RU2798300C1 - Air intake device for helicopter gas turbine engine - Google Patents

Abstract

FIELD: helicopter gas turbine engines.

SUBSTANCE: air intake device for a helicopter gas turbine engine contains an external air intake tunnel (8) having an inlet (5) with a collector lip (5') in the front part and a barrel-shaped shell with a circular cross section, ending in the rear part of the tunnel with an outlet (17) adjacent to the motor inlet (17). The central (1) and outer (8) air intake tunnels are located coaxially and in such a way that the central tunnel with its tail part (7) enters through the inlet (5) of the outer tunnel (8) into its inner cavity, forming in the free space between the walls of the tunnels an annular curved channel (9) of the air-cleaning system of the device. Along the length of the air-cleaning channel there is a curved section of the inertial separator. After the separator section, a separator of separated particles is installed in the air-cleaning channel.

EFFECT: increased efficiency of the air intake device.

1 cl, 1 dwg

Description

The invention relates to the field of helicopter engineering, specifically to air intake devices for helicopter gas turbine engines (GTE), performing simultaneously with air intake from the surrounding space, the function of cleaning air from dust particles, sand and other foreign objects. The entry of these particles into the gas-air path of the engine leads to nicks and erosive wear of the engine compressor blades, a decrease in engine power and reserves of its gas-dynamic stability (to surge), as well as other dangerous and unprofitable consequences, such as a decrease in the reliability and safety of flights, a decrease in the overhaul period service life of engines, an increase in the cost of repairing engines, a deterioration in fuel efficiency, operational manufacturability, and more.

Known devices designed to solve this problem, their descriptions are given in [1, 2, 3], these devices are widely used in the helicopter industry and in the operation of domestic and foreign helicopters.

In the domestic helicopter industry, the device [1] is widely used - a dust protection device (PDD) of the "fungal" type, made in the form of an inertial separator of heavy particles in a curvilinear flow. Since the 70s of the last century, this ROM has been installed on almost all mass-produced domestic helicopters with gas turbine engines. It made it possible to eliminate early removal of engines due to their abrasive wear. This was achieved by operating helicopters mainly in the climatic conditions of Russia on engines that had a turnaround time of 750-1000 hours. However, with the expansion of the use of domestic helicopters in countries with hot and dry climates, the presence of sandy deserts and high mountains, as well as due to the increase in the overhaul life of modern gas turbine engines, the problem of early removal of engines due to their abrasive wear again becomes relevant.

The disadvantages of the "fungal" ROM should include increased power losses and engine efficiency that accompany the operation of helicopters, as well as the need to provide the ROM with an effective and energy-intensive anti-icing system due to the presence of an increased area of interaction of the ROM structural elements with an air flow containing supercooled water drops under conditions icing and simultaneous action of intensive inertial separation. The last two drawbacks to a large extent also apply to the device - analogue [2], which is an air-cleaning module included in the design of the T-700 helicopter gas turbine engine (USA).

Unlike the above analogues in the device [3] made according to the multi-cyclone scheme (from direct-flow cyclones), the air-cleaning function of the device does not adversely affect the engine performance when flying in clean air and does not lead to a deterioration in helicopter performance. This is achieved due to the presence in the device [3] openable "bypass" input, combined with the collection chamber of cyclones. However, these devices have found application in a rather limited form - on transport and troop transport helicopters. Their use on combat helicopters is hampered by factors such as:

- increased overall dimensions and weight characteristics;

- low combat survivability of the device under the influence of damaging factors, due to the many details and openwork of the perforated shells of the structure, which can introduce additional damaging factors for the engine;

- potentially low operational manufacturability, tendency to clog dust channels, the need for their inspection and cleaning;

- risks in providing the device with an effective and reliable anti-icing system in a wide range of conditions for the use of helicopters.

The technical task to be solved by this proposal is the creation of a helicopter air intake device that provides:

- effective air purification from foreign objects in a wide range of their dispersed composition in helicopter operation modes near the ground surface (taxiing, takeoff, landing, hovering, movement above the surface), while the required level of air purification efficiency should ensure the operation of the helicopter engine in conditions of increased dustiness during the overhaul life of engines of both old and new modifications (with an increased resource);

- the permissible level of reduction in the flight performance (LTH) of the helicopter from the impact of the air intake device by providing an acceptable level of hydraulic resistance of the device when the helicopter is operating in the air cleaning mode near the ground, as well as by minimizing the loss of total pressure and velocity head of the air flow during the flight of the helicopter in clean air conditions;

- the possibility of using the air intake device in various operating conditions, including conditions of negative temperature and icing conditions, as well as in real operating conditions in accordance with the intended purpose of the helicopter type;

- the possibility of using the air intake device in the conditions of size and layout restrictions of the structures of power plants (PS) of existing helicopters.

Comparative analysis of known analogue devices [1, 2, 3] in terms of the possibility of their use for solving the problem shows that, for various reasons, none of them is able to fully satisfy the set of requirements for an air intake device with air purification.

Most fully in terms of performing the air-cleaning function, the air intake device proposed in the present invention corresponds to the analog [1] - the domestic ROM of the "fungal" type, and we will consider it the prototype of the considered air intake device for a helicopter gas turbine engine.

Due to the solution of the above problem, when installing the proposed air intake device on a helicopter, a smaller amount of sand and dust will enter the engine, the overhaul life of the engines, respectively, increases, early engine removals due to erosive wear of the compressor blades are stopped, the engines develop an overhaul life. At the same time, the flight performance of the helicopter is improving - in terms of carrying capacity, flight range, fuel efficiency. At the same time, initial studies give reason to expect that the installation of a new air intake device on a serial helicopter will not lead to a serious and costly alteration of the airframe and systems. As for the compliance of the new device with many other requirements for helicopter air intakes, in the first approximation, the device under consideration can be considered equivalent to its prototype device [1] - a "fungal" type ROM, including in terms of combat survivability and operational manufacturability.

The essence of the proposed air intake device for a helicopter gas turbine engine, which simultaneously performs the function of air purification from sand particles, dust and other foreign objects, simultaneously with air intake from the surrounding space, is as follows.

In the air intake device, two flow channels are made, formed by two air intake tunnels - central and external. The central air intake tunnel has an inlet on the front side with a collector lip facing towards the oncoming air flow during helicopter flight, and a tail section made in the form of a cylindrical tunnel ending with an outlet facing the engine inlet.

The external air intake tunnel also has an inlet with a collector lip in the front part and a middle part in the form of a barrel-shaped shell of a circular cross section, ending in an outlet adjacent to the engine inlet. The diametrical and axial dimensions of the external air intake tunnel are made on the basis of the condition of providing the possibility of placing in its internal cavity the tail section of the central tunnel and elements of the air cleaning system of the device. In the described device, the central and external air intake tunnels are located coaxially and in such a way that the central tunnel with its tail part enters through the inlet of the external tunnel into its internal cavity, forming an annular curvilinear channel of the air cleaning system of the device in the free space between the walls of the tunnels. Said air cleaning system includes an inlet annular opening with a radial direction of the incoming air flow, formed by an axial space between the rear wall of the central tunnel collector lip and the outer tunnel lip. Further along the air-cleaning channel there is a separation section with a turn of the incoming air flow at an angle α ~120°±20°. It is followed by the site of location of the separated particles concentrator, made in the form of a conical louvered grille of several annular elements, providing the rotation of the purified air in the direction of the main flow velocity. At the end of the grate, an annular collector of foreign particles separated and concentrated in a small part of the air (dust concentrate) is installed, which communicates with the system for draining and removing the concentrate from the device located in the same zone of the channel using an electric suction fan. The air intake device includes a shut-off valve installed in the zone of the central tunnel inlet, which closes and opens the air passage to the engine through the central tunnel of the device. Also, a metal mesh is installed in front of the inlet annular hole in the air-cleaning channel, which prevents the passage of dangerous large particles and foreign objects into the device and into the engine.

When the air intake device is operating in the air cleaning mode, the rotary flaps of the shutter are set to a position where they close the direct passage of air to the engine through the central air intake tunnel, and the air enters through the air cleaning channel of the device, where it is cleaned of contaminants, after which it enters the engine inlet , and the separated objects are thrown into the surrounding space in the form of a dust concentrate.

When the helicopter operates in clean air, the shut-off valve opens the air passage through the central air intake tunnel and the air flow without pressure loss goes directly to the engine.

The essence of the claimed invention "Air intake device for a helicopter gas turbine engine" is illustrated by the scheme of Fig. 1, which shows a longitudinal section of the device. The air intake device includes a central air intake tunnel-1, consisting of an inlet manifold lip-2 (the front wall of the lip) and a tail section-7 of the tunnel, made in the form of a cylindrical shell with an inlet-1' and an outlet-15 facing towards the inlet engine holes-17.

The device also includes an external air intake tunnel - 8, which has an inlet-5 with a collector lip-5', a barrel-shaped shell in the middle part and an outlet-16 adjacent to the inlet of the engine-17.

In the described air intake device, the central air intake tunnel-1 and the outer tunnel-8 are located coaxially and in such a way that the central tunnel with its tail part - 7 enters through the inlet-5 of the outer tunnel-8 into its inner barrel-shaped cavity, forming in the free space between the walls tunnels annular channel - 9 air purifying device system. Said air-cleaning system of the device includes an annular inlet-3 formed by an axial space between the rear wall 2' (inlet manifold lip 2) and the manifold lip -5' of the outer tunnel-8. After the inlet, separation section-4 follows, in which the annular channel is rotated through an angle α ~120°±20°.

Further, after the turn, in the channel-9 there is a separated particles concentrator, made in the form of a set of several annular elements-10 of a conical louvered grille, while the geometry of these grille elements is made to ensure the movement of air cleaned from clogging particles in the direction of the main flow of clean air. An annular collector-11 is installed at the exit from the grate, formed by the sheet wall of the shell-11' and the end part of the central tunnel-7. The inner cavity of the collector-11 with the help of several hollow racks-12 communicates with the collection chamber-13 formed by the shell of the outer tunnel-8 and the walls-13'. The concentrate removal system from the device includes a fan-21 with an electric drive, which is installed on the collection chamber-13 (or next to it).

The air intake device includes a shut-off valve designed to open and close the air passage through the central air intake tunnel-1. In the design of the device under consideration, a shutter with two rotary synchronously operating shutters-23,-25, having a two-position working position and controlled by means of a hydraulic cylinder-19, rods-22 and levers-22', is described. At the same time, flaps-23, -25 are installed directly in the inlet-1' of the tunnel-1, the remaining elements of the shutter are installed outside the working cavity of the device. On FIG. 1, the flaps are shown in different positions: on the upper half of the scheme, flap - 23 is shown in the open position, on the bottom - flap - 25 blocks the central flow channel -24.

In the air intake device under consideration, in order to more reliably protect the helicopter gas turbine engine from large foreign objects entering its gas-air path, a metal mesh-6 is installed in front of the inlet-3 in the air-cleaning channel-9.

When the helicopter is operating in a polluted atmosphere, the air intake device is set to the air purification mode. At the same time, the rotary shutters-23 and -25 of the shut-off shutter are set to the "Closed" position with the help of a hydraulic cylinder-19, rods-22 and levers 22' and block the inlet-1' into the central air intake tunnel-1 (in Fig. 1 in a closed lower sash-25 is shown).

Under the action of the vacuum created by the running engine, air with foreign particles enters the annular inlet-3 of the air-cleaning system of the device, while passing through the grid-6, the air is cleared of foreign objects with dimensions exceeding the passage size of the grid cell. Further, the air with particles enters in the direction of the arrow-29 into the turning section-4, in which the air flow is rotated from the inlet direction along the arrow-26 at the angle a-position-27 to the flow direction along the arrow-28. As a result of inertial separation, when the flow turns, heavy particles shift their trajectories towards the outer wall of the rotary channel, concentrate in the annular zone near the surface of the rear wall 2' (lip-2) and cylinder-7. The main part of the air that has passed through the separation section, cleared of foreign particles, enters the annular inlet-31 of the channel-33. A smaller part of the air with separated particles enters the inlet-30 of the channel-32, which is the internal channel of the conical louvre concentrator-10.

Passing through the inter-annular ducts of elements-10, the air with foreign particles is subjected to cleaning, the purified air also enters the channel-33 and moves along the arrows-34 to the outlet-14 from the channel-9, and then along the arrow-20 to the outlet-16 engine inlet. A small part of the air (a few percent), together with foreign particles trapped in the separator and concentrator, enters along the arrows-35 into the annular collector-11, from which the rack-12 passes through several radial hollows into the collection chamber-13, from which the concentrate is removed from the device with using fan-36.

When the helicopter operates in clean airspace (flying along the route at cruising speed), the total time of which is a multiple of the time of operation in polluted air near the earth's surface, the shut-off air shutter of the device opens a direct passage for air through the central air tunnel-1. Turning flaps-23,-25 are set to the "Open" position, in FIG. 1 this mode corresponds to the position of the leaf-23. Clean air freely passes into the inlet-G of the tunnel in the direction of the oncoming flow-24 ', passes the internal space-24 of the tunnel and in the direction of the arrow-18 exits the device into the engine, while a certain amount of air from the external air cleaner can be sucked into the main air flow channel-9.

Information sources

1. V.A. Danilov, V.M. Zanko, N.P. Kalinin, A.I. Krivko Helicopter Mi-8 MTV, Moscow, Transport 1995 (p. 164 Dust protection device).

2. US patent No. 4527387 07/09/1985 F02G 3/00.

3. US patent No. 3421296 01/14/1969 B64s 21/00, B01d 45/12.

Claims (1)

An air intake device for a helicopter gas turbine engine, which includes a central air intake tunnel having an inlet with a collector lip on the front side facing towards the oncoming air flow during the flight of the helicopter, and the tail section of the tunnel ending in an outlet opening facing the engine inlet, also The device includes an air cleaning system made in the form of an inertial separator of heavy particles in a curvilinear air flow, characterized in that the air intake device includes an external air intake tunnel, which has an inlet with a collector lip in the front part and a barrel-shaped shell with a round cross section, ending in the rear part of the tunnel with an outlet adjacent to the engine inlet, while the dimensions of the external air intake tunnel are made on the basis of the possibility of placing the tail section of the central tunnel and elements of the air cleaning system in its internal cavity, in the assembled state, the central and external air intake tunnels are located coaxially and in such a way that the central tunnel with its tail part enters through the inlet of the outer tunnel into its inner cavity, forming in the free space between the walls of the tunnels an annular curved channel of the air-cleaning system of the device, which includes an annular inlet formed by the axial space between the rear wall of the collector lip of the central tunnel and the inlet lip of the outer tunnel, then along the length of the air-cleaning channel there is a curved section of the inertial separator, which is a spatial rotation of the annular air-cleaning channel at an angle of α ~ 120°±20°, made with the possibility of inertial separation of the bulk of foreign particles to the surface of the rear wall of the collector lip of the central tunnel and to the cylindrical surface of the tail part of the central tunnel, after the separator section in the air-cleaning channel, a separated particle concentrator is installed, made in the form of a conical louvered grille assembled from several annular elements and an annular collector, the internal cavity of which is made communicating with the help of several hollow radial racks with dust concentrate removal and removal system, which includes a collection chamber and an electric suction fan, the air intake device also includes a shut-off valve installed in the zone of the inlet of the central tunnel, closing and opening the air passage to the engine through the central tunnel of the device, in addition to a metal mesh is installed at the inlet annular hole in the air-cleaning channel of the device, which is designed to prevent the passage of dangerous large particles and foreign objects into the device and into the engine.

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