An acoustic closed-end boundary condition simulation device

Abstract

The present invention discloses an acoustic closed-end boundary condition simulation device, which relates to the technical field of simulation devices, and aims to solve the problem in the prior art that the isolation effect of the simulation device for medium and low frequency excitation is poor, resulting in a large error in the final test result. The acoustic closed-end boundary condition simulation device includes: a first diversion pipe and a plurality of connecting members. Two first diversion pipes are arranged opposite to each other and at intervals. The first end of each first diversion pipe is correspondingly communicated with the first end of a connecting member, and the second ends of the two connecting members are far away from each other. The second ends of the two first diversion pipes are communicated through at least one connecting member, wherein the assembled first diversion pipe and the connecting member form an accommodation space with an open end.

Description

Technical Field

[0001] The present invention relates to the technical field of simulation devices, and particularly to an acoustic closed-end boundary condition simulation device. Background Art

[0002] In a liquid oxygen / kerosene staged combustion cycle engine, due to the high-speed rotation of the turbine pump blades, the flow pulsation after the pump is approximately zero. In tests and simulations, the pump outlet can be approximately considered as an acoustic closed-end boundary condition. Based on this, in order to ensure that the boundary conditions of the test system are consistent with those of the real engine, it is necessary to set large impedance elements to simulate the acoustic closed-end after the engine pump.

[0003] In the prior art, a liquid flow system acoustic closed-end inlet boundary condition simulation device is usually adopted, and the impedance of the closed-end device is increased by the inertia and resistance of the pipeline together to achieve the closed-end effect.

[0004] However, it is found in the actual test process that the above device has a poor isolation effect on medium and low frequency excitations, resulting in a large error in the final test results. Summary of the Invention

[0005] The purpose of the present invention is to provide an acoustic closed-end boundary condition simulation device for enhancing the isolation effect on medium and low frequency excitations to reduce the error of test results.

[0006] To achieve the above purpose, the present invention provides an acoustic closed-end boundary condition simulation device. The acoustic closed-end boundary condition simulation device includes: a first diversion pipe and a plurality of connecting members. The two first diversion pipes are arranged opposite to each other and at intervals. The first end of each first diversion pipe is correspondingly connected to the first end of a connecting member, and the second ends of the two connecting members are away from each other. The second ends of the two first diversion pipes are connected through at least one connecting member, wherein the assembled first diversion pipe and connecting member form a receiving space with an open end.

[0007] Compared with the prior art, in the acoustic closed-end boundary condition simulation device provided by the present invention, since the second ends of the two first diversion pipes are connected through at least one connecting member, and the assembled first diversion pipe and connecting member form a receiving space with an open end. At this time, the two first diversion pipes are not only connected for subsequent tests. At the same time, an included angle is formed between the two first diversion pipes, and at this time, the refraction loss effect of the transmitted wave can be increased to enhance the isolation effect on medium and low frequency excitations, thereby reducing the error of the test results and achieving the closed-end effect. Description of the Drawings

[0008] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation to the present invention. In the drawings:

[0009] Figure 1 Schematic diagram of the structure of the acoustic closed - end boundary condition simulation device in the embodiment of the present invention Figure 1 ;

[0010] Figure 2 Schematic diagram of the structure of the acoustic closed - end boundary condition simulation device in the embodiment of the present invention Figure 2 ;

[0011] Figure 3 Schematic diagram of the structure of the acoustic closed - end boundary condition simulation device in the embodiment of the present invention Figure 3 ;

[0012] Figure 4 Schematic diagram of the structure of the connecting member in the embodiment of the present invention;

[0013] Figure 5 Schematic diagram of the relative position relationship between two first diversion tubes in the embodiment of the present invention Figure 1 ;

[0014] Figure 6 Schematic diagram of the relative position relationship between two first diversion tubes in the embodiment of the present invention Figure 2 ;

[0015] Figure 7 Schematic diagram of the relative position relationship between two first diversion tubes in the embodiment of the present invention Figure 3 ;

[0016] Figure 8 Schematic diagram of the connection between the connecting member and the connecting flange in the embodiment of the present invention.

[0017] Reference numerals:

[0018] 1 - First diversion tube, 2 - Connecting member, 20 - First body,

[0019] 21 - Second body, 3 - Open end, 4 - Connecting flange. Detailed implementation manners

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0023] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0024] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and may be the communication inside two elements or the interaction relationship between two elements. 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 circumstances.

[0025] Combined with the background art section, in the prior art, in addition to using the acoustic closed-end inlet boundary condition simulation device of the liquid flow system, a throttle with a large flow resistance is also used to simulate the acoustic closed end. However, since the throttle increases the impedance solely by relying on the flow resistance (i.e., increasing the fluid pressure loss before and after the throttle), it is necessary to greatly increase the tank pressure to ensure the normal operation of the liquid flow system. Based on this, the additional tank pressure will increase significantly.

[0026] To solve the above technical problems, an embodiment of the present invention provides an acoustic closed-end boundary condition simulation device. Refer to Figure 1 and Figure 2 , the acoustic closed-end boundary condition simulation device may include: a first diversion pipe 1 and a plurality of connecting members 2. Two first diversion pipes 1 are opposite and spaced apart. The first end of each first diversion pipe 1 is correspondingly connected to the first end of a connecting member 2, and the second ends of the two connecting members 2 are away from each other. The second ends of the two first diversion pipes 1 are connected through at least one connecting member 2. Among them, the assembled first diversion pipe 1 and the connecting member 2 form an accommodating space with an open end 3.

[0027] The materials of the above-mentioned first diversion pipe and the connecting member can be selected according to the actual situation, and no specific limitation is made here. Further, the inlet pipeline of the test bench or the pipeline of the test piece can be connected to the acoustic closed-end boundary condition simulation device through the connecting member.

[0028] See Figure 1 , in the acoustic closed-end boundary condition simulation device provided by the embodiment of the present invention, since the second ends of the two first diversion pipes 1 are connected through at least one connecting member 2, wherein the assembled first diversion pipes 1 and the connecting member 2 form a receiving space with an open end 3. At this time, the two first diversion pipes 1 are not only connected for subsequent tests. At the same time, an included angle Q is formed between the two first diversion pipes 1. At this time, the refraction loss effect of the transmitted wave can be increased to enhance the isolation effect on the mid-low frequency excitation, thereby reducing the test result error and achieving the closed-end effect. It should be understood that the above-mentioned included angle Q is greater than 0° and less than or equal to 180°. For example, the included angle Q can be 1°, 15°, 45°, 60°, 90°, 135°, 150° or 180°, etc.

[0029] In an alternative manner, see Figure 1 , since the second ends of the two connecting members 2 are far away from each other, at this time, each connecting member has an included angle P. Based on this, the refraction loss effect of the transmitted wave can be further increased to further enhance the isolation effect on the mid-low frequency excitation, thereby reducing the test result error and achieving the closed-end effect. It should be understood that the above-mentioned included angle P is greater than 0° and less than 180°. For example, the included angle P can be 1°, 15°, 45°, 60°, 90°, 135°, 150° or 179°, etc.

[0030] In an alternative manner, when the space for accommodating the acoustic closed-end boundary condition simulation device is large enough, since the device disclosed in the patent with the application number 201711447549.5 is a straight pipe type, when the length of the space occupied by the acoustic closed-end boundary condition simulation device is equal to that of the straight pipe type closed-end device, since the two first diversion pipes in the acoustic closed-end boundary condition simulation device are arranged oppositely, the total length of the acoustic closed-end boundary condition simulation device must be greater than that of the straight pipe type closed-end device. At this time, compared with the straight pipe type closed-end device and the throttle ring, the pipeline inertia of the simulation device provided by the embodiment of the present invention increases, and the flow resistance increases, thereby increasing the impedance of the acoustic closed-end. At the same time, since each connecting member has an included angle, the refraction loss effect of the transmitted wave can be increased. Based on this, not only the isolation effect on the mid-low frequency excitation is further enhanced, but also the test result error is further reduced. At the same time, the simulation device with a longer total length will not cause a large increase in the additional storage tank pressure (i.e., the inlet pressure), thereby avoiding exceeding the maximum pressure that the fluid storage tank can withstand.

[0031] As a possible implementation manner, see Figure 4, each connecting member 2 includes a first body 20 and a second body 21. The first end of the first body 20 is connected to the first end of the second body 21, and there is an included angle A between the first body 20 and the second body 21. The included angle A is greater than or equal to 80° and less than or equal to 100°. The first end of each first conduit 1 corresponds to and communicates with the second end of a second body 21. Exemplarily, the above included angle A can be 80°, 85°, 90°, 96° or 100°, etc. The structure of the above connecting member 2 is simple, facilitating assembly and improving work efficiency. It should be understood that the above included angle A, included angle Q and included angle P all refer to the included angle between the first body and the second body.

[0032] In an alternative embodiment, referring to Figure 2 , the second ends of the two first conduits 1 are connected through two connecting members 2, and the four included angles A of the four connecting members 2 are all 90°.

[0033] At this time, the above acoustic closed-end boundary condition simulation device includes four right angles. Based on this, not only can the refraction loss effect of the transmitted wave be further increased to further enhance the isolation effect on medium and low-frequency excitations and further reduce the test result error. At the same time, it is more conducive to installation in a straight pipe system. Specifically, in actual use, since the simulation device includes four right angles, there is no need to change the pipeline layout before and after the simulation device, so as to save adapting to the structure of the simulation device itself. Exemplarily, the above connecting member can be a right-angle elbow in the prior art.

[0034] Since the two first conduits are arranged opposite to each other and at intervals, there are various relative position relationships between the two first conduits. The following describes several possible situations as examples. It should be understood that the following description is only for understanding and not for specific limitation.

[0035] Example 1: Referring to Figure 5 , the two first conduits 1 are parallel to each other, and the axial direction of each first conduit 1 is inclined relative to the horizontal plane.

[0036] Example 2: Referring to Figure 6 , the axial directions of the two first conduits 1 are both inclined relative to the horizontal plane, and the two first conduits 1 are not parallel.

[0037] Example 3: Referring to Figure 7 , one first conduit 1 is inclined relative to the horizontal plane, and one first conduit 1 is horizontal relative to the horizontal plane.

[0038] Example 4: Referring to Figure 2 , along the direction perpendicular to the axial direction of the first conduit 1, the two first conduits 1 are parallel to each other. Further, when the acoustic closed-end boundary condition simulation device includes four right angles, the overall acoustic closed-end boundary condition simulation device is generally in a "Ji" shape.

[0039] As a possible implementation, refer to Figure 2 The above acoustic closed - end boundary condition simulation device further includes: a connecting flange 4. Two connecting flanges 4 are respectively located at the first ends of each first diversion pipe 1, and the first ends of each connecting flange 4 are respectively in corresponding communication with the second ends of the communicating member 2. The inner diameter of the first diversion pipe 1 is 30% to 40% of the inner diameter of the second end of the connecting flange 4. For example, it can be 30%, 35%, 36% or 40%, etc.

[0040] At this time, not only can the closed - end effect be achieved to ensure the normal progress of the test, but also the additional storage tank pressure (i.e., the inlet pressure) can be prevented from increasing significantly to avoid exceeding the maximum pressure that the fluid storage tank can withstand.

[0041] In an alternative manner, refer to Figure 8 The connection taper angle B between the above - mentioned connecting flange 4 and the communicating member 2 is greater than or equal to 30° and less than or equal to 60°. For example, the connection taper angle B can be 30°, 35°, 40°, 55° or 60°, etc. In the embodiment of the present invention, the above - mentioned connection taper angle B is 60°, and at this time, the firmness of the connection between the connecting flange 4 and the communicating member 2 can be ensured, so as to ensure the firmness and stability of the acoustic closed - end boundary condition simulation device.

[0042] In an alternative manner, the above - mentioned acoustic closed - end boundary condition simulation device may further include: a filter element. A filter element is provided in at least one of the connecting flanges, and the filter element is used to filter impurities.

[0043] In the case of adopting the above - mentioned technical solution, the filter element can not only filter the impurities of the test bench to ensure the safety of the test piece, but also, due to the filter element having a certain flow resistance, the impedance of the entire simulation device can be increased through the flow resistance effect, thereby improving the acoustic closed - end effect.

[0044] Exemplarily, during actual installation, the filter element is inserted into the connecting flange (i.e., before the contraction section), and the position of the filter element is fixed by the inner edge boss and the sealing structure of the connecting flange. Of course, the relative position relationship and installation method between the filter element and the connecting flange can be changed according to the actual situation, not limited to the above description. Further, in the embodiment of the present invention, when the above - mentioned acoustic closed - end boundary condition simulation device is installed at the "outlet" of the liquid flow system, the filter element may not be installed.

[0045] In an alternative manner, the above - mentioned filter element is a filter screen or a filter element, and the mesh number of the filter screen or the filter element is greater than or equal to 200 meshes. For example, 200 meshes, 300 meshes, 350 meshes or 400 meshes, etc.

[0046] In an alternative manner, the above acoustic closed-end boundary condition simulation device may further include: a second diversion pipe. The second diversion pipe is located between the second ends of the two first diversion pipes, and both ends of the second diversion pipe are respectively communicated with the two connecting members.

[0047] In the case of adopting the above technical solution, without changing the sizes of the first diversion pipe and the connecting member, due to the addition of the second diversion pipe, the total length of the acoustic closed-end boundary condition simulation device is further increased. At this time, not only is the isolation effect on the mid-low frequency excitation further enhanced, but the test result error is further reduced. At the same time, it is also possible to avoid a large increase in the additional tank pressure (i.e., the inlet pressure).

[0048] As a possible implementation manner, refer to Figure 3 , the total length L of the above acoustic closed-end boundary condition simulation device is greater than or equal to 5.4 times the value of the frequency, and the frequency is less than or equal to 300 Hz. At this time, the acoustic closed-end boundary condition simulation device provided by the embodiments of the present invention can be applicable to mid-low frequency dynamic characteristic tests. Exemplarily, when the frequency is 300 Hz, the above total length is 1620 mm. When the frequency is 200 Hz, the above total length is 1080 mm. It should be understood that when the acoustic closed-end boundary condition simulation device only includes the first diversion pipe and multiple connecting members, the total length of the acoustic closed-end boundary condition simulation device is equal to the sum of the length of the first diversion pipe and the lengths of the multiple connecting members. When the acoustic closed-end boundary condition simulation device includes the first diversion pipe, the second diversion pipe and multiple connecting members, the total length of the acoustic closed-end boundary condition simulation device is equal to the sum of the length of the first diversion pipe, the length of the second diversion pipe and the lengths of the multiple connecting members.

[0049] The structure of the acoustic closed-end boundary condition simulation device will be described below by taking a possible implementation manner as an example. It should be understood that the following description is only for understanding and is not used for specific limitation.

[0050] For the convenience of description, the two connecting flanges are respectively defined as an inlet connecting flange and an outlet connecting flange. A filter element is provided in the inlet connecting flange. The above inlet connecting flange is used to connect the test bench inlet pipeline, and the outlet connecting flange is used to connect the test piece pipeline. The two first diversion pipes are respectively defined as a first diversion pipe a and a first diversion pipe b. The inlet connecting flange is communicated with the first end of the first diversion pipe a through the first connecting member, and the connection cone angle is 60°. The second end of the first diversion pipe a is communicated with the first end of the second connecting member. The second end of the second connecting member is communicated with the first end of the third connecting member. The second end of the third connecting member is communicated with the second end of the first diversion pipe b. The first end of the first diversion pipe b is communicated with the outlet connecting flange through the fourth connecting member, and the connection cone angle is 60°. The included angle A of the above four connecting members is 90°, and along the axial direction perpendicular to the first diversion pipe, the two first diversion pipes are parallel to each other.

[0051] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any one or more embodiments or examples in a suitable manner.

[0052] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An acoustic closed - end boundary condition simulation device, characterized in that, Including: A first diversion pipe, with two of the first diversion pipes arranged opposite to each other and at intervals; A plurality of connecting members, the first end of each first diversion pipe is correspondingly connected to the first end of one connecting member, and the second ends of the two connecting members are away from each other; the second ends of the two first diversion pipes are connected through at least one connecting member, and the fluid flows inside the first diversion pipes and inside the plurality of connecting members; The connecting member for connecting the second ends of the two first diversion pipes has an included angle, and the included angle of the connecting member is used to increase the refraction loss of the transmitted wave to enhance the isolation of mid-low frequency excitation; Wherein, the outer walls of the assembled first diversion pipes and the outer walls of the connecting members enclose an outer shape structure of a receiving space with an open end.

2. The acoustic closed - end boundary condition simulation device according to claim 1, characterized in that, Each connecting member includes a first body and a second body; the first end of the first body is connected to the first end of the second body, and there is an included angle between the first body and the second body, and the included angle is greater than or equal to 80° and less than or equal to 100°; the first end of each first diversion pipe is correspondingly connected to the second end of one second body.

3. The acoustic closed-end boundary condition simulation device according to claim 2, wherein The second ends of the two first diversion pipes are connected through two connecting members; the four included angles of the four connecting members are all 90°.

4. The acoustic closed-end boundary condition simulation device according to claim 1, characterized in that The two first diversion pipes are parallel to each other, and the first diversion pipes are parallel to the horizontal plane.

5. The acoustic closed-end boundary condition simulation device according to claim 1, wherein The acoustic closed-end boundary condition simulation device further includes: Connecting flanges, two of the connecting flanges are respectively located at the first ends of each first diversion pipe, and the first ends of each connecting flange are respectively correspondingly connected to the second ends of the connecting members; The inner diameter of the first diversion pipe is 30% to 40% of the inner diameter of the second end of the connecting flange.

6. The acoustic closed-end boundary condition simulation device according to claim 5, characterized in that, The connection taper angle between the connecting flange and the connecting member is greater than or equal to 30° and less than or equal to 60°.

7. The acoustic closed-end boundary condition simulation device according to claim 5, characterized in that, The acoustic closed-end boundary condition simulation device further includes: A filter element, one filter element is arranged in at least one of the connecting flanges; the filter element is used to filter impurities.

8. The acoustic closed-end boundary condition simulation device according to claim 7, wherein, The filter element is a filter screen or a filter element; The mesh number of the filter screen or the filter element is greater than or equal to 200 meshes.

9. The acoustic closed - end boundary condition simulation device according to claim 3, wherein, The acoustic closed-end boundary condition simulation device further includes: A second diversion pipe, located between the second ends of the two first diversion pipes, and the two ends of the second diversion pipe are respectively connected to the two connecting members.

10. The acoustic closed-end boundary condition simulation device according to any one of claims 1 to 9, characterized in that, The total length of the acoustic closed-end boundary condition simulation device is greater than or equal to 5.4 times the value of the frequency; the frequency is less than or equal to 300 Hz.

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