CN113916175B - Rocket engine nozzle inner and outer wall gap measuring method - Google Patents

Abstract

The invention provides a method for measuring the clearance between the inner wall and the outer wall of a rocket engine nozzle, which comprises the following steps: establishing a functional relation between the spot welding surface topography characteristic parameters and the inner and outer wall gaps; spot welding is carried out on the outer wall of the spray pipe, the outer wall of the spray pipe is welded through, and the bottom of a molten pool falls on the rib top of the inner wall of the spray pipe; measuring the surface appearance characteristic parameters of the spot welding; and inversely calculating the clearance between the inner wall and the outer wall according to the functional relation between the spot welding surface topography characteristic parameters and the clearance between the inner wall and the outer wall. The measuring method achieves the purpose of measuring the clearance between the inner wall and the outer wall on the premise of not disassembling the spray pipe.

Description

A method for measuring the gap between the inner and outer walls of a rocket engine nozzle

technical field

The invention relates to the field of liquid rockets, in particular to a method for measuring the gap between the inner and outer walls of a nozzle of a rocket engine.

Background technique

The nozzle of the liquid rocket engine is composed of an inner wall and an outer wall, the inner wall is processed with channels, and the sandwich structure composed of the inner wall and the outer wall is used to circulate the high-pressure liquid propellant to cool the nozzle. Usually the most important process in its production process is to connect the inner and outer walls with grooves, but when the inner and outer walls of the nozzle are assembled together, the gap at both ends can only be measured through the gap sheet. For the gap in the middle position Hard to be sure. Current ultrasonic testing methods cannot detect this gap. At the same time, because the inner wall is usually equipped with a solid tooling, it is impossible to use a caliper to measure the thickness for inverse calculation of the gap.

Therefore, it is urgent to design a method for measuring the gap between the inner and outer walls of a rocket engine nozzle without disassembling the inner and outer walls of the nozzle.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for measuring the gap between the inner and outer walls of a rocket engine nozzle.

The invention provides a method for measuring the gap between the inner and outer walls of a rocket engine nozzle. The bottom of the pool falls on the top of the rib on the inner wall of the nozzle; the characteristic parameters of the spot welding surface morphology are measured; and the inner and outer wall gaps are inversely calculated according to the functional relationship between the said spot welding surface morphology characteristic parameters and the inner and outer wall gaps.

According to an embodiment of the present invention, before performing the spot welding on the outer wall of the nozzle, the method includes: setting parameters for the spot welding.

According to an embodiment of the present invention, the spot welding parameters include spotting power and spotting time.

According to an embodiment of the present invention, the dotting power W=(B*100+300)/t*50; wherein, B is the thickness of the outer wall, and t is the dotting time.

According to an embodiment of the present invention, the setting of the spot welding parameters includes: selecting a test panel with the same material and thickness as the outer wall; performing spot welding on the test panel; recording the spot welding penetration as 1 to 1.5 times the test Spot welding spotting parameters when the thickness of the wall plate; the recorded spot welding spotting parameters are set as parameters for spot welding spotting on the outer wall.

According to an embodiment of the present invention, the recorded spot welding parameters when the penetration depth of the spot welding is 1.3 times the thickness of the test wall plate are set as the parameters for spot welding the outer wall.

According to an embodiment of the present invention, before the setting of the spot welding parameters includes: measuring the thickness of the outer wall.

According to an embodiment of the present invention, the characteristic parameters of the surface morphology of the spot welding include: the depth of the spotting depression and the diameter of the spotting depression.

According to an embodiment of the present invention, the gap between the inner and outer walls is

F=k*(0.6*h+(0.5*d)^0.5); wherein, k is the revision coefficient, h is the depth of the dotted depression, and d is the diameter of the dotted depression.

According to an embodiment of the present invention, 4-6 longitudinal positions are selected on the circumference of the outer wall of the nozzle, and 3-15 points are set on each longitudinal position for spot welding.

According to the method for measuring the gap between the inner and outer walls of the rocket engine nozzle of the present invention, spot welding is performed on the outer wall of the nozzle, and by establishing the functional relationship between the characteristic parameters of the spot welding surface and the gap between the inner and outer walls, the gap between the inner and outer walls is calculated inversely. Disassemble the inner and outer walls, and measure the gap between the inner and outer walls.

It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to limit the scope of the invention as claimed.

Description of drawings

The accompanying drawings, which are part of the specification of the invention, illustrate exemplary embodiments of the invention and, together with the description of the specification, serve to explain the principles of the invention.

1-3 are flowcharts of a method for measuring the gap between the inner and outer walls of a rocket engine nozzle according to an embodiment of the present invention;

Fig. 4 is the schematic diagram that the rocket engine nozzle outer wall of one embodiment of the present invention is dotted;

FIG. 5 is a cross-sectional view taken along line A-A of FIG. 4 .

Description of reference numbers:

1- Nozzle outer wall; 2- Inner and outer wall gap; 3- Laser beam; 4- Point position; 5- Dot concave diameter; 6- Nozzle inner wall; 7- Dot concave depth.

Detailed ways

The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention, are used to exemplify the principles of the present invention, and are not configured to limit the present invention. Additionally, the machine components in the figures are not necessarily drawn to scale. For example, the dimensions of some of the structural elements or regions in the figures may be exaggerated for other structural elements or regions to facilitate an understanding of embodiments of the present invention.

Orientation words appearing in the following description are all directions shown in the drawings, and do not limit the specific structure of the embodiments of the present invention. In the description of the present invention, it should be noted that, unless otherwise specified, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integrated ground connection; either directly or indirectly through an intermediary. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific conditions.

Furthermore, the terms "comprising," "comprising," "having," or any other variation thereof are intended to encompass a non-exclusive inclusion such that a structure or component that includes a list of elements includes not only those elements, but also includes not explicitly listed or inherently belong to structural parts, other mechanical parts on components. Without further limitation, an element defined by the phrase "comprising" does not preclude the presence of additional identical elements in the article or device comprising the element.

Spatial relational terms such as "below," "below," "below," "lower," "above," "above," "higher," etc. are used to facilitate description to explain an element relative to a The orientation of the two elements means that these terms are intended to encompass different orientations of the device in addition to orientations other than those shown in the figures. In addition, for example, "one element is on/under the other" may mean that two elements are in direct contact with each other, or that there are other elements between the two elements. Furthermore, terms such as "first", "second", and the like, are also used to describe various elements, regions, sections, etc. and should not be regarded as limiting. Similar terms refer to similar elements throughout the description.

In the process of describing the present invention below, only "rocket", "launch vehicle" or "missile" may be used in the description of certain scenarios, which is only for the convenience of description, and its connotation is not limited to the specific words used. Typically, the rockets of the present invention may include launch vehicles, missiles, space vehicles, and the like capable of delivering payloads into the air. When interpreting the above specific terms, those skilled in the art should not limit the carrier to only one of the launch vehicles or missiles according to the specific terms used to describe the scene, so as to narrow the protection scope of the present invention.

It will be apparent to those skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present invention by illustrating examples of the invention.

1-3 is a flow chart of a method for measuring the gap between the inner and outer walls of a rocket engine nozzle according to an embodiment of the present invention; FIG. 4 is a schematic diagram of dots on the outer wall of a rocket engine nozzle according to an embodiment of the present invention; FIG. 5 is a cross-sectional view A-A in FIG. 4 .

As shown in Figure 1, the present invention provides a method for measuring the gap between the inner and outer walls of a rocket engine nozzle, which is characterized in that, comprising:

S100 establishes the functional relationship between the surface topography characteristic parameters of spot welding and the gap between the inner and outer walls;

S200 performs spot welding on the outer wall of the nozzle, penetrates the outer wall of the nozzle and makes the bottom of the molten pool fall on the top of the rib on the inner wall of the nozzle;

S300 measures the characteristic parameters of spot welding surface topography;

S400 inversely calculates the inner and outer wall gaps according to the functional relationship between the spot welding surface topography characteristic parameters and the inner and outer wall gaps.

Specifically, the nozzle of the liquid rocket engine is composed of an inner wall and an outer wall, the inner wall is processed with channels, and the sandwich structure composed of the inner wall and the outer wall circulates the high-pressure liquid propellant to cool the nozzle. Usually the most important process in its production process is to connect the inner and outer walls with grooves, but when the inner and outer walls of the nozzle are assembled together, the gap at both ends can only be measured through the gap sheet. For the gap in the middle position Hard to be sure.

The matching gap between the inner wall and the outer wall is related to the optimal welding parameters. For places with too large gaps, it is easy to produce welding through defects during welding, resulting in product welding failure. Therefore, it is necessary to measure the fitting clearance after the inner wall and outer wall are assembled, and to optimize the welding sequence where the welding clearance is large, so as to avoid the occurrence of welding through. Especially in the inner part away from the end face of the outer wall, the gap here directly affects the welding position, welding sequence and welding quality. For example, when the assembly gap between the inner wall and the outer wall of the nozzle is within 0-1mm, better welding quality can be obtained when the gap is less than 0.4mm, and defects such as welding penetration and welding leakage are easy to be obtained when the gap exceeds 0.5mm. Therefore, it is necessary to optimize the welding parameters for the position where the gap is larger than 0.5mm before welding. At the same time, the preferential welding gap is less than 0.5mm, and the welding gap can be gradually improved and narrowed by welding shrinkage. Therefore, it is necessary to measure the gap between the inner and outer walls when welding or repairing the weld between the two wall plates, so as to obtain the best welding position.

Since the inner profile of the inner wall is filled with tooling, it is necessary to accurately measure the gap at each position of the inner wall and the outer wall without disassembling the inner wall and the outer wall after the nozzle is assembled. Current ultrasonic testing methods cannot detect this gap. At the same time, because the inner wall is usually equipped with solid tooling, it is impossible to use a caliper to measure the thickness for back calculation.

In this embodiment, by establishing a functional relationship between the characteristic parameters of the spot welding surface topography and the inner and outer wall gaps, the inner and outer wall gaps are calculated inversely according to the measured characteristic parameters of the spot welding surface topography. The purpose of accurately measuring the gap between the inner and outer walls is achieved without disassembling the inner and outer walls and without repositioning the product. At the same time, the connection between the inner and outer walls can be strengthened by spot welding.

The measurement method provided in this embodiment has no size limitation on the nozzle, and can realize the measurement of the gap of a large wall panel, with large effective working space, low cost and high efficiency.

As shown in Figure 2, in this embodiment, before the spot welding is performed on the outer wall of the nozzle, it includes:

S201 sets the parameters of spot welding.

Specifically, by setting appropriate parameters for spot welding and spot welding on the outer wall of the nozzle, it is possible to ensure that the outer wall is penetrated and the bottom of the molten pool falls on the top of the inner wall rib.

In this embodiment, the spot welding parameters include spotting power and spotting time. Specifically, set a suitable spotting power and spotting time, and perform spot welding and spotting on the outer wall according to the spotting power. The spot welding spotting time should meet the preset spotting time, so as to ensure that the outer wall is penetrated and the bottom of the molten pool falls to the top of the inner wall rib. superior.

Further, the dotting power is: W=(B*100+300)/t*50; wherein, B is the thickness of the outer wall, and t is the dotting time. Specifically, the spotting time interval is 20ms-200ms, and a spotting time is selected in this interval (for example, a stainless steel plate with a thickness of 1mm is selected 100ms), and the spotting power is calculated according to the functional relationship between the spotting power and the spotting time. The spotting time and the calculated spotting power are the appropriate spotting time and spotting power. Spot welding and spotting on the outer wall according to the spot welding parameters can ensure that the outer wall is penetrated and the bottom of the molten pool falls on the top of the inner wall rib.

As shown in Figure 3, according to an embodiment of the present invention, setting the parameters of spot welding includes:

S2011 Select the test panel with the same material and thickness as the outer wall;

S2012 Spot welding on the test panel;

S2013 record the spot welding parameters when the spot welding penetration is 1 to 1.5 times the thickness of the test wall;

In S2014, the recorded spot welding parameters are set as parameters for performing spot welding on the outer wall.

Specifically, carry out the spot welding spotting test on the test panel with the same material and thickness as the outer wall, record the spot welding spotting parameters when the spot welding penetration is 1 to 1.5 times the thickness of the test panel, and set this parameter to The parameters of spot welding on the outer wall, and spot welding on the outer wall. Since the test panel with the same material and thickness as the outer wall is selected, it can truly reflect the effect of spot welding on the outer wall. Taking the spot welding parameters when the penetration depth of spot welding is 1 to 1.5 times the thickness of the test wall as the spot welding parameters of the outer wall, it can ensure that the outer wall is penetrated and the bottom of the molten pool falls on the top of the inner wall rib.

For example, spot welding is performed on the test panel, the recorded spot welding penetration is 1.3 times the thickness of the test panel, and the recorded spot welding parameters are used as the outer wall spot welding parameters.

According to an embodiment of the present invention, before setting the spot welding parameters, the method includes: measuring the thickness of the outer wall.

According to an embodiment of the present invention, the characteristic parameters of the spot welding surface topography include: the depth of the spot and the diameter of the spot.

In this embodiment, the inner and outer wall clearance is F=k*(0.6*h+(0.5*d)^0.5); where k is the revision coefficient, h is the depth of the dotted depression, and d is the diameter of the dotted depression.

Specifically, as shown in FIG. 4 and FIG. 5 , taking laser spotting as an example, the laser beam 3 is used to perform spot welding on the outer wall 1 of the nozzle, so as to penetrate the outer wall 1 of the nozzle and make the bottom of the molten pool fall on the inner wall 6 of the nozzle. On the top of the rib, measure the characteristic parameters of the surface morphology of the spot welding, that is, measure the depth of the dotted depression 7 and the diameter of the dotted depression 5. When the outer wall material is stainless steel, k=1; when the outer wall material is titanium alloy, k=0.8. According to the functional relationship between the above-mentioned dotted recess depth 7, dotted recess diameter 5 and the inner and outer wall clearance 2, the inner and outer wall clearance 2 is inversely calculated. Using the above formula to measure the inner and outer wall clearance of the spot welding spot, the accuracy error range is less than 0.1mm.

The above embodiments take laser spot welding as an example, and are not intended to limit the present invention. You can also choose arc welding, electronic welding, etc. In addition, the stainless steel and titanium alloy mentioned in the above embodiments are only used for illustration and are not used to limit the present invention. The above method is also applicable to the measurement of inner and outer walls of aluminum alloys.

As shown in FIG. 4 , according to an embodiment of the present invention, 4-6 longitudinal positions are selected on the outer wall 1 of the nozzle in the circumferential direction, and 3-15 points 4 are set on each longitudinal position for spot welding. Selecting multiple points for spot welding can evaluate the gap between the inner and outer walls near the points, and then evaluate the assembly gap between the overall inner and outer walls.

The above-mentioned embodiments of the present invention can be combined with each other and have corresponding technical effects.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. within.

Claims (8)

1. A method for measuring the gap between the inner wall and the outer wall of a rocket engine nozzle is characterized by comprising the following steps:

establishing a functional relation between the spot welding surface topography characteristic parameters and the inner and outer wall gaps;

spot welding is carried out on the outer wall of the spray pipe, the outer wall of the spray pipe is welded through, and the bottom of the molten pool falls on the rib top of the inner wall of the spray pipe;

measuring the surface topography characteristic parameters of the spot welding; inversely calculating the clearance between the inner wall and the outer wall according to the functional relation between the characteristic parameters of the spot welding surface appearance and the clearance between the inner wall and the outer wall;

the spot welding surface topography characteristic parameters comprise: dotting recess depth and dotting recess diameter;

the inner wall and the outer wall have a clearance F ═ k ^ (0.6 ^ h + (0.5 ^ d) ^ 0.5);

wherein k is a revision coefficient, h is a dotting recess depth, and d is a dotting recess diameter.

2. The measuring method of claim 1, wherein the spot welding on the outer wall of the nozzle comprises: and setting spot welding parameters.

3. The measurement method according to claim 2, wherein the spot welding parameters include spot power and spot time.

4. The measurement method according to claim 3, wherein the dotting power is W ═ 100+300)/t × 50;

wherein B is the wall thickness of the outer wall, and t is the dotting time.

5. The measurement method according to claim 2, wherein the setting of the spot welding parameters comprises:

selecting a test wallboard which has the same material and thickness as the outer wall;

spot welding is carried out on the test wallboard;

recording spot welding parameters when the spot welding penetration is 1 to 1.5 times of the thickness of the tested wallboard;

and setting the recorded spot welding parameters as the parameters for performing spot welding on the outer wall.

6. The measuring method according to claim 5, wherein the recorded spot welding parameters for a spot welding penetration of 1.3 times the thickness of the test panel are set as parameters for spot welding the outer wall.

7. The measuring method according to any one of claims 2 to 4, wherein the setting of the spot welding parameters comprises: and measuring the wall thickness of the outer wall.

8. The measuring method according to claim 1, wherein 4-6 longitudinal positions are selected on the outer wall of the nozzle in the circumferential direction, and 3-15 spot welding points are arranged at each longitudinal position.

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