular, to bench tests of an aircraft engine gas generator or a full-size aircraft engine, and is intended to measure the parameters of the working fluid behind the combustion chamber (at the inlet to the high-pressure turbine).

The process of developing new aerodynamic technologies for the turbine, as well as the process of analyzing the performance of the combustion chamber (CC) in terms of the uniformity of the gas flow in the circumferential direction, despite the active intrusion into this area of numerical experiment, continues to be based on experimental verification and testing on test benches. Bench testing of an aircraft engine gas generator or a full-size aircraft engine involves measuring gas flow parameters using sensors. The process of installing sensors in the flow path, accompanied by their attachment to the surfaces of the blade and the further withdrawal of the connection conductors, is called preparation. For this, cast blades of a standard design are traditionally used, modified for the installation of pressure and temperature receivers. The sensors are installed in stamped or turned diffusers fixed on the blade, and the output of the sensor connection conductors is closed with foil overlays.

There are a number of problems in the existing method for preparing turbine nozzle blades:

- the duration of the cycle of the traditional technology for the manufacture of cast blades (casting, regular machining, refinement of the blade for preparation);

- the geometry of the blade profile is violated, the flow is disturbed;

- completion of the blades for preparation (cleaning of coatings, mechanical refinement for unfastening and removal of conductors) significantly reduces the strength of the blades;

- the cooling system of the prepared blades is broken;

- the reliability of the existing preparation is low;

- as a rule, prepared shoulder blades are enough for one full-size test.

A good alternative to the traditional method of preparation are additive technologies that make it possible to manufacture nozzle blades of almost any geometry and get rid of unnecessary technological operations, for example, in the form of manual creation of foil preparation overlays. In addition, the monolithic geometry of the nozzle vane, obtained using this technology, allows you to get rid of leaks that cannot be modeled and taken into account during development.

A well-known design of the blade of the nozzle apparatus (patent SU 1036090, IPC F01D 9/02, publ. 10.12.2005) containing a hollow perforated pen, thermocouples installed in its holes, and equipped with cylindrical screens. In order to increase the accuracy of measurements, the holes are made in the area of the input edge of the pen, the thermocouples are equipped with tubes with sections protruding above its surface, and the screens are placed eccentrically last and fixed on the pen.

A well-known design of the blade feather (patent GB2452026A, IPC F01D17 / 02; F01D5 / 14; G01F1 / 46, publ. 05.05.2010), additively made with built-in channels for the preparation output and built-in places for installing pressure and / or temperature sensors directly on the surface . The pen is intended for installation in a gas turbine engine, including an experimental setup. A method is proposed for determining the temperature of combustion products by taking a gas sample from the leading edge of the nozzle blade through tubes cooled in the cavities of the blade and further in the sampling system, and feeding the gas sample to the analyzer. Sampled gas analysis involves determining the concentration of one or more of its components. Based on the concentration value and data on the composition and parameters of the fuel and air, the temperature of the combustion products in the sampling area is calculated.

The disadvantage of the known design is the lack of a cooling system, which imposes a limitation on the temperature range of the product.

The closest in technical essence and selected for the prototype is the design of the blade (patent RU 2740069, IPC F01D 25/12, F01D 5/18, publ. 12/31/2020), containing a perforated outer and inner shelf, a hollow deflector.

The disadvantages of the known design are all the problems that are typical for the preparation of blades made by the traditional method (casting), as mentioned above.

The technical problem, the solution of which is provided by the implementation of the proposed invention and cannot be implemented using the prototype, is:

- the lack of the possibility of separating the process of assembling nozzle blades into a nozzle apparatus (SA) and the preparation process, which significantly increases the time for carrying out these works, reduces the quality of preparation due to the inconvenience of working with large-sized assembly units;

- the inability to replace temperature sensors that failed during the test or due to the need for additional measurements without disassembling the SA;

- the inability to save the material part (a set of cast nozzle blades) for use in the operation of engines.

The technical objective of the invention is the possibility of replacing the element of the blade (insert), simulating the input edge with installed sensors, as well as the possibility of outputting conductors for connecting sensors through the internal channel of the insert and the possibility of unfastening and soldering the conductors directly on the removable element, regardless of the overall design of the product.

The technical result of the claimed invention is to increase the reliability and manufacturability used in the preparation of the nozzle blade.

The technical result is achieved by the fact that a cooled nozzle blade of a high-pressure turbine of a turbojet engine with a replaceable nose for bench tests, containing a hollow perforated feather with the possibility of installing deflectors , a perforated outer and inner shelf, according to the invention, a hollow perforated feather is made prefabricated, containing a blade and a replaceable insert, and the blade is made with two cavities with individual cooling systems, and the replaceable insert acts as the leading edge of the blade with a step in the flow in relation to the profile of the blade, while it is made with an internal cavity and a built-in deflector with an individual cooling system, and on the outer part of the replaceable insert, a bracket is installed, in addition, a rectangular groove is made on the outer shelf of the blade with the possibility of installing the outer part of the replaceable insert in it, repeating its shape, and on the inner shelf of the blade there is a blind centering a hole with the possibility of fixing in it a protruding element of a cylindrical shape located on the lower part of the replaceable insert; additionally, the input edge of the replaceable insert contains at least five diffusers with the possibility of installing sensors in them and contains at least five channels for the output of conductors for connecting sensors.

As a result, in the proposed invention, in contrast to the prototype, three cavities are organized inside the airfoil of the nozzle blade (the front cavity of the replaceable insert, the middle and rear cavity in the blade) with individual cooling systems. Deflectors are integrated into the front (insertion cavity) and middle cavities, traditional cooling systems are used to cool the rear cavity (installation of a standard deflector). This increases reliability, allows effective cooling of the blade, and eliminates burnouts during testing at high temperatures.

The dimensions of the profile part of the insert exceed (slightly) the dimensions of the blade profile, providing a ledge between the profiles. This makes it possible to avoid off-design flow around the blade as a whole in the event of an unfavorable combination of tolerances in the manufacture of the blade and insert.

Additionally, the blade has a rectangular groove on the outer shelf and a blind hole on the inner shelf for installing and fixing a replaceable insert, while the outer part of the insert repeats the shape of the groove in the blade and the shape of the flow path of the outer shelf of the blade, and the lower part of the insert contains a precise, protruding element of the cylindrical forms with lead-in chamfer for fixation in the blade. In addition, the lower end part of the insert repeats the shape of the inner shelf of the blade, and the leading edge of the insert has the most streamlined shape. All this makes it possible to provide the calculated flow around and the thermal state of the profile of the prefabricated nozzle blade during bench tests of the gas generator of an aircraft engine or a full-size aircraft engine.

Additionally, at least five diffusers are located on the inlet edge of the insert, made integral with the insert profile. Due to the integration of diffusers into the deflector, a channel isolated from the cooling cavity of the insert was obtained, which makes it possible to place sensors, for example, pressure receivers, thermocouples, etc. to measure parameters, for example, total pressure, total temperature, etc.

Taking into account the limited dimensions of the internal cavity of the insert, the method of installing the sensors has been changed. Sensors can only be installed from the inside. For this purpose, a reverse ledge is organized in the built-in diffusers, which allows you to fix the measuring point. At the rear end of the insert, a vertical groove is made for the entire height of the blade profile through which the sensors are installed. As isolation from the oncoming flow, a ceramic nozzle is used on the junction wires, fixed to the cement in the diffuser from the inside. After preparation, the vertical groove is filled with cement to prevent the incoming flow from entering the insert.

Additionally, a bracket is integrated into the outer part of the insert for the output, soldering and unfastening of conductors from thermocouples or pressure receivers. The presence of the bracket allows you to isolate from the main structure of the SA. The area of the working part of the bracket directly depends on the number of measurements on the input edge of the insert, as well as on the need for a solder joint.

Placing conductors from sensors from diffusers inside a cooled insert allows protecting the conductors from the effects of an external environment with a high temperature, which reduces the likelihood of their failure during testing. The placement of the sensor connection conductors inside the insert also makes it possible to exclude their placement in the flow path, ensuring the calculated flow around the nozzle blade profile and the correct functioning of the cooling system, excluding burnouts.

In FIG. 1 - shows the main view of the nozzle vane with a replaceable input edge-insert.

In FIG. 2 - a top view with a section of the feather of the nozzle blade and insert is shown.

In FIG. 3 is a rear view of the insert with a local cut in the area of the transition of the insert profile to the bracket with an image of an integrated cooled deflector.

The cooled nozzle blade (without position) of the high-pressure turbine of a turbojet engine consists of the actual blade 1 and a replaceable, removable insert 2.

Blade 1 includes perforated outer 6 and inner 7 shelves and a blade (without position), in which two cavities are implemented: middle 4 and rear 5. Cavity 4 includes an integrated deflector 11. Cavity 5 is made with the possibility of installing a standard deflector in it. cast blade. The blade 1 has a rectangular groove 8 on the outer shelf 6 and a blind hole 9 on the inner shelf 7 for installing and fixing the replaceable insert 2.

A deflector 10 is integrated into the front cavity 3 of the insert 2.

In each of the cavities 3, 4 and 5, individual cooling systems (without a position) are organized, including: a method for supplying cooling air, a deflector and holes in the blade blade. In the front cavity 3 of the insert, cooling air is supplied from above through a two-sided slot 26, distributed in the cavity 25 and released into the perforations 18 of the insert 2. Cooling of the cavities 4, 5 and shelves 6, 7 occurs similarly to the cooling of the profile and shelves of the cast blade with perforation holes 16.

The outer part 12 of the insert 2 repeats the shape of the rectangular groove 8 of the blade 1. The surface 20 repeats the shape of the flow part of the outer shelf 6 of the blade 1, and the lower part (without position) of the insert 2 contains a protruding element 13 of a cylindrical shape with a lead-in chamfer (without position) for fixing in blind centering hole 9 of the blade 1. In addition, the lower end surface 21 of the insert 2 repeats the shape of the inner shelf 7 of the blade 1, and the leading edge 14 of the insert 2 has the most streamlined shape.

At the inlet edge 14 of the insert 2, at least five diffusers 15 are integrated, implemented, for example, in the form of cylindrical screens with equal height pitch, in which holes 23 are made on both sides to discharge the oncoming flow. Diffusers 15 are made with the possibility of installing sensors in them, for example, pressure receivers, thermocouples, etc., for this, diffusers 15 are made with a reverse ledge 24.

And on the rear end of the insert 2, adjacent to the front end 19 of the blade 1, a vertical groove 17 is made for the entire height of the profile.

Bracket 22 is integrated into the outer part of insert 2 for the output, soldering and unfastening of conductors from thermocouples or pressure receivers.

The described nozzle blade is designed to measure the parameters of the oncoming flow behind the combustion chamber (at the inlet to the high-pressure turbine) in bench tests of a gas generator or a full-size engine, as well as in experimental facilities. Insert 2 is prepared with pressure gauges and/or thermocouple transducers for total pressure and/or total temperature, which are set using auxiliary solutions that allow both transducers and their connection wires to be fixed. The insert preparation process is separated from the gas generator assembly process. Already prepared inserts are installed on the gas generator directly on the test stand through the grooves in the body part, repeating the shape of the rectangular groove 8 of the blade 1.

Blade 1 and insert 2 are made using additive technology by laser sintering.

Blades with inserts and preparations successfully passed 3 tests as part of a gas generator, providing high-quality measurement of the temperature of the gas field behind the combustor in all modes. The design made it possible to change the inserts on the gas generator without removing it from the stand.

The present invention with the above distinctive features makes it possible to increase the reliability and manufacturability used in the preparation of a cooled nozzle blade of a high-pressure turbine of a turbojet engine with a replaceable nose for bench tests.

Claims (1)

A cooled nozzle blade of a high-pressure turbine of a turbojet engine with a replaceable nose for bench tests, containing a hollow perforated feather with the possibility of installing deflectors and perforated outer and inner shelves, characterized in that the hollow perforated airfoil is made prefabricated, containing a blade and a replaceable insert, and the blade is made with two cavities with individual cooling systems, and the replaceable insert acts as the leading edge of the blade, providing a step downstream in relation to the blade profile, while it is made with an internal cavity and a built-in deflector with an individual cooling system, and a bracket is installed on the outer part of the replaceable insert, in addition, a rectangular groove is made on the outer shelf of the blade with the possibility of installing the outer part of the replaceable insert in it, repeating its shape, and on the inner shelf of the blade there is a blind centering hole with the possibility of fixing in it a protruding element of a cylindrical shape, located on the lower part of the replaceable insert, in addition, the input edge of the replaceable insert contains at least five diffusers with the possibility of installing sensors in them and at least five channels for outputting conductors for connecting sensors.

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