GB2509349A

GB2509349A - Mixing tube for solid charge propulsion unit

Info

Publication number: GB2509349A
Application number: GB1316836.4A
Authority: GB
Inventors: Didier Zanelli
Original assignee: Roxel France SA
Current assignee: Roxel France SA
Priority date: 2012-09-21
Filing date: 2013-09-23
Publication date: 2014-07-02
Anticipated expiration: 2033-09-23
Also published as: GB2509349B; GB201316836D0; FR2995941B1; ITTO20130764A1; DE102013110435A1; NO20131268A1; GB2509349B8; NO341284B1; FR2995941A1

Abstract

The invention relates to a nozzle 61 for a propulsion unit with solid charge comprising a mixing tube 7 through which passes, between an inlet section SA and an outlet section SB , a flow of combustion gas for a solid charge (3, figure 1a). The nozzle comprises a number of fins 81-84 exposed to the flow of gas between the inlet section and the outlet section. Each fin comprises a leading edge 103 orientated towards the inlet section. Each fin is mountable on the mixing tube and capable of relative rotational movement so as to be able to deflect a portion of the flow of gas thus orienting a thrust vector generated by the flow. The nozzle comprises a number of deflectors 111 attached to the mixing tube, and positioned upstream of the fins so as to at least partially protect the leading edge of the fins by deflection of a gas flow portion directed towards the leading edge.

Description

I

Mixing tube with jet deflectors for propulsion units with solid charge The present invention relates to the field of propulsion units with solid charge provided with a nozzle responsible for ejecting the combustion gases and ensuring the thrust of the propulsion unit. More specifically, the invention falls within the field of mixing tubes with jet deflectors that make it possible to orient the thrust vector.

To improve the performance of the propulsion units, and in particular their agility at low or med Fun speed, the aim is to orient the ejection of the combustion gases so as to control the thrust vector. Devices are then used such as jet deflectors, moving nozzles on a mechanical abutment, flexible nozzles or even the asymmetrical injection of liquid or gas into the mixing tube. The mixing tubes with jet deflectors have the benefit of allowing for a control of the propulsion unit in three rotations, in yaw, in pitch and in roll. By way of comparison, a complex and costly alternative solution requires two moving nozzles on a mechanical abutment to obtain the same control of is the propulsion unit. The mixing tubes with jet deflectors offer numerous advantages, notably reduced weight, volume or cost, which render these devices particularly well suited to propulsion units of small size for which accurate and rapid control of the trajectory is sought. The mixing tubes with jet detlectors do, however, suffer from drawbacks, notably the drag of the jet deflectors. The installation of jet deflectors in the mixing tube disrupts the flow of combustion gas by creating shockwaves, boundary layers, turbulence in their drag wake. These phenomena, even when the deflectors are at zero incidence, that is to say when the thrust vector is not deflected, are responsible for a loss of thrust, typically of the order of 1 to 3%. Efforts are made to limit this loss while preserving the benefits of mixing tubes with jet d eflectors.

There are now a number of types of nozzles provided with a mixing tube with jet deflectors for a propulsion unit with solid charge. The principle of these devices is illustrated in figures la and lb. Thus, a propulsion unit 1 comprising a body 2, for example cylindrical on a main axis Z, contains a solid charge 3, such as a propellant. The combustion of the solid charge 3 is initiated by a central channel 4. The combustion gases are expelled by the effect of the pressure in the central channel 4 through a nozzle 5 placed at the rear of the propulsion unit 1. The nozzle 5 comprises a convergent first element 5A and a divergent second element 5B. The nozzle has a section of smaller surface area at the level of a neck 5C between the convergent element 5A and the divergent element 53. The thrust is obtained by the expansion of the combustion gases in the mixing tube. In figure la, the mixing tube SB of the nozzle 5 is a standard fixed mixing tube, without jet deflector.

Figure lb represents a known implementation of a nozzle provided with a mixing tube 7 with jet deflector. The internal surface, substantially tapered (typically a half-angle of approximately 15°), of the mixing tube 7, in contact with the combustion gases, is referenced 71. The mixing tube 7 comprises four fins 61, 82 83 and 84 linked to the mixing tube 7 by four links 91, 92, 93 and 94. The four links 91, 92, 93 and 94 are positioned in two mutually orthogonal planes containing the axis Z. X and Y are used to denote two axes respectively contained in one of the two orthogonal planes and forming, with ZI, an orthogonaL reference frame.

The links 91, 92, 93 and 94 allow the rotation of the fins 81, 82, 83 and 84 relative to the mixing tube 7 on an axis contained in one of the orthogonal planes described previously. Xl, X2, X3 and X4 are used to denote the axis of rotation of each of the fins 81, 82, 83 and 84.

Each of the fins, for example 83, comprises two main surfaces, referenced SB3A and SS3B in the figure, facing one another, linked by two main edges, a first edge called leading edge oriented towards the inlet section of the nozzLe and a second edge called trailing edge oriented towards the outlet section of the nozzle. The notion of zero incidence applies when the fins are aligned with the flow of the combustion gases: the main surfaces then being substantially parallel to the flow of gas. This position makes it possible to minimize the turbulence generated on the flow of gas. The deflection of the flow is nil, the flow is symmetrical relative to the axis 1 By controlling the rotation of each of the fins, it is possible to steer the thrust vector of the propulsion unit 1. Typically, the steering on the yaw axis is possible by rotation of the fins 81 and 83; the steering on the pitch axis is possible by rotation of the fins 82 and 84; the steering on the roll axis is possible by rotation of the fins Sito 84.

The combustion gases for the solid charge are at high temperature, and supersonic velocity and are therefore highly ablative. The fins are exposed to a very aggressive environment, in particular the leading edge of the fins. Moreover, the flow of gas exerts a significant force on the surface of the fin when the taller is steered so as to generate a deflection of the flow of gas. For these reasons, the fins that are implemented today, which require a significant thickness, generate a disruption of the flow of gas that is significant even at zero incidence The invention aims to propose an alternative solution for a mixing tube with jet deflectors of a propulsion unit with solid charge by mitigating the implementation difficulties cited above.

To this end, the subject of the invention is a nozzle for a propulsion unit with solid charge comprising a mixing tube through which can pass, between an inlet section and an outlet section, a flow of combustion gas for a solid charge, and comprising a number of fins exposed to the flow of gas between the inlet section and the outlet section, linked to the mixing tube and capable of being driven in rotation relative to the mixing tube so as to generate a deflection of a portion of the flow of gas, variable depending on the angular position of the fin, and make it possible to orient a thrust vector generated by the flow of gas through the nozzle; each of the fins comprising a first edge, called leading edge, oriented towards the inlet section of the nozzle. The nozzle also comprises a number of deftectors attached to the mixing tube, positioned between the inlet section (SA) and the outlet section (S3), and upstream of the fins relative to the flow of gas so as to at least partially protect the leading edge of the fins by deflection of a gas flow portion directed towards the leading edge; the deflectors making it possible to structure the flow of gas upstream of the fins without restricting the inlet section (SA) of the nozzle (61).

The invention also relates to a propulsion unit with solid charge comprising a nozzle having the features described previously.

The invention also relates to a method for manufacturing a nozzle having the features described previously, characterized in that the deflectors are produced by direct moulding; a preform being incorporated in the mould of the mixing tube.

The invention finally relates to a method for manufacturing a nozzle having the features described previously, characterized in that the deflectors are produced by separate moulding and then fixed to the mixing tube by means of a glue, a screw-nut system or a rivet system.

The invention will be better understood and other advantages will become apparent on reading the detailed description of embodiments given by way of example in the following figures.

Figures Ia and lb. already discussed, describe a known implementation of a propulsion unit with solid charge provided with a mixing tube, figures 2a, 2b and 2c represent a first implementation of a nozzle provided with a mixing tube with jet deflector according to the invention, figures 3a, 3b and 3c represent a second implementation of a nozzle provided with a mixing tube with jet deflector according to the invention, figures 4a and 4b represent the fins of a mixing tube according to the two implementations of the invention, figure 5 represents an example of a deflector and its fixing means on a mixing tube according to the invention.

In the interests of clarity, the same elements will bear the same references in the different figures. The figures describe the invention from different views, in perspective or from the side; some references mentioned in the text are not included in the drawings but are deduced.Logically from the references present in the figures.

Figures 2a, 2b and 2c repiesent a first implementation of a nozzle provided with a mixing tube with jet deflector according to the invention. A nozzle 61 comprises a mixing tube 7 of which an internal surface 71, for example tapered, is exposed to a flow of combustion gas for a solid charge 3 for a propulsion unit 1. The flow of gas passes through the nozzle and the mixing tube 7 along a main axis Z. As previously described in figures la and lb, the nozzle 61 comprises four fins 81, 82, 83 and 84 linked to the mixing tube 7 by four links 91, 92, 93 and 94. The four links 91, 92, 93 and 94 are positioned in two mutually orthogonal planes containing the axis Z. X and 1 $ denote two axes respectively contained in one of the two orthogonal planes and forming, with Z, an orthogonal reference frame. The links 91, 92, 93 and 94 allow the rotation of the fins 81, 82! 83 and 84 relative to the mixing tube 7 on an axis contained in one of the orthogonal planes previously described.

Xl, X2, X3 and X4 denote the axis of rotation of each of the fins 81, 82. 83 and 84.

According to the invention, the nozzle 61 comprises a mixing tube 7 through which can pass, between an inlet section 5A and an outlet section SB, a flow of combustion gas for a solid charge 3. The nozzle 61 comprises a number of fins 81, 82, 83 and 84, exposed to the flow of gas between the inlet section SA and the outlet section 5B, linked to the mixing tube 7 and capable of being driven in rotation relative to the mixing tube 7 so as to generate a deflection of a portion of the flow of gas, variable depending on the angular position of the fin 81, 82, 83 or 84. The fins thus make it possible to orient a thrust vector generated by the flow of gas through the nozzle 61.

Each of the fins 81, 82, 83 and 84 comprises two main surfaces, 553A, 583B, facing one another and linked by two main edges, a first edge 101, 102, 103 and 104, called leading edge, oriented towards the inlet section 5A of the nozzle 61, and a second edge lOif, 102f, 103f and 104f, called trailing edge, oriented towards the outlet section 55 of the nozzle 61.

According to the invention, the nozzle 61 also comprises four detlectors 111, 112, 113 and 114 attached to the mixing tube 7. The deflectors 111, 112, 113 and 114 are respectively positioned upstream of the fins 81, 82, 83 and 84 relative to the flow of gas. Each.of the deflectors makes it possible, by its form and its location in the mixing tube, to deflect a gas flow portion that is otherwise directed towards the leading edge of each fin; the duly configured deflectors making it possible to structure the flow of gas upstream of the fins. As represented in the figures, the deflectors are preferentially of substantially planar form and substantially contained in the two orthogonal planes previously described; said orthogonal planes containing the axes of rotation of the fins.

In a first embodiment represented in figures 2a, 2b and 2c, the deflectors 1111 112, 113 and 114, having the form of a thin control surface, are attached to the substantially tapered internal surface 71 by a first edge.

The deflectors 111, 112, 113 and 114 comprise a second edge substantially parallel to the axis Z and exposed to the flow of gas, and a third edge 121, 122, 123 and 124 substantially paraflel to the leading edge, respectively 101, 102, 103 and 104, of the fin facing the deflector, respectively 81, 82, 83 and 84. The deflectors take the form of a control surface, the leading edge of which1 corresponding to the second edge substantially parallel to the axis Z, extends from the inlet section SA of the mixing tube, that is to say in proximity to the neck of the nozzle, towards the outlet section SB of the mixing tube 7.

As previousLy described, the expression fin position with zero incidence" is used to describe the position of a fin that minimizes the deflection of the flow of gas. Typically, this is the case in figure 2b of the fins 81, 82 and 83 for which the main surfaces, SB3A and S833, are substantially parallel to the flow of gas. When all the fins are positioned with zero incidence, the thrust vector generated by the flow of gas is aligned on the axis Z. In this first embodiment, the leading edges 1011 102, 103 and 104 of the fins 81, 82, 83 and 84 positioned with zero incidence as represented in figure 2b are protected from the flow of gas by the edges 121, 122, 123 and 124 of the deflectors 111, 112,113 and 114.

When a fin is not in a position with zero incidence, that is to say when it is driven in rotation to allow for the deflection of the flow of gas, as is the case, for example, of the fin 82 in figure 2c, theleading edge 102 of the fin is exposed at least partially to the flow of gas.

In other words, the nozzle 61 comprises a number of deflectors 111, 112, 113 and 114, attached to the mixing tube 7, exposed to the flow of gas between the inlet section 5A and the outlet section S6 and positioned upstream of the fins 81, 82, 83 and 84, relative to the flow of gas, so as to at least partialLy protect the leading edge 101, 102, 103 and 104 of the fins 81, 82, 83 and 84 by deflection of a gas flow portion directed towards the leading edge 101, 102, 103 and 104. The control surface form of the deflectors extending from the inlet section of the mixing tube is particularly advantageous. In practice, this particular form makes it possible to structure the flow of gas upstream of the fins, in the supersonic part. By originating on the inlet section 5A of the mixing tube, in the extension of the neck of the nozzle, the deflectors do not reduce the effective section of the neck of the nozzle. By this particular form and location, the deflectors make it possible to structure the flow of gas upstream of the fins and therefore to protect the latter. They also make it possible to limit both the thrust losses and the erosion by the flow of gas, which would follow from a location where the deflectors originated upstream of the inlet section 5A of the mixing tube, in the neck of the nozzle. Similarly, by making it possible to structure the flow of gas upstream of the fins, this implementation of the deflectors makes it possible to minimize the losses by shockwaves at the level of the fin when there is zero steer.

Advantageously, for each of the fins 81, 82, 83 and 84, the leading edge 101, 102, 103 and 104 is entirely protected from the flow of gas by a deflector 111, 112, 113, 114, when the fin is in a position minimizing the deflection of the flow of gas, called position with zero incidence. For example, for a fin 83 in a position with zero incidence, the main surfaces 553A and SS3B of the fin 83 being substantially aligned with a gas flow transport axis Z, the deflector 113 has an edge 123 substantially parallel to the leading edge 103 of the fin 83 positioned with zero incidence, and with a length substantially equal to the length of the leading edge 103 of the fin 83.

Advantageously, at least one of the deflectors can be configured so as to be exposed by a portion of its surface to a subsonic flow of gas, in proximity to the entry of the flow of gas into the nozzle, and by a portion of its surface to a supersonic flow of gas, in proximity to the output of the gas flow in the nozzle.

Advantageously, the nozzle 61 comprises four fins 81, 82, 83 and 84, linked to a substantially tapered internal surface 71 of the mixing tube 7, by means of four links 91, 92, 93 and 94, contained in two mutually orthogonal planes containing the axis Z. The nozzle 61 aLso comprises a deflector 111, 112, 113 and 114, positioned facing each of the four fins 81, 82, 83 and 84, of substantially planar form and contained in the same plane as the fin; each of the four deftectors liii 112, 113 and 114 comprising a first edge fixed to the internal surface 71 of the mixing tube 7, a second longilinear edge substantially parallel to the gas flow transport axis Z, and a third longilinear edge 121, 122, 123 and 124 substantially parallel to the leading edge of the fin concerned 81, 82, 83 or 84.

This first embodiment is particularly advantageous because it makes it possible to protect the leading edge of a fin positioned with zero incidence. This implementation makes it possible to significantly reduce the Foss of power with zero incidence. By originating downstream of the neck of the nozzle, the deflectors make it possible to structure the flow of gas to protect the fins without generating a significant loss of thrust.

Advantageously, the fins implemented in this first embodiment have a first part of their surface situated upstream of the axis of rotation and a second part of their surface situated downstream of the axis of rotation.

This implementation is particularly advantageous because it makes it possible to limit the torque to be appFied for the rotation of the fin; the forces applied by the flow of gas over the first part of the surface being partially compensated by the forces applied by the flow of gas over the second part of the surface.

Figures 3a, 3b and 3c represent a second implementation of a nozzle provided with a mixing tube with jet deflector according to the invention.

In this second implementation, a nozzle 62 comprises the same components as described previously for the first implementation represented by figures 2a, 2b and 2c. This second implementation differs from the first by the form of the fins and of the deflectors.

The four fins are referenced Bib, 82br 83b and 84b. The leading edges of the fins are referenced bib, 102b, 103b and 104b. The four deflectors are referenced ilib, 112b, 113b and li4b. The edges of the deflectors facing the fins Sib, 02b, 83b and 84b are substantially parallel to the leading edge of the fins bib, 102b, 103b and 104b and are respectively referenced 121b, 122b, 123b and 124b.

In this second embodiment, each of the fins 81b, 82b, 83b and 84b is configured so that the leading edge bib, 102b, 103b or 104b is substantially aligned on the axis of rotation of the fin. Unlike the first embodiment, the surface of the fin is essentially situated downstream of the axis of rotation.

Thus, when a fin 8ih, 82b, 83b or 84b is in a position with zero incidence, the leading edge is entirely protected from the flow of gas by means of a deflector lilb, 112b, 113b or 114b. Similarly, when a fin is steered, like, for example, the fin 52b in figure 3c, its leading edge 102b remains entirely protected from the flow of gas by means of the deflector 112b.

In other words, each of the fins 81b, 82b, 83b and 84b is configured so that its leading edge bib, 102b, 103b and 104b is substantially aligned with the axis of rotation Xi, X2, X3 and X4 of the fin Bib, 82b, 83b and 84b, making it possible for the defLectors ilib, 112b, ii3b and il4b to entirely protect the leading edge bUlb, 102b, iOSb and I 04b of the fin Bib, B2b, 83b and 84b regardless of its angular position.

Figures 4a and 4b represent the fins of a mixing tube according to the two implementations described previously.

Figure 4a shows a fin 81 as implemented in a nozzle 61 for the first implementation described in figures 2a, 2b and 2c. Thus, the fin 81 has a first part of its surface situated upstream of the axis of rotation Xl and a is second part of its surface situated downstream of the axis of rotation Xl, making it possible to limit the torque to be applied for the rotation of the fin.

Figure 4b shows a fin 8th as implemented in a nozzle 62 for the second implementation described in figures 3a, 3b and 3c. Thus, the surface of the fin 81 b is essentially situated downstream of the axis of rotation Xl, making it possible to entirely protect its leading edge bib, regardless of the orientation of the fin. A small surface remains necessary upstream of the axis of rotation Xi for the implementation of the rotation link between the fin and the mixing tube 7.

Figure 5 shows a deflector and its fixing means on a mixing tube in a variant according to the invention.

The deflector lilb, having substantially the form of a thin control surface, comprises a first edge 221b fixed to the mixing tube 7, a second edge 32th substantially parallel to the axis Z, and a third edge l2lb. This edge 121b being substantially.parallel to the leading edge lOib of a fin 81b as previously described for figures 3a, 3b and 3c.

Advantageously, the deflectors can be configured so that an upstream portion of their surface is exposed to a subsonic flow of gas, in proximity to an inlet section of the nozzle, and a downstream portion of their surface is exposed to a supersonic flow of gas; upstream and downstream being defined relative to the flow of gas.

Thus, the flow of gas is deflected by the deftectors in an area upstream of the mixing tube; the duly configured deflectors making it possible to structure the flow of gas upstream of the fins. The flow of gas is then more weakly disrupted in an area downstream of the mixing tube by the deflectors and also the fins positioned with zero incidence. This implementation is particularly advantageous because it makes it possible to limit the turbulence generated by the fins in a position with zero incidence. Thus, the power losses of the thrust vector are limited, these power losses being a traditional limitation of the mixing tubes with jet deflectors. Typically, a thrust loss of 0.5 to 2% is obtained with zero incidence in a mixing tube according to the invention, compared to a loss of 1 to 3% in a mixing tube known from the

prior art.

In a first embodiment of the invention, the mixing tube 7 and the deflectors form a monolithic assembly, obtained by direct moulding or by machining. The material forming the internal surface of the mixing tube in contact with the combustion gases is an erosion-resistant material.

In a second embodiment of the invention as described in figure 5, the deflectors comprise an internal structure, for example metallic, and an erosion-resistant material exposed to the flow of gas. The internal structure can be directly attached to an internal structure of the mixing tube 7, or else be fixed to the mixing tube 7 by one or more fixing means. As represented in the figure, a deflector is, for example, provided with two fixing means 202 and 203, positioned on the edge 221b. The fixing means are, for example, of screw-nut type or of rivet type. In this case, the material in contact with the combustion gases, erosion-resistant, can be directly incorporated in the material forming the internal surface 71 of the mixing tube 7 (direct moulding), or be fixed subsequently to the mixing tube.

so Advantageously, the deflector comprises an erosion-resistant material consisting of phenolic glass, phenolic silica, phenolic carbon or ceramic. Alternatively, the phenolic resin of the ablative material (phenolic glass, phenolic silica, phenolic carbon) is replaced by a resin that has fire-resistance properties and temperature-resistance properties similar to phenolic resins. Thus, the materials of cyanate ester type are particularly suited to the deflectors according to the invention. Finally, materials based on carbon and/or silicon carbide are also envisaged. Advantageously, the materials with the registered brand names Sepcarb or Sepcarbinox, commercially available, will be used.

A number of methods have been developed for the manufacture of a nozzle according to the invention. In a first possible manufacturing method, the deflectors are produced by direct moulding, also called integral moulding, a preform being incorporated in the mould of the mixing tube.

In a second possible manufacturing method, the deflectors are produced by means of a moulding separate from the moulding of the mixing tube. They are then fixed to the internal surface of the mixing tube by means of a glue, a screw-nut system or a rivet system.

Thus, a manufacturing method according to the invention consists in producing a mixing tube and deflectors comprising a metallic internal 16 structure and an erosion-resistant material, then fixing the deflectors to the mixing tube via the metalUc internal structure.

The invention also relates to a propulsion unit with solid charge, comprising a nozzle 61 or 62 having the features described previously.

Claims

CLAIMS1. Nozzle (61; 62) for a propulsion unit with solid charge comprising a mixing tube (7) through which can pass, between an inlet section (SA) and an outlet section (SB), a flow of combustion gas for a solid charge (3), and comprising a number of fins (81, 82, 83, 84; SIb, 82b, 83b, 84b) exposed to the flow of gas between the inlet section (SA) and the outlet section (Ss)1 linked to the mixing tube (7) and capable of being driven in rotation relative to the mixing tube (7) so as to generate a deflection of a portion of the flow of gas, variable depending on the angular position of the fin (81, 82, 83, 84; Bib, 82b, 83b, 84b), and make it possible to orient a thrust vector generated by the flow of gas through the nozzle (61; 62); each of the tins (83) comprising a first edge (103), called leading edge, oriented towards the inlet section (SA) of the nozzle (61), characterized in that it also comprises a number of deflectors (111, 112, 113, 114; ilib, 112b, 113b, 114b) attached to the mixing tube (7), positioned between the inlet section (54 and the outlet section (Se), and upstream of the fins (81, 82, 83, 84; BIb, 82b, 83b, 84b) relative to the flow of gas so as to at least partially protect the leading edge (121, 122, 123, 124; 121b, 122b, 123b, 124b) of the fins (81, 82, 83, 84; 81b, 82b, B3b, 84b) by deflection of a gas flow portion directed towards the leading edge (121, 122, 123, 124; 121b, 122b, 123b, 124b); the deflectors making it possible to structure the flow of gas upstream of the fins without restricting the inlet section (54 of the nozzle (61).
2. Nozzle (61; 62) according to Claim 1, characterized in that, for each of the fins (81, 82, 83, 84; Sib, 82b, 83b, 84b), the leading edge (121, 122, 123, 124; 121b, 122b, 123b, 124b) is entirely protected from the flow of gasbyadeflector(111, 112, 113, 114; Ilib, 112b, 113b, 114b)whenthefin (83) is in a position minimizing the deflection of the flow of gas, called position with zero incidence, said deflector (113) having an edge (123) substantially parallel to the leading edge (103) of the fin (83) positioned with zero incidence, and with a length substantially equal to the length of the leading edge (103) of the fin (83).
3. Nozzle (62) according to Claim 2. characterized in that each of the fins (Sib, 82b, 83b, 84b) is configured so that its leading edge (bib, 102b, 103b, 104b) is substantially aligned with the axis of rotation (Xl, X2, X3, X4) of the fin (81b, 82b, 83b, 84b), making it possible for the defiectors (ilib, 112b, 113b, 114b) to entirely protect the leading edge (bib, 102b, 103b, 104b) of the fin (Bib, 82b, 83b, 84b) regardless of its angular position.
4. Nozzle (61; 62) according to one of the preceding claims, characterized in that at least one of the deflectors (111 b) is configured so that an upstream portion of its surface is exposed to a subsonic flow of gas, in proximity to the entry of the flow of gas into the nozzle (61; 62), and a downstream portion of its surface is exposed to a supersonic flow of gas; upstream and downstream being defined relative to the flow of gas.
5. Nozzle (61; 62) according to one of the preceding claims, characterized in that at least one of the defectors (111, 112, 113, 114; ilib, 112b, 113b, 114b) comprises an erosion-resistant material exposed to the flow of combustion gas and a metallic internal structure.
6. Nozzle (61; 62) according to Claim 5, characterized in that at least one of the defléctors (111, 112, 113, 114; 11Th, 112b, 113b, 114b) is fixed to the mixing tube via its metallic internal structure by one or more fixing means (202, 203).
7. Nozzle (61; 62) according to one of the preceding claims, characterized in that at least one of the deflectors (111, 112, 113, 114; ilib, 112b. 113b, 114b) comprises an erosion-resistant material consisting of glass, silica1 phenolic carbon or ceramic.
8. Nozzle (61; 62) according to one of the preceding claims, characterized in that at least one of the deflectors (111, 112, 113, 114; ilIb, 112b, 113b, 114b) comprises a material based on carbon and/or silicon carbide.
9. Nozzle (61; 62) according to one of the preceding claims, characterized in that it comprises tour fins (81, 82, 83, 84; BIb, 82b, 83b, 84b), linked to a substantially tapered internal surface (71) of the mixing tube (7), by means of four links (91, 92, 93, 94; 91b, 92b, 93b, 94b), contained in two mutually orthogonal planes containing a gas flow transport axis (Z), and inthatitcomprisesadeflector(i11, 112, 113, 114; ilib, 112b, 113b, 114b), positioned facing each of the four fins (81, 82, 83, 84; 81b, 82b, 83b, 84b); said deflector being of substantially planar form and contained in the same plane as said facing tin.
10. Nozzle (61; 62) according to one of the preceding claims, characterized in that it comprises a deflector (111, 112, 113, 114; ilib, 112b, 113b, 114b) positioned facing each of the fins (81, 82, 83, 84; Sib, 82b, 83b, 84b); each deflector (iii, 112, 113, 114; IlIb, li2b, 113b, 114b) comprising a first edge fixed to the internal surface of the mixing tube, a second longilinear edge substantially parallel to the gas flow transport axis (7), and a third bngilinear edge (121, 122, 123, 124; 121b, 12Th, 123b, 124b) substantially parallel to the leading edge (101, 102, 103, 104; bib, 102b, 103b, 104b) of the fin concerned (81, 82, 83,84; 81b, 82b, 83b, 84b).
11. Propulsion unit (1) with solid charge comprising a nozzle (61; 62) according to one of the preceding claims.
12. Method for manufacturing a nozzle (61; 62) according to one of Claims ito 10, characterized in that the deflectors (111, 112, 113, 114; ilib, 112b, li3b, 114b) are produced by direct moulding; a preform being incorporated in the mould of the mixing tube (7).
13. Method for manufacturing a nozzle (61; 62) according to one of Claims 1 to 10, characterized in that the deflectors (111, 112, 113, 114; lilb, 112b, 113b, 114b) are produced by separate moulding and then fixed to the mixing tube (7) by means of a glue, a screw-nut system (202, 203) or a rivet system.