Calculation of the disc and blade of the compressor NK-8

Contents

Introduction

1. General information about NK-8-2U engine

1.2. Systems providing engine operation and monitoring:

1.3. Engine design

1.3.1. Compressor

1.3.2. Combustion chamber

1.3.3. Turbine

1.3.4. Jet nozzle

1.3.5. Reverser

1.4. Lubrication and breathing system

1.5. Fuel system

1.6. Engine starting system

1.7. Auxiliary power plant TA-6A

2. High pressure compressor (description of its unit)

3. Patent studies on the topic: Anti-surge devices

3.1. Patent No.

3.2. Patent No.

Method of protection of turbocompressor against surge and device for its implementation

3.3. Patent No.

4.4. Analysis and development of patent selection proposal for anti-surge device

Introduction

When designing an engine, it is necessary to take into account the features of the modern methodology for developing a newly created engine, based on a rational combination of organizational and technical principles.

The creation of efficiently and reliably operating compressors is one of the difficult problems of the development of aviation gas turbine engines. Working and nozzle blades are important elements of the compressor.

The development of a separate engine assembly is preceded by the solution of layout issues. Such issues include:

- selection of design scheme of the engine, which is the basis of implementation of the selected gas-dynamic scheme with observance of the conditions of strength, vibration resistance, reliability and operating conditions;

- determination of engine power circuit supplementing the structural circuit. In particular, clarification of methods of force transfer from rotors to engine housing, conditions of connection of its main units;

- meeting the general requirements for the engine in terms of the possibility of its operation according to its technical condition .

In this work, the design of the high-pressure compressor of the NK8 engine is taken as the basis.

The NK82U turbofan engine is a double-circuit, two-stage, gas turbine engine with a mixture of air and gas flows (Fig. 1).

This engine is a modification of the NK82 engine, it has increased thrust, reduced specific fuel consumption and increased reverse thrust. At take-off and cruising modes the NK82U engine has higher reserves of gas-dynamic stability. On the NK82U engine the alarm system of dangerous temperature of STP3 bearings and the system of restriction of temperature of the coming-out PT129AT gases is installed. In the oil system, in the oil pumping line from the supports there are magnetic plugs that allow you to judge the state of the parts of the rotor supports. For inspection during operation of the engine flow section, LP and HP compressor blades, as well as turbine blades, special windows are provided through which grinding of bottoms on the blades can be carried out without removal of the engine. Besides, engine is provided with operations increasing reliability of units and their life. By Tu154A aircraft in a tail part of the fuselage three NK8 2U engines (fig. 1 and 2) are installed.

Two external engines - the first and the third - are installed in easily removable nacelles on horizontal pylons, and the second engine is installed on the internal nacelles inside the fuselage. Thrust reversal is installed on external engines to improve aircraft landing characteristics. For convenience of operation, all units are located in the lower part of the engine. Maximum length and number of pipelines are reduced. Rice. 1. NK82U engine with reverse (left view) 2 Fig. 2. NK82U engine with nozzle (right view).

Analysis and development of patent selection proposal for anti-surge device

1) DEVICE TO PREVENT SURGE OF AIRCRAFT TWO-CIRCUIT TURBOJET ENGINE (TRDD) AT TAKE-OFF MODE (2251012)

PROS:

1. The invention allows to reduce hydraulic losses in the cooling channel at the best weight characteristics of the device preventing surge of the aircraft two-circuit turbojet engine at take-off mode.

2. at surge start, some fuel is bypassed from fuel line to fuel tank.

CONS:

1. they react to the surge that has already occurred and prevent its further development, but at the same time there is a significant decrease in engine thrust.

2. annular cooler enclosing the high-pressure compressor housing is the inner shell of the bypass duct. Air entering the intermediate volume between the outer and inner circuits through the inlets and exiting through the outlets flows over the compressor housing at a very low speed and cannot effectively cool the compressor housing. Air flow is carried out constantly and on take-off.

3. inlet holes for introducing air into the intermediate volume between the external and internal circuits are not adjustable;

4. the outlets are also non-adjustable.

2) METHOD OF PROTECTION OF TURBOCOMPRESSOR AGAINST SURGE AND DEVICE FOR ITS IMPLEMENTATION.

Pros:

simultaneous control of reverse temperature values and their averaged threshold values, and air pressure downstream the compressor.

this method and device make it possible to increase reliability of engines operation, and therefore provide safety of aircraft flight

Cons:

low speed and reliability of detection and elimination of surge due to absence of control of engine parameters complex and their threshold value obtained by interpolation (averaging).

low speed and reliability of protection of the turbocompressor from surge due to absence of simultaneous control of parameters of reverse values of temperatures and air pressure downstream the compressor.

3) METHOD OF GAS TURBINE ENGINE PROTECTION AGAINST SURGE

PROS:

high quality of operation of the automatic control system in terms of protecting the gas turbine engine from surge and, as a result, high reliability of the gas turbine engine and aircraft safety.

CONS:

low efficiency and impossibility of use on single-engine aircraft (LA).

Stopping of fuel supply to combustion chamber usually provides removal of engine compressor from surge. But the process of loss and restoration of gas dynamic stability reserves (GDU)