Variable area vectorable nozzle

The present invention relates to improvements in Patent 9401114, relating to improvements in axisymmetric nozzles of variable geometry and orientation of the flow, which are intended for gas turbine engines.

Axisymmetric nozzles of variable geometry are known which are capable of realizing three functions, namely: regulating the throat area A₈ in accordance with a given law; symmetrically varying the exit area A₉ with respect to an immobilized throat area; and vectoring the thrust in 360°.

The axisymmetric nozzle which is the object of Patent 9401114 has, as new feature over the previously known nozzles, the ability to effect a fourth function, namely axisymmetrically to correct the exit area during the vectoring. The nozzle comprises a convergent zone which defines a throat of variable area and is formed by convergent master petals and by convergent slave petals resting on the adjacent convergent master petals, followed in the direction of the flow of gas by a divergent zone formed of divergent master petals and of divergent slave petals resting on the adjacent divergent master petals and connected to said adjacent divergent master petals by a centering mechanism, the petals of said convergent and divergent zones being distributed circumferentially around the longitudinal axis of the engine, and every convergent master petal being connected to its divergent master petal by a tangential cylindrical articulation with axis perpendicular to the longitudinal axis of the engine; and each petal of the divergent zone being divided into two segments, the upstream segment and the downstream segment, attached to each other by cylindrical articulations having an axis perpendicular to said tangential cylindrical articulation between convergent master petal and divergent master petal; and it also comprises control means for adjusting the throat area and vectoring the thrust which comprise an inner ring, another intermediate ring, and an outer ring, which rings are concentric to each other and to the longitudinal axis of the engine, and of a plurality of linear actuators, each with its upstream end and its downstream end, and of a mechanism for regulating the throat area, the convergent master petals being attached to the inner ring by tangential cylindrical articulations having axes perpendicular to the longitudinal axis of the engine; and all the linear actuators being connected articulately at their upstream ends to a fixed structure of the engine, as well as the fact that one part of the linear actuators have their downstream end attached to spherical articulations of the outer ring and the other part of said linear actuators have their downstream end connected to spherical articulations of the intermediate ring; and each of said rings being connected independently to the fixed structure of the engine by support means which does not interconnect them and maintains each ring fixed laterally; and it also comprises a set of biarticulated bars, one for each divergent master petal, which interconnect the downstream segments of the divergent master petals with the outer ring; the vectoring, in 360 degrees, of the thrust in the divergent zone being obtained by the inclination of the outer ring with a center of swing located on the longitudinal axis of the engine through the set of biarticulated bars; with the feature that the outer ring includes two outer ring segments which are biarticulated to each other by a pair of cylindrical articulations which make it possible to vary symmetrically, by a simultaneous, oppositely directed swinging of the two outer ring segments, the exit area with respect to an immobilized throat area and, during the vectoring of the flow of gas, by an independent swinging of one of the two outer ring segments, to correct the exit area asymmetrically while the other outer ring segment remains immobilized.

Among the advantages of an axisymmetric nozzle of variable geometry and orientation of flow having the new outer ring configuration, the following may be mentioned: <ul id="ul0001" list-style="none"><li>1. By the fact alone of being able to vector the divergent petals by individual groups, there can be avoided the separations of the inner stream of the flow which take place with large angles of average orientation of the flow and low pressure conditions, which are typical of any landing. In order to avoid said separation, there is obtained a better coefficient of thrust without loss of effectiveness of the orientation of the flow, since the energy dissipated upon generating the recirculation is utilized in thrust. Furthermore, the processes of separation of fluid streams always result in inherent instabilities of not very high frequency which, in a limit case, could be coupled with the frequency itself of the system. </li><li>2. If the geometrical vectoring of part of the petals is smaller, the area of oriented flow which the stream outside the plane sees is less; so that the separations of said outer stream associated with the orientation of the flow are of less intensity; therefore, the instabilities of such stream decrease, including the overall drag of the airplane.</li><li>3. In the approach for landing, the vectoring of the exit area A9 of the nozzle is downward. Upon decrease of the vectoring of the petals closest to the ground there is a greater distance to it in the rear part of the plane for the same angle of attack; this makes it possible to land with a larger angle of attack and therefore with greater lift or, its equivalent, with less speed.</li></ul>

In said Spanish Patent No. 9401114, two embodiments of the four-function nozzle described are described and claimed.

In the first of the embodiments, called a single control system, the inner and intermediate rings and the interarticulated outer ring segments are interconnected by two pairs of cylindrical articulation bolts, one pair perpendicular to the other pair, and one of the pairs of cylindrical articulation bolts connects the intermediate ring to the inner ring, and the other pair of cylindrical articulation bolts connects the intermediate ring to the articulated ends of the outer ring segments, so as to constitute a single control system in combination with the plurality of linear actuators and the mechanism for regulating the throat area, in which the regulation of the area of the throat is obtained by an axial displacement of the assembly of rings and outer ring segments, and in which the symmetric variation of the exit area with respect to an immobilized throat area is obtained by a simultaneous swinging in opposite direction of the two outer ring segments and in which the vectoring of the thrust is obtained by a simultaneous swinging in the same direction of the two outer ring segments with the centers of swing on the longitudinal axis of the engine and in which the asymmetric correction of the exit area during the vectoring of the flow of gas is obtained by an independent swinging of one of the two outer ring segments while the other outer ring segment remains stationary.

In the second of the embodiments, corresponding to the general case known as two-control systems, the inner and the intermediate rings and the interarticulated two outer ring segments are not connected to each other and constitute, in combination with the plurality of linear actuators and the throat area regulating mechanisms, two control systems in which the regulating of the throat area is obtained by axial displacement of only the intermediate ring, and in which the symmetric variation of the exit area with respect to an immobilized throat area is obtained by a simultaneous swinging in opposite direction of the two outer ring segments, and in which the vectoring of the thrust is obtained by a simultaneous swinging in the same direction of the two outer ring segments with a single center of swing on the longitudinal axis of the engine, and in which the asymmetric correction of the exit area during the vectoring of the flow is obtained by an independent swinging of one of the two outer ring segments, while the other outer ring segment remains stationary.

In this general case, the embodiment with two control systems has the advantage, in addition to those mentioned, of a spherical configuration of the inner part of the fairing of the nozzle around the outer ring, since the two outer ring segments have a single point of swing.

The axisymmetric nozzles of variable geometry and orientation of the thrust in 360 degrees are optimum when there is concerned applying them on a gas turbine for airplanes having a single engine or a single jet. However, in the case of planes equipped with two engines or twin jets, when the two engines are very close to each other, there are generally difficulties in orienting the flow in 360 degrees. However, on the other hand, a twin jet equipped with nozzles of double symmetry or 2-D nozzles has, in theory, properties of maneuverability which are very close to those exhibited by a single jet with engine equipped with nozzle which vectors the thrust in 360 degrees. Since, although the 2-D nozzle vectors the thrust in a single plane which is the plane of pitch of the airplane, the presence of two 2-D nozzles makes it possible, after an initial maneuver of rotation of the plane about its longitudinal axis by vectoring the thrust of a single one of the nozzles or the thrusts of both nozzles simultaneously and in opposite direction, to orient the plane by vectoring the thrusts of the two nozzles simultaneously and in the same direction, in any of the directions. It is true that the 2-D nozzles have the drawback of greater weight, in addition to great difficulties in the sealing of their components.

In the present invention, there is described and claimed a nozzle which, being axisymmetric and of variable geometry and with the ability of effecting the four functions described, that is to say, similar in its entirety to the nozzle already claimed in Spanish Patent No. 9401114, represents an addition to said patent since, as sole change, it presents a vectoring ability which is limited to a single plane, the plane of pitch of the airplane, which makes it possible, so that it is suitable for engines of twin-jet planes, to simplify part of their mechanical components, specifically the intermediate ring and the outer ring segments, as well as the articulation means which connect them together and to the fixed structure.

In the general embodiment, corresponding to an axisymmetric nozzle of variable geometry and orientation of the flow, the regulation of the throat area of which and the symmetric variation of the exit area of which, and vectoring of the thrust and asymmetric correction of the exit area are effected by two independent systems of control, the pair of cylindrical articulation bolts which interconnect the articulated ends of the two outer ring segments are fixed in the stationary structure of the engine, the axis of said bolts being normal to the longitudinal axis of the engine and being in the horizontal main theoretical plane which contains said longitudinal axis of the engine. This has as advantage, in addition to a greater rigidity of the assembly of outer ring segments by presenting a single degree of freedom as compared with the floating or flexible connection of the outer ring on the axisymmetric nozzles covered by US Patent No. 336,369 and Spanish Patent No. 9,200,369, a smaller number of linear control actuators for the vectoring of the thrust, since at least two of the linear actuators which are necessary for vectoring the thrust in 360 degrees disappear.

All of the characteristics set forth as well as other characteristics of the invention, as contained in the claims, will be understood better from the following description given with reference to the accompanying drawing, in which there are shown three possible embodiments, given by way of illustration, two for the general case of the axisymmetric nozzle of variable geometry with orientation of the flow having two control systems, one for regulating the throat area A8 and the other for symmetrically varying the exit area with respect to an immobilized throat area, vectoring the thrust and asymmetrically correcting the exit area during the vectoring of the thrust, which has: an inner ring which, being the bearer of the upstream ends of each convergent petal, is rigidly attached to the fixed structure of the engine; an intermediate ring moved axially by the actuators of a first control system for regulation of the throat area A8; and an outer ring, formed by two outer ring segments the ends of which are interconnected articulately by two cylindrical articulation bolts, bearing the upstream ends of the biarticulated bars which support the downstream segments of the divergent master petals and swung by the actuators of a second control system to vector the thrust, symmetrically vary the exit area A9, and correct said exit area asymmetrically and which, in addition to the features set forth in Spanish Patent No. 9,401,114, has the novelty of having said cylindrical articulation bolts fixed in the stationary structure of the engine. A third possible embodiment for the special case of an axisymmetric nozzle of variable geometry with orientation of the flow having a single control system for regulating the throat area A8, symmetrically varying the exit area, vectoring the flow and correcting the exit area, which has a single ring, bearing the upstream ends of each convergent petal, and an outer ring bearing the upstream ends of the biarticulated bars which support the downstream segments of the divergent master petals formed by two outer ring segments the ends of which are interconnected articulately by two cylindrical articulation bolts fixed in said inner ring in order, together with the linear actuators and the regulating mechanism of the throat area A8, to constitute a single control system which, by moving axially, regulates the throat area A8 and by swinging the outer ring segments symmetrically varies the exit area, vectors the flow, and corrects the exit area.

In the drawings:

Figure 1 is a perspective view, partially in section, of an axisymmetric nozzle of variable geometry and orientation of flow, formed by two systems of control and perimetral mechanism for regulation of the throat area A8, formed in accordance with the description given.

Figure 2 is a longitudinal half section, in the horizontal main longitudinal plane of the nozzle, with two control systems, which is shown in Figures 1 to 10, the nozzle in this Figure 2 being in the closed-throat position, without variation and correction of the exit area, and without vectoring of the thrust.

Figure 3 is a longitudinal half section in the vertical main longitudinal plane of this first nozzle with two control systems which is shown in Figures 1 to 10, the nozzle being in the same position in this Figure 3 as shown in Figure 2.

Figure 4 is a longitudinal half section, in a plane which forms an angle of 45 degrees with respect to the horizontal main longitudinal plane, of this first nozzle with two control systems which is shown in Figures 1 to 10, the nozzle being in the same position in this Figure 4 as shown in Figure 2.

Figure 5 is a cross section through this first nozzle with two control systems and perimetral mechanism, along the section line B-B of Figure 6, in order to show the connections between the different rings and ring segments which, together with the linear actuators, form the two control systems.

Figure 6 corresponds to the longitudinal section of this first nozzle with two control systems and perimetral mechanism, in its vertical main longitudinal plane, along the section line B-B of Figure 5, in closed-throat position, the exit area varied symmetrically and without vectoring of the thrust. The arrows indicate the direction of the swinging of the two outer ring segments.

Figure 7 shows the same longitudinal section through this first nozzle with two systems of control and perimetral mechanism, in position of closed-throat area and vectoring the thrust.

Figure 8 corresponds to the same longitudinal section of this first nozzle with two control systems and perimetral mechanism, in closed-throat position, vectoring the thrust and the exit area asymmetrically corrected. The arrow indicates the direction of the swinging movement of the lower outer ring segment in order to correct the excessive angle of the lower divergent petals.

Figures 9 corresponds to the same longitudinal section of this first nozzle with two control systems and perimetral mechanism, but in position of open throat area and the exit area varied symmetrically.

Figure 10 corresponds to the same longitudinal section of this first nozzle with two control systems, in position of open throat area, vectoring the flow of gas and without symmetrically varying the throat area or correcting it asymmetrically.

Figure 11 shows the perimetral mechanism for regulating the area of the throat A8.

Figure 12 is a perspective view, partially in section, of an axisymmetric nozzle of variable geometry and orientation of the flow, formed with a single control system, both in order to regulate the area of the throat A8 and to vary asymmetrically the exit area, orient the flow, and asymmetrically correct the exit area, the control system of which includes the perimetral mechanism for regulating the area of the throat A8 set forth in Spanish Patent No. 9,401,114.

Figure 13 is a longitudinal half section in the horizontal main longitudinal plane of this second nozzle with a single control system and perimetral mechanism, shown in Figures 12 to 18, it being in this figure in closed-throat position, exit area without variation or correction and without vectoring the thrust.

Figure 14 is a longitudinal half section in the vertical main longitudinal plane of this second nozzle with a single control system and perimetral mechanism, shown in Figures 12 to 18, the nozzle in this Figure 14 being in the same position as shown in Figure 13.

Figure 15 is a longitudinal half section in the horizontal main longitudinal plane of this second nozzle, with a single control system and perimetral mechanism, shown in Figures 12 to 18, the nozzle being with open throat, exit area without variation or correction and without vectoring of the thrust.

Figure 16 is a cross section through this second nozzle with a single control system and perimetral mechanism, along the section line B-B of Figure 17, in order to show the connections between the inner ring and the two outer ring segments which, together with the linear actuators, form the single control system.

Figure 17 corresponds to the longitudinal section of this second nozzle with a single control system and perimetral mechanism, in its vertical main longitudinal plane along the section line B-B of Figure 16, the nozzle being in the position of closed throat, vectoring of the thrust and exit area without variation or correction. The arrows indicate the directions of the swinging movement of each one of the two outer ring segments.

Figure 18 corresponds to the same longitudinal section of this second nozzle with a single control system and perimetral mechanism, in position of open-throat area, vectoring of the thrust and exit area without variation or correction.

Figure 19 is a longitudinal half section, in the horizontal main longitudinal plane of another embodiment of the nozzle with two independent control systems, one to regulate the throat area A8 and the other to symmetrically vary the exit area with respect to an immobilized throat area and to vector the flow of gas and asymmetrically correct said exit area, a conventional cam and roller mechanism, known in the prior art, forming part of the system for regulating the area of the throat. In this specific case of the third embodiment, Figure 5 also represents the cross section through this nozzle with two control systems.

Figure 20 is a longitudinal half section in the vertical main longitudinal plane of this third nozzle with two control systems and cam and roller regulating mechanism, the nozzle being in open-throat position without vectoring of the thrust and exit area without variation or correction.

Figure 21 is a longitudinal half section in a longitudinal plane which forms an angle of 45 degrees with the horizontal main longitudinal plane of this third nozzle with two control systems and cam and roller regulating mechanism, the nozzle being in open-throat position, without vectoring of the thrust, and exit area without variation or correction.

Figure 22 corresponds to the longitudinal section of this third nozzle with two control systems and cam and roller mechanism, in its vertical main longitudinal plane along the section line B-B of Figure 5, in position of closed throat area, the exit area varied symmetrically and without vectoring the thrust or correcting the exit area. The arrows indicate the direction of swing of the two outer ring segments.

Figure 23 corresponds to the same longitudinal section of this third nozzle of two control systems and cam and roller mechanism in closed-throat position, vectoring the thrust, and exit area without variation or correction.

Figure 24 corresponds to the same longitudinal section through this third nozzle with two control systems, cam and roller mechanism, in closed-throat position, without symmetrically varying the exit area, vectoring the thrust, and exit corrected asymmetrically. The arrow indicates the direction of swing of the lower ring segment for correcting said exit area.

Figure 25 corresponds to the same longitudinal section of this third nozzle of two control systems, cam and roller mechanism, in open-throat position, vectoring the thrust, and exit area without variation or correction.

Figures 1 to 11 show the first nozzle formed with two independent control systems, one for regulating the throat area A8 and the other for symmetrically varying the exit area with respect to an immobilized throat area and for vectoring the flow of gas and asymmetrically correcting said exit area, a perimetral mechanism such as is disclosed in Spanish Patent No. 9,401,114 forming part of the system for regulating the throat area.

Figures 12 to 18 correspond to the second nozzle formed with a single control system for regulating the throat area A8, symmetrically varying the exit area A9, vectoring the thrust and asymmetrically correcting the exit area, the same perimetral mechanism as shown in Figure 11 forming part of the single control system for regulating the throat area A8.

Figures 19 to 25 correspond to the third nozzle in accordance with a second embodiment with two independent control systems, one to regulate the throat area A8 and the other symmetrically to vary the exit area A9, vector the thrust and asymmetrically correct the exit area, a cam and roller mechanism forming part of the system for regulating the throat area A8.

Figure 1 is a diagrammatic perspective view, partially in section, of one of the nozzles forming the object of the description, the direction of flow or circulation of the gases being indicated by the arrow. In the same way as the traditional variable-geometry axisymmetric nozzles, the one shown in Figure 1 includes a rear carcass indicated by the numeral 1 which constitutes the final end of the fixed structure of the engine, a convergent zone bearing the reference numeral 2 and a divergent zone bearing the reference numeral 3. The convergent zone 2 is formed by a plurality of master petals 4 and slave petals 33. In the same way, the divergent zone 3 is formed by master petals 5 and the slave petals bearing the reference numeral 34 and is divided into two parts: 3a designates non-vectorable and 3b designates vectorable. The nozzle also includes a control system for regulating the throat area A8, indicated by the reference numeral 12 in Figures 12 and 13, and defined by the intersection between the convergent master petals 4 and the divergent master petals 5, and another independent control system for orientation of the flow, symmetric variation of the exit area A9, indicated by the reference numeral 13 in Figures 2 to 13, and asymmetric correction of said exit area.

The asymmetric variation of the exit area A9, the orientation of the flow and the asymmetric correction of said exit area are produced by a control system which is formed, in combination, by two biarticulated outer ring segments 6a and 6b which together form the outer ring 6, concentric to the longitudinal axis 14 of the engine, and by a set of linear actuators 9b which are articulated at their upstream end to the fixed structure of the engine 1.

The system for regulating the throat A8 is formed, in combination, of a ring referred to as the inner ring which is concentric to a longitudinal axis of the engine and indicated by the reference numeral 8 which, being connected rigidly to the fixed structure 1 of the engine, bears at its downstream end the cylindrical joints 10 which connect articulately to the upstream ends of the convergent master petals 4, and of another ring, referred to as the intermediate ring and bearing the reference numeral 7, which bears on its downstream side a perimetral mechanism, shown in Figure 11, which connects said intermediate ring 7 to each of the convergent master petals 4, and of a second set of linear actuators 9a which are articulated at their upstream end to the fixed structure of the engine 1 and, at their downstream end, are articulately connected by spherical articulations 11, Figures 4 and 21, to the upstream side of said intermediate ring 7.

The two outer ring segments are interconnected, at their articulated ends, by cylindrical articulation bolts, Figures 2, 5 and 13, fixed in the fixed structure 1 itself of the engine, to which the inner ring 8 is rigidly attached. Furthermore, the outer ring segments 6a and 6b are related to the divergent master petals 5 by biarticulated bars 15 which are mounted concentrically around the axis 14 of the engine. The connection of each biarticulated bar 15 to the outer ring segments 6a and 6b is effected by the cylindrical articulation 16 and its connection to the divergent master petal 5 is effected by a cylindrical articulation 17. Both cylindrical articulations 16 and 17 are arranged in such a manner that, without orientation of the flow, they are tangent to a theoretical circumference concentric to the longitudinal axis of the engine and located in a theoretical plane perpendicular to said longitudinal axis of the engine.

On their part, the outer ring segments 6a and 6b are guided laterally by flat systems of articulated bars the components of which bear the numerals 50 to 55, together with the fixed structure 1 of the engine, Figure 1, which permit the swinging of these outer ring segments 6a and 6b around the cylindrical articulation bolts 20, each of said flat systems of articulated bars being articulately connected at its downstream end with one of the outer ring segments, while, at its upstream end, it is connected also in a pivoted manner, with the fixed structure of the engine. The guide systems described for the outer ring segments 6a and 6b have to absorb the net shear forces which appear during the orientation of the flow and those to asymmetry of the loads.

The perimetral mechanism for the regulating of the throat area A8, shown in Figure 11, is formed by each convergent master petal 4, a single connecting rod 37, a two-arm crank 38, and a peripheral bar 39, said connecting rod 37 being connected at its upstream end by means of a spherical articulation 40 to the downstream of the intermediate ring 7 and, at its downstream end, to one of the arms 41 of said crank 38 which is mounted pivotally on a pivot which, forming an integral part of said convergent master petal 4, has its axis perpendicular to the base of said convergent master petal, while the other arm 43 of said crank 38 is connected, by spherical articulation 44, to one of the ends of the peripheral bar 31, while the other end of said peripheral bar is connected by a spherical articulation to the pivot of the adjacent convergent master petal in order for the assembly of cranks 38 and peripheral bars 39 of all the convergent master petals 4 to form a peripheral system which is closed on itself.

The arrangement described, shown in the figures, permits, by activation in one direction or the other of the control actuators 9, the following functions which have already been mentioned: <ul id="ul0002" list-style="none"><li>1. Axial movement of the intermediate ring 7, together with the biarticulated bars 15, and the convergent and divergent petals, in order to regulate the throat area A8, referenced by the numeral 12. Said axial movement of the intermediate ring causes an angular displacement of the convergent master petals 4 through the perimetral mechanism for the regulation of the area of the throat A8 around the articulation 10. Said convergent master petals 4, due to the connecting rod 37, the two-arm crank 38, and the peripheral bar 39 open or close in radial direction, defining, together with the biarticulated bars 15, the position of the divergent master petals 5. In this function, the control actuators 9 always have the same length.</li><li>2. The outer ring segments 6a and 6b swing, as a single body, on the bolts 20 which pivotally interconnect them and are fixed in the fixed structure 1 of the engine, in order to obtain, through the biarticulated bars 15, the orientation of the flow in a plane normal to the axis of said bolts 20.</li><li>3. To the above movement there is added the possibility of symmetric relative swinging between the outer ring segments 6a and 6b in order to obtain, through the biarticulated bars 15, a bisymmetric variation of the exit area A9, referenced by the numeral 13, with respect to an immobilized throat area A8, both during the orientation of the flow and when it is not oriented.</li><li>4. In an oriented flow geometry, with independent swinging of only one of the outer ring segments 6a or 6b, the exit area A9, referenced by the reference numeral 30, is asymmetrically connected through the biarticulated bars 15. In this fourth function, only those actuators of the control system which move the swung outer ring segment present a negative increment.</li></ul>

The four functions can be realized simultaneously.

In the vectoring function, the biarticulated bars 15, which are connected by a cylindrical articulation 16 to the outer ring segments 6a or 6b, turn with said outer ring segments and compel the divergent master petals 5 to move in radial direction and also in tangential direction, thus making it possible to obtain the orientation of the flow. For this, the divergent master petal is divided into two segments, indicated by the numerals 5a and 5b, and referred to as non-vectorable and vectorable respectively, which are connected to each other by a cylindrical articulation 24 arranged in direction perpendicular to the center line of the base of the petal 5. The segment 5a is connected by a cylindrical articulation 25 to the convergent master petal 4 The downstream segment 5b of each divergent master petal is formed by an upstream intermediate bar 26 and a downstream intermediate bar 27 plus a stiffened plate 28 the inner surface of which is seen by the flow of gases, as described in Spanish Patent Application No. 9,302,455 of 1993. The upstream intermediate bar 26 is interconnected to the biarticulated bar by a cylindrical articulation 30 and to the vectorable 5b of the divergent master petal by a spherical joint 31, while said cylindrical articulation 30 is connected to the downstream end of said vectorable 5b of the divergent master petal by the downstream intermediate bar 27 with spherical joints 32 and 29.

Similar radial and tangential movements with respect to the articulation axis 20 are present in the third function; and only in half circumference when the fourth function is concerned.

In Figures 2 to 10 and 13 to 25, for reasons of clarity there have not been shown the movable members 35 and 36 which constitute the movable carcass of the nozzle, which members are similar to those described in Spanish Patent No. 9,200,369 of 1992. Said movable members 35 and 36 are shown only in Figures 1 and 12.

In Figures 12 to 18 there are set forth the particular details of the axisymmetric nozzle of variable geometry established with a single control system which, differing from the nozzle described in Figures 1 to 10, has no intermediate ring, and the two cylindrical articulation bolt which interconnect the articulated ends of the two outer ring segments are connected rigidly to the inner ring 8, the fixed structure 1 of the engine having two longitudinal grooves 88 through which the articulation bolts 20 reach the inner ring 8.

In Figure 12 there is shown a diagrammatic, perspective view, partially in section, of this second axisymmetric nozzle of variable geometry which is the object of description, the arrow A indicating the direction of the flow or circulation of the gases. In the same was as the traditional nozzles, the one shown in Figure 12 includes a rear carcass, indicated by the numeral 1, which constitutes the final end of the fixed structure of the engine, a convergent zone which is indicated by the numeral 2 and a divergent zone which is indicated by the numeral 3. The convergent zone 2 is formed of a plurality of master petals indicated by the numeral 4 and slave petals 33 which define a throat A8 indicated by the numeral 12. In the same way, the divergent zone 3 is formed by master petals 5 and slave petals 34 and is divided into two parts: 3a designates non-vectorable and 3b designates vectorable.

The regulating of the throat area A8 and the orientation of the flow are effected by a single control system which is formed, in combination, by a movable ring in a single piece, known as internal ring 8, and by two biarticulated outer ring segments designated 6a and 6b which together form the outer ring 6, the components of said combination of ring and ring segments being concentric to each other and to the longitudinal axis 14 of the engine, and by a plurality of control actuators 9 which are articulated at their upstream end to the fixed structure of the engine 1.

The convergent master petals 4 are connected, at their upstream end, to the inner ring 8. This connection is effected by cylindrical articulations 10 tangential to a theoretical circumference concentric to the longitudinal axis of the engine and located in a theoretical plane perpendicular to said longitudinal axis of the engine.

To the outer ring segments 6a and 6b and to the cylindrical articulation connecting said outer ring segments, defined by the bolts 20, Figures 13 and 15, there are connected, by the spherical articulations 11, Figures 13 and 15, the downstream ends of the control actuators 9. Furthermore, the outer ring segments 6a and 6b are connected to the divergent master petals 5 by biarticulated bars 15 which are mounted concentrically around the axis 14 of the engine. The connection of each biarticulated bar 15 to the outer ring segments 6a and 6b is effected by the cylindrical articulation 16, and its connection to the divergent master petal 5 is effected by a cylindrical articulation 17. Both cylindrical articulations 16 and 17 are disposed in such a manner that, without orientation of the flow, they are tangent to a theoretical circumference concentric to the longitudinal axis of the engine and located in a theoretical plane perpendicular to said longitudinal axis of the engine.

The control system of the nozzle includes, furthermore, a mechanism for regulating the throat area A8, already shown in Figure 11, which is formed, for each convergent master petal, of a single connecting rod 37, a two-arm crank 38, and a peripheral bar 39, said connecting rod 37 being connected at its upstream end, by a spherical articulation 40, to the downstream end of the fixed structure 1 of the engine and, at its downstream end, to one of the arms 41 of said crank 38 which is articulately mounted on a pivot, which, forming an integral part of said convergent master petal 4, has its axis perpendicular to the base of said convergent master petal, while the other arm 43 of said crank 38 is connected, by spherical articulation 44, to one of the ends of the peripheral bar 39, while the other end of said peripheral bar is connected by spherical articulation to the pivot of the adjacent convergent master petal in order for the assembly of cranks 38 and peripheral bars 38 of all the convergent master petals to form a peripheral system closed on itself.

As can be seen from Figures 12 to 15, the inner ring 8 has a cylindrical extension 8a by which the after-burner is sealed during the adjustment of the throat area A8 12 of the nozzle. The axis of this cylindrical extension 8a has to be located always on the longitudinal axis of the engine 14, for which there are present on the upstream end of said cylindrical extension 8a at least three hinges for connection to the fixed structure 1 of the engine, each having two leaves, designated 48 and 49 in Figure 12, which will make it possible to move the inner ring 8 only in axial direction.

For their part, the outer ring segments 6a and 6b are guided laterally by flat systems of articulated bars, the members of which are indicated by the numerals 64 to 68, for connection with the fixed structure 1 of the engine, Figure 12, which make it possible to move the outer ring segments only in axial direction, permitting the swinging of these outer ring segments 6a and 6b around the cylindrical articulation bolts 20, each of said flat systems of articulated bars being connected articulately at its downstream end to the assembly of articulated outer ring segments 6a and 6b while, at its upstream end, it is connected, also in articulated manner, to the fixed structure 1 of the engine. The guide systems described for the outer ring segments 6a and 6b and inner ring 8 must absorb the net shear forces which appear during the orientation of the flow and those due to asymmetries of the loads.

The description described, shown in the figures, permits, by activation in one direction or the other of the control actuators 9, the following functions which have already been mentioned: <ul id="ul0003" list-style="none"><li>1. Axial movement, in the same direction, of the assembly of outer ring segments 6a and 6b and inner ring 8, together with the biarticulated bars and the convergent and divergent petals, in order to regulate the throat area A8 indicated by the numeral 12. Said axial movement of the outer ring segments 6a and 6b and ring 8 causes an angular displacement of the convergent master petals 4 through the perimetral mechanism for the regulating of the area of the throat A8 around the articulation 10. Said convergent master petals 4, due to the connecting rod 37, the two-arm crank 38, and the peripheral bar 39, open or close in radial direction, defining, together with the biarticulated bars 15, the position of the divergent master petals 5. In this function, the control actuators 9 always have the same length.</li><li>2. The outer ring segments 6a and 6b swing, as a single body, on a theoretical spherical surface centered on the longitudinal axis 14 of the engine, the inner ring 8 remaining immobilized in any axial position in order to obtain, through the biarticulated bars 15, the orientation of the flow in any direction around the longitudinal axis 14 of the engine. In this second function, the control actuators 9 have different lengths.</li><li>3. To the preceding movement there is added the possibility of symmetric relative swinging between the outer ring segments 6a and 6b in order to obtain, through the biarticulated bars 15, a bisymmetric variation of the exit area A9, indicated by the numeral 13 in Figures 13 to 15, with an immobilized throat area A8, both orienting and without orienting the flow. In this third function, the actuators of the control systems which move the outer ring segments have equal path increments.</li><li>4. In an oriented flow geometry, with independent swinging of only one of the outer ring segments 6a or 6b, the exit area A9 is corrected asymmetrically through the biarticulated bars 15. In this fourth function, only those actuators of the control system which move the swung outer ring segment have a negative increment.</li></ul>

The four functions can be realized simultaneously.

The participation of the other components of this single control system nozzle is identical to what has already been described for the first embodiment.