Universal adjusting pull rod for rocket engine

Abstract

A universal adjusting pull rod for a rocket engine relates to the field of aerospace propulsion and comprises a universal adjusting pull rod body, the universal adjusting pull rod body is installed between a spray pipe and a turbine exhaust pipe of the rocket engine, and the spray pipe and the turbine exhaust pipe are both connected to a turbine pump; the universal adjusting pull rod comprises double-lug seats, adjusting screw rods and a pull rod body, the two ends of the pull rod body are each in threaded connection with one adjusting screw rod, the adjusting screw rods and the pull rod body are coaxial, the end, away from the pull rod body, of each adjusting screw rod is rotationally connected with one double-lug seat, and the rotating axes of the double-lug seats and the adjusting screw rods are perpendicular to the axes of the adjusting screw rods; and each double-lug seat is used for being in threaded connection with a spray pipe or a turbine exhaust pipe. And a displacement and angle adjustment compensation function in a certain range is realized.

Description

Technical Field

[0001] The invention relates to a structure and a design method of a universal adjustment pull rod for a rocket engine, which can be used in the field of aerospace propulsion. Background Art

[0002] In the assembly of aerospace vehicles, there is a common problem that the gap and the relative size of the supporting parts cannot be accurately determined due to the cumulative tolerance of each component. Therefore, it is necessary to design an adjustment structure with angle and displacement adjustment and compensation functions to meet the requirements of aerospace assembly structure. When the rocket is started and ignited, there is a high temperature and large vibration environment, and the selected materials and structural design should be able to withstand this environment. Summary of the invention

[0003] The technical problem solved by this application is: to overcome the shortcomings of the prior art and provide a universal adjustment rod mechanism for rocket engines to achieve displacement and angle adjustment compensation within a certain range. And through simulation calculation of the rocket engine startup ignition process and vibration test data distribution calculation, the temperature and vibration conditions of the rocket engine during operation are obtained to perform structural verification.

[0004] This patent uses liquid rocket engines as the application object and designs a universal adjustment rod. Through the linkage of 4 rotating pairs and 2 spiral pairs, it can realize the space distance, angle compensation and adjustment functions within a certain range. The left and right thread design can realize clockwise screwing in different directions, and the length is shortened; the nut adopts a self-locking structure design to achieve locking after installation, and has the function of preventing loosening, which can adapt to the high vibration level of the rocket when it is working. The temperature and vibration environment at the time of rocket startup and ignition are determined through theoretical simulation combined with statistical maximum envelope.

[0005] The technical solutions provided by this application are as follows:

[0006] A universal adjustment rod for a rocket engine comprises a universal adjustment rod, which is installed between a nozzle and a turbine exhaust pipe of the rocket engine, and both the nozzle and the turbine exhaust pipe are connected to a turbine pump; the universal adjustment rod comprises a double-ear seat, an adjustment screw and a rod body, each end of the rod body is threadedly connected to an adjustment screw, the adjustment screw is coaxial with the rod body, and the end of each adjustment screw away from the rod body is rotatably connected to a double-ear seat, and the rotation axis of the double-ear seat and the adjustment screw is perpendicular to the axis of the adjustment screw; each double-ear seat is used for threaded connection with the nozzle or the turbine exhaust pipe.

[0007] The double-ear seat includes a U-shaped piece and a connecting rod, the connecting rod is fixedly connected to the outer side of the closed end of the U-shaped piece, the end of the adjusting screw away from the pull rod body extends into the opening of the U-shaped piece, and the pin passes through the U-shaped piece and the end of the adjusting screw, and the nut is threadedly connected to the other end of the pin passing through the U-shaped piece.

[0008] The nozzle has a nozzle mounting surface, the nozzle mounting surface is provided with a first mounting hole, a connecting rod at one end of the universal adjustment rod is threadedly connected to the first mounting hole, a turbine exhaust pipe mounting surface is provided on the nozzle mounting surface, the turbine exhaust pipe mounting surface is provided with a second mounting hole, and a connecting rod at the other end of the universal adjustment rod is threadedly connected to the second mounting hole.

[0009] The pull rod body includes a pull rod base, a left screw sleeve and a right screw sleeve. The pull rod base is a hollow cylindrical structure. The left screw sleeve and the right screw sleeve are respectively fixedly connected to the two ends of the pull rod base. The thread rotation directions of the two adjusting screws are different. The left screw sleeve and the right screw sleeve are respectively matched with one adjusting screw thread.

[0010] The installation method of the universal adjustment rod includes:

[0011] Screw the adjusting screw into the tie rod body;

[0012] According to the actual spatial position of the two ends of the adjusting screw, the double-ear seat is rotated so that the connecting rod of the pull rod body and the double-ear seat are in a straight line;

[0013] Connect one connecting rod to the nozzle, adjust the screw length by screwing, and at the same time, connect the other connecting rod to the turbine exhaust pipe, adjust it into place, and tighten the nut.

[0014] In summary, this application at least includes the following beneficial technical effects:

[0015] The beneficial effects of the present invention and the prior art are as follows: the present invention designs a universal adjustment rod, which includes 4 rotation pairs and 2 screw pairs. It can realize spatial distance, angle compensation and adjustment within a certain range. The working environment conditions of the universal adjustment rod are determined by theoretical simulation calculation combined with the statistical envelope of test data, so as to carry out structural design and verification. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a functional diagram of the universal adjustment rod installation;

[0017] Figure 2 It is a schematic diagram of the universal adjustment rod;

[0018] Figure 3 It is the pull rod body structure;

[0019] Figure 4 To adjust the screw structure;

[0020] Figure 5 It is a double-ear seat structure;

[0021] Figure 6 Assemble the coordinate system for the engine;

[0022] Figure 7Simplify the modeling meshing for the rocket engine thrust chamber 1 / 6;

[0023] Figure 8 This is the simulation calculation result of the temperature field of the rocket engine thrust chamber at a certain moment of ignition.

[0024] Description of the accompanying figures: 1. Nozzle; 2. Turbine pump; 3. Turbine exhaust pipe; 4. Universal adjustment rod;

[0025] 41. Double ear seat; 42. Adjusting screw; 43. Pull rod body; 44. Pin; 45. Nut;

[0026] 431. Tie rod base; 432. Left threaded sleeve; 433. Right threaded sleeve. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] The embodiment of the present application discloses a universal adjustment rod for a rocket engine, comprising a universal adjustment rod, which is installed between the nozzle 1 and the turbine exhaust pipe 3 of the rocket engine and is used to fix the turbine exhaust pipe 3. The nozzle 1 and the turbine exhaust pipe 3 are both connected to the turbine pump 2. Figure 1 .

[0029] The universal adjustment rod comprises a double-ear seat 41, an adjustment screw 42, a rod body 43, a pin 44 and a nut 45. Figure 2 .

[0030] like Figure 2 and Figure 4 As shown, each end of the rod body 43 is threadedly connected to an adjusting screw 42, and the adjusting screw 42 is coaxial with the rod body 43. The connection between the adjusting screw 42 and the rod body 43 allows the adjusting screw 42 and the rod body 43 to rotate relative to each other. Each end of the adjusting screw 42 away from the rod body 43 is connected to a double-ear seat 41; Figure 5 As shown, the double-ear seat 41 includes a U-shaped part and a connecting rod, the connecting rod is fixedly connected to the outer side of the closed end of the U-shaped part, the end of the adjusting screw 42 away from the pull rod body 43 extends into the opening of the U-shaped part, and the pin 44 passes through the ends of the U-shaped part and the adjusting screw 42, and the nut 45 is threadedly connected to the other end of the pin 44 passing through the U-shaped part to connect the U-shaped part and the adjusting screw 42; the connecting rod is perpendicular to the pin 44; the U-shaped part and the adjusting screw 42 can rotate around the axis of the pin 44.

[0031] The nozzle has a nozzle mounting surface 11, which is provided with a first mounting hole, and a connecting rod at one end of a universal adjustment rod is threadedly connected to the first mounting hole. The nozzle mounting surface has a turbine exhaust pipe mounting surface 31, which is provided with a second mounting hole, and a connecting rod at the other end of the universal adjustment rod is threadedly connected to the second mounting hole. The threaded connection between the connecting rod and the nozzle allows the connecting rod and the nozzle to rotate relative to each other.

[0032] The axis of the pin 44 is defined as the Y axis, the axis of the connecting rod is defined as the X axis, and the axis of the adjusting screw 42 is defined as the Z axis.

[0033] The axial length can be adjusted by adjusting the screws 42 on both sides; the double-ear seats 41 on both sides can rotate around the X and Y axes to achieve angle compensation. After being assembled in place, it is locked by the self-locking nut 45 to prevent loosening.

[0034] like Figure 3 As shown, the rod body 43 includes a rod base 431, a left screw sleeve 432 and a right screw sleeve 433. The rod base 431 is a hollow cylindrical structure, and the left screw sleeve 432 and the right screw sleeve 433 are respectively fixedly connected to the two ends of the rod base 431. The two adjusting screws 42 have different thread directions, namely left and right threads, and the right screw sleeve 433 is a left thread structure design; the two adjusting screws 42 are respectively matched with the left screw sleeve 432 and the right screw sleeve 433 of the rod body 43.

[0035] The coordinate system for calculating the spatial dimensions of the universal adjustment rod is shown in Figure 3 , a method for determining the telescopic length range of a pull rod of a universal adjustment pull rod mechanism comprises the following steps:

[0036] Step 1: Establish a 3D engine assembly simulation model to determine the spatial dimensions of the nozzle and turbine exhaust pipe installation surfaces. Specifically include:

[0037] 1) In establishing the three-dimensional assembly simulation model of the engine, the dimensions of the relevant components and assembly parameters are taken as the nominal values ​​of the design;

[0038] 2) Determine the theoretical space dimension L between the nozzle mounting surface and the turbine exhaust pipe mounting surface through the three-dimensional model 0 ;

[0039] 3) According to L 0 , determine the size L of the tie rod body 43 1 , Adjustment screw 42 size L 2 , Screw adjustment amount L 3 And double ear seat 41 size L 4 .

[0040] 4) Structural design. The 3-axis rotational freedom scheme is selected to compensate for any spatial angle. The screw is made of high-temperature alloy material with good high-temperature mechanical properties, which can adapt to the long-term high-temperature environment of rocket engines above 1000℃. The thread adopts rolling processing technology to ensure fatigue life. The root of the thread can adapt to the long-term strong vibration environment when the engine is working.

[0041] 5) Fatigue analysis and material mechanical strength.

[0042] Step 2: Determine the initial length of the universal adjustment rod according to the actual space dimension L between the nozzle mounting surface and the turbine exhaust pipe mounting surface;

[0043] Step 3: Determine the theoretical upper and lower limits of L according to the relevant dimensions that affect the actual spatial dimension L change, such as the nozzle and turbine exhaust pipe assembly dimensions. max , L min ;

[0044] Step 4: According to L max , L min Determine the adjustment range of the pull rod. The design adjustment range should cover the theoretical upper and lower limits L. max , L min , and leave a 20% margin to complete the design;

[0045] Operation method introduction:

[0046] Step 1: Screw the adjusting screw 42 into the pull rod body 43;

[0047] Step 2: According to the actual spatial positions of the two ends of the adjusting screw 42, the double-ear seat 41 is rotated to ensure that the pull rod body 43 and the double-ear seat 41 are in a straight line;

[0048] Step 3: Use the left and right threads to adjust the screw rod 42 to a certain length. After the adjustment is in place, tighten the self-locking nut 45 to complete the assembly.

[0049] Obtaining the mechanical and environmental boundary conditions when the rocket starts ignition:

[0050] Step 1: The ambient temperature is obtained by modeling the combustion and chemical reactions in the engine and performing simulation calculations.

[0051] Step 2: The vibration conditions are obtained by statistically distributing multiple test data.

[0052] The coordinate system for calculating the spatial dimensions of the universal adjustment rod is shown in Figure 3 , the specific steps of calculation are:

[0053] 1) Establish a three-dimensional assembly simulation model of the engine;

[0054] 2) Determine the initial spatial dimension L of the nozzle and turbine exhaust pipe mounting surface through the three-dimensional model 0 ;

[0055] 3) The engine assembly coordinate system is established with the nozzle top as the reference. The origin of the coordinate system can be the center of mass of the engine, such as Figure 6 Among them, the nozzle and the turbine pump are positioned by tooling, and the assembly error between the two is ignored to simplify the calculation.

[0056] 4) Calculate the theoretical limit deviation of point A on the nozzle installation surface. Set it as A(△X a , △Y a , △Z a ), where △X a is the X-direction distance of point A relative to the origin of the coordinate system, △Y a is the Y distance of point A relative to the origin of the coordinate system, △Z a is the Z-direction distance of point A relative to the origin of the coordinate system. The specific calculation method is as follows:

[0057] △X a =△X a1 +△X a2 +△X a3 ……△X an

[0058] Among them, △X a1 It is the theoretical maximum value of the X-direction gap or deviation of the first pair of assembly flanges or butt welds, and so on until the nth pair.

[0059] △Y a =△Y a1 +△Y a2 +△Y a3 ……△Y an

[0060] Among them, △Y a1 This is the theoretical maximum Y-direction gap or deviation of the first pair of assembly flanges or butt welds, and so on until the nth pair.

[0061] △Z a =△Z a1 +△Z a2 +△Z a3 ……△Z an

[0062] Among them, △Z a1 This is the theoretical maximum Z-direction clearance or deviation of the first pair of assembly flanges or butt welds, and so on until the nth pair.

[0063] 5) Using the same method, calculate the theoretical limit deviation of point B on the turbine exhaust pipe installation surface. Set it as B(△X b ,

[0064] △Y b , △Z b )

[0065] 6) Calculate the theoretical limit distance change △L between points A and B:

[0066]

[0067] 7) Determine the theoretical limit distance between points A and B, and determine the upper and lower limits of the universal adjustment rod size L:

[0068] L max =L 0 +△L

[0069] L min =L 0 -△L:

[0070] Component sizes are allocated based on the upper and lower limits of the total size calculated theoretically.

[0071] The main structural design solutions are as follows:

[0072] The pull rod body consists of a pull rod base and a left and right screw sleeve, and is used in conjunction with an adjusting screw. The two ends are designed as left and right threads respectively, for the purpose of convenient operation, that is, both sides are screwed out counterclockwise, which is consistent with operating habits. The size L1 of the pull rod body is the theoretical maximum size after connecting with the adjusting screw. The thread depths of the left and right screw sleeves are designed to be L1a and L1b respectively, which are the adjustment amount, and L1-L1a-L1b is the theoretical minimum size.

[0073] The two adjusting screws are identical except for the direction of the threads (one of which is left-handed). Dimension L3 is the screw adjustment amount, L2 is the theoretical maximum dimension after connection, and L2-L3 is the theoretical minimum dimension after connection.

[0074] The double-ear seat is connected to the adjusting screw, the angle can be adjusted freely, but the linear dimension cannot be adjusted. L4 is the theoretical dimension.

[0075] The pin connects the adjusting screw and the double ear seat so that it can rotate freely. In this case, it is designed as The end is designed with an M8 thread structure, which can be locked after installation.

[0076] Self-locking nuts have locking and anti-loosening functions. They can be locked after being installed in place and have the function of preventing loosening.

[0077] The main steps for obtaining temperature and vibration environmental conditions are as follows:

[0078] 1) According to the main structural dimensions of the engine thrust chamber, a finite element model is established. Considering that the thrust chamber is a rotating body structure, in order to optimize the calculation efficiency, a 1 / 6 model is established to calculate the temperature field (such as Figure 7 ).

[0079] 2) According to the characteristics of the combustion structure, the eddy dissipation concept (EDC) model in the component transport model is used to simulate the combustion process by solving the component transport equations of reactants and products. This model should cover the main chemical reactions in the ignition process. Taking this engine as an example, the statistical reaction equation is as follows. Parameters such as activation energy and temperature index can be obtained by looking up the table.

[0080] Table 1 Main chemical reactions and model parameters

[0081]

[0082] 3) Using the discrete phase model calculation module of Fluent, the above chemical reaction equations and parameters are substituted to calculate the temperature field at the moment of ignition (such as Figure 8 ) as the working temperature boundary condition of the universal adjustment rod.

[0083] 4) The vibration environment boundary conditions are determined by probability distribution. The vibration data of engines with similar main parameters and structures are used for frequency domain analysis, and the maximum envelope is statistically obtained as the vibration boundary conditions.

[0084] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0085] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A universal adjustment rod for a rocket engine, characterized in that: The invention comprises a universal adjustment rod, which is installed between a nozzle (1) and a turbine exhaust pipe (3) of a rocket engine, and the nozzle (1) and the turbine exhaust pipe (3) are both connected to a turbine pump (2); The universal adjustment rod comprises a double-ear seat (41), an adjustment screw (42) and a rod body (43); the two ends of the rod body (43) are respectively threadedly connected to an adjustment screw (42); the adjustment screw (42) and the rod body (43) are coaxial; the end of each adjustment screw (42) away from the rod body (43) is rotatably connected to a double-ear seat (41); the rotation axis of the double-ear seat (41) and the adjustment screw (42) is perpendicular to the axis of the adjustment screw (42); each double-ear seat (41) is used for threaded connection with a nozzle (1) or a turbine exhaust pipe (3).

2. The universal adjustment rod for a rocket engine according to claim 1, characterized in that: The double-ear seat (41) includes a U-shaped piece and a connecting rod, the connecting rod is fixedly connected to the outer side of the closed end of the U-shaped piece, the end of the adjusting screw (42) away from the pull rod body (43) extends into the opening of the U-shaped piece, and the pin (44) passes through the U-shaped piece and the end of the adjusting screw (42), and the nut (45) is threadedly connected to the other end of the pin (44) passing through the U-shaped piece.

3. The universal adjustment rod for a rocket engine according to claim 2, characterized in that: The nozzle has a nozzle mounting surface (11), the nozzle mounting surface is provided with a first mounting hole, a connecting rod at one end of the universal adjustment rod is threadedly connected to the first mounting hole, a turbine exhaust pipe mounting surface (31) is provided on the nozzle mounting surface, the turbine exhaust pipe mounting surface is provided with a second mounting hole, and a connecting rod at the other end of the universal adjustment rod is threadedly connected to the second mounting hole.

4. The universal adjustment rod for a rocket engine according to claim 1, characterized in that: The pull rod body (43) comprises a pull rod base (431), a left screw sleeve (432) and a right screw sleeve (433); the pull rod base (431) is a hollow cylindrical structure; the left screw sleeve (432) and the right screw sleeve (433) are respectively fixedly connected to the two ends of the pull rod base (431); the thread rotation directions of the two adjusting screws (42) are different; the left screw sleeve (432) and the right screw sleeve (433) are respectively matched with the thread of one adjusting screw (42).

5. The universal adjustment rod for a rocket engine according to claim 2, characterized in that: The installation method of the universal adjustment rod includes: Screw the adjusting screw (42) into the pull rod body (43); According to the actual spatial positions of the two ends of the adjusting screw rod (42), the double-ear seat (41) is rotated so that the pull rod body (43) and the connecting rod of the double-ear seat (41) are in a straight line; Connect one connecting rod to the nozzle (1), adjust the screw length of the adjusting screw (42) by screwing, and simultaneously connect the other connecting rod to the turbine exhaust pipe (3), adjust to the right position, and tighten the nut (45).

6. The universal adjustment rod for a rocket engine according to claim 1, characterized in that: The method for determining the telescopic length range of the universal adjustment rod includes: Establish a three-dimensional assembly simulation model of the engine and determine the coordinate origin; The theoretical space dimension L0 between the nozzle mounting surface and the turbine exhaust pipe mounting surface is determined through the engine three-dimensional assembly simulation model; According to L0, determine the size L1 of the pull rod body (43), the size L2 of the adjusting screw (42), the screw adjustment amount L3 and the size L4 of the double ear seat 41; Determine the initial length of the universal adjustment rod according to the actual space dimension L between the nozzle mounting surface and the turbine exhaust pipe mounting surface; Determine the theoretical upper and lower limits of L according to the nozzle assembly dimensions and turbine exhaust pipe assembly dimensions that affect the actual space size L change. max , L min ; According to L max , L min Determine the adjustment range of the pull rod. The design adjustment range should cover the theoretical upper and lower limits L. max , L min , and leave a 20% margin.

7. The universal adjustment rod for a rocket engine according to claim 6, characterized in that: The theoretical limit deviation of point A on the nozzle installation surface is A(△X a , △Y a , △Z a ), where △X a is the X-direction distance of point A relative to the origin of the coordinate system, △Y a is the Y distance of point A relative to the origin of the coordinate system, △Z a is the Z-direction distance of point A relative to the coordinate origin; The theoretical limit deviation of point B on the turbine exhaust pipe installation surface is B(△X b , △Y b , △Z b ), △X b is the X-direction distance of point B relative to the origin of the coordinate system, △Y b is the Y distance of point B relative to the origin of the coordinate system, △Z b is the Z-direction distance of point B relative to the coordinate origin; The theoretical limit distance change △L between points A and B is: According to the theoretical limit distance between points A and B, determine the upper and lower limits of the universal adjustment rod size L: L max =L0+△L;L min =L0-△L.

8. The universal adjustment rod for a rocket engine according to claim 7, characterized in that: The △X a =△X a1 +△X a2 +△X a3 ……△X an ; Among them, △X a1 The theoretical maximum value of the X-direction radial clearance or deviation of the first pair of assembly flanges or butt welds, and so on until the nth pair; △Y a =△Y a1 +△Y a2 +△Y a3 ……△Y an Among them, △Y a1 The maximum theoretical value of the Y-direction radial clearance or deviation of the first pair of assembly flanges or butt welds, and so on until the nth pair; △Z a =△Z a1 +△Z a2 +△Z a3 ……△Z an Among them, △Z a1 This is the theoretical maximum value of the Z-direction axial clearance or deviation of the first pair of assembly flanges or butt welds, and so on until the nth pair.

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