Abstract:
A chevron nozzle ( 13, 14, 21, 22, 30 ) for an engine ( 10, 12 ) of an aircraft ( 11 ), having at least one nozzle ring ( 31 ) and chevrons ( 32 ) arranged on the nozzle ring ( 31 ). The aim of the invention is to further save fuel and further reduce sound emissions. For this purpose, the nozzle ring ( 31 ) together with the chevrons ( 32 ) is designed so as to be freely rotating with at least one rotational speed such that a position of the chevrons ( 32 ) can be continuously varied.

Description:
[0001]    The invention relates to a chevron nozzle according to the preamble to claim  1 . 
         [0002]    Such chevron nozzles are used in aviation or in modern passenger aircraft, for example, the Dreamliner and the Boeing 787 or the Airbus A319. 
         [0003]    Chevrons are sawtooth-shaped pattern at the exhaust nozzle of a jet engine. Chevron nozzles have virtually teeth and tooth gaps. 
         [0004]    Chevrons have the advantage that they reduce noise emissions. However, chevrons can a minimum, however, undesirable thrust loss, for example, 0.25%, have the effect according to Wikipedia. 
       STATE OF THE ART 
       [0005]    A chevron nozzle is known from DE 12 69819441. 
         [0006]    WO 2008 045 090 A1 discloses a chevrondiise, relative to each other in the two chevron nozzle elements are rotatable about a very limited angle in relation to each other to change a geometry and to achieve an adaptation to different flight conditions. A confirmation copy twistable, overlapping nozzle device changes the surface and geometry of the flow path during certain flight conditions. 
         [0007]    These publications teach how a fuel saving can be achieved and indeed closely related to different flight conditions such as charge and start. 
         [0008]    Another chevron nozzle is known from WO 2007 122 368 A1. This document describes such a nozzle in which the region of intervening gaps can be reduced. This nozzle should have improved performance and lower noise emissions. This is achieved by a certain adaptation of the tooth gaps. There can be large gaps and small gaps that are adjusted. 
         [0009]    The document EP 2444645 A2 shows a recliner or control mechanism for a chevron nozzle. 
       OBJECT OF THE INVENTION 
       [0010]    The present invention has for its object to provide a chevron nozzle of the generic type, in which a further fuel savings and a further reduction of noise emissions can be achieved. 
       SOLUTION AND ADVANTAGES OF THE INVENTION 
       [0011]    The object of the present invention is achieved by a device having the features specified in the characterizing part of claim  1  in conjunction with the preamble thereof. The invention is based on the realization that vortices are thereby reduced by a constant rotation of chevron teeth in that the position of the teeth is constantly changing. Thus, the rotation of the invention reduces interference and turbulence in the outlet area of the nozzle. The reduction of such turbulence or interference vortex ensures fuel savings and an increase in thrust over known solutions. 
         [0012]    The chevron nozzle invention with rotation is designed for gas turbines. The rotation can be free and thereby adapt to the vortices and/or aerodynamically directed and/or mechanically produce a specific rotation rate and/or direction. Special holes in the engine mount and/or the housing can be arranged so that the rotation operation. The idea in this nozzle is to form a tight helix between input and output flow. Thus, sound waves are captured and exhaust noise effectively damped. The rotation takes place in a reduction upstream directed disturbances, whereby turbulent flows are stabilized. 
         [0013]    Another advantage of the rotation according to the invention is that the chevrons may be made smaller, which affects among other things, the engine output positive or a higher thrust possible. 
         [0014]    By the helix formed by the rotation of the air stream (core stream and side stream) have more contact surfaces to the surrounding air mass, whereby a higher pushing force is possible. 
         [0015]    Thus, such gas turbine engines with rotating nozzle for gas turbines are very beneficial. 
         [0016]    A lower fuel consumption and lower sound emissions are important goals in commercial airliners and existing aircraft engines. Consequently, turbofan engines have become popular. But even in the military attempts to avoid noise or sound emissions have been made, so that the inventive concept can also be applied there. These goals have been achieved, although the introduction of chevron nozzles partially. This cold and hot air streams are mixed in principle. This principle has been taken in the inventive solution. 
         [0017]    In the embodiment of the nozzle according to the invention, various patterns and shapes of the rear edges or teeth of this nozzle drive could be considered. For example, a radius at the tips of the teeth or the tooth spaces are optimized. Also, the height of the teeth can be adjusted. These geometric variations can be adapted to a rotational speed ceased. Also changes in tooth size according to the model of the prior art described are possible. 
         [0018]    With a nozzle according to claim  1  both fuel economy and thrust increase or a reduction of noise emissions can be achieved. 
       ADVANTAGEOUS EMBODIMENTS OF THE INVENTION AND FURTHER ADVANTAGES 
       [0019]    Further advantageous embodiments of the invention are characterized in the dependent claims set forth hereinbelow. 
         [0020]    In an advantageous development of the inventive nozzle there is provided that the nozzle ring is provided with a bearing which is fixed to an engine part, in particular an engine cowling, an engine housing and/or a core shell portion. The bearing mounting allows free rotation of the chevron rings. The rotation may be linksherung or clockwise. 
         [0021]    Preferably, the bearing is a plain bearing such as a hydrodynamic bearing, a roller bearing or a magnetic bearing. The bearings can be relatively easily carried out, which has a favorable action on the moment of inertia and the engine mount. The roller bearing is relatively low-maintenance. A magnetic bearing has virtually no friction, so fuel can be saved. Conceivable are also other camps, such as ball bearings, and the like. 
         [0022]    In order to control the rotational speed of the chevron rings, it is expedient that the nozzle ring is driven by a motor with a drive. The drive can be an electric motor and is therefore easily controlled or regulated so that there is always an optimal rotational speed, and depending on flight operations is adjustable. A controlled rotation may thus be achieved by the use of motors. 
         [0023]    Alternatively, the nozzle ring can have free rein, the rotation by at least one drive element, in particular by fins, carried out that are aerodynamically driven by the engine flame. Advantageously, the nozzle ring is independent of an additional motor drive. In this mode, the free rotation of the chevron rings in direction and/or rotational speed can adapt to Austrittssströmung. It can also be aerodynamically affected to rotate in a specific direction and/or rate. 
         [0024]    The chevrons may be square at the tips and/or the indentations or rounded. In a further advantageous embodiment of the invention, the chevrons instruct the chevron tips and/or to the chevron recesses, preferably in both places, a radius of at least 2 cm in particular. This reduces noise emissions. 
         [0025]    The engine is preferably provided with an air inlet, a fan, a compressor, a combustor, a turbine, an exhaust nozzle and a housing. However, other engine versions, such as turboprop engines are also conceivable. 
         [0026]    A particularly preferred embodiment of the invention is characterized in that the engine is provided with an engine mount, and the engine mount has at least one recess or an opening for at least one nozzle ring. In the recess or opening the nozzle ring can rotate freely. The engine housing and/or the engine cowling at the end of the nozzle is well fastened to a wing, so that a stable suspension is possible. 
         [0027]    Because it must be especially in wide-bodied aircraft on low noise emissions, it is advantageous if the nozzle of the invention is used in a turbofan engine, the nozzle for a nuclear power and/or a by-pass is used. 
         [0028]    Because also in the military field is desired to reduce noise emissions, it is advantageous if the nozzle of the invention is used in a jet engine. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    Embodiments are described with reference to the drawings, wherein further advantageous developments of the invention and advantages thereof are disclosed. 
           [0030]    Shown are: 
           [0031]      FIG. 1  is a perspective view of a turbofan engine with two nozzles according to the invention, wherein the engine is disposed on an aircraft by an engine mount structure and provided with a housing, and a first chevron rotary nozzle for a nuclear power and a second nozzle is provided for a bypass. 
           [0032]      FIG. 2  is a perspective view of a jet engine with a chevron-atomiser according to the invention. 
           [0033]      FIG. 3  a perspective view of the nozzle ring chevron rotation nozzle, as shown in  FIG. 1  or  FIG. 2  for use in engines with gas turbines. 
           [0034]      FIG. 4  is a schematic representation of an engine with the chevron nozzle invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]      FIGS. 1 to 4  illustrate a chevron rotary nozzle  20  for an engine  10  ( FIG. 1 ) or  19  ( FIG. 2 ) of an aircraft  11  ( FIG. 1 ) comprising at least one nozzle ring  25  and arranged on the nozzle ring  25  chevrons  26 . The aircraft  11  is shown only symbolically. 
         [0036]    The nozzle ring  25  is made is freely rotatable together with the chevrons  26  ( FIG. 3 ) having at least a rotational speed, so that a position of the chevrons  26  is continuously variable. 
         [0037]      FIG. 1  illustrates a use of chevron nozzle in an engine  10  with an engine mount  12 , wherein the engine mount has at least one recess or an opening  15 ,  16  for at least one nozzle ring  25 . 
         [0038]    More specifically, two chevron nozzles  13 ,  14  in a turbofan engine  10  are provided, wherein the first nozzle  13  is used for a core stream, and the second nozzle  14  for a turbofan. 
         [0039]    By engine mount  12 , the engine  10  is mounted in a known manner on a wing of the aircraft  11  and mounted. 
         [0040]    The engine  10  thus comprises a core current chevron nozzle  13  and a turbofan chevron atomiser  14 . 
         [0041]    By known mounting means, rotation of the nuclear power-chevron rotary nozzle  13  and the turbofan-chevron-rotating nozzle  14  would be impossible. 
         [0042]    Therefore, the engine mounting for the nozzles  13 ,  14  according to the invention comprises  12 , the openings  15 ,  16 , extending through the nozzle ring  25 , so that free rotation is possible. 
         [0043]    Another advantage of the invention with turbofan engines  10  is that interactions between the core stream  17  and stream  18  can be effectively reduced by the rotation of the invention. An improved performance and low noise level is the result. 
         [0044]      FIG. 2  shows a chevron nozzle  20  in a jet engine  19  with a nuclear power  17  has The engine  19  is a single chevron atomiser  20 . 
         [0045]      FIG. 3  shows that the chevrons  26  wherein the chevron tips  27  and the chevron recesses  28 , ie 2 cm to 20 cm is present in both places in each case rounded, and in each case about a radius of more than 2 cm, for example. 
         [0046]      FIG. 4  shows that the nozzle ring  25  is provided with a bearing  42  which is fixed to an engine part  29 , such as a cowl, an engine housing or a sheath-core part. 
         [0047]    As further illustrated  FIG. 4 , the nozzle ring  25  is connected to an electric motor drive  30  so that the nozzle ring  25  is driven by a motor with the drive. 
         [0048]    This may be  32  fixedly connected to a shaft  31  of the drive a first drive member. 
         [0049]    This element  32  drives a second drive element  33 , which is firmly connected to the nozzle ring  25 . 
         [0050]    Both elements  32 ,  33  may be gears and form a gear. 
         [0051]    The wheel  33  is located outside of the ring  25  and has about the same diameter as the ring  25 . 
         [0052]    Alternatively, the nozzle ring can have free rein to be run without a drive motor. The rotation of the ring  25  is carried out by a non-motorized drive element, for example, by slanted slats  34 . 
         [0053]    The slats  34  may act as propellers and are aerodynamically driven by the exhaust plume. 
         [0054]    With the free mode, the rotation of the nozzle in the direction  23  ( FIG. 3 ) and/or the rotational speed of flow  24  ( FIG. 3 ) will adjust. The rotation can also be aerodynamically affected to rotate in a specific direction  23  and/or rate. 
         [0055]    A more controlled rotation (direction  23 ) may be achieved by the use of motors  30  ( FIG. 4 ). 
         [0056]    Freely rotatable means that the ring  25  can rotate more than 360 degrees. When the ring  25  only to a limited angle could turn, that would be no free rotation. Free running means that no electric motor or the like is used in order to achieve the rotation of the ring  25 . 
         [0057]    The engine ( FIG. 4 ) has an air inlet  35 , a so-called fan  36 , a compressor  37 , a combustor  38 , a turbine  39 , the exhaust nozzle  40 , a shaft  43  and a housing  41 , at which the drive  30  may be attached. 
         [0058]      FIGS. 3 and 4  thus show that  22  can be used in conjunction with the chevron nozzle  25  and exhaust nozzle  40  of the connections  21  and storage systems. 
         [0059]    The invention is not limited to these examples, as well as other engines like turboprop or turbofan engines other can be used. 
         [0060]    Also, each described or shown example feature can be combined with one shown or described feature an another example. 
         [0061]    Thus, characteristics of the engine of  FIG. 1  incorporating features of the engine according to  FIG. 4  with each other are combined. For example, a drive used  30  of  FIG. 4  for both nozzles  13 ,  14 . Also, a nozzle  13  can have a free run and the other nozzle  14  have a motor drive and vice versa. 
       LIST OF REFERENCE NUMBERS 
       [0000]    
       
           10  turbofan engine 
           11  aircraft 
           12  engine mounting 
           13  nuclear power chevron atomiser 
           14  turbofan chevron atomiser 
           15  first opening 
           16  second opening 
           17  Kemstrom 
           18  sidestream 
           19  jet engine 
           20  nuclear power 
           19  Motor 
           21  Chevron-atomiser 
           22  chevron-atomiser 
           23  connections 
           24  storage systems 
           25  direction 
           26  flow 
           27 — 
           28 — 
           29 — 
           30  chevron nozzle 
           31  nozzle ring 
           32  chevrons 
           33  chevron tips 
           34  chevron recesses 
           35  engine part 
           36  electric motor drive 
           37  wave 
           38  first drive element 
           39  second drive element 
           40  slats 
           41  air inlet 
           42  fan 
           43  compressor 
           44  combustor 
           45  turbine 
           46  exhaust nozzle 
           47  housing 
           48  available 
           49  wave