Abstract:
A fluid flow nozzle is formed by a plurality of adjacent L-shaped channels forming successive channel pairs. Each channel has a linking member joined to a radial member. Each linking member is welded to an adjacent linking member forming a contiguous surface of linking members. Each radial member is oriented approximately perpendicular to a first side of the contiguous surface. A circumferentially enclosed chamber is formed on a second side of the contiguous surface. Each radial member is laser welded to a jacket at a distal end of each radial member. The jacket is oriented approximately parallel with the contiguous surface and separably spaced from the contiguous surface by the radial members. Each radial member forms one of a plurality of flow chambers between its adjacent radial member, the jacket and the contiguous surface. The flow chambers advantageously contain fluid in the event of a radial member rupture.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a divisional of U.S. patent application Ser. No. 10/186,131 filed on Jun. 28, 2002. The disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to flow nozzles, and more specifically to flow nozzles having an inner and an outer wall separated by interstitial flow spacing.  
       BACKGROUND OF THE INVENTION  
       [0003]     Rocket engine nozzles are currently configured in two general shapes, conical and ramp configuration, both in various sizes and materials to suit the high temperature and pressure environment for which they are designed. A common design for conical shaped rocket nozzles provides a single pass, multiple brazed-tube nozzle wall. A plurality of tubes are joined side-to-side to form an outer wall of a nozzle wherein the tubes also act as flow channels for the combustion fuel. Combustion fuel enters each of the tubes from a manifold, is preheated as it traverses the tubes, and simultaneously acts to cool the nozzle. This conventional design includes a plurality of circular tubes numbering approximately 1,000 to approximately 1,100 tubes. The individual tubes are drawn and swaged such that a diameter of each tube decreases and its wall thickness increases from a nozzle discharge end to a nozzle inlet end. This conventional tube design includes materials that are difficult to weld, particularly in a tube-wall to tube-wall configuration. A brazing process is therefore used to join the tubes. Each of the drawn and swaged tubes is first coated with a nickel material which is suitable to braze the plurality of tubes in a side-to-side configuration. The swaged and coated tubes are arranged having the larger diameter ends adjacent to one another to form the nozzle conical shape and the arrangement is collectively furnace brazed.  
         [0004]     One drawback of brazed rocket nozzles is that repair of reusable nozzles is difficult and expensive. The heat of combustion as well as the number of cycles of heating and cooling that a reusable nozzle is subjected to cause the materials to fatigue and crack. Because the tube materials are difficult to weld, nozzle repair is generally limited to brazing techniques on each tube. Brazing of individual tubes is time consuming and often incapable of repairing large cracks. If a tube cannot be braze-repaired, the tube is sealed. When a specified percentage of tubes are sealed, the nozzle can no longer be used.  
         [0005]     A common rocket nozzle has a diameter of approximately 76.2 cm (30 in) adjacent to the main combustion chamber of the rocket engine. The large diameter or distal end of the nozzle has approximately a 183 cm (6 ft) diameter. A further drawback of the brazed nozzle design is that attempts to repair a nozzle of this size itself creates problems in that heat input during the repair process can create sequential problems with the brazed material in adjacent or local tubes.  
         [0006]     A further drawback of the common brazed nozzle design is that the brazed joint is the weakest link. Even a small rupture in a brazed tube-to-tube joint can result in either reduced cooling at the upper nozzle (i.e., adjacent to the combustion chamber) or a leak of preheated fuel into the nozzle flame, either of which can result in catastrophic nozzle failure.  
         [0007]     A need therefore exists for a nozzle design providing a repairable configuration which does not rely on the brazing process. A need also exists to replace the tube-to-tube design commonly used with a configuration which is easier to form and which permits either repair of individual flow channels or replacement of segments of flow channels.  
       SUMMARY OF THE INVENTION  
       [0008]     According to a preferred embodiment of the present invention, a fluid flow nozzle is provided comprising a plurality of adjacent L-shaped channels. Each L-shaped channel includes a channel linking member and a channel radial member, said channel radial member being arranged approximately perpendicular to said channel linking member. Each channel linking member is joined to an adjacent L-shaped channel linking member forming a contiguous surface of linking members. A distal end of each channel linking member is weldably joined to its adjacent L-shaped channel at an intersection between its channel linking member and its channel radial member. The plurality of channel linking members thus joined form the contiguous surface having an inner face and an outer face. The plurality of L-shaped channels thus joined are then formed in a desired geometric shape having each of the channel radial members extending outwardly from a central axis point defining the geometric shape. Each channel radial member extends radially outward from the outer face of the contiguous surface.  
         [0009]     A jacket is circumferentially disposed about the contiguous wall in contact with a distal end of each of the channel radial members. A predetermined position of each channel radial member is mapped through the jacket wall. A weld joint is formed through the jacket wall along each intersection between a jacket inner wall to the distal end of each channel radial member. The weld joints are preferably laser welds made by a laser welding torch programmed to follow the predetermined position of each channel radial member.  
         [0010]     The plurality of channel linking members forms both a nozzle inside boundary and an inside surface for a plurality of flow channels each formed by adjacent pairs of the channel radial members. The jacket weldably joined to each of the channel radial members forms an outside surface of each of the plurality of flow channels. In a preferred embodiment, each channel radial member has a reduced wall thickness compared to both the channel linking members and the jacket. By reducing the wall thickness of each channel radial member, a pressure from a fluid flowing within the flow channels, upon reaching a critical pressure, will collapse one or more channel radial members before rupturing the pressure boundary formed by either the channel linking members or the jacket. This design choice results in containment of the fluid within the flow channels reducing the chance of combustible fluid escape to either the nozzle inside chamber or to the atmosphere outside of the jacket.  
         [0011]     In still another preferred embodiment of the present invention, the plurality of channel linking members form an outer surface of a nozzle and the jacket forms an inner surface of the nozzle. The plurality of channel linking members form a contiguous surface having an inner face and an outer face. The plurality of L-shaped channels thus joined are then formed in a desired geometric shape having each of the channel radial members extending inwardly from the contiguous surface inner face toward a central axis point defining the geometric shape.  
         [0012]     In a preferred embodiment of the present invention, each L-shaped channel is drawn and swaged such that a distal end of each channel linking member has a reduced wall thickness and an increased width relative to its proximate end. Each drawn and swaged L-shaped channel is placed in a preformed tool to control spacing between L-shaped channels and provide a desired geometric shape. The geometric shape of the preformed tool comprises preferably one of a circle, an oval, a cone, a cylinder, an ellipsoid, a paraboloid, and a hyperboloid. Each of the channel linking members are joined at their narrower proximate ends to form a first end of a nozzle assembly. Each of the channel linking members are similarly joined at their wider distal ends to form a second end of a nozzle assembly. A geometric shape approximating a cone is formed thereby.  
         [0013]     In another preferred embodiment, the nozzle assembly is preferably constructed in quarter or similar sub-unit sections. Each quarter section has an edge seam weldable to an adjacent quarter section edge seam. Assembly using quarter sections potentially improves the nozzle manufacturing time by permitting a non-repairable defect in one section of the nozzle to be removed and replaced quickly and easily. Later maintenance of the nozzle is also improved by allowing sections which have non-repairable cracks or leaks formed therein to be replaced in quarter sections, along edge seams. A non-repairable crack or rupture in any quarter section of the nozzle assembly will therefore not result in plugged flow channels or non-reusable nozzles. Quarter sections of different nozzle designs can be preassembled for either initial construction use or later maintenance replacement.  
         [0014]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. The features, functions, and advantages can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0016]      FIG. 1  is a perspective view of a circular assembly of L-shaped channels encompassed by a jacket in accordance with a preferred embodiment of the present invention;  
         [0017]      FIG. 2  is an exploded perspective view of Area  2  of  FIG. 1 , showing the assembly of individual L-shaped channels and the jacket;  
         [0018]      FIG. 3  is an exploded top view of Area  3  of  FIG. 2  showing the corner weld joint assembly of a preferred embodiment of the present invention;  
         [0019]      FIG. 4  is an exploded top view similar to  FIG. 3 , showing an alternate embodiment of the present invention having beveled edges at distal ends of each of the channel linking members;  
         [0020]      FIG. 5  is a perspective view of a subassembly of channel linking members arranged into a cone shape prior to longitudinal laser welding of the channel linking members;  
         [0021]      FIG. 6  is the perspective view of  FIG. 5  further including a jacket disposed approximately three quarters of the perimeter of the cone shaped nozzle of  FIG. 5  to illustrate an edge seam of the present invention;  
         [0022]      FIG. 7  is a partial exploded view taken from  FIG. 6  showing the external laser welds joining the jacket to each of the channel radial members and the longitudinal laser welds joining each of the channel linking members;  
         [0023]      FIG. 8  is the perspective view of  FIG. 5  further showing exemplary flow channel flow patterns for a two pass flow channel embodiment of the present invention;  
         [0024]      FIG. 9  is a partial top section view taken from area  9  of  FIG. 8  showing narrow radial spacing between channel radial members at an upper or narrow cone end of a nozzle assembly of the present invention;  
         [0025]      FIG. 10  is a partial top section view taken from area  10  of  FIG. 8  showing wide radial spacing between channel radial members at a lower or wide conical end of a nozzle assembly of the present invention;  
         [0026]      FIG. 11  is a perspective view of a single L-channel of the present invention showing a swaged channel linking member having a reduced wall thickness and wider flange on a distal end compared to its proximate end; and  
         [0027]      FIG. 12  is a partial perspective view of a preferred embodiment of the present invention, having an inverted arrangement of the linking members and jacket. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0029]     Referring to  FIG. 1 , a cylindrical nozzle assembly  10  of a preferred embodiment of the present invention is shown. The nozzle assembly  10  comprises a plurality of L-shaped channels  12  each joined by a longitudinal weld joint  14 . A jacket  16  encloses the plurality of L-shaped channels having butted ends welded at an exemplary jacket edge seam  18 .  
         [0030]     Referring to  FIG. 2 , an exploded view of the partial area  2  of  FIG. 1  is shown. Each of the plurality of L-shaped channels  12  comprises a channel linking member  20  and a channel radial member  22 . The channel radial member  22  is arranged approximately perpendicular to the channel linking member  20 . Each of the L-shaped channels  12  are arranged such that each channel linking member  20  lies approximately perpendicular to a center of curvature A. A nozzle inner wall  23  is thereby formed about the center of curvature A along an assembly radius C. Each channel radial member  22  is centrally aligned approximately parallel with each of a plurality of radial lines B.  
         [0031]     A distal end of each channel linking member  20  forms a corner joint with an adjacent L-shaped channel at an outside facing corner between the channel linking member  20  and the channel radial member  22 . A longitudinal weld joint  14  is formed at each corner joint which will be described in further detail in  FIG. 3 . The jacket  16  is disposed about the outer perimeter of the nozzle assembly  10  and is welded to a distal end of each channel radial member  22  at a plurality of exterior laser weld joints  26 .  
         [0032]     The nozzle inner wall  23  formed by the plurality of channel linking members  20  and the jacket  16  encloses a plurality of flow channels  24 . Each channel radial member  22  forms a boundary between adjacent flow channels  24 . Each flow channel  24  is sealed and separated from its adjacent flow channel by the plurality of longitudinal weld joints  14  and the plurality of exterior laser weld joints  26 . Each flow channel  24  permits a fluid flow in either direction as shown in  FIG. 2  for a combustible fluid such as a rocket fuel.  
         [0033]     Referring now to  FIG. 3 , an exemplary pair of L-shaped channels  12  are shown. A distal end of one channel linking member  20  identified as a butted end  28  is aligned with the adjacent L-shaped channel  12  prior to welding. A laser torch  30  having a laser beam  32  is used to form each of the longitudinal weld joints  14  (shown in  FIG. 2 ) at the junction between the butted end  28  and the adjacent L-shaped channel  12 . In a preferred embodiment, no filler weld material is added to the longitudinal weld joints  14 .  
         [0034]     Each pair of L-shaped channels  12  is held in the general configuration shown in  FIG. 3  prior to welding by one or more assembly tools (not shown) which are known in the art and will therefore not be further discussed herein. The assembly tool maintains fit-up between each pair of the L-shaped channels  12 . A radial member distal end  33  is also positioned by the assembly tool adjacent to the jacket  16  to maintain fit-up to weldably join the jacket  16  to each radial member distal end  33  using one of the plurality of exterior laser weld joints  26  shown in  FIG. 2 . A laser torch  34  and its associated laser beam  36  are used to cut through the thickness of the jacket  16  to each radial member distal end  33  to join the jacket  16  to each radial member distal end  33 . Similar to the longitudinal weld joints  14 , no filler material is used to make the exterior laser weld joints  26  in the preferred embodiment shown.  
         [0035]     The longitudinal weld joints  14  formed at each butted end  28  of the channel linking members  20  are easily accessible for welding. The exterior laser weld joint  26  formed at the radial member distal end  33  to the jacket  16  requires indication of the location of each radial member distal end  33  prior to making the weld joint. The location of each radial member distal end  33  can be found in several ways. In one technique known in the art, an x-ray machine (not shown) is used to identify the location of each radial member distal end  33  through the thickness of the jacket  16  to ensure proper alignment for the exterior laser weld joint  26 . Similarly, an ultrasonic sensor (not shown), also known in the art, can also be used to identify the location of each radial member distal end  33  prior to making the exterior laser weld joint  26  through the jacket  16 . Fit-up between each radial member distal end  33  and the jacket  16  for making the exterior laser weld joint  26  is obtained through tooling (discussed above) which is known in the art. The tooling forces each channel radial member  22  into approximate contact with the jacket  16  to retain the minimal required clearances for welding fit-up.  
         [0036]     Referring now to  FIG. 4 , an alternate embodiment of the present invention is shown. A beveled end  38  for each channel linking member  20  is formed. The beveled end  38  is known in the art, and is used if a filler material (not shown) is desired in forming the longitudinal weld joint  14  between each channel linking member  20  and its adjacent channel linking member  20 . A beveled end of the channel radial member  22  is undesirable because it would reduce the contact surface for the exterior laser weld joint  26 , and the use of a filler material adds unnecessary time and expense to the process of making these welds. Other joint designs known in the art can also be substituted.  
         [0037]     Referring to  FIGS. 5, 6  and  7 , the assembly stages of a conical nozzle  40  are shown. The conical nozzle  40  is formed using a plurality of swaged L-channels  42  each having a radial member  44 . A swaged L-channel  42  is further detailed in  FIG. 11 . The plurality of swaged L-channels  42  are arranged in a tool (not shown) to hold each of the swaged L-channels  42  prior to welding in a configuration of the conical nozzle  40 . An expansion tool (not shown) known in the art can also be used to force each of the swaged L-channels  42  into substantial contact with the tool. Each longitudinal weld  50  is made at this time to form the inside wall of the conical nozzle  40 . A conical jacket  46  is then disposed about each of the radial members  44  as shown in  FIG. 6 . The closure for the conical jacket  46  is formed by at least one conical jacket edge seam  48 . In a preferred embodiment of the present invention, the conical nozzle  40  is formed in quarter sections, as indicated by arrows P in  FIG. 6 , such that a quantity of 4 conical jacket edge seams  48  are used to join the assembly. By forming the conical nozzle  40  in quarter sections, stack-up tolerances as each of the swaged L-channels  42  are joined can be controlled and if a problem during manufacture of the conical nozzle  40  is encountered, a quarter section of the assembly can be removed and replaced.  FIG. 7  also shows the exterior laser weld joints  52  which are formed similar to the exterior laser weld joints  26  of  FIG. 2 .  
         [0038]     Referring to  FIG. 8 , the conical nozzle  40  having the plurality of swaged L-channels  42  is shown in further detail. A plurality of tapered flow channels  56  are formed in the conical nozzle  40 . A manifold  54  is also shown which will collect fluid at a lower portion of the conical nozzle  40  for redirection of the fluid. The manifold  54  is known in the art and will therefore not be discussed in further detail herein. A downward flow direction arrow D and an upward flow direction arrow E are shown to designate that adjacent tapered flow channels  56  provide fluid flow in opposite directions. Flow in each tapered flow channel  56  in the downward flow direction arrow D will collect in the manifold  54  for redirection in the uppward flow direction arrow E.  
         [0039]     Referring to  FIG. 9 , the plurality of swaged L-channels  42  are shown having a narrow radial spacing F. A full linking member thickness G is indicated in this upper section of the conical nozzle  40  for the channel linking members of the swaged L-channels  42 . Each of the swaged L-channels  42  has a radial member length J and a radial member thickness H.  
         [0040]     Referring to  FIG. 10 , in a lower area of the conical nozzle  40 , each of the swaged L-channels  42  has a wide radial spacing L as shown. A reduced linking member thickness K results from forming the wide radial spacing L at this lower end of the conical nozzle  40  as more fully explained in reference to  FIG. 11  herein. It should be noted that the radial member length J and the radial member thickness H are the same in this lower area as in the upper area of  FIG. 9 .  
         [0041]     Referring now to  FIG. 11 , an exemplary swaged L-channel  42  is shown having a radial member  58  and a linking member  60 . The radial member thickness H and the radial member length J are retained at both ends of the swaged L-channel  42 . The full linking thickness G (shown in  FIG. 9 ) results at the narrow linking width M proximate end. The swaging process results in the reduced linking member thickness K (shown in  FIG. 10 ) and the wide linking member width N distal end of the swaged L-channel  42 . It should be noted that the radial member thickness H of the radial member  58  is thinner than either the full linking member thickness G or the reduced linking member thickness K of the linking member  60 . As previously discussed, this permits the radial member  58  of each swaged L-channel  42  to rupture prior to a failure of the linking member  60 . Since the radial member  58  will rupture before either the linking member  60  or the conical jacket  46 , fluid is retained within the tapered flow channel  56  (shown in  FIG. 8 ).  
         [0042]     Because of the increased stiffness from the structure of the L-shaped channels of the present invention, the number of L-shaped channels required to produce a nozzle assembly can be reduced from the quantity of tubes previously used for nozzles known in the art. In an exemplary embodiment, approximately 1,000 to approximately 1,100 tubes are required to produce a rocket nozzle having an upper diameter of approximately 76.2 cm (30 in) and a lower diameter of approximately 183 cm (6 ft). Using the L-shaped channels of the present invention, the number of L-shaped channels required for a similarly sized rocket nozzle is approximately 940.  
         [0043]     In a preferred embodiment of the present invention, material for the L-shaped channels comprises one of the “superalloy” materials, including an iron-nickel-chromium based A-286 material or a JBK 75 material. In a preferred embodiment, the jacket material is one of a JBK 75 or a nickel-chromium-iron 718 material. Other metals, including other alloys of nickel-chromium-iron, can be substituted for the materials of the present invention. Lower strength/temperature range materials, including stainless steels known in the art, can be substituted if a nozzle is designed for single use. The preferred materials of the present invention are selected to provide a nozzle design which is capable of reuse requiring a multiple cycle life. In a preferred embodiment, quartered sections of the nozzle are preassembled and are joined together to form each of the nozzle assemblies. Sections may be more or less than the quarter sections indicated at the discretion of the assembler. Construction of each nozzle from a plurality of sections allows a damaged nozzle assembly to be repaired by doing individual work on separate flow channels or by replacing an entire segment. The use of segments also permits a stock-pile of segments to be prepared in advance such that damage to a nozzle assembly under construction can be repaired using one of the segments.  
         [0044]     Referring to  FIG. 12 , an inverted arrangement of L-shaped channels is shown. A plurality of channel linking members  62  form a nozzle outer surface  64 , and a jacket  66  (similar to the jacket  16 ) forms a nozzle inner surface  68 . Each of a plurality of channel radial members  70  extend radially inward from the nozzle inner surface  68  toward a central axis point  0  defining the nozzle geometric shape. A preformed tool (not shown) is constructed to constrain the arrangement of channel radial members  70  relative to the jacket  66  of this embodiment. Each of a plurality of longitudinal welds  72  is used to join the jacket  66  to a distal end  74  of each of the channel radial members  70 . Access to weld the plurality of channel linking members  62  is therefore available on the nozzle outer surface  64 .  
         [0045]     The L-shaped channel and jacket assembly of the present invention can also be used as a heat exchanger jacket around the perimeter of items requiring heat transfer. A cooling fluid can be circulated through the flow channels of the present invention in either a single pass or a double pass configuration. Nozzles assembled using the L-shaped channel and jacket of the present assembly can also be used in other applications including jet nozzles.  
         [0046]     The nozzle assembly of the present invention offers several advantages. The welded L-shaped channels of the present invention replace the brazed tubes known in the art. The tubes known in the art require a coating of nickel material to allow them to be brazed to each other. The coating step is also eliminated by the present invention. By designing each of the channel radial members with a reduced wall thickness, an over-pressure condition in one of the flow chambers results in a failure of the local channel radial member and contains leakage within the adjacent L-shaped channels of the nozzle assembly. By assembling a plurality of L-shaped channels using segments, an entire segment can optionally be replaced rather than attempting to individually repair a damaged section.  
         [0047]     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.