RU62374U1 - GAS-TURBINE ENGINE OUTPUT DEVICE - Google Patents

Abstract

The proposal relates to mechanical engineering and can be used as an output device of a turboshaft gas turbine engine with a free turbine when it is mounted on a helicopter.

The output device of a gas turbine engine, mainly for a helicopter, contains a diffuser body, an exhaust pipe made with rotation of the gas flow at an angle to the axis of the engine, and a hollow cowl located inside the exhaust pipe for outputting the shaft back, while the rotation angle is 55-65 °, and the exhaust pipe is profiled from a circular cross-section of the diffuser to an oval output section at the junction with the nozzle of the helicopter, while the fairing along the flow is equipped with an ejector and an element with radial nalami for intake of cooling air with the possibility of its receipt to the first inner surface of the shroud, then through the eductor along the outer surface.

The offer allows to obtain an output device of optimum sizes, light in weight and capable of working at high temperature, of optimal size with maximum diffusivity.

1 n.p.ph., 2 s.p.f., 5 ill.

Description

The proposal relates to mechanical engineering, in particular to the design of the output devices of gas turbine engines and can be used as an output device of a turboshaft gas turbine engine with a free turbine when it is mounted on a helicopter.

The output device is designed to exhaust exhaust gases in the turbines outside the power plant with minimal hydraulic losses.

A known output device of a gas turbine engine comprising an outer casing and a cowl located inside the casing [1].

The disadvantage of this device is that it provides exhaust hot gases along the longitudinal axis of the engine and is unsuitable for aircraft, for example, for helicopters with two engines, which require a turn of the gas flow from the specified axis.

Also known nozzles to the exhaust pipe of a gas turbine engine of a twin-engine power plant of the helicopter, made in the form of a tubular element adjacent to the outlet of the exhaust pipe [2].

An output device with such a nozzle allows you to deploy a gas stream, divert exhaust hot gases outside the aircraft and improve the characteristics of the power plant of the helicopter.

A disadvantage of the known device is its significant dimensions and weight.

It should also be noted that the details of the flow part of the output devices operate in difficult conditions. They are heated by a stream of hot gases, while the temperature field of the gas stream inside the output device is heterogeneous, which can cause warping of parts and local burnout.

A known output device of a gas turbine engine, comprising a housing, an internal channel for passage of the shaft back, formed by a conical surface inside the gas path of the engine, and a screen for protecting the walls of the housing and channel from high temperatures [3].

A disadvantage of the known device is the presence of an additional device to protect the walls from overheating, which leads to an increase in the mass of the engine.

The closest in technical essence and the achieved result to the claimed solution is the output device of a turboshaft gas turbine engine, including an inlet diffuser, an output shaft casing, an exhaust channel and a rack [4].

The disadvantages of the known device are significant losses of total pressure due to insufficient smoothness of the flow part, as well as the possibility of overheating of structural elements.

The technical result of the proposed solution is to reduce the mass of the engine due to the lightweight and efficient at high temperature output device of optimal size, obtained by ensuring its maximum diffusivity and reduce the loss of total pressure.

To achieve the specified technical result in the output device of a gas turbine engine, mainly for a helicopter, comprising a diffuser body, an exhaust pipe made with the rotation of the gas flow at an angle to the axis of the engine, and located inside

the exhaust pipe is a hollow cowl for outputting the shaft back, according to the proposal, the rotation angle is 55-65 °, and the exhaust pipe is profiled from the circular cross section of the diffuser to the oval output section at the junction with the nozzle of the helicopter, while the cowling along the flow is equipped with an ejector and an element with radial channels for the intake of cooling atmospheric air with the possibility of further flow first to the inner surface of the fairing, and then through the ejector along the outer surface.

Also, according to the proposal, heat shields are installed on the inner surface of the fairing, and at the junction of the exhaust pipe with the nozzle of the helicopter, a coupling clamp with a seal is installed.

The presence of distinctive features, namely, a gas flow turn at an angle of 55-65 ° to the axis of the engine, the exhaust pipe is curved, profiled from the circular cross section of the diffuser to the oval output section at the junction with the helicopter nozzle, the fairing with an ejector at the inlet of the device, and at the exit from it - with an element, for example a flange equipped with radial channels for intake of cooling atmospheric air with the possibility of its further flow first to the inner surface of the fairing, and then through the ejector along the outer surface, indicates the conformity of the claimed technical solution to the patentability criterion of "novelty."

The essence of the proposal is illustrated by drawings, where figure 1 shows a General view of the output device; figure 2 presents a General view of the output device with a view of the fairing located inside the exhaust pipe; figure 3 schematically shows a longitudinal section of the output device; figure 4 presents the node seal of the junction of the exhaust pipe and nozzle of the helicopter; figure 5 presents the ejector.

It should be noted that in the drawings for clarity only those details are presented that are necessary for understanding the essence

technical solutions, and the accompanying elements, well known to specialists in this field, are not shown in the drawings.

In the above example, a specific implementation of the inventive output device is made on an aircraft turboshaft gas turbine engine mounted on a helicopter. The engine is a heat engine in which the energy released during fuel combustion is converted into mechanical work on the output shaft of a free turbine kinematically not connected with the compressor turbine. Being the main source of energy, it serves to drive the main (main and steering) propellers and units of various helicopter systems.

The output device of this engine is made in the form of an expanding subsonic diffuser. It provides exhaust hot gases at an angle from the axis of the engine outside the helicopter power plant.

The device includes a diffuser housing 1 and an exhaust pipe 2, each of them is a welded structure made of titanium alloy (figure 1). The exhaust pipe 2 is made in the form of a specially profiled pipe, bent in the horizontal plane at an angle to the engine axis α = 60 ° and having varying cross-sectional shapes from the annular section at the gas flow inlet to the oval at the outlet (figure 2). Inside the exhaust pipe 2 there is a turbine hollow conical cone fairing 3 with a free turbine shaft, which is brought back along the longitudinal axis of the engine and at the same time crosses the exhaust pipe 2 (Fig. 3). To the output of the exhaust pipe 2 adjoins nozzles 4 of the helicopter with a seal assembly (Fig. 4). The seal assembly includes a flange 5 of the exhaust pipe 2 and a flange 6 of the nozzle 4, which are interconnected by a connecting clamp 7. Between the outer surface of the wall of the exhaust pipe 2, flanges 5 and 6, an annular seal 8 is installed, made for example of asbestos cord.

At the entrance of the gas stream to the output device on the fairing 3 is made

ejector 9 (figure 5).

The device also contains an element 10 made in the form of a flange with radial channels 11, which are intended for intake of atmospheric air for cooling parts of the output device.

Along the inner surface of the fairing 3 to protect against high temperatures located inside its shaft, heat shields 12 are installed.

The device operates as follows.

During engine operation, the conversion of thermal energy into mechanical work occurs as a result of the implementation of compression processes - expansion of the working fluid (air and gas) during its movement along the gas-air path of the engine.

The initial state is the parameters of the working fluid in an unperturbed flow, where they correspond to standard atmospheric conditions.

To increase the power of a free turbine, it is made with over-expansion of gas in it. Therefore, in the cavity behind the free turbine, namely in front of the body of the diffuser 1 of the output device, the pressure is lower than atmospheric. At the exit of the free turbine, the gases have a pressure of P = 0.098 MPa, a temperature of T = 437 ° C, and an axial velocity of 154 m / s.

In the output device, the gas flow is decelerated, as a result of which the static pressure increases to atmospheric pressure, and the absolute velocity decreases to 50 m / s.

The gases leaving the engine have a certain amount of thermal energy, but practically do not create jet propulsion. This is a specific feature of a helicopter gas turbine engine with flow rotation in the output device.

The cooling of the parts of the output device is carried out in two ways: by cooling air coming from the body of the nozzle apparatus of the free turbine and by air from the environment, a fence

which is carried out through radial channels 11.

The above rarefaction in the cavity behind the free turbine is used to organize air cooling of the fairing 3. Due to the presence of the ejector 9, the cooling air flow changes the direction of movement. While the gas flow moving in the flow part, the cooling air is pressed against the fairing 3, forming an air curtain around it and thereby ensuring its effective cooling.

The device was designed and manufactured at the V.Ya. Klimov plant and was successfully used at the customer’s enterprise.

From the above it follows that the manufacture of this device in an industrial way does not cause difficulties, involves the use of developed materials and standard equipment, which indicates the compliance of the claimed technical solution with the patentability criterion of "industrial applicability".

Information sources:

1. Patent RU No. 2096631, F 01 D 25/30, F 02 K 1/04, 1997;

2. Patent RU No. 2230005, B 64 D 33/04, F 01 N 7/00, F 01 N 7/08, 2004;

3. Certificate RU No. 9202, B 64 D 33/08, 1999;

4. Maslennikov MM, Shalman Yu.N., “Aircraft gas turbine engines”, M., “Engineering”, 1975, p. 466, fig. 14.1, d.

Claims (3)

1. The output device of a gas turbine engine, mainly for a helicopter, comprising a diffuser housing, an exhaust pipe made with rotation of the gas flow at an angle to the axis of the engine, and a hollow cowl located inside the exhaust pipe to output the shaft back, characterized in that the rotation angle is 55- 65 °, and the exhaust pipe is profiled from a circular cross-section of the diffuser to an oval output section at the junction with the nozzle of the helicopter, while the fairing along the flow is equipped with an ejector and an element with radial intake channels for cooling air with the possibility of its receipt to the first inner surface of the shroud, then through the eductor along the outer surface. 2. The output device of the gas turbine engine according to claim 1, characterized in that heat shields are installed on the inner surface of the fairing. 3. The output device of the gas turbine engine according to claim 1, characterized in that at the junction of the exhaust pipe with the nozzle of the helicopter a coupling clamp with a seal is installed.