FR2662783A1 - VARIABLE GEOMETRY AND SELF-ACTUATING SWIRLING DEVICE. - Google Patents

Abstract

The present invention relates to a variable geometry swirl device (60) that includes a variable geometry, self-actuating vane system for initially mixing fuel and air. The swirl device (60) has a plurality of swirl vanes (84) made of a temperature sensitive material, these vanes being movable between open and closed positions as a function of temperature when the swirl vanes (84) are subjected to heat.

Description

The present invention relates generally to

  combustion of gas turbine engines

  and more particularly a whirlpool device

  variable geometry which allows air and fuel to be mixed in these combustion systems. Many combustion devices located inside gas turbine engines use flow modifiers such as swirl chambers to mix fuel and air and to assist in the distribution of the mixture.

  resulting inside the combustion device.

  Air which is in vortex flow increases the tendency of the fuel to atomize, so that the mixture is better and therefore the combustion of the mixture in the combustion device

  is performed at a better yield.

  The swirl device can typically-

  understand a swirl cup which

  is placed around a fuel nozzle inside

  laughing of a dome at the upstream end of a

  hollowed out shirt which forms the combustion device.

  The swirl cup has a plurality of radial or axial swirl vanes or

  consisting of a hybrid combination of radiant vanes

  and axial, these vortex vanes being

  placed inside the swirl cup-

  upstream of the fuel outlet plane The swirl vanes provide a highly turbulent flow which generates rapid atomization and mixing of fuel and air These chambers

  of swirling classically present a geomen-

  fixed sort That is to say that the quantity and the direction of discharge or swirl angle of the air which comes from the swirl device is relatively constant having regard to the quantity of fuel which is injected inside the device

combustion.

  These swirling chambers with fixed geometry cannot, however, ensure stable operation and high efficiency over a wide range of conditions of temperature increase, which is

  required in perfected gas turbine engines

  Conventional tioned At lower power conditions, weak air flows in the dome of the combustion device are necessary for a

  good combustion stability In addition, the conditions

  start-up (i.e. when the engine is started

  fuel) and idling require fuel-

  relatively rich air and low air velocities in the dome of the combustion device to obtain

  stable operation Furthermore, under conditions

  high power, when the outlet temperature of the combustion device approaches high values, the combustion device requires high air flow and high velocities in the dome of the combustion device to provide high combustion efficiency , little smoke

  important as well as a weak generation of N Ox.

  This problem can be solved by using variable geometry vortex chambers in which fuel and air are initially mixed Variable geometry vortex chambers have been used successfully to provide the desired stoichiometry for the dome of the combustion device on a wide range of conditions

  temperature increase The vortex chambers

  Variable geometry generally includes a swirl cup with externally actuated vane vane systems Vortex vane systems

  externally actuated whirlpool chambers

  However, variable geometry requires a very complex arrangement of rotation shafts, large connecting rings and levers to mechanically move the swirl vanes and to vary the air flow in the swirl cup. mechanically result in additional weights and

  affect the reliability of the combustion system.

  Therefore, an essential object of this

  invention is to provide a whirlpool device

  variable geometry that does not require a

  externally operated system.

  Another object of the present invention is to provide a geometry swirl device

  variable which does not require a mechanically operated system

nically complex.

  Yet another object of the present invention is to provide a variable geometry swirl device which has as few elements as possible for reduced cost and reduced engine weight. Yet another object of the present invention

  is to provide a self-powered system

  which eliminates certain necessities or certain

engine control mechanisms.

  The objects briefly mentioned above are achieved by means of the particular embodiment of the present invention in which a single variable geometry swirl device is provided with a self-actuating variable geometry system for

  initially mix fuel and air More

  specifically, the geometrical whirlpool device

  variable sort includes a plurality of turn blades

  ridging made of a temperature-sensitive material which is liable to move between open and closed positions depending on the temperature when the swirl vanes are

subjected to heat.

  According to a particular embodiment of the

  present invention, a lathe device is provided.

  ridging to surround a nozzle

  burant in a combustion engine engine

  gas turbine, this whirling device

  taking: a means which forms a vortex cup-

  This cup having an upstream end which surrounds the fuel nozzle and extending axially up to a downstream end to define an annular flow path between the cup and the

  nozzle; anda self-swirling vane means

  actuation which is placed in said flow path-

  to generate a vortex air flow

  at the downstream end of the flow path.

  According to another particular embodiment of the present invention, a swirl device is provided making it possible to surround a fuel nozzle in a combustion device of an engine

  gas turbine, this swirl device comprises

  taking: a Venturi cone which surrounds the fuel nozzle; a swirl cup which partially surrounds said Venturi cone and which cooperates with to define an annular flow path therebetween; a plurality of swirl vanes which are placed in said flow path and which are designed to swirl air passing through said flow path; and temperature sensitive means which allows said swirl vanes to be moved between open and closed positions as a function of temperature when said vanes

  swirl are subjected to heat.

  According to another particular embodiment of the present invention, a swirl device is provided making it possible to surround a fuel nozzle in a combustion device of an engine

  gas turbine, this swirl device comprises

  taking: a Venturi cone which has an extremi-

  upstream tee which surrounds the fuel nozzle and which extends axially to a downstream end, said

  Venturi cone comprising an annular disc extending

  radially; a swirl cup which surrounds said Venturi cone and which comprises a

  radially extending collar which is axially spaced

  lement of said annular disc and which cooperates with to define an annular flow path between the cone

  and the cup; a plurality of vortex vanes-

  which are positioned between said annular disc

  laire and said radial flange and which are designed to swirl air passing through said

  flow path; a first axis which extends axially-

  between said annular disc and said flange

  radial; and said swirling vanes

  dials which have a first end which is fixed to said first axis and a second movable end, said radial swirl vanes being made of a bimetallic material which moves said second end between open and closed positions according to a temperature which is situated in a range between 204 C and 316 C respectively when said swirl vanes

  radials are subjected to heat.

  Therefore, the present invention does not require

  site no externally operated systems for

  the variable geometry swirl device.

  As a result, the present invention eliminates the

  need for external connection rings,

  control systems usually found in a complex mechanically actuated system Furthermore, the present invention requires few components, which reduces the weight and mechanical complexity of the engine and which leads to a less engine. expensive Furthermore, the present invention provides an automatically operated system, which eliminates

  engine control equipment or mechanisms.

  Other objects, features and advantages of the present invention will be readily appreciated by those skilled in the art when the present invention is

  better understood with reference to the following description that

  we will read in relation to the appended figures among which: FIG. 1 is a cross-sectional view of a gas turbine engine;

  Figure 2 is an enlarged view of the part in

  circled in Figure 1 which shows a combustion device; and Figure 3 is a partial view taken along the

  line 3-3 of figure 2 and it represents the dispo-

  self-variable swirling sitive

  actuated according to the present invention.

  If we refer to the figures in which identical reference indexes correspond to

  similar elements, attention is firstly diri-

  gée vers Figure 1 In Figure 1 is shown a conventional gas turbine engine 10 such as a gas turbine engine with double flow reactor (commonly called turbofan) The gas turbine engine 10 has an external frame or nacelle 12 whose upstream end forms an entrance generally indicated at 14 which is

  dimensioned to ensure a predefined air flow

  finished Inside entrance 14 is a blower (commonly called a fan) which is indicated

  generally at 16 Fan 16 pressurizes the flow

  air coming from the inlet 14 Downstream of the fan 16 is a motor core indicated so

  general in 18 The engine core 18 includes a

  axial flow presser indicated generally in 20 Pressurized air which comes from the fan 16 enters the motor core 18 and is then compressed by the compressor 20 then discharged into a combustion device indicated generally in 22 the combustion device 22, fuel is burned to supply high energy combustion gases which drive a motor core turbine indicated generally at 24 The motor core turbine 24

  in turn drives compressor 20 through

  diary of a shaft 26, this drive being carried out in a usual manner for a gas turbine engine Hot combustion gases can then reach a fan turbine indicated in general at 28 and drive it, this fan turbine in turn driving the fan 16 via a shaft 30, this drive being carried out in a known manner for a gas turbine engine A

  more detailed description of the gas turbine engine 10

  is presented either in the patent of the United States of America

  No. 3,879,941, or in U.S. Patent No. 4,080,785, these two patents being due to

  the same plaintiff as that of the present invention

tion.

  In Figure 2 is shown an enlarged view

  of the combustion device 22 The combustion device

  bustion 22 is preferably a combustion device

  annular tion which has multiple nozzles

  fuel which are arranged circumferentially-

  inside the annular combustion device

  It should however be noted that the combustion device 22 can be an annular arrangement of the

  combustion device in which multiple

  positive combustion are arranged circumferentially around the gas turbine engine 10. The combustion device 22 includes a hollow jacket 32 which defines a combustion chamber 34 inside The hollow jacket 32 has a longitudinal upstream dome 36 which body with as it is

  of course for those skilled in the art, the

  bustion 34 can be of the annular type or of the tubular type

  laire. The combustion device 22 also comprises an external chassis 38 and an internal chassis 40 which surround the hollowed-out jacket 32 and which, in cooperation with the hollowed-out jacket 32, define respective external and internal passages 42 and 44 As is understood for the skilled in the art, passages 42 and 44 are designed to deliver part of the pressurized air which comes from an appropriate source such as the compressor 20 inside the

  combustion 34 via appropriate openings

  prayers 46 made in the hollowed-out folder 32.

  Pressurized air is delivered from the compressor.

  outlet 20 through a stepped diffuser 50 at the level of which the air is divided between the external and internal passages 42 and 44, part of the air flow passing through an opening 52 formed by an element beak shape 54 which is positioned upstream of the dome 36 and which cooperates with it to form an annular chamber 56 The beak-shaped element 54 can be integral with the dome 36 or can be fixed to it and can be fixed to the external frame 38 by means such as bolts 58 The air flow from the annular chamber 56 enters a swirl device indicated generally at 60 The pressurized air which is conveyed to the passages 42 and 44 cools the jacket hollowed out 32 and circulates through openings 46 to dilute the gaseous combustion products, as is well known to those skilled in the art. An igniter 61 engages by screwing in the

  external frame 38 and extends inside the chamber

  combustion bre 34, near the downstream end of the swirl device 60, to ignite the

  fuel-air mixture as is well known to man

me of art.

  The fuel required for combustion is

  powered from a fuel source (not shown

  tee) and is routed to a hollow fuel tube 62 which is connected to the outer frame 38 by means of a mounting bracket 64 The mounting bracket 64 is fixed to the outer frame 38 by means such as bolts 66 Le fuel tube 62 is curved to fit inside the opening 52 of the spout-shaped member 54 A fuel nozzle 68 is placed at the end of the fuel tube

  62, inside the annular chamber 56.

  The swirl device 60 is placed around the fuel nozzle 68, surrounds it and is connected to the dome 36 The swirl device

  60 has a general swirl cup-

  cylindrical 70 which can be integrated with the dome

  36 or which can be attached to it The vortex cup-

  lonnement 70 is surrounded by a flared trumpet-shaped outlet 72 which is located at

  the downstream end which extends inside the chamber

  combustion bre 34 The swirl cup has an annular flange extending radially 73 at the upstream end A venturi cone 74 is placed partially inside the swirl cup 70 and is placed around

  from the end of the fuel nozzle 68 or the

  toure The Venturi cone 74 has an annular disc 76 which can be integrated with the cup

  swirl 70 or which can be fixed to it The dis-

  that annular 76 is spaced axially from the radial flange 73 so as to define a fluid passage through which air enters from a generally radial direction, as indicated by arrows, to form a secondary flow which must be mixed with fuel coming out of the Venturi cone

  74 The Venturi cone 74 has a general element

  L-shaped annular element 78 which extends between the fuel nozzle 68 and the annular disc 76 and which can form a body with the annular disc 76 or which can be fixed to it The swirl device 60 can also include a plurality of conduits fluid or openings 80 formed in the L-shaped member 78 through which air enters from a generally radial and axial direction, as indicated by arrows, inside the Venturi cone 74 to form a flow primary which must

  be mixed with fuel in the Venturi 74 cone.

  If we refer to Figures 2 and 3, the provision

  swirl sitive 60 has a plurality of swirl vanes 84 which are self-actuated

  to form a geometrical whirling device

  self-actuating variable sorting according to the present invention The swirl vanes 84 extend

  radially and are arranged circumferentially-

  inside the swirl device

  60, between the radial flange 73 and the annular disc

  laire 76 It should be noted that the whirlpool device

  ment 60 may have a different geometry so that the swirl vanes 84 may be blades which extend axially or blades which extend in a hybrid direction

radial and axial.

  il The swirl blades 84 have a first end 86 which is fixed around a first axis 88 which extends axially between the radial flange 73 and the annular disc 76 The swirl blades 84 have a second end 90 whose stroke is limited by stops such as second and third respective axes 92 and 93 which extend axially from either the radial flange 73 or the annular disc 76 As shown in FIG. 3, the second axis 92 limits the travel of the

  blades and precisely positions the vortex blade

  lonnement 84 according to the fully open position, as shown in solid lines The third axis 93 limits the stroke of the blades and precisely positions the swirl vane 84 according to the position of

  total closure shown in dotted lines.

  The swirl vane 84 is made in one

  bimetallic material which is sensitive to temperature

  ture The swirl vane 84 may comprise a first sheet of ribbon 94 made of a first material and a second sheet of tape 96 made of a second material, this second sheet of tape being fixed to the first sheet of tape 94 or forming a body with The second strip sheet 96 is temperature sensitive to move the first strip sheet 94

  depending on the temperature when heated.

  In the particular embodiment, the swirl vanes 84 deflect from the closed position counterclockwise when the temperature of the inlet air flow increases, which has the effect of increasing the measurement spaces as well as the air flow of the swirl device A special range for the change of state of the swirl blades 84 is between 2040 C (4000 F blades closed) and 316 C (600 F blades open) It should be noted that a sheet

  bimetallic tape could be used to ac-

  operate a lever that would move the vortex blades

  84 or that a material of the type "alloy with

  temperature sensitive memory could be useful

  to activate the swirl vanes 84.

  During operation, an air flow pres-

  surise which comes from the compressor 20 penetrates through the opening 52 inside the annular chamber 56 The air flow which comes from the annular chamber 56 flows through the conduits to

  fluid 80 and the Venturi cone 74 to form a flow

  The primary flow of air from the annular chamber 56 penetrates through the passages between the annular disc 76 and the radial flange 73 The swirl vanes 84 impart a swirl movement or vortex movement to the air which flows through the passage to form a secondary flow When fuel leaves the fuel nozzle 68, it is mixed with the air in the

  swirl device 60 and the resulting mixture

  as long as it enters combustion chamber 34 to be burnt therein The swirling movement or vortex movement of the air flow mixes the air with the fuel which comes from the fuel nozzle 68 inside the cone of Venturi 74, which causes the atomization of the

  fuel and therefore provides a better mixture.

  Therefore, the swirl vanes 84

  are self-actuated to move between positions

  open and closed in response to the expansion and contraction of the bimetallic material or ribbon sheet which constitutes the vortex vane 84 The variable geometry of the vortex vanes 84 which results from the movement or actuation of these vanes provides a positive control of the stoichiometry of the

  dome of the combustion device Since all mechanis-

  operated externally is eliminated for them

  swirl vanes 84, vortex vanes

  lonnement 84 constitute a simple, reliable and

  low weight Because the vortex vanes-

  84 are self-actuated, an automatically operated system for swirl vanes 84 is provided, eliminating the need for control

of the motor.

  The present invention has been described by means

  of illustrations It is understood that the termino-

  logy which was used intends to reflect the nature of

  terms used in the description and does not mean

  constitute a limitation of the description.

  Many modifications and variations of the present invention are possible in light of the

  lessons mentioned above It is therefore

  of course the present invention can be

  implemented otherwise than in the specified manner

  as described above provided that we remain in the

part of the present invention.

Claims (11)

  1 Whirling device for surrounding a fuel nozzle (68) in a combustion device (22) of a turbine engine   gas (10), this swirling device being characterized in that it includes:   a means which forms a vortex cup-   nement (70), this cup having one end   upstream which surrounds the fuel nozzle (68) and extends   extending axially to a downstream end to define an annular flow path between the cup and the nozzle; and   a self-swirling vane means   actuation which is placed in said flow path   also to generate a vortex air flow   at the downstream end of the flow path.   2 swirl device according to claim 1, characterized in that said means   self-actuating blade includes a plurality of   swirl bes (84) which include a pre-   first fixed end (86) and a second end mobile (90).   3 swirl device according to claim 2, characterized in that said plurality of swirl blades (84) are made of a temperature sensitive material which is designed to move said second end (90) between   first and second positions depending on the temperature   erasures when said plurality of vortex blades   The reason (84) is subjected to heat.   4 swirl device according to claim 3, characterized in that it comprises means (92, 93) which makes it possible to limit the stroke of said second end (90).   5 Swirl device allowing   to surround a fuel nozzle (68) in a dispo-   combustion sitive (22) of a gas turbine engine   (10), this swirling device being characterized   laughed in that it comprises: a Venturi cone (74) which surrounds the fuel nozzle (68); a swirl cup (70) which partially surrounds said venturi cone (74) and which cooperates with to define an annular flow path therebetween; a plurality of swirl vanes (84) which are placed in said flow path and which are designed to swirl air passing through said flow path; and temperature sensitive means (94, 96) which allows said swirl vanes (84) to be moved between open and closed positions in accordance   of the temperature when said vortex vanes-   (84) are subjected to heat.   6 swirl device according to claim 5, characterized in that said swirl vanes (84) and said temperature sensitive means (94, 96) define a sheet of bimetallic strip. 7 swirl device according to claim 5, characterized in that said temperature-sensitive means (94, 96) comprises at least one sheet metal strip (96) made of a material sensitive to heat to effect a displacement in function of the temperature.   8 swirl device according to claim 7, characterized in that said strip sheet (96) moves between open positions and   closed when the temperature is in an oven-   chette between 204 C and 316 C respectively. 9 swirl device according to claim 8, characterized in that said strip sheet (96) has a first fixed end (86) and   a second movable end (90).   10 swirl device according to claim 9, characterized in that it comprises means (92, 93) which makes it possible to limit the travel of said second end (90).   11 Swirl device allowing   to surround a fuel nozzle (68) in a dispo-   combustion sitive (22) of a gas turbine engine   (10), this swirling device being characterized laughed at in that it includes:   a Venturi cone (74) which has an end   upstream mite which surrounds the fuel nozzle (68) and which extends axially to a downstream end,   said Venturi cone (74) comprising an annular disc   the radially extending strip (76);   a swirl cup (70) which   rotates said Venturi cone (74) and which has a radially extending flange (73) which is axially spaced from said annular disc (76) and which cooperates with to define an annular flow path between the cone and the cup; a plurality of swirl vanes (84) which are positioned between said annular disc (76) and said radial flange (73) and which are designed to swirl air passing through said flow path; a first axis (88) which extends axially between said annular disc (76) and said radial flange (73); and said radial swirl vanes (84) which have a first end (86) which is fixed to said first axis (88) and a second end   movable (90), said swirl vanes   dials (84) being made of a bimetallic material which displaces said second end (90) between   open and closed positions depending on a temperature   ture which is within a range included respec-   tively between 204 C and 316 C when said radial swirl vanes (84) are subjected to heat.