Detachable spraying pipe ground test run external pressure instability resisting device

Abstract

A detachable spraying pipe ground test run external pressure instability resisting device comprises connecting bases, reinforcing plates and reinforcing plate connecting pieces, and the multiple connecting bases are evenly arranged on the outer wall face of a spraying pipe in the circumferential direction and welded to the outer wall of the spraying pipe; each connecting base is provided with a group of convex lug pairs, a gap is formed between two convex lugs of each group of convex lug pairs, and opposite bolt holes are formed in the upper parts of the two convex lugs; each reinforcing plate is of a semi-circular ring structure, and the two reinforcing plates are installed in gaps of all the lug pairs along the circumference where the connecting base is located and form a complete circular ring reinforcing plate through the reinforcing plate connecting piece; a plurality of long-circle-shaped thermal deformation coordination holes are evenly formed in the reinforcing plate in the radial direction, and the thermal deformation coordination holes are connected with the bolt holes of the lug pairs in a one-to-one correspondence mode. The device can be used during ground hot test run of the spray pipe, and structural instability and deformation caused by the fact that internal pressure of the spray pipe is far lower than external environment pressure are avoided.

Description

Technical Field

[0001] The invention relates to a detachable nozzle ground test anti-external pressure instability device, belonging to the field of liquid rocket engines. Background Art

[0002] Liquid rocket engines improve engine performance by increasing the nozzle exit area ratio. The mainstream combustion gas expands faster in the nozzle, gradually increasing its velocity while decreasing its temperature and pressure. As the nozzle area ratio increases, the need for thermal protection and structural strength decreases. Large-area-ratio nozzles typically use thin-walled structures. During ground test runs, when starting high-altitude simulation equipment before starting an engine, or when starting the engine, the ambient pressure on the nozzle's outer wall may exceed the pressure on the inner wall. When this pressure difference exceeds the critical pressure the structure can withstand, the nozzle can become unstable and wrinkle under the action of external pressure. To prevent the nozzle from becoming unstable due to external pressure, a reinforcement structure is usually welded to the nozzle's outer wall. This welded reinforcement adds additional structural weight, restricts thermal expansion and deformation of the nozzle, and affects its normal operation. Summary of the Invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the existing technology and provide a detachable nozzle ground test anti-external pressure instability device, which can be used during the ground hot test of the nozzle to avoid structural instability and deformation caused by the internal pressure of the nozzle being much lower than the external environmental pressure.

[0004] The technical solution of the present invention is: a detachable nozzle ground test anti-external pressure instability device, comprising: a connecting base, a reinforcement plate and a reinforcement plate connecting piece, wherein:

[0005] A plurality of connecting bases are evenly arranged along the circumferential direction on the outer wall of the nozzle and welded to the outer wall of the nozzle; each connecting base is provided with a set of lug pairs, a gap is provided between the two lugs of each lug pair, and upper portions of the two lugs have opposing bolt holes;

[0006] Each reinforcement plate is a semi-circular ring structure. The two reinforcement plates are installed in the gap between the lug pairs along the circumference of the connecting base. The two reinforcement plates form a complete circular reinforcement plate through the reinforcement plate connecting piece; multiple oblong thermal deformation coordination holes are evenly arranged along the radial direction of the reinforcement plate, and the thermal deformation coordination holes and the bolt holes of the lug pairs are connected one by one.

[0007] Preferably, the gap L1 between the two lugs of each lug pair is determined according to the thickness of the reinforcing plate:

[0008] L1 is 0.2 mm to 0.5 mm larger than the thickness of the reinforcement plate, ensuring that the reinforcement plate can move freely in the gap between the lug pairs.

[0009] Preferably, each reinforcing plate is provided with bolt holes at both end ends;

[0010] Two through holes are provided on each reinforcing plate connecting piece;

[0011] At each connection point of the two reinforcing plates, a reinforcing plate connecting piece is placed on each side, and the two through holes on the reinforcing plate connecting piece correspond to the two bolt holes when the two reinforcing plates are connected; the two reinforcing plate connecting pieces and the two reinforcing plates are connected using bolts and nuts to form a complete circular reinforcing plate.

[0012] Preferably, the cross-sectional shape of the reinforcement plate is designed to be T-shaped or inverted L-shaped, so as to enhance the structural rigidity of the reinforcement plate.

[0013] Preferably, the thermal deformation coordination hole and the bolt holes of the lug pair are connected one-to-one by bolts; when the bolt is at the top of the thermal deformation coordination hole, the position of the bolt is defined as the top dead center, and when the bolt is at the bottom of the thermal deformation coordination hole, the position of the bolt is defined as the bottom dead center; the length between the bolt axes corresponding to the top dead center and the bottom dead center is the thermal deformation length provided by the thermal deformation coordination hole.

[0014] Preferably, the method for determining the thermal deformation length L2 provided by the thermal deformation coordination hole is:

[0015] The wall temperature and material thermal expansion coefficient of the single-wall nozzle at the connection base are calculated to obtain the radial thermal expansion deformation of the nozzle at the connection base. On the basis of the above radial thermal expansion deformation, the radial thermal expansion deformation is further increased by 10% to 20% to provide the thermal deformation length L2 provided by the thermal deformation coordination hole.

[0016] Preferably, after the detachable nozzle ground test anti-external pressure instability device is assembled:

[0017] In the initial state, the bolts for connecting each set of lug pairs with the thermal deformation coordination holes are located at the bottom dead center of the thermal deformation coordination holes;

[0018] During ground test runs, when the high-altitude simulation equipment is started or when the engine is started, the ambient pressure on the outer wall of the nozzle may be greater than the pressure on the inner wall. The single-wall nozzle wall tends to deform inward. The bolts connecting each set of lug pairs to the thermal deformation coordination holes are located at the bottom dead center of the thermal deformation coordination holes. The reinforcement plate serves to limit the inward deformation of the nozzle wall.

[0019] When the engine is working, the nozzle is in a high-temperature state and expands due to the heat, driving the connecting base and the lug pair to move radially outward, gradually approaching but not contacting the top dead center of the thermal deformation coordination hole of the reinforcement plate, so that the reinforcement plate does not affect the expansion and deformation of the nozzle.

[0020] Preferably, the connecting base and the lug pair are integrally formed, and the reinforcement plate is removed when the nozzle is delivered for flight. At the same time, the lug pair is removed by lathing without damaging the outer wall structure of the nozzle.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) Improve the ability of the nozzle thin-wall structure to resist instability due to external pressure so that it can adapt to ground environment hot test;

[0023] (2) A detachable structure is used. When there is no external pressure instability environment during actual flight, it can be removed to reduce the structural weight;

[0024] (3) The thermal deformation coordination hole is designed in the anti-external pressure instability device to ensure that the thermal expansion deformation of the nozzle is not constrained during the hot test, and the influence of the anti-external pressure instability device on the working state of the single-wall nozzle is eliminated as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of the detachable nozzle ground test device for resisting external pressure instability of the present invention;

[0026] Figure 2 This is a schematic structural diagram of the connecting base of the present invention;

[0027] Figure 3 Schematic diagrams of the reinforcing plate structure of the present invention: (a) is a front view of the reinforcing plate and a partial schematic diagram of the thermal deformation coordination hole, (b) is an inverted L-shaped reinforcing plate and a cross-sectional schematic diagram, and (c) is a T-shaped reinforcing plate and a cross-sectional schematic diagram;

[0028] Figure 4 This is a schematic diagram of the reinforcement plate connection of the present invention;

[0029] Figure 5 Schematic cross-sections of the nozzle and bolts of the present invention at the bottom dead center and top dead center, respectively: (a) is a schematic diagram showing the bolts connecting each set of lug pairs to the thermal deformation coordination holes at the bottom dead center of the thermal deformation coordination holes; (b) is a schematic diagram showing the lug bolts at the top dead center of the thermal deformation coordination holes of the reinforcement plate.

[0030] Figure ID:

[0031] 1-nozzle, 2-connecting base, 3-reinforcement plate, 4-reinforcement plate connecting piece, 21-lug pair, 22-bolt hole on the lug pair, 31-thermal deformation coordination hole, 32-bolt hole. DETAILED DESCRIPTION

[0032] The present invention designs a detachable nozzle ground test anti-external pressure instability device, the reinforcement plate is connected to the connection base of the outer wall of the single-wall nozzle by bolts, realizing the detachable design of the reinforcement plate, and the reinforcement plate is designed with a thermal deformation coordination hole along the radial direction. Through structural size design, the bolts on the connection base lug are located at the lower dead point of the thermal deformation coordination hole during assembly, limiting the inward deformation of the nozzle caused by external pressure instability and improving its resistance to external pressure instability. During the hot test, the nozzle expands due to heat, and the single-wall nozzle drives the connection base to slide along the thermal deformation coordination hole toward its lower dead point, avoiding the restriction of the reinforcement plate on the thermal expansion deformation of the single-wall nozzle.

[0033] A detachable nozzle ground test anti-external pressure instability device, such as Figure 1 shown.

[0034] A plurality of connecting bases 2 are evenly arranged along the circumferential direction of the outer wall of the nozzle 1 (for example, 12 are evenly distributed around the entire circumference), and the connecting bases 2 are welded to the outer wall of the nozzle 1 .

[0035] like Figure 2 As shown, the connecting base 2 extends a set of lug pairs 21 perpendicular to the axis of the nozzle 1. Bolt holes 22 are provided on the outer sides of the lug pairs 21. The gap L1 between the lug pairs 21 is determined by the thickness of the reinforcing plate 3. To ensure that the reinforcing plate 3 can move freely in the lug pairs 21, the gap L1 between the lug pairs 21 is 0.2 to 0.5 mm larger than the thickness of the reinforcing plate 3.

[0036] like Figure 3 As shown, the reinforcement plate 3 is a semicircular ring structure with multiple oblong thermal deformation coordination holes 31 evenly arranged radially. The specific number is determined by the number of designed connection bases 2. That is, the thermal deformation coordination holes 31 and the bolt holes of the lug pairs 21 are connected one-to-one by bolts. When the bolt is at the top of the thermal deformation coordination hole 31, the bolt position is defined as the top dead center, and when the bolt is at the bottom of the thermal deformation coordination hole 31, the bolt position is defined as the bottom dead center. The length between the top dead center and the bottom dead center of the bolt axis is the thermal deformation length L2 provided by the thermal deformation coordination hole 31. The radial thermal expansion deformation of the structure at the connection base 2 is calculated based on the wall temperature of the single-wall nozzle at the connection base 2 and the thermal expansion coefficient of the material. Based on this radial thermal expansion deformation, a certain margin is considered to determine the thermal deformation length L2 provided by the thermal deformation coordination holes 31. The margin is recommended to be 10% to 20%. Bolt holes 32 are left at both ends of the reinforcement plate 3. The outer side (cross-sectional shape) of the reinforcing plate 3 can be designed to be L-shaped or T-shaped to enhance the structural rigidity of the reinforcing plate, thereby improving the ability of the device to resist instability caused by external pressure of the nozzle.

[0037] During assembly, the reinforcing plate 3 is installed into the gap between the lugs of the connecting base 2. The two reinforcing plates 3 are connected at the bolt holes 32 at the ends using the reinforcing plate connecting pieces 4 and bolts and nuts to form a reinforcing plate that is full of circumference. Each reinforcing plate connecting piece 4 is provided with two through holes; Figure 4 As shown, at each connection point of the two reinforcing plates 3, a reinforcing plate connecting piece 4 is placed on each side, and the two through holes on the reinforcing plate connecting piece 4 correspond to the two bolt holes 32 when the two reinforcing plates are connected; the two reinforcing plate connecting pieces 4 and the two reinforcing plates 3 are connected using bolts and nuts to form a complete circular reinforcing plate.

[0038] The thermal deformation coordination holes 31 on the reinforcing plate 3 are aligned with the bolt holes on the connecting base lugs, and the reinforcing plate 3 is fixed in the gaps between the connecting base lugs using bolts and nuts.

[0039] According to the design, the bolts connecting the base lugs are located at the bottom dead center of the thermal deformation coordination hole 31 of the reinforcement plate 3 during assembly. Figure 5 As shown, when the high-altitude simulation equipment for ground test is started or the engine is started, there is a situation where the ambient pressure on the outer wall of the nozzle is greater than the pressure on the inner wall, and the wall of the single-wall nozzle tends to deform inward. The bolts at the connecting base lug are located at the lower dead point of the thermal deformation coordination hole 31 of the reinforcing plate 3, and the reinforcing plate 3 plays a role in limiting the inward deformation of the nozzle wall; when the engine is working, the nozzle is in a high-temperature state, and the nozzle expands due to heat, driving the connecting base 2 to move radially outward, gradually approaching but not contacting the upper dead point of the thermal deformation coordination hole 31 of the reinforcing plate 3. When the engine is working, the reinforcing plate 3 does not affect the expansion and deformation of the nozzle, reducing the stress caused by non-free expansion.

[0040] When the nozzle is delivered for flight, the reinforcement plate 3 can be removed and the connection base lug pair 21 can be removed by turning as much as possible without damaging the outer wall structure of the nozzle to reduce the structural weight to the greatest extent.

[0041] The detachable nozzle ground test anti-external pressure instability device designed in the present invention can improve the nozzle's ability to resist external pressure instability, and will not restrict the thermal expansion of the nozzle during hot testing, thereby minimizing the impact on the nozzle's working state. It can also be removed during actual flight to reduce the structural weight. The present invention can be applied in the field of aerospace propulsion.

[0042] The contents not described in detail in the specification of the present invention belong to the prior art known to those skilled in the art.

Claims

1. A detachable nozzle ground test anti-external pressure instability device, characterized by include: Connecting the base (2), the reinforcing plate (3) and the reinforcing plate connecting piece (4), wherein: A plurality of connecting bases (2) are evenly arranged along the circumferential direction on the outer wall of the nozzle and are welded to the outer wall of the nozzle; each connecting base (2) is provided with a group of lug pairs (21), a gap is provided between the two lugs of each lug pair (21), and the upper parts of the two lugs are provided with opposing bolt holes; Each reinforcing plate (3) is a semi-circular ring structure. The two reinforcing plates (3) are installed in the gap between the lug pair (21) along the circumference of the connection base (2). The two reinforcing plates (3) form a complete circular reinforcing plate through the reinforcing plate connecting piece (4). A plurality of oblong thermal deformation coordination holes (31) are evenly arranged along the radial direction on the reinforcing plate (3). The thermal deformation coordination holes (31) and the bolt holes of the lug pair (21) are connected in a one-to-one correspondence.

2. The detachable nozzle ground test anti-external pressure instability device according to claim 1, characterized in that: The gap L1 between the two lugs of each lug pair (21) is determined according to the thickness of the reinforcing plate (3): L1 is 0.2 mm to 0.5 mm greater than the thickness of the reinforcing plate (3), ensuring that the reinforcing plate (3) can move freely in the gap between the lug pairs (21).

3. The detachable nozzle ground test anti-external pressure instability device according to claim 1, characterized in that: Each reinforcing plate (3) is provided with bolt holes (32) at both ends; Each reinforcing plate connecting piece (4) is provided with two through holes; At each connection point of the two reinforcing plates (3), a reinforcing plate connecting piece (4) is placed on each side, and the two through holes on the reinforcing plate connecting piece (4) correspond to the two bolt holes (32) when the two reinforcing plates are connected; the two reinforcing plate connecting pieces (4) and the two reinforcing plates (3) are connected using bolts and nuts to form a complete circular reinforcing plate.

4. The detachable nozzle ground test anti-external pressure instability device according to claim 1, characterized in that: The cross-sectional shape of the reinforcement plate (3) is designed to be T-shaped or inverted L-shaped, so as to enhance the structural rigidity of the reinforcement plate.

5. The detachable nozzle ground test anti-external pressure instability device according to claim 1 is characterized by: The thermal deformation coordination hole (31) and the bolt holes of the lug pair (21) are connected in a one-to-one correspondence through bolts; when the bolt is at the top of the thermal deformation coordination hole (31), the position of the bolt is defined as the top dead center, and when the bolt is at the bottom of the thermal deformation coordination hole (31), the position of the bolt is defined as the bottom dead center; the length between the bolt axes corresponding to the top dead center and the bottom dead center is the thermal deformation length provided by the thermal deformation coordination hole (31).

6. The detachable nozzle ground test anti-external pressure instability device according to claim 5, characterized in that: The method for determining the thermal deformation length L2 provided by the thermal deformation coordination hole (31) is: The wall temperature and material thermal expansion coefficient of the single-wall nozzle at the connection base (2) are calculated to obtain the radial thermal expansion deformation of the nozzle at the connection base (2). After further increasing the radial thermal expansion deformation by 10% to 20% on the basis of the above radial thermal expansion deformation, the thermal deformation length L2 provided by the thermal deformation coordination hole (31) is obtained.

7. The detachable nozzle ground test anti-external pressure instability device according to claim 5, characterized in that: After the detachable nozzle ground test device is assembled to resist external pressure instability: In the initial state, the bolts for connecting each set of lug pairs (21) with the thermal deformation coordination hole (31) are located at the bottom dead center of the thermal deformation coordination hole (31); When the high-altitude simulation equipment for ground test driving is started or the engine is started, there is a situation where the ambient pressure on the outer wall of the nozzle is greater than the pressure on the inner wall, and the wall surface of the single-wall nozzle tends to deform inward. The bolts for connecting each set of lug pairs (21) and the thermal deformation coordination hole (31) are located at the bottom dead center of the thermal deformation coordination hole (31), and the reinforcing plate (3) plays a role in limiting the inward deformation of the nozzle wall surface; When the engine is operating, the nozzle is in a high temperature state and expands due to the heat, driving the connecting base (2) and the lug pair (21) to move radially outward, gradually approaching but not contacting the upper dead center of the thermal deformation coordination hole of the reinforcement plate (3), so that the reinforcement plate (3) does not affect the expansion and deformation of the nozzle.

8. The detachable nozzle ground test device for resisting external pressure instability according to claim 1, characterized in that: The connecting base (2) and the lug pair (21) are integrally formed. When the nozzle is delivered for flight, the reinforcing plate (3) is removed. At the same time, the lug pair (21) is removed by machining without damaging the outer wall structure of the nozzle.

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