JP6180005B2 - Nozzle structure and manufacturing method of nozzle structure - Google Patents

Description

This application is filed on July 3, 2012, claiming priority of 61 / 525,604, filed August 19, 2011, which is incorporated herein by reference in its entirety. Claims the priority of previously filed US non-provisional patent application No. 13 / 541,495.

  The present invention relates generally to aircraft, and more particularly to a nozzle structure and method for manufacturing the nozzle structure for use in a supersonic jet engine.

  The acoustic disturbance created by the nacelle cowling surface of the propulsion system at sonic flight speeds, along with the acoustic disturbance from the flow tube aerodynamic interface that the inlet draws in and the jet plume exhaust from the nozzle, all Affects the perceived loudness. Conventionally designed nacelles produce many shock waves that eventually become one with the noise range of the entire vehicle. The challenge in reducing the strength of these shock wave features lies in the inherent problem of changing the streamline of the flow to another route without creating another disturbance in a supersonic flow field.

  Leakage (Spillage) is a characteristic of an air intake that has a great influence on the intensity of impact sound. Leakage is excess flow that is not available by the propulsion system, and is excessive flow that is inevitably diverted ("leaked") by the inlet compression field around the sides of the inlet. In a typical design, the leak is generated by a terminal shock wave, which is the only physical mechanism that can cause a leak in a typical inlet design. For example, if more leakage is required due to operation out of engine design, the inlet end shock wave will inevitably become stronger and will have a greater negative impact on the impact sound. Because of the shock wave, this feature is discrete and will impact the vehicle's acoustic field. And because of its discrete nature, the impact characteristics are difficult to attenuate or counteract using other low-impact sound design techniques.

  Angling the cowling surface in the direction of flow, both at the inlet and at the nozzle outlet, as well as the cowl bulge or bulge used to align the nacelle around an engine projection such as a transmission, is a Contributes to the strength of The angle of the cowl at the inlet and the ledge of the nacelle create features that interfere with the approaching supersonic flow that generates the compression shock wave. Also, the angle of the cowl along the downstream surface of any cowl ledge at the nozzle outlet creates an expansion wave fan that tends to re-adapt to local flow fields due to compression shock waves.

  Finally, typical designs generate strong compression and expansion reshock waves along the shear plane due to misalignment of the flow angle with the nacelle cowling and imperfect application of the exhaust outlet pressure to the nozzle exit area The exhaust jet plume itself exacerbates the local acoustic field due to the feature that it causes. Operation out of engine design further exacerbates this flow angle and pressure mismatch. These problems are illustrated in FIGS. 1-3 which depict a conventional supersonic jet engine.

  FIG. 1 schematically illustrates a prior art supersonic jet engine 20 comprising an inlet structure 22 and a nozzle structure 24 configured to operate at a predetermined Mach speed. The intake port structure 22 includes a cowl 26 and a central body 28. The central body 28 is arranged coaxially with the cowl 26. The cowl 26 includes a cowl edge 30 and the central body 28 includes a compression surface 32 and a pointed end 34 (also referred to as a “tip”). Both the cowl edge 30 and the compression surface 32 define an inlet 36 that allows air to enter the turbomachine 37.

A protrusion 38 (also referred to as a “spike”) of the central body 28 extends forward from the cowl edge 30 by a distance L ₁ . A supersonic air flow (not shown) approaching the prior art supersonic jet engine 20 will encounter the protrusion 38 before entering the inlet 36. Supersonic flow will first encounter the tip 34 and produce an initial shock wave (not shown) that will extend at an oblique angle in the backward direction. The diagonal angle corresponds to the Mach speed at which the prior art supersonic jet engine 20 is advancing, although there are several factors. Traditionally, the length of the projecting portion is the length of the initial shock wave that extends from the tip 34 to the cowl edge 30 when the aircraft moves at a predetermined Mach speed (also known as `` design speed '' or `` cruising speed ''). It is recommended to give to 38. The length of the protrusion that causes the initial shock wave to extend from the tip 34 to the cowl edge 30 as the aircraft moves at a given Mach speed is referred to herein as the "conventional spike length". To.

  The nozzle structure 24 includes a nozzle 40 having a trailing edge 42. The nozzle structure 24 further includes a plug body 44 having a surface. The trailing edge 42 and the surface 46 define an exhaust port 48. The plug body 44 is configured to suppress the expansion of exhaust gas (referred to herein as the “exhaust plume”) exhausted from the turbomachine 38 during operation of the prior art supersonic jet engine 20. Yes. The plug body 44 has a diameter that continuously decreases as the exhaust plume progresses downstream along the plug body 44, thereby providing a space for containing the expanding gas of the exhaust plume. The ability of the plug body 44 to suppress the expansion of exhaust gas in the exhaust plume is interrupted at the rear end 50 of the plug body 44. At a point downstream of the rear end 50, the exhaust plume exhaust gas will fully expand.

As shown in FIG. 1, the projecting portion 52 of the plug body 44, a distance L _2, it extends from the rear edge 42 of the cowl 40. As is known in the art, the distance L ₂ propagates off the inner surface of the trailing edge 42 when the prior art supersonic jet engine 20 is operated at a power setting corresponding to a predetermined Mach number. It is selected by the engine designer to correspond to the crossing position of the Mach line. The length of the protrusion corresponding to the crossing position of the Mach lines propagating away from the inner surface of the rear edge portion 42 is referred to as “conventional plug body length” in this specification.

  FIG. 2 shows a prior art supersonic jet engine 20 that travels at a predetermined Mach speed. As the prior art supersonic jet engine 20 travels along the planned path, the free air flow 52 approaches the protrusion 38. A portion of the free flow 52 is shown in phantom so as to form a flow tube 54. The flow tube 54 has a diameter corresponding to the diameter of the cowl edge 30 and has a length corresponding to the discontinuous time intervals of operation of the turbomachine 38. All the air in the flow tube 54 will have some interaction with the inlet structure 22, some of the air in the flow tube 54 enters the intake 36 and the rest of the air is in the intake 36. It will be leaked outside.

  Interaction between the free flow 52 and the tip 34 produces an initial shock wave 56. The interaction of the free flow 52 with the cowl edge 30 produces a terminal shock wave 58 that propagates inward toward the compression surface 32. Also, the interaction of the free flow 52 with the cowl edge 30 produces a cowl shock wave 60 that propagates outward from the prior art supersonic jet engine 20. The strength of the cowl shock wave 60 corresponds in part to the angle at which the cowl edge 30 is slanted with respect to the horizontal. As the angle increases, the cowl shock wave 60 becomes stronger.

  The conventional supersonic jet engine 20 is configured to consume air at a predetermined mass flow rate while proceeding along a predetermined path at a predetermined Mach speed. The prior art supersonic jet engine 20 consumes a volume of air that is less than the volume of air available in the flow tube 54 when moving along the planned path. Thus, some of the air in the flow tube 54 will enter the inlet 36, but some of the air in the flow tube 54 will be leaked ("excess air"). The excess air in the flow tube 54 must move in a direction that is radially outward with respect to the inlet 36 in order to leak. However, the excess air cannot move out of the path approaching the inlet 36 until after passing through the end shock wave 58. This is because, while the jet engine approaches the flow tube 54 at a speed exceeding the speed of sound, the pressure disturbance resulting from the movement of the jet engine and directed to the flow tube 54 via air moves only at the speed of sound. Thus, the first opportunity for excess air to move out of the path of the inlet 36 does not occur until after the excess air passes through the end shock wave 58. This phenomenon is illustrated in FIG.

  FIG. 3 shows the outer layer 62 of the flow tube 54 as the flow tube 54 approaches the inlet 36. The outer layer 62 represents a portion of the flow tube 54 that is not consumed by excess air, ie, the turbomachine 38 (see FIG. 2) and therefore does not enter the inlet 36. As the outer layer 62 passes through the terminal shock wave 58, it encounters pressure disturbances associated with the movement of the prior art supersonic jet engine 20 via the free flow 52. Then, as shown in the drawing, the outer layer 62 is pushed to the side and flows around the cowl edge 30 and overflows. This leakage, in which the outer layer 62 goes out of the way to the inlet 36 and wraps around the cowl edge 30, causes the cowl shock wave 60 to move forward of the cowl edge 30, thereby increasing the strength of the cowl shock wave 60. I will let you. As this shock wave becomes stronger, the noise disturbance associated therewith becomes larger.

  Referring to FIG. 2, the exhaust plume 63 is discharged from the exhaust port 48. In the illustrated example, the exhaust plume 63 includes a straight cylindrical exhaust gas that moves downstream away from the nozzle structure 24. Free-flowing air 64 approaching the trailing edge 42 of the nozzle 40 travels at an angle with respect to the straight cylinder formed by the exhaust plume 63. When free-flowing air 64 passes through the trailing edge 42 and encounters the exhaust plume 63, the shear layer created by the exhaust plume 63 behaves like a solid surface, and the free-flowing air 64 suddenly changes direction. It is done. This sudden change in direction creates a tailshock 66. Encountering free-flowing air 64 and exhaust plume 63 can also cause the exhaust plume 63 gas to suddenly change direction, creating additional shock waves downstream in the plume (not shown). The strength of the trailing shock wave 66 (and the additional shock wave in the plume) will depend on the amount of deviation between the free-flowing air 64 and the exhaust plume 63.

  As the exhaust plume 63 passes downstream of the rear end 50, it will quickly reach a fully expanded state. From the location where the exhaust plume 63 is fully expanded and moving downstream, the exhaust plume 63 and the free flow 64 will flow parallel to each other, both in the direction parallel to the longitudinal axis of the plug body 44. Will flow into. Transition regions where free flow 64 begins where it first encounters exhaust plume 63 and ends where exhaust plume 63 and free flow 64 flow parallel to the longitudinal axis of plug body 44 are close to tail shock wave 66 This can cause expansion and compression that can affect the perceived loudness of the impact sound resulting from the movement of the prior art supersonic jet engine 20 at a given Mach speed.

U.S. Patent Application No. 11 / 639,339 U.S. Patent Application No. 13 / 338,005 U.S. Patent Application No. 13 / 338,010 US Provisional Patent Application No. 60 / 960,986 U.S. Patent Application No. 12 / 000,066

  Accordingly, it is desirable to provide an inlet structure that is configured to alleviate the aforementioned concerns. It would also be desirable to provide a method for assembling such an inlet structure. Furthermore, other desirable features and characteristics will become apparent from the accompanying drawings and the foregoing technical field and background, as well as the following summary and detailed description and appended claims.

  Nozzle structure for use in a supersonic jet engine configured to provide an exhaust plume when operating at a predetermined power setting and traveling at a predetermined Mach speed, and the nozzle structure A method is disclosed herein.

  In a first non-limiting embodiment, the nozzle structure comprises a nozzle configured to exhaust an exhaust gas plume, but is not so limited. The nozzle includes a trailing edge that is oriented at a predetermined angle with respect to the axial direction of the nozzle. Furthermore, the nozzle structure includes a plug body that is partially disposed in the nozzle and arranged coaxially with the nozzle. The plug body includes an expansion surface and a compression surface downstream of the expansion surface. The protrusion of the plug body extends downstream of the rear edge with a length that exceeds the length of the conventional plug body. The protrusion of the plug body has a substantially circular cross section along substantially the entire longitudinal length of the protrusion of the plug body. The plug body forms an exhaust gas plume such that the exhaust gas plume flows substantially parallel to the direction of free flow of air flowing away from the nozzle trailing edge near the nozzle trailing edge. Further, the exhaust gas plume is free from the trailing edge of the nozzle so that the free air flowing away from the trailing edge moves in a direction parallel to the longitudinal axis of the plug body. Is isotropically turned at a location downstream of the trailing edge of the nozzle.

  In another non-limiting embodiment, the nozzle structure comprises, but is not limited to, a nozzle configured to generate an exhaust gas plume. The nozzle includes a trailing edge that is oriented at a predetermined angle with respect to the axial direction of the nozzle. Furthermore, the nozzle structure includes a plug body that is partially disposed in the nozzle and arranged coaxially with the nozzle. In addition, the nozzle structure includes, but is not limited to, a bypass wall disposed between the nozzle and the plug and configured to direct a bypass air flow out of the nozzle. The plug body includes an expansion surface and a compression surface downstream of the expansion surface. The protrusion of the plug body extends downstream of the rear edge with a length that exceeds the length of the conventional plug body. The protrusion of the plug body has a substantially circular cross section along substantially the entire longitudinal length of the protrusion of the plug body. The plug body includes an exhaust plume and a bypass air flow such that the exhaust plume and bypass air flow flow substantially parallel to the direction of the free air flow away from the nozzle trailing edge near the nozzle trailing edge. The exhaust plume and the bypass air flow are configured to form a bypass air flow, and further, such that the free flow of air flowing away from the trailing edge moves in a direction parallel to the longitudinal axis of the plug body, A free stream of air flowing away from the trailing edge of the nozzle is configured to turn isentropically at a location downstream of the trailing edge of the nozzle.

  In a third non-limiting embodiment, the method includes, but is not limited to, providing a nozzle and a plug body. The nozzle is configured to discharge an exhaust gas plume. The nozzle includes a trailing edge that is oriented at a predetermined angle with respect to the axial direction of the nozzle. The plug body includes an expansion surface and a compression surface downstream of the expansion surface. Further, the method is such that the plug body is arranged in the same axis as the nozzle while being partially disposed in the nozzle, and the protrusion of the plug body is longer than the length of the conventional plug body and is downstream of the rear edge. Positioning the plug body relative to the nozzle so as to extend, but is not limited thereto. The protrusion of the plug body has a substantially circular cross section along substantially the entire length of the protrusion of the plug body. The plug body reduces the exhaust plume and bypass air flow so that the exhaust plume flows substantially parallel to the direction of free air flow away from the nozzle trailing edge near the nozzle trailing edge. Configured to form. In addition, the plug body has a free air flow from the nozzle trailing edge so that the free flow of air flowing away from the trailing edge moves in a direction parallel to the longitudinal axis of the plug body. The flow is configured to turn isentropically at a location downstream of the trailing edge of the nozzle.

  The present invention is described below with reference to the following drawings, in which like numerals indicate like elements.

It is the schematic which shows the jet engine of a prior art. FIG. 2 is a schematic diagram showing the prior art jet engine of FIG. 1 moving in free flow with a predetermined Mach number. FIG. 3 is an enlarged view of a portion of the prior art jet engine of FIG. 2 showing leakage around the cowl edge of the inlet. 1 is a schematic diagram illustrating a portion of a jet engine, depicting the air that the jet engine will consume and the fully expanded exhaust plume that the jet engine will generate. 1 is a schematic diagram illustrating an embodiment of a jet engine comprising an inlet structure and a nozzle structure made in accordance with the present invention. FIG. 6 is a view from the axial direction of the air intake structure of FIG. FIG. 6 is a view from the axial direction of the nozzle structure of FIG. FIG. 6 is a schematic view of the jet engine of FIG. 5 traveling in free flow at a predetermined Mach speed. FIG. 6 is an enlarged view of a part of the air inlet structure of FIG. FIG. 6 is a schematic view of the jet engine of FIG. 5 showing a technique for designing a plug body of a nozzle structure. FIG. 3 is a flow diagram illustrating an embodiment of a method for making an inlet structure in accordance with the present invention. FIG. 3 is a flow diagram illustrating an embodiment of a method for making a nozzle structure in accordance with the present invention.

  The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

Disclosed herein is an intake structure that substantially eliminates leakage of excess air from the flow tube when the flow tube encounters the inlet of a supersonic jet engine moving at supersonic speeds. In an embodiment, the inlet structure includes an extended central body comprising an extended protrusion that pre-leaks air from the flow tube before the flow tube encounters the inlet shock wave and / or end shock wave. I have. The length of the central body is increased so that the length L ₁ (see FIG. 1) exceeds the length of the conventional spike. The protrusion also has a profile and dimensions such that substantially all excess air is pushed out of the path approaching the inlet as the flow tube passes through the protrusion. As a result, when the jet engine is moving at a given Mach speed and operating at a given power setting, the flow tube air that remains in the path to the inlet will have a mass that matches the turbomachine consumption rate of the jet engine. It will have a flow rate. This substantially eliminates leakage at the air intake and allows the cowl shock wave to remain substantially directly at the cowl edge. This greatly reduces the strength of the cowl shock wave and, as a result, reduces the perceived noise associated with the cowl shock wave.

  Also, according to at least one embodiment, according to the inlet structure disclosed herein, the cowl can have a substantially smaller cowl angle compared to conventional inlet structures. . A smaller cowl angle will cause the inlet to have a larger diameter, but by properly sizing and configuring the protrusion, the flow tube approaching the inlet will be matched to the larger diameter of the inlet. Whatever size is required for the can be increased to that size. In addition, due to the extended length of the protrusion, the flow tube approaching the inlet can not only be increased, but also the length of the central body to be aligned more closely with the smaller cowl angle. It can also be turned to align with the direction axis. The reduced cowl angle further reduces the strength of the cowl shock wave, thereby reducing the perceived noise associated with the cowl shock wave.

Disclosed herein is a nozzle structure that substantially eliminates misalignment between free-flowing air flowing through the nozzle trailing edge and the exhaust plume. According to one embodiment, the nozzle structure comprises an elongated plug body with extended protrusions such that the length L ₂ (see FIG. 1) exceeds the length of the conventional plug body. Yes. Further, the plug body is configured such that the exhaust plume exits the nozzle in a direction substantially aligned with the direction of free-flowing air flowing through the nozzle's trailing edge. Such a configuration would reduce or eliminate shock waves that would result from a sudden change in the direction of free flow when encountering a displaced exhaust plume.

According to yet another embodiment, increasing the L ₂ allows the jet engine to move further along the planned path compared to a conventional jet engine with a conventional plug body for full expansion of the exhaust plume gas. Can be delayed. This extends the transition phase of the exhaust plume and also gives the opportunity to turn free flow isentropically in a direction parallel to the longitudinal axis of the jet engine, thereby causing a change in the direction of the free flow, etc. Eliminate any shock waves that may be. In yet another embodiment, the plug body can be further configured such that the trailing edge of the nozzle can have a small angle compared to the angle of the trailing edge of a conventional jet engine nozzle. .

  As described above, compared to the cowl edge and nozzle trailing edge of conventional inlet structures and nozzle structures, both the inlet structure and nozzle structure disclosed herein are Each cowl edge and nozzle trailing edge can be at a relatively shallow angle to free-flowing air. These shallow angles substantially reduce the cross-sectional shape of the inlet structure and nozzle structure for free flow during supersonic flight. As a result, the inlet structure and nozzle structure of the present disclosure significantly increase the drag acting on a supersonic jet engine comprising either or both of the inlet structure and nozzle structure disclosed herein, respectively. To lower.

  The foregoing solutions, and methods for implementing those solutions, can be further understood by examining the illustrations accompanying this application and the following detailed description.

  FIG. 4 is a schematic diagram showing a general-purpose supersonic jet engine 70 having an inlet 72 and a nozzle 74. As shown in FIG. For the sake of simplicity, the general-purpose supersonic jet engine 70 is depicted without the central body disposed at the inlet 72 and the plug body disposed at the nozzle 74. The general-purpose supersonic jet engine 70 is provided with a turbo machine 76, and the turbo machine 76 consumes air at a predetermined speed while moving at a predetermined speed while operating at a predetermined output setting. The exhaust gas is generated at a speed and a predetermined pressure.

  The flow tube 78 is located in front of the general-purpose supersonic jet engine 70. The flow tube 78 has a diameter corresponding to the diameter of the inlet 72 and represents free-flowing air on the path taken by the inlet 72 as the universal supersonic jet engine 70 travels upstream. . Thus, all of the air contained in the flow tube 78 will interact with the inlet 72 in some way. A part of the air passes through the air inlet 72, but the remaining air cannot be consumed by the turbomachine 76, and therefore leaks from the cowl edge of the air inlet 72.

  A residual flow tube 80 is shown inside the flow tube 78. The residual flow pipe 80 represents the air inside the flow pipe 78 that will be consumed by the turbomachine 76 of the general purpose supersonic jet engine 70. All of the air in the flow pipe 78 other than the residual flow pipe 80 will leak around the cowl edge of the inlet 72 when the flow pipe 78 encounters the inlet 72. One purpose of the inlet structure of the present disclosure is to remove all non-air contained in the residual flow pipe 80 out of the way to the inlet 72 before the flow pipe 78 encounters the inlet 72. To push it out.

  An exhaust plume 82 is located downstream of the general purpose supersonic jet engine 70. The exhaust plume 82 represents the volume of gas that will be exhausted by the turbomachine 76 when the general purpose supersonic jet engine 70 is operating at a predetermined power setting and moving at a predetermined speed. As shown, the exhaust plume 82 has a diameter that is smaller than the diameter of the nozzle 74. However, when the exhaust gas exits the nozzle 74, the outer periphery of the exhaust gas has a diameter equal to the diameter of the nozzle 74. After the exhaust gas moves downstream and escapes the effects of the plug body, the exhaust gas diameter is such that the exhaust gas is fully expanded and the static pressure of the exhaust gas is equal to the static pressure of the free flow around the exhaust plume 82. Until it becomes, it will shrink. One purpose of the nozzle structure of the present disclosure is to change direction with isentropy (i.e., without shock waves) when the free flow flowing outside the nozzle 74 is united with the fully expanded exhaust plume 82. Is to ensure.

  FIG. 5 is a schematic diagram illustrating a supersonic jet engine 90 comprising an inlet structure 92 and a nozzle structure 94 made in accordance with the teachings of the present disclosure. The supersonic jet engine 90 further comprises a turbomachine 96, which is at a predetermined speed when the supersonic jet engine 90 is moving at a predetermined speed and operating at a predetermined output setting. The exhaust gas is generated at a predetermined speed and a predetermined pressure while consuming air. Although the inlet structure 92 is depicted as including an axisymmetric inlet structure, it should be understood that other configurations are possible in other embodiments.

  The air inlet structure 92 includes a cowl 98 including a cowl edge 100 and a center body 102. The center body 102 is arranged at least partially within the cowl 98 and is arranged coaxially with the cowl 98. The central body 102 includes a protrusion 104 having a length that exceeds the length of a conventional spike. For comparison purposes, a protrusion 106 having a conventional spike length is indicated by phantom lines and is superimposed on the tip of the central body 102. The length of the protrusion 104 corresponds to the desired use and / or specification for the supersonic jet engine 90, and the flow tube required to meet the desired impact loudness metric. Including the amount of leakage before the shock wave in the design, which is required to keep the inlet matched to the smoothness characteristics of and the low leakage after the shock wave in off-design conditions. It may be determined based on many factors, without being limited to:

  The central body 102 is an exemplary central body consistent with the teachings of the present disclosure and includes a top 108, an initial compression surface 110, an expansion surface 112, and an end compression surface 114. In other embodiments, the central body 102 may omit the intermediate expansion surface (expansion surface 112). The cowl edge 100 is spaced from the final compression surface 114 to define an inlet 116 through which air passes for consumption / use by the turbomachine 96. As shown, the top 108 is located significantly upstream of the inlet 116 so that it collides with the flow tube approaching the supersonic jet engine 90 long before the flow tube encounters the inlet 116. be able to.

  When the flow tube encounters the top 108, the flow tube air will be diverted away from the central body 102 in a radially outward direction. As a result of this outward movement, some of the diverted air is moved out of the path to the inlet 116. Since the protrusion 104 has a diameter that increases in the downstream direction, as the flow tube continues to move toward the inlet 116, more air is diverted out of the path to the inlet 116. Will be. A characteristic curve method may be used to determine the contour of the central body 102. The characteristic curve method is well known in the art and uses classical gas dynamic relations and equational progression methods for high-speed preliminary analysis of supersonic shapes and supersonic bodies that can be expected. By using the characteristic curve method, the exact contour and dimensions of the central body 102 and the protrusion 104 can be obtained so that the flow tube air remaining in the path to the inlet 116 is substantially equal to the predetermined speed of air consumption by the turbomachine 96. Can be selected to match. As a result, substantially all of the remaining air that passes through the end shock wave will be consumed by the turbomachine 96 and substantially no air leakage will occur at the cowl edge 100. When using the characteristic curve method to create a suitable surface configuration, first the curvature of the desired surface that stipulates that the surface of the flow tube is continuously smooth and isentropically increased to the cowl edge of the inlet. Is selected for the flow tube to be sucked. The characteristic curve method is then used to design the curvature of the protruding surface 104 of the central body that produces a supersonic compression field and supersonic expansion field that have the desired flow tube shape (ie, a “reverse design” technique). Additional important parameters that the characteristic curve method uses in this example include the free flow Mach number, the desired level of relaxation isentropic compression, and the distribution of the Mach number along the end shock wave. Using this information, the characteristic curve method can be used to create an appropriate surface shape for the central body 102.

  In order to ensure that the dispersion of air by the initial compression surface 110 does not generate shock waves, in one embodiment, the initial compression surface 110 may be configured to be an isentropic compression surface. As is known in the art, an isentropic compression surface has a continuous curved shape without any separating discontinuities that would cause separate shock waves. Once the flow tube air is dispersed by the initial compression surface 110, it may be desirable to turn the flow tube back in a direction that is more aligned with the longitudinal axis of the supersonic jet engine 90. This is achieved by the expansion surface 112, which, due to its curvature, turns the flow tube back in the axial direction. This allows the cowl edge 100 to have a very shallow angle with respect to local free flow, thereby substantially reducing the intensity of the cowl shock wave generated by the cowl edge 100.

  The end compression surface 114 is close to the same purpose performed by the conventional compression surface of a conventional supersonic jet engine, i.e. before the flow tube encounters the end shock wave and before the flow tube enters the inlet. Reduce the speed of the incoming flow tube. As is known in the art, supersonic airflow can be decelerated using curved surfaces to change the direction of airflow. It is also desirable to avoid any shock wave generation during this stage of final compression. Thus, in some embodiments, an isentropic compression surface may be used. In other embodiments, it may be desirable to configure the final compression surface 114 to be in a relaxed isentropic compression configuration. Relaxed isentropic compression surfaces are known in the art and are disclosed and described in pending U.S. Patent Application No. 11 / 639,339, U.S. Patent Application No. 13 / 338,005, and U.S. Patent Application No. 13 / 338,010. Each of these patent applications is hereby incorporated by reference in its entirety. By configuring the final compression surface 114 to have a relaxed isentropic compression configuration, the supersonic jet engine in the air flow approaching the inlet 116 is compared to the amount of turning caused by the conventional isentropic compression surface. The amount of turning from the 90 axial direction is reduced. This contributes to the cowl edge 100 having a relatively small angle with respect to the axial direction of the supersonic jet engine 90, and thus contributes to a reduction in the intensity of the resulting cowl shock wave.

  The supersonic jet engine 90 further includes a bypass unit 118. The bypass section 118 is a supersonic jet engine commonly used to pass turbulent air having relatively high pressure distortion around and past the turbomachine 96 without passing through the turbomachine 96. Alternative flow path through 90. The bypass portion, such as the bypass portion 118, further contributes to the cowl edge 100 having a relatively shallow angle with respect to the longitudinal axis of the supersonic jet engine 90. Thereby, it is known in the art to use a bypass part in a supersonic jet engine that further reduces the intensity of the cowl shock wave formed by the cowl edge 100. For example, bypass sections are disclosed and described in U.S. Provisional Patent Application No. 60 / 960,986 and U.S. Patent Application No. 12 / 000,066, each of which is hereby incorporated by reference in its entirety. Has been incorporated.

  The intake port structure 92 includes a bypass branch portion 120. The bypass branch 120 is a physical structure that divides (branches) the air that enters the intake port 116. A part of the air travels along the bypass 118, and another part of the air is turbocharged. Advance along path 122 leading to machine 96. The turbo machine 96 goes through a plurality of power settings when the aircraft accelerates to a predetermined Mach speed. At each power setting, the turbomachine 96 will consume air at a corresponding mass flow rate that will be different from the predetermined mass flow rate at a predetermined Mach speed. As described above, the central body 102 and the protrusion 104 pre-determine the amount of air that will substantially match the amount of air entering the inlet 116 with the mass flow rate at a predetermined Mach speed and a predetermined output setting. It is configured to leak. As long as there is any mismatch between the air entering the inlet 116 and the air that will be consumed by the turbomachine 96 when traveling at the predetermined Mach speed while operating at the predetermined power setting and As long as the mismatch becomes a leak, the leak will occur at the bypass branch 120, not at the cowl edge 100. Leakage at the bypass branch 120 does not affect the strength of the cowl shock wave. For other Mach speeds and for other power settings, the speed of the air entering the inlet 116 will not match the speed at which the turbomachine 96 consumes air. For those Mach speeds and power settings, excess air entering the inlet 116 will leak from the bypass branch 120 to the bypass 118. In this manner, the bypass 118 serves as an overflow path for air that cannot be consumed by the turbomachine 96.

  The nozzle structure 94 includes a nozzle 124 having a rear edge 126 and a plug main body 128 arranged at least partially within the nozzle 124 and arranged coaxially with the nozzle 124. The plug body 128 includes a protrusion 130 having a length that exceeds the length of the conventional plug body. For comparison purposes, a protrusion 132 having the length of a conventional plug body is indicated by phantom lines and is superimposed on the tip of the plug body 128. The length of the protrusion 130 corresponds to the desired use and / or specification for the supersonic jet engine 90, and the required flow tube to meet the desired impact loudness metric. And may be determined based on a number of factors including, but not limited to, the smoothness characteristics, jet outlet pressure and Mach number, and maximum practical length in design terms.

  The plug body 128 includes a rear end portion 134, an expansion surface 136, and a compression surface 138. The expansion surface 136 is spaced from the trailing edge 126 and defines an exhaust port 140 through which exhaust gas passes and is formed in the exhaust plume. Exhaust gas is generated by the turbomachine 96 at a predetermined mass flow rate when the turbomachine 96 is operated at a predetermined output setting. As a result, the size and shape of the exhaust port 140 can be configured to obtain a desired total thrust.

  The exhaust plume discharged from the nozzle 124 corresponds to the exit area of the exhaust port 140, and further, when the turbomachine 96 operates at a predetermined output setting, and the supersonic jet engine 90 moves at a predetermined Mach speed. Sometimes, it has a predetermined static pressure corresponding to the mass flow rate of the exhaust gas flowing out of the turbomachine 96. The trailing edge 126 has a smaller angle with respect to the axial direction of the supersonic jet engine 90 as compared to a conventional nozzle of a conventional supersonic jet engine. The smaller trailing edge angle creates a smaller drag when the free flow passes through the outer surface of the nozzle 124 and makes the free flow a shallower angle when the free flow flows past the trailing edge 126.

  The presence of the bypass portion 118 contributes to the nozzle 124 having a fairly shallow angle with respect to the longitudinal axis of the supersonic jet engine 90. In order to accept the presence of the bypass portion 118, the nozzle structure 94 includes a bypass wall 141. The air passing through the bypass part 118 flows over the bypass wall 141 and forms an exhaust plume such as exhaust gas exhausted by the turbomachine 96. Despite the illustration of FIG. 5 of an embodiment of a supersonic jet engine with a bypass section, it is understood that the teachings disclosed herein are consistent with a supersonic jet engine without a bypass section. Should.

  As will be described below, the nozzle 124 has an annular configuration. As a result, the exhaust plume discharged from the nozzle 124 also has an annular configuration. The nozzle structure 94 has a protrusion 130 that exceeds the length of the conventional plug body, so that the exhaust plume can be held in an annular configuration at a longer distance than the conventional nozzle structure. it can. Thus, the plug body 128 does not quickly collapse into the fully expanded exhaust plume depicted in FIG. 4, but keeps the exhaust plume in an annular configuration as the exhaust plume moves downstream. (However, the annular configuration contracts). By extending the distance that the exhaust plume remains in the annular configuration, the distance that the free flow turns to align with the longitudinal axis of the supersonic jet engine 90 is increased. This helps prevent shock waves from occurring.

  By providing the plug body 128 with a protrusion 130 that exceeds the length of the conventional plug body, the shape and contour of the annular exhaust plume can be well controlled after the exhaust plume is exhausted from the nozzle 124, and The exhaust plume can be adapted to flow in contact with a free flow that moves beyond the trailing edge 126. By configuring the plug body 128 to have a surface shape that causes the exhaust plume to have a static pressure that is substantially equal to the static pressure of the free flow that flows past the trailing edge 126, the plug body 128 is free of free flow. The speed at which the supersonic jet engine 90 turns in the axial direction can be controlled. As will be described below, the contour and configuration of the plug body 128 and the protrusion 130 can be determined using the characteristic curve method.

  FIG. 6 shows a view from the axial direction of the inlet structure 92 according to one embodiment. As illustrated, the air inlet structure 92 has an axisymmetric configuration. The top 108 is positioned on the longitudinal axis of the supersonic jet engine 90. The central body 102 is aligned with the bypass bifurcation 120 on the same longitudinal axis as the coaxial, thereby aligning coaxially with the cowl edge 100. In one embodiment, the inlet structure 92 need not be axisymmetric and may have other configurations.

  FIG. 7 shows an axial view of the nozzle structure 94 according to one embodiment. As illustrated, the nozzle structure 94 has an axisymmetric configuration. The rear end 134 is positioned on the longitudinal axis of the supersonic jet engine 90. The plug body 128 is arranged coaxially with the bypass wall 141, and thereby arranged coaxially with the rear edge portion 126.

  FIG. 8 is a schematic diagram showing the supersonic jet engine 90 when the supersonic jet engine 90 is traveling at a predetermined Mach speed and the turbomachine 96 is operating at a predetermined output setting. The cowl shock wave 142 and the terminal shock wave 144 are shown to propagate outward and inward from the cowl edge 100, respectively. The flow tube 78 is located upstream of the supersonic jet engine 90 and has a diameter equal to the diameter of the inlet 116. The residual flow pipe 80 is shown inside the flow pipe 78 and represents the volume of air that will be consumed by the turbomachine 96.

  When the flow tube 78 encounters the top 108, the air in the flow tube 78 begins to divert radially outward. This movement pushes some of the air in the flow tube 78 out of the way to the inlet 116. As the flow tube 78 continues to move toward the air inlet 116, the air in the flow tube 78 is continuously pushed outward in the radial direction by the surface of the central body 102 having a diameter that increases in the downstream direction. The movement of excess air in the flow tube 78 out of the path to the inlet 116 is depicted by arrow 143. Expansion of the residual flow pipe 80 in the radial direction of the outer diameter is depicted by arrow 145. By the time that the residual flow pipe 80 advances from the position shown in FIG. 8 to the position immediately upstream of the intake port 116, the outer diameter of the residual flow pipe 80 is expanded to be equal to the diameter of the intake port 116. ing.

  Thanks to the contour and diameter of the central body 102, in particular the contour and dimensions of the protrusion 104 (see FIG. 5), the volume of air in the residual flow pipe 80 is such that the turbomachine 96 draws air at predetermined time intervals. It is substantially equal to the speed consumed. As a result, substantially all of the air in the residual flow pipe 80 enters the inlet 116 and is consumed by the turbomachine 96 after passing through the end shock wave 144. As a result, the terminal shock wave 144 can be kept in contact with the cowl edge 100. In addition, the central body 102 reduces the air flow in the residual flow pipe 80 so that the air flow enters the inlet 116 at a very shallow angle compared to the angle at which the air flow enters the conventional supersonic jet engine. It is configured to control and direct. This allows the cowl edge 100 to be at a relatively shallow angle, resulting in a relatively weak cowl shock wave.

  In the nozzle 124, the exhaust gas is at a predetermined mass flow rate and at a static pressure that is determined in part by the area and shape of the exhaust port 140 and is also determined by the speed and pressure of the gas exhausted by the turbomachine 96. The air is discharged from the exhaust port 140. As the exhaust gas moves beyond the trailing edge 126, it is no longer constrained by the walls of the nozzle 124. Thus, due to the natural nature of the exhaust gas, it will expand outward in a direction transverse to the downstream direction as the exhaust gas moves downstream. The movement of the exhaust gas in the direction transverse to the downstream direction is hindered by the free flow static pressure flowing past the trailing edge 126. Similarly, movement of the free flow moving past the trailing edge 126 in the direction transverse to the downstream direction is hindered by the static pressure of the exhaust gas. As a result, at the position where the free flow and the exhaust gas move beyond the trailing edge 126, the free flow and the exhaust gas will encounter and repel each other. If one flow is at a higher static pressure than the other flow, both flows will be diverted towards a smaller static pressure flow.

  The nozzle structure 94 is configured such that the exhaust gas has a static pressure that matches the local free flow at the nozzle outlet. For this reason, and because of the profile and configuration of the plug body 128, the two flows do not turn in the direction of the free flow. In the exhaust port 140, the plug body 128 has a contour that exhibits an expansion surface (expansion surface 136, see FIG. 5) with respect to the exhaust gas, and allows the exhaust gas to expand in a direction away from the free flow. By selecting the specific contour and configuration of the plug body 128 and the protrusion 130 (see FIG. 5), the outer periphery of the plug body 128 and the protrusion 130 can be freed from an appropriate amount of static pressure. It is possible to expand radially inward at a speed that can be brought to the flow, and to bring the appropriate amount of static pressure to the free flow is a rapid change of direction between the free flow and the exhaust gas. So that they flow in contact with each other at their shear planes without any damage.

  If the exhaust gas continues to move away from the outlet 140 in the downstream direction, the exhaust gas will continue to expand in the radially inward direction and continue to expand until the diameter of the protrusion 130 (see FIG. 5) disappears. it can. At a certain position along the surface of the plug body 128, the exhaust gas moves away from the expansion surface 136 (see FIG. 5) and further moves on the compression surface 138 (see FIG. 5). Here, when the exhaust gas faces the compression surface, the ability to expand in the radially inward direction decreases, and as a result, the exhaust gas begins to return to a flow aligned in the axial direction. By providing a proper contour and configuration for the protrusion 130 (see FIG. 5), the protrusion 130 has a static pressure around its exhaust gas during the outward expansion that diverts the free flow with isentropy. I will let you.

  Eventually, the exhaust gas moves beyond the rear end 134, and at the position of the rear end 134, the plug body 128 does not further affect the expansion of the exhaust gas. Immediately thereafter, the exhaust gas reaches a fully expanded state where its static pressure is equal to the static pressure of the free flow. From this position, the exhaust gas (exhaust plume 82) and free flow will flow downstream in parallel with each other.

  The influence of the plug body 128 on the free flow can be summarized as follows. The free flow is diverted from a direction in contact with the outer wall of the trailing edge 126 to a direction parallel to the longitudinal axis of the supersonic jet engine 90. During this transition phase, free flow is diverted as a result of the static pressure exerted by the exhaust gas. The contour of the plug body 128 controls the static pressure of the exhaust gas. Therefore, by selecting an appropriate contour and configuration of the plug body 128, the free flow can be turned with isentropy without generating a shock wave.

  FIG. 9 shows an enlarged view of a part of the air inlet structure 92. This figure compares a conventional supersonic jet engine with a conventional central body 146 (shown in phantom) and a supersonic jet engine 90 with a central body 102 mounted. The conventional supersonic jet engine includes a conventional cowl 148 and a conventional bypass branch 150, while the supersonic jet engine 90 includes a cowl 98 and a bypass branch 120. As shown, the cowl 98 has a much shallower angle with respect to free flow than the conventional cowl 148. This reduction of the cowl angle is made possible by the central body 102 with protrusions having a length that exceeds the length of conventional spikes, as described above. Due to the additional length of the central body 102, the central body 102 has the opportunity to turn the direction of free flow over the central body 102 in a direction aligned with the longitudinal axis of the supersonic jet engine 90. It is done. The angle of the bypass bifurcation 120 has also been modified to accept an approaching air flow that crosses the end shock wave 144 and enters the inlet 116 having a more longitudinal flow direction. By allowing a sudden reduction of the cowl angle, the central body 102 contributes to a substantial decrease in the intensity of the cowl shock wave generated by the cowl edge 100.

  FIG. 10 provides a visual depiction of the technique for designing the plug body 128. Depending on the anticipated use of the supersonic jet engine 90, the designer may want the exhaust gas to reach a fully expanded state and that the exhaust gas begin to flow parallel to the direction of free flow. A downstream location will be selected. In FIG. 10, this location is identified by an arrowhead 152. The arrowheads 152 are spaced apart by a distance equal to the diameter of the exhaust plume 82 (see FIG. 8), corresponding to the known output of the turbomachine 96. The location of the arrowheads 152 in the longitudinal axis can vary based on design criteria, but the distance between the arrowheads 152 in the lateral direction is fixed based on the output setting of the turbomachine 96.

  Once the designer has selected the location of the arrowhead 152, the next step is to determine the location of the rear end 134 of the plug body 128. The location of the rear end 134 is determined based on the well-known principle of Mach line propagation. The Mach line propagates from the surface of the supersonic flow at an angle β determined by the following equation.

  β = arcsine (1 / Mach number)

  Thus, with respect to the known Mach velocity of the exhaust gas traveling through the rear end 134, the Mach line 154 will propagate from the rear end 134 at an angle β. Using both the angle β and the location of the arrowhead, the location of the rear end 134 is the location where the ends of each Mach line 154 at each arrowhead 152 are positioned and the Mach lines intersect when viewed in the upstream direction Can be determined by determining The tolerance position is where the rear end 134 will be located. Once the location of the rear end 134 is determined, the overall length of the plug body 128 can be determined.

  The desired curvature is then selected to turn the free flow. This curvature is represented by a virtual line 155 and is selected by the nozzle designer. One criterion may be to select a curvature that results in an isentropic change in the direction of the free flow. Once the desired curvature is selected, the profile and configuration of the plug body 128 can be determined using the characteristic curve method. When using the characteristic curve method, the virtual line 155 is considered to be a boundary condition, and the contour and configuration of the plug body 128 selects the curvature of the plug body 128 that will cause the exhaust gas to follow the virtual line 155. Calculated by Other techniques can also be used when determining the shape of the plug body 128, such as using computational fluid dynamics software.

  FIG. 11 illustrates intake air for use with a supersonic jet engine configured to consume air at a predetermined mass flow rate when the supersonic jet engine operates at a predetermined power setting and moves at a predetermined Mach speed. FIG. 5 is a flow diagram illustrating a method 156 for manufacturing a mouth structure.

  In step 158, a cowl, a central body, and a bypass branch are prepared. In some embodiments, the supersonic engine may not include a bypass section. For such embodiments, this step will not involve preparing a bypass branch. The cowl has a cowl edge. The center body includes a top, a first compression surface disposed downstream of the top, and a second compression surface disposed downstream of the first compression surface.

  In step 160, the central body is coaxial with the cowl, the central body protrusion extends upstream of the cowl edge beyond the length of the conventional spike, and the second compression surface is Positioned relative to the cowl so as to be spaced from the cowl edge so as to define an inlet with the cowl edge.

  In step 162, for a supersonic engine configured with a bypass bifurcation, the bypass bifurcation is a second predetermined when the supersonic jet engine is moving at a predetermined Mach speed while operating at a predetermined output setting. Positioned between the cowl and the central body to form a bypass portion configured to receive air at a mass flow rate.

  When properly implemented, method steps 158-162 are performed when the jet of the center body is traveling at a predetermined Mach speed while operating at a predetermined power setting so that the protrusion of the central body is routed to the inlet. An air intake configured to divert the air flow located at the outside of the path to the air intake while preventing the remaining flow of air entering and approaching the air intake from becoming greater than a predetermined mass flow rate A structure will be created. For an embodiment of a supersonic jet engine with a bypass, when the jet engine is operating at a predetermined power setting and moving at a predetermined Mach speed, the central body is positioned in the path to the inlet. While diverting the air flow out of the path to the inlet, the remaining air that enters closer to the inlet becomes the first predetermined mass flow rate (i.e., the air is driven by the turbomachine of the supersonic jet engine). It is configured so that it does not become larger than the combined flow rate of the predetermined speed consumed) and the second predetermined mass flow rate (that is, the speed at which the bypass portion passes the air flow around the turbomachine).

  FIG. 12 shows a nozzle structure for use in a supersonic jet engine configured to generate an exhaust gas plume when the supersonic jet engine operates at a predetermined power setting and moves at a predetermined Mach speed. FIG. 7 is a flow diagram illustrating a method 164 for manufacturing

  In step 166, the nozzle, plug body, and bypass wall are provided. In some embodiments, no bypass is utilized. For such embodiments, no bypass wall is provided. The nozzle is configured to discharge an exhaust gas plume and includes a trailing edge oriented at a predetermined angle with respect to the axial direction of the nozzle. The plug body includes an expansion surface and a compression surface downstream of the expansion surface.

  In step 168, the plug body is arranged partially in the nozzle and arranged coaxially with the nozzle, and the protrusion of the plug body exceeds the length of the conventional plug body and is downstream of the rear edge. So as to extend to the nozzle.

  In step 170, for embodiments that utilize a bypass section, the bypass wall will be positioned between the nozzle and the plug body.

  When properly implemented, the method steps 166-170 include a nozzle wherein the protrusion of the plug body has a substantially circular cross section along substantially the entire longitudinal length of the protrusion of the plug body. A structure will be created. The plug body forms an exhaust gas plume such that the exhaust gas plume flows substantially parallel to the direction of free flow of air flowing away from the nozzle trailing edge near the nozzle trailing edge. Further, the exhaust gas plume is free from the trailing edge of the nozzle so that the free air flowing away from the trailing edge moves in a direction parallel to the longitudinal axis of the plug body. Is isotropically turned at a location downstream of the trailing edge of the nozzle. In an embodiment utilizing a bypass section, the plug body is configured such that the exhaust gas plume and the bypass air flow are plugged into a free stream of air away from the rear edge of the nozzle at a location downstream of the rear edge of the plug body. It is configured to turn with isentropy in a direction parallel to the longitudinal axis of the body.

  While at least one exemplary embodiment has been presented in the foregoing detailed description of the disclosure, it should be understood that many variations exist. It should also be understood that this exemplary embodiment or other embodiments are merely illustrative and are not intended to limit the scope, application, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient guide for implementing the exemplary embodiments of the invention. It will be understood that various changes may be made in the function and arrangement of the elements described in the exemplary embodiments without departing from the scope of the disclosure as set forth in the appended claims. right.

70 General purpose supersonic jet engine
72 Air intake
74 nozzles
76 turbomachine
78 Flow tube
80 Residual pipe
82 Exhaust plume
90 supersonic jet engine
92 Inlet structure
94 Nozzle structure
96 turbomachine
98 cowl
100 cowl edge
102 Center body
104 Protrusion
108 top
110 Initial compression surface
112 Expansion surface
114 Final compression
116 Air intake
118 Bypass section
120 Bypass branch
122 career path
124 nozzles
126 Trailing edge
128 plug body
130 Protrusion
134 Rear end
136 Expansion surface
138 Compression surface
140 Exhaust port
141 Bypass wall
142 cowl shockwave
144 End shock wave
152 Arrowhead
154 Mach Line
155 virtual lines

Claims (20)

A nozzle structure for use with the supersonic jet engine configured to generate an exhaust gas plume when the supersonic jet engine is operating at a predetermined power setting and moving at a predetermined Mach speed. There,
The nozzle structure is
A nozzle configured to discharge the plume of exhaust gas, the nozzle comprising a trailing edge;
A plug body that is partially disposed in the nozzle and arranged coaxially with the nozzle, the expansion body, a compression surface downstream of the expansion surface, and the plug body extending downstream of the trailing edge A plug body having a protruding portion of
The protrusion of the plug body has a concave surface near the end of the plug body;
The plug body has a profile and dimensions determined by the use of properties or computational fluid dynamics methods;
The contour and dimensions are such that the plume of exhaust gas flows away from the trailing edge of the nozzle when the supersonic jet engine is moving at the predetermined Mach speed while operating at the predetermined power setting. The plume of exhaust gas is configured to flow substantially parallel to the direction of the free flow of
Further, when the supersonic jet engine is operating at the predetermined power setting and moving at the predetermined Mach speed, the free flow of air moves in a direction parallel to the longitudinal axis of the plug body. In particular, the plume of exhaust gas has a contour and dimensions configured to isentropically redirect the free flow of air at a location downstream of the trailing edge of the nozzle.   The nozzle structure according to claim 1, wherein the compression surface comprises an isentropic compression surface.   2. The nozzle structure according to claim 1, wherein a part of the expansion surface is upstream of the trailing edge of the nozzle.   The plug body allows the free flow of air from which the plume of exhaust gas flows away from the rear edge of the nozzle to a location downstream of the rear edge of the plug body and the longitudinal direction of the plug body. 2. The nozzle structure according to claim 1, wherein the nozzle structure is configured to turn with isentropy in the direction parallel to the axis.   The nozzle of claim 1, wherein the trailing edge of the nozzle is substantially axisymmetric, and the trailing edge of the nozzle and the expansion surface of the plug body define an annular exhaust port of the nozzle. Structure.   The nozzle structure according to claim 1, wherein the expansion surface and the compression surface are in contact with each other.   7. The nozzle structure according to claim 6, wherein the surface of the plug main body has no discontinuous part to be separated in a region where the expansion surface transitions to the compression surface. A nozzle structure for use with the supersonic jet engine configured to generate an exhaust gas plume when the supersonic jet engine is operating at a predetermined power setting and moving at a predetermined Mach speed. There,
The nozzle structure is
A nozzle configured to discharge the plume of exhaust gas, the nozzle comprising a trailing edge;
A plug body arranged in a coaxial manner with the nozzle while being partially disposed in the nozzle;
A bypass wall disposed between the nozzle and the plug body and configured to direct a bypass air flow out of the nozzle;
The plug body includes an expansion surface, a compression surface downstream of the expansion surface, and a protrusion of the plug body extending downstream of the rear edge portion,
The protrusion of the plug body has a concave surface near the end of the plug body;
The plug body has a profile and dimensions determined by the use of properties or computational fluid dynamics methods;
The contours and dimensions are such that when the supersonic jet engine is operating at the predetermined power setting and moving at the predetermined Mach speed, the plume of exhaust gas and the bypass air flow are at the trailing edge of the nozzle. Configured to form the plume of exhaust gas and the bypass air flow to flow substantially parallel to a direction of free flow of air flowing away from the section; and
Further, when the supersonic jet engine is operating at the predetermined power setting and moving at the predetermined Mach speed, the free flow of air moves in a direction parallel to the longitudinal axis of the plug body. A nozzle structure having a profile and dimensions configured to cause the plume of exhaust gas and the bypass air flow to be isentropically diverted at a location downstream of the trailing edge of the nozzle.   9. The nozzle structure according to claim 8, wherein the compression surface comprises an isentropic compression surface.   9. The nozzle structure according to claim 8, wherein a part of the expansion surface is upstream of the trailing edge of the nozzle.   The plug body is configured such that the plume of exhaust gas and the bypass air flow allow the free flow of air to flow away from the rear edge of the nozzle at a location downstream of the rear edge of the plug body. 9. A nozzle structure according to claim 8, wherein the nozzle structure is configured to turn with isentropy in the direction parallel to the longitudinal axis of the body.   9. The nozzle of claim 8, wherein the trailing edge of the nozzle is substantially axisymmetric, and the trailing edge of the nozzle and the expansion surface of the plug body define an annular exhaust port of the nozzle. Structure.   9. The nozzle structure according to claim 8, wherein the expansion surface and the compression surface are in contact with each other.   14. The nozzle structure according to claim 13, wherein the surface of the plug main body has no discontinuous portion to be separated in a region where the expansion surface transitions to the compression surface. A nozzle structure for use with the supersonic jet engine configured to generate an exhaust gas plume when the supersonic jet engine is operating at a predetermined power setting and moving at a predetermined Mach speed. A method of manufacturing comprising:
Providing a nozzle configured to discharge the plume of exhaust gas and having a trailing edge; and a plug body comprising an expansion surface and a compression surface downstream of the expansion surface;
The plug body is arranged so that the plug body is arranged coaxially with the nozzle while being partially disposed in the nozzle, and the protruding part of the plug body extends downstream of the rear edge part. Positioning with respect to the nozzle, and
The protrusion of the plug body has a concave surface near the end of the plug body;
The plug body has a profile and dimensions determined by the use of properties or computational fluid dynamics methods;
The contour and dimensions are such that the plume of exhaust gas flows away from the trailing edge of the nozzle when the supersonic jet engine is moving at the predetermined Mach speed while operating at the predetermined power setting. The plume of exhaust gas is configured to flow substantially parallel to the direction of the free flow of
The plug body further includes a direction in which the free flow of air is parallel to a longitudinal axis of the plug body when the supersonic jet engine is moving at the predetermined Mach speed while operating at the predetermined power setting. The plume of exhaust gas has a contour and dimensions configured to redirect the free flow of air isentropically at a location downstream of the trailing edge of the nozzle.   16. The method of claim 15, wherein preparing the plug body with a compression surface includes providing a plug body with an isentropic compression surface.   16. The method of claim 15, wherein providing the plug body with an expansion surface and the compression surface comprises providing a plug body with an expansion surface in contact with the compression surface.   Providing the plug body with an expansion surface in contact with the compression surface includes providing a plug body without any separating discontinuities between the expansion surface and the compression surface; The method of claim 17.   16. The method of claim 15, further comprising providing and placing a bypass wall between the nozzle and the plug body.   The step of providing the plug body comprising an expansion surface and a compression surface comprises the plume of exhaust gas and the bypass air flow, the free flow of air flowing away from the trailing edge of the nozzle, the rear of the plug body. 20. The method of claim 19, comprising providing a plug body that is isentropically turned at a location downstream of an edge in the direction parallel to the longitudinal axis of the plug body.

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