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PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 1 Pedagogical guide 29 April, 2015.

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Presentation on theme: "PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 1 Pedagogical guide 29 April, 2015."— Presentation transcript:

1 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 1 Pedagogical guide 29 April, 2015 GAS TURBINE ENGINE EXHAUST

2 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 2 Pedagogical guide 29 April, 2015 TABLE OF CONTENTS CHAPTER 1 - CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION S/C: Location S/C: Function CHAPTER 2 - CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES CHAPTER 3 - ENGINE NOISE REDUCTION CHAPTER 4 - THRUST REVERSERS S/C: Function S/C: Location S/C: Principle S/C: Turbo-propellers

3 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 3 Pedagogical guide 29 April, 2015 Location  In a single flow turbojet, the exhaust duct is an element located within the engine behind the turbine and by which the gas stream, having undergone the engine thermodynamic cycle, is ejected  In the case of a dual-flow turbojet, the hot flow exhaust duct is positioned on the turbine outlet as on a single flow engine; the cold flow exhaust duct is located behind the fan. CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

4 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 4 Pedagogical guide 29 April, 2015 Location  The stations associated with the exhaust ducts of a turbojet: The stations associated with the exhaust ducts of a turbojet : -For a single flow turbojet: station 4: exhaust duct inlet station 5: exhaust duct outlet CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

5 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 5 Pedagogical guide 29 April, 2015 Location  The stations associated with the exhaust ducts of a turbojet: -For a dual flow turbojet: Hot flow (or primary flow):Cold flow (or secondary flow): station 5: exhaust duct inlet station 15: exhaust duct inlet station 6: exhaust duct outlet station 18: exhaust duct outlet CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

6 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 6 Pedagogical guide 29 April, 2015 Function  The exhaust duct’s function is to convert post-turbine gas energy into kinetic energy. This transformation is an expansion; -it is obtained by the shape (convergent in general) of the exhaust duct. -It involves an acceleration of gases. This acceleration generates a thrust force. -It can be the main thrust of the engine (single flow engines) -or a secondary thrust known as "residual thrust" (double flow engine). CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

7 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 7 Pedagogical guide 29 April, 2015 Function CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

8 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 8 Pedagogical guide 29 April, 2015 Construction  Joining line. It comprises an external casing. Inside, a cone (taper) is fixed by struts. Its role is to channel the hot gases leaving the turbine and to transform their annular flow into circular flow.  The taper. Its role is to streamline the rear face of the turbine. It can support the rear bearing of the turbine.  Struts. The number of struts is variable, depending on the type of engine. They convey the gas flow in an axial direction. Struts are hollow and can be thus used, due to fresh air circulating inside, to cool the rear face of the turbine or to pressurize the turbine bearing.. CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

9 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 9 Pedagogical guide 29 April, 2015 Joining line CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

10 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 10 Pedagogical guide 29 April, 2015 Taper CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

11 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 11 Pedagogical guide 29 April, 2015 Construction  Struts. The number of struts is variable, depending on the type of engine. They convey the gas flow in an axial direction. Struts are hollow and can be thus used, due to fresh air circulating inside, to cool the rear face of the turbine or to pressurize the turbine bearing.  Tail pipe. It is a cylindrical conduit intended to ensure the connection between the joining line and exhaust nozzle. Note that it is optional, depending on how the engine is installed in the airframe or in the nacelle. CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

12 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 12 Pedagogical guide 29 April, 2015 Construction  Nozzle. The nozzle enables expansion of gases leaving the turbine to obtain maximum kinetic energy. For a given subsonic speed of gases, the expansion nozzle is convergent in shape. For a given supersonic speed of gases, the nozzle is convergent- divergent in shape. CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

13 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 13 Pedagogical guide 29 April, 2015 Dual flow turbojet CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

14 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 14 Pedagogical guide 29 April, 2015 Fixed area convergent nozzle : Mixed flow bi-pass turbojet CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

15 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 15 Pedagogical guide 29 April, 2015 Variable outlet section convergent nozzle : Eyelids CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

16 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 16 Pedagogical guide 29 April, 2015 Variable outlet section convergent nozzle : Device with multiple flaps CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

17 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 17 Pedagogical guide 29 April, 2015 Primary nozzle, convergent, multi-tab nozzle CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

18 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 18 Pedagogical guide 29 April, 2015 Secondary nozzle, eyelids nozzle CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

19 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 19 Pedagogical guide 29 April, 2015 Materials  Tail pipe. CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

20 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 20 Pedagogical guide 29 April, 2015 Materials  Exhaust Pipe. CONSTRUCTIONAL FEATURES AND PRINCIPLES OF OPERATION

21 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 21 Pedagogical guide 29 April, 2015 Introduction  An exhaust duct is composed mainly: of a joining line, including an outer jacket and a cone, the function of which is to assure the continuity of gas flow leaving the turbine, of a tail pipe, ensuring the connection between the joining line and the nozzle. -The tail pipe is optional. -Its installation depends on how the engine is placed in the frame. of a nozzle of fixed or variable exhaust area, intended to expand and accelerate gases.  Nozzle architecture can vary sharply, and is classified in two groups: fixed convergent area ducts, found on most commercial aircraft engines, variable area ducts (convergent or convergent-divergent), found on engines equipped with exhaust reheaters (Concorde or fighter aircraft). CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

22 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 22 Pedagogical guide 29 April, 2015 Exhaust duct CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

23 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 23 Pedagogical guide 29 April, 2015 Nozzle types CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

24 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 24 Pedagogical guide 29 April, 2015 Fixed convergent area nozzle  Single flow turbojet. On this type of turbojet the exhaust duct is single. It is composed mainly: -of an exhaust cone, including two parts: a casing and an internal cone. The casing is directly attached to the turbine case. Its shape is convergent. The internal cone’s function is to adapt the annular section of the flow in the turbine outlet in circular section. The internal cone is linked to the casing by struts which rectify the flow. -of a duct. On some engines, the duct precedes a tail pipe. The duct is a convergent channel in which the expansion of hot gases produces their acceleration. CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

25 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 25 Pedagogical guide 29 April, 2015 Fixed convergent area nozzle  Dual flow turbojet. Double flow turbojets have two ducts. Both flows may be separate: -The exhaust duct containing hot flow enables the expansion and the acceleration of the gas stream in the same way as in single flow turbojets. This acceleration, however, represents only one small part of the turbofan’s thrust (about 20% on takeoff), and is called residual thrust. -The exhaust duct containing cold flow makes it possible to accelerate the gas stream, which is the main source of a turbofan’s thrust. It is of convergent shape and consists of two partitions. The internal partition is the casing surrounding hot parts of the gas generator. The external partition constitutes the rear part of the engine nacelle. It usually features a thrust reverser. CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

26 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 26 Pedagogical guide 29 April, 2015 Fixed convergent area nozzle CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

27 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 27 Pedagogical guide 29 April, 2015 Fixed convergent area nozzle  Variable ejector nozzle. Engines equipped with variable area nozzles adjust more easily to their flight envelopes (as broad as possible for fighters). Moreover, engines using re-heaters must be equipped with such nozzles in order to compensate for the increase in mass flow rate. Variable ejector nozzles are classified in two groups: those with a convergent section and those with a convergent – divergent section -Convergent shapes limit gas exhaust velocities to Mach 1 (in nozzle throat).. -To continue accelerating gases (assuming they still have energy) and reach supersonic exhaust velocities, convergent nozzles must be prolonged with a divergent duct. CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

28 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 28 Pedagogical guide 29 April, 2015 Variable ejector nozzle CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

29 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 29 Pedagogical guide 29 April, 2015 Study of convergent jet nozzles  Fixed exhaust convergent area nozzle. Space upstream meets the conditions of pressure, temperature, and velocity in the turbine outlet. The downstream space meets conditions of pressure and temperature characteristic of the atmosphere. P t 5 = pressure turbine outlet and nozzle inlet T t 5 = temperature turbine outlet and nozzle inlet P 0 = atmospheric pressure T 0 = atmospheric temperature When pressure P t5 is higher than P 0, a flow originates in the upstream space and moves towards the downstream space. -The larger the difference between pressures, the greater the flow As the nozzle is convergent, gases are accelerated by expansion. CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

30 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 30 Pedagogical guide 29 April, 2015 Study of convergent jet nozzles  Fixed exhaust convergent area nozzle. If upstream pressure P t5 continues to increase, gases reach a maximum speed in the nozzle throat. -This speed is equal to sonic speed (M=1). -As speed is maximum, so is the gas mass flow rate and thrust. The relationship between total pressure and static pressure in the throat, known as critical ratio Rc, takes the value : Rc  1,9. In practice, the real ratio Rr is different from Rc. CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

31 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 31 Pedagogical guide 29 April, 2015 Study of convergent jet nozzles  Fixed exhaust convergent area nozzle. CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

32 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 32 Pedagogical guide 29 April, 2015 Study of convergent jet nozzles  Fixed exhaust convergent area nozzle. CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

33 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 33 Pedagogical guide 29 April, 2015 Study of convergent jet nozzles  Fixed exhaust convergent area nozzle. CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

34 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 34 Pedagogical guide 29 April, 2015 Study of convergent jet nozzles  Fixed exhaust convergent area nozzle. Conclusion: -Every constant section nozzle is adapted to a given altitude and to a precise turbojet engine rating. -Complete expansion is thus carried out only under well defined conditions. -The ideal compromise is thus sought when designing an exhaust duct for an engine intended to propel an aircraft at subsonic speeds. CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

35 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 35 Pedagogical guide 29 April, 2015 Study of convergent jet nozzles  Variable exhaust convergent area nozzle. For the nozzle to adapt continuously to every engine rating, manufacturers have developed various processes: -the bucket (or half-shell) system. -the multi-flap system. They allow the adaptation to various engine ratings. They enable, indirectly, the control of turbine temperature CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

36 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 36 Pedagogical guide 29 April, 2015 Variable exhaust convergent area nozzle: The bucket system CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

37 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 37 Pedagogical guide 29 April, 2015 Variable exhaust convergent area nozzle: The multi-flap system CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

38 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 38 Pedagogical guide 29 April, 2015 Study of convergent - divergent exhaust nozzle  The Mach number behind the turbine is lower than 1 (M < 1).  The duct behind the turbine always has a convergent shape.  Principle of operation By connecting a divergent channel to the convergent nozzl after the throat, the flow can be accelerated (Hugoniot’s Theorem) If the generating pressure Pt5 is sufficient, gases circulate past the nozzle’s throat at Mach 1, and continue expanding in the divergent duct, with an increasing exhaust velocity: M > 1 CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

39 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 39 Pedagogical guide 29 April, 2015 Study of convergent - divergent exhaust nozzle  The convergent-divergent duct enables supersonic exhaust velocities (past the throat).  Because engine ratings are variable, the divergent duct must also be variable. The primary duct is convergent and has a variable section The secondary duct may have a variable section, depending on flight conditions (convergent or divergent). CONVERGENT, DIVERGENT AND VARIABLE AREA NOZZLES

40 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 40 Pedagogical guide 29 April, 2015 Origin of the noise  The streamwise vortices generated in a jet flow, in addition to the azimuthal (or ring type) vortices, have been found to mix fluid streams even more efficiently) Both the azimuthal and streamwise vorticities are of equal importance to jet mixing process and they are not independent of each other. The distortion of azimuthal vortex structure may lead to streamwise vortices under certain conditions. The streamwise vortices in jet mixing flows can be generated by many methods. ENGINE NOISE REDUCTION

41 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 41 Pedagogical guide 29 April, 2015 Exhaust noise ENGINE NOISE REDUCTION

42 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 42 Pedagogical guide 29 April, 2015 Solutions  Flow mixture. Design enabling flow mixture before their backward ejection. Significant reduction in exhaust gas noise, and in some cases, an improvement in nacelle aerodynamics. ENGINE NOISE REDUCTION

43 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 43 Pedagogical guide 29 April, 2015 Solutions  Lobed nozzles. A lobed nozzle used to generate large-scale streamwise vortices in a jet flow has been considered to be a promising method for jet mixing enhancement. ENGINE NOISE REDUCTION

44 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 44 Pedagogical guide 29 April, 2015 Turbofan Lobed Mixer Nozzle ENGINE NOISE REDUCTION

45 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 45 Pedagogical guide 29 April, 2015 Turbofan Lobed Mixer Nozzle ENGINE NOISE REDUCTION

46 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 46 Pedagogical guide 29 April, 2015 Function  Reverse the whole or part of the propelling flow in order to create an aerodynamic braking force.  This makes it possible to assist the braking of the aircraft. They improve deceleration on slippery runway. They reduce brake wear. THRUST REVERSERS

47 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 47 Pedagogical guide 29 April, 2015 Location  Generally, thrust reversers are located in the rear part of a single flow turbojet and in an intermediate position in a modern dual flow turbojet. THRUST REVERSERS Single flow turbojet Dual flow turbojet

48 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 48 Pedagogical guide 29 April, 2015 Study of the gas stream  When analysing the formula, we realize that in order to obtain an effective opposite thrust, are required: a high aircraft speed (i.e. as soon as possible after landing), a re-orientation of the ejected flow as forward as possible (manufacturers limit the angle to 45° forward to avoid engine stall and runway remains ingestion). THRUST REVERSERS

49 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 49 Pedagogical guide 29 April, 2015 Principle  Thrust reversers obey the same principle: to try and redirect the propelling flow ahead for it to hit atmospheric air head-on.  So as to avoid interferences between the air sucked by the engine and the reversed flow, the ejection angle of reversed flow is generally limited to 45°. The unfolding of thrust reversers occurs when engine idles. Engine rating increases only when the spreading out sequence is completed. The resulting reversed thrust is about 40% of takeoff thrust (full power). THRUST REVERSERS

50 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 50 Pedagogical guide 29 April, 2015 Various types  Eyelid (shell) type thrust reversers. THRUST REVERSERS

51 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 51 Pedagogical guide 29 April, 2015 Various types  Cascade type thrust reversers. THRUST REVERSERS

52 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 52 Pedagogical guide 29 April, 2015 Various types  Petal (prop-fan) type thrust reversers. THRUST REVERSERS

53 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 53 Pedagogical guide 29 April, 2015 Turbo-propellers  The thrust reversing on a turbo-propeller is carried out by inverting the pitch of the propeller. This is done thanks to the propeller governor: -when thrust reversing is engaged, it swivels each blade ; -when engine power increase, a thrust force opposite to the direction of aircraft motion is created. THRUST REVERSERS

54 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 54 Pedagogical guide 29 April, 2015 Reversers spreading out  As soon as levers are switched: The reverse system opens, driven by jacks, Indicators describing the system unlocked state light up (amber warning lights): [REV UNLK]. Indicators describing the system opened state light up (green lights) : [REV ] Amber lights [ REV UNLK ] go out Reverse thrust levers are then free of movement. Reverse thrust can be increased by pulling the reverse levers backwards THRUST REVERSERS

55 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 55 Pedagogical guide 29 April, 2015 Thrust reverse lever and indicators THRUST REVERSERS

56 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 56 Pedagogical guide 29 April, 2015 Interfaces  The thrust reverse assembly on an aircraft equipped with turbojet is often connected to the brake system. Thus the aerodynamic brake system, called " Ground Spoilers " function (which acts on the automatic deployment of slowing down surfaces on the ground) can be activated as soon as the reverse lever has its deployment position unlocked, For that purpose it is necessary of course that all the usual operation conditions of such a system should be met (aircraft on ground, throttle control levers in idling position,...).  The thrust reverser assembly on an aircraft equipped with turbojet is often connected to the anti-stall control system. The VBV position can be affected by the use of the thrust reverse assembly. Thus the theoretical opening surface of the valves can be increased up to reaching a fixed value when reversers are used THRUST REVERSERS

57 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 57 Pedagogical guide 29 April, 2015 V.B.V. THRUST REVERSERS

58 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 58 Pedagogical guide 29 April, 2015 Maintenance  The forces actuating thrust reversers are very significant in order to ensure the correct operation in spite of the aerodynamic and mechanical stresses.  The greatest precaution is required when inspecting or repairing this system. It is important for the system to be deactivated when work is to be done on it, so as to prevent any risk of accident. It may also be deactivated and set in locked position in order to allow the departure of an aircraft: thrust reversers would be inoperative : THRUST REVERSERS

59 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 59 Pedagogical guide 29 April, 2015 Maintenance THRUST REVERSERS

60 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 60 Pedagogical guide 29 April, 2015 Maintenance THRUST REVERSERS

61 PART- 66 COURSEWARE MODULE 15 GAS TURBINE ENGINE B1 category Lesson 07 EXHAUST Table of contents Study and Operation 61 Pedagogical guide 29 April, 2015 Maintenance THRUST REVERSERS


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