Method, device, equipment and medium for extending low Mach number of high-speed wind tunnel of Loudwig pipe

Abstract

The invention discloses a method, a device, equipment and a medium for extending a low Mach number in a high-speed wind tunnel of a Loudwig pipe, which are applied to a target Loudwig pipe wind tunnel. A target Ludwig pipe wind tunnel comprises an air storage section, a quick-opening valve, a first throat, a first stable section, a second stable section, a second throat and a target spray pipe, and the method comprises the steps that high-pressure air is released through the quick-opening valve and transmitted to the first throat, and the high-pressure air is converted into supersonic airflow based on the first throat; judging whether a target ratio of the first stable section to the first throat is within a target range or not; if the supersonic airflow is within the target range, converting the supersonic airflow into subsonic airflow, and transmitting the subsonic airflow to a second stable section; and inputting the obtained decelerated airflow into a target spray pipe by using a second throat, and accelerating the decelerated airflow to obtain a target low Mach number flow field meeting a target condition. On the premise that an original wind tunnel core component is not changed, extension of the high-speed wind tunnel of the Ludwig pipe from the basic Mach number to the low Mach number is achieved.

Description

Technical Field

[0001] This invention relates to the field of high-speed wind tunnel technology, and in particular to a method, apparatus, equipment and medium for extending a high-speed wind tunnel to a low Mach number using a Ludwig tube. Background Technology

[0002] High-speed aircraft experience low incoming flow noise in real flight environments. To simulate these environments and study high-speed boundary layer transition / turbulence mechanisms, high-speed wind tunnels with low incoming flow noise are necessary. However, current high-speed, low-noise, and quiet wind tunnels have relatively small nozzle diameters (300mm), limiting the simulated Reynolds numbers and failing to meet engineering application requirements. To improve the experimental capabilities and Reynolds numbers of high-speed, low-noise, and quiet wind tunnels, large-diameter low-noise and quiet wind tunnels (on the 600mm scale) need to be developed. Ludwig tube wind tunnels are widely used as the overall aerodynamic layout scheme for high-speed, low-noise, and quiet wind tunnels due to their advantages such as constant total pressure and temperature, simple structure, high operating efficiency, and good economy. To achieve multiple operating Mach numbers in a single wind tunnel, a common method is to keep the nozzle exit diameter constant while replacing it with different nozzle specifications. According to the Mach number-area relationship, higher Mach numbers correspond to smaller nozzle throat diameters.

[0003] Existing technology includes a Ludwig pipe wind tunnel and its extended high Mach number method. Based on the traditional Ludwig pipe wind tunnel (the upstream gas storage section is connected to the quick-opening valve and then directly connected to the downstream nozzle), a stabilization section is added. The stabilization section includes a stabilization section inlet section, a stabilization section throat, a stabilization section expansion section, and a stabilization section outlet section. The inlet diameter of the stabilization section is the same as the outlet diameter of the quick-opening valve. The internal contraction profile and throat of the stabilization section inlet are designed according to the basic Mach number of the wind tunnel. The outlet diameter of the stabilization section is the same as the diameter of the gas storage section and the inlet diameter of the nozzle, forming a stable subsonic flow field between the quick-opening valve and the nozzle. This invention can extend the operating Mach number of a Ludwig tube wind tunnel from the base Mach number to a higher Mach number (e.g., from the base Mach number 5 to 6, 7, 8, or 9, etc.) simply by replacing nozzles of different specifications (the inlet size is the same, the throat diameter is different, and the outlet size is the same between different nozzles) without changing other components of the Ludwig tube wind tunnel. At this time, the cross-sectional area of ​​the nozzle throat becomes smaller, and the cross-sectional area of ​​the upstream stable section throat (i.e., the first throat) is larger than the cross-sectional area of ​​the downstream nozzle throat (i.e., the second throat). The limitation of this technology is that it can only be extended to higher Mach numbers (requiring the first throat cross-sectional area to be larger than the second throat cross-sectional area). If it is extended to lower Mach numbers, the increased nozzle throat cross-sectional area will have two adverse effects: First, the outlet diameter of the stable section, i.e. the nozzle inlet diameter, may not meet the nozzle contraction ratio requirements; second, the first throat cross-sectional area is smaller than the second throat cross-sectional area, resulting in supersonic jets in the stable section, which not only leads to high flow field pulsation in the stable section, but also causes the nozzle to malfunction, poor Mach number uniformity in the experimental section, and high flow field pulsation.

[0004] As can be seen from the above, how to extend the high-speed wind tunnel from the basic Mach number to a lower Mach number without changing the core components of the original wind tunnel is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method, apparatus, equipment, and medium for extending a Ludwig tube high-speed wind tunnel to a lower Mach number, which can achieve the extension of a Ludwig tube high-speed wind tunnel from its base Mach number to a lower Mach number without modifying the core components of the original wind tunnel. The specific solution is as follows: In a first aspect, this application provides a method for extending a Ludwig tube high-speed wind tunnel to a low Mach number, applied to a target Ludwig tube wind tunnel; the target Ludwig tube wind tunnel includes a gas storage section, a quick-opening valve, a first throat, a first stabilizing section, a second stabilizing section, a second throat, and a target nozzle; wherein, the method includes: High-pressure air is obtained by compressing air and injecting it into the storage section. After the target Ludwig tube wind tunnel is started, the high-pressure air is released by a quick-opening valve and transmitted to the first throat, so as to convert the high-pressure air into a supersonic airflow based on the first throat. Determine whether the target ratio corresponding to the first stable segment and the first throat is within the target range; the first cross-sectional area of ​​the first stable segment is greater than the second cross-sectional area of ​​the first throat; the target ratio is the ratio between the second cross-sectional area and the first cross-sectional area; If the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stabilization section, and the subsonic airflow is transmitted to the second stabilization section to obtain decelerated airflow; the diameter of the second stabilization section is larger than the diameter of the first stabilization section. The decelerated airflow is input into the target nozzle through the second throat, and the target nozzle accelerates the decelerated airflow to obtain a target low Mach number flow field that meets the target conditions; the target nozzle is a nozzle with an exit Mach number lower than a preset Mach number; the diameter of the second throat is larger than the diameter of the first throat.

[0006] Optionally, the process of compressing air to obtain high-pressure air and injecting the high-pressure air into the air storage section, and then releasing the high-pressure air using a quick-opening valve and transmitting it to the first throat after starting the target Ludwig tube wind tunnel, so as to convert the high-pressure air into a supersonic airflow based on the first throat, includes: Air is compressed to a high pressure state using a pre-set compression device to obtain high-pressure air, which is then injected into the air storage section for sealing. After the target Ludwig tube wind tunnel is started, the high-pressure air is released and transmitted to the first throat using a quick-opening valve connected to the gas storage section. The high-pressure air is accelerated using the first throat to obtain a supersonic airflow; The diameter of the first throat is determined based on a preset Mach number; the preset Mach number is the Mach number of the target Ludwig tube wind tunnel determined based on simulation requirements.

[0007] Optionally, the first stabilizing section includes a sintered mesh assembly, a honeycomb unit, and a sleeve for adjusting the position of the sintered mesh assembly and the honeycomb unit; The sintered mesh assembly is a component constructed using a metal wire mesh and a grid-shaped support frame; the front end of the grid-shaped support frame is flat, and the rear end is wedge-shaped.

[0008] Optionally, determining whether the target ratio corresponding to the first stable segment and the first larynx is within the target range includes: The target ratio between the first cross-sectional area and the second cross-sectional area is determined using the average Mach number and specific heat ratio of the first stable segment, and it is determined whether the target ratio is within the target range.

[0009] Optionally, the target Ludwig tube wind tunnel is also equipped with a transition section; Accordingly, if the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stabilization section, and the subsonic airflow is transmitted to the second stabilization section to obtain decelerated airflow, including: If the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stable section, and the subsonic airflow is transmitted to the transition section connecting the first stable section and the second stable section, so as to expand the subsonic airflow using the transition section to obtain the expanded airflow. The expanded airflow is transmitted to the second stabilization section to decelerate the expanded airflow and obtain a decelerated airflow.

[0010] Optionally, the step of inputting the decelerated airflow into the target nozzle through the second throat, and accelerating the decelerated airflow through the target nozzle to obtain a target low Mach number flow field that meets the target conditions, includes: The decelerated airflow is guided into the target nozzle by the second throat, and the target nozzle is used to accelerate the decelerated airflow to obtain a target low Mach number flow field with a Mach number lower than the target value.

[0011] Optionally, the target Ludwig tube wind tunnel is also equipped with an experimental section, a diffusion section, and a vacuum tank; Accordingly, after accelerating the decelerated airflow using the target nozzle to obtain a target low Mach number flow field that meets the target conditions, the process further includes: The target low Mach number flow field is stored in the experimental section to obtain the experimental data corresponding to the target low Mach number flow field and to obtain the airflow after the experiment. The gas flow after the experiment is decelerated and depressurized using a diffuser section to obtain a depressurized gas flow, which is then input into a vacuum tank.

[0012] Secondly, this application provides a low Mach number extension device for a Ludwig tube high-speed wind tunnel, applied to a target Ludwig tube wind tunnel; the target Ludwig tube wind tunnel includes a gas storage section, a quick-opening valve, a first throat, a first stabilizing section, a second stabilizing section, a second throat, and a target nozzle; wherein, the device includes: The high-pressure air conversion module is used to compress air to obtain high-pressure air and inject the high-pressure air into the air storage section. After the target Ludwig tube wind tunnel is started, the high-pressure air is released by a quick-opening valve and transmitted to the first throat, so as to convert the high-pressure air into supersonic airflow based on the first throat. The target ratio judgment module is used to determine whether the target ratio corresponding to the first stable segment and the first throat is within the target range; the first cross-sectional area of ​​the first stable segment is greater than the second cross-sectional area of ​​the first throat; the target ratio is the ratio between the second cross-sectional area and the first cross-sectional area; An airflow transmission module is used to convert the supersonic airflow into subsonic airflow using the first stabilization section if the target ratio is within the target range, and then transmit the subsonic airflow to the second stabilization section to obtain decelerated airflow; the diameter of the second stabilization section is larger than the diameter of the first stabilization section. The target flow field determination module is used to input the decelerated airflow into the target nozzle through the second throat, and to accelerate the decelerated airflow through the target nozzle to obtain a target low Mach number flow field that meets the target conditions; the target nozzle is a nozzle with an exit Mach number lower than a preset Mach number; the diameter of the second throat is larger than the diameter of the first throat.

[0013] Thirdly, this application provides an electronic device, comprising: Memory, used to store computer programs; A processor is used to execute the computer program to implement the aforementioned method for extending the high-speed wind tunnel of the Ludwig tube to a low Mach number.

[0014] Fourthly, this application provides a computer-readable storage medium for storing a computer program, wherein the computer program, when executed by a processor, implements the aforementioned method for extending a Ludwig tube high-speed wind tunnel to a low Mach number.

[0015] This application compresses air to obtain high-pressure air, injects the high-pressure air into a storage section, and after starting the target Ludwig tube wind tunnel, releases the high-pressure air using a quick-opening valve and transmits it to the first throat, so as to convert the high-pressure air into a supersonic airflow based on the first throat; determines whether the target ratio corresponding to the first stable section and the first throat is within the target range; the first cross-sectional area of ​​the first stable section is larger than the second cross-sectional area of ​​the first throat; the target ratio is the ratio between the second cross-sectional area and the first cross-sectional area; if the target ratio is within the target range, the supersonic airflow is converted into a subsonic airflow using the first stable section, and the subsonic airflow is transmitted to the second stable section to obtain a decelerated airflow; the diameter of the second stable section is larger than the diameter of the first stable section; the decelerated airflow is input to the target nozzle using the second throat, and the decelerated airflow is accelerated using the target nozzle to obtain a target low Mach number flow field that meets the target conditions; the target nozzle is a nozzle with an exit Mach number lower than a preset Mach number; the diameter of the second throat is larger than the diameter of the first throat.

[0016] As can be seen from the above, this application converts compressed air into supersonic airflow through a first throat, pre-checking whether the target ratio between the cross-sectional area of ​​the first stabilizing section and the cross-sectional area of ​​the first throat is within the target range to avoid airflow anomalies caused by an excessively large or small ratio, and the cross-sectional area of ​​the first stabilizing section is larger than that of the first throat; then, the decelerated airflow is obtained through two stabilizing sections, wherein the diameter of the second stabilizing section is larger than that of the first stabilizing section; the decelerated airflow is converted into a target low Mach number flow field through the second stabilizing section and a target nozzle with an exit Mach number lower than a preset Mach number. In this way, by replacing the low Mach number nozzle and adding a matching second-stage stabilizing section, the high-speed wind tunnel can be extended from the basic Mach number to a low Mach number, and the flow field pulsation at the outlet of the stabilizing section can be reduced, thereby improving the flow field quality of the experimental section. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1This application discloses a flowchart of a method for extending a high-speed wind tunnel to a low Mach number using a Ludwig tube. Figure 2 A schematic diagram of a target Ludwig tube wind tunnel provided for this application; Figure 3 A schematic diagram of a first stable segment structure provided in this application; Figure 4 This application provides a schematic diagram of a sintered mesh support frame, wherein... Figure 4 (a) is a front view of a sintered mesh support frame; Figure 4 (b) in the figure is a rear view of a sintered mesh support frame; Figure 4 (c) in the figure is a cross-sectional view of a sintered mesh support frame; Figure 5 This is a schematic diagram of a Ludwig tube high-speed wind tunnel extension low Mach number device disclosed in this application; Figure 6 This is a structural diagram of an electronic device disclosed in this application. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Currently, existing technology can extend the operating Mach number of a Ludwig tube wind tunnel from the base Mach number to a higher Mach number simply by replacing the nozzles with different specifications, without changing other components of the tunnel. In this case, the nozzle throat cross-sectional area decreases, and the upstream stable section throat cross-sectional area is larger than the downstream nozzle throat cross-sectional area. The limitation of this technology is that it can only extend to higher Mach numbers, requiring the first throat cross-sectional area to be larger than the second throat cross-sectional area. If extended to lower Mach numbers, the increased nozzle throat cross-sectional area will lead to two adverse effects: first, the stable section exit diameter (i.e., the nozzle inlet diameter) may not meet the nozzle contraction ratio requirements; second, with the first throat cross-sectional area smaller than the second throat cross-sectional area, supersonic jets appear in the stable section, resulting not only in high flow field pulsation in the stable section but also in the nozzle's inability to function properly, poor Mach number uniformity in the experimental section, and high flow field pulsation. To this end, this application provides a method for extending a high-speed wind tunnel to a low Mach number using a Ludwig nozzle. By replacing the nozzle with a low Mach number nozzle and adding a matching second-stage stabilization section, the high-speed wind tunnel can be extended from the base Mach number to a low Mach number, and the flow field pulsation at the outlet of the stabilization section can be reduced, thereby improving the flow field quality of the experimental section.

[0021] See Figure 1As shown, this invention discloses a method for extending a Ludwig tube high-speed wind tunnel to a low Mach number, applied to a target Ludwig tube wind tunnel; the target Ludwig tube wind tunnel includes a gas storage section, a quick-opening valve, a first throat, a first stabilizing section, a second stabilizing section, a second throat, and a target nozzle; wherein, the method includes: Step S11: Compress the air to obtain high-pressure air, and inject the high-pressure air into the air storage section. After starting the target Ludwig tube wind tunnel, release the high-pressure air using a quick-opening valve and transmit it to the first throat, so as to convert the high-pressure air into a supersonic airflow based on the first throat.

[0022] In this embodiment, Figure 2 This embodiment provides a schematic diagram of a target Ludwig duct wind tunnel. The storage section contains high-pressure gas. The pressure range of the high-pressure air before injection into the storage section is typically 22 MPa to 25 MPa, and after depressurization, the pressure range of the injected gas generally does not exceed 3 MPa. The release of the high-pressure gas is controlled by a connected quick-opening valve. When the quick-opening valve opens, the high-pressure gas passes through a first throat. Due to the narrowness of the first throat, it accelerates the high-pressure gas, resulting in a supersonic airflow. The diameter of the first throat is determined based on the fundamental Mach number of the target Ludwig duct wind tunnel.

[0023] Specifically, the process of compressing air to obtain high-pressure air and injecting the high-pressure air into the storage section, and then releasing the high-pressure air using a quick-opening valve and transmitting it to the first throat after starting the target Ludwig tube wind tunnel, so as to convert the high-pressure air into a supersonic airflow based on the first throat, includes: compressing air to a high-pressure state using a preset compression device to obtain high-pressure air, injecting the high-pressure air into the storage section and sealing it; releasing the high-pressure air using a quick-opening valve connected to the storage section and transmitting it to the first throat after starting the target Ludwig tube wind tunnel; accelerating the high-pressure air using the first throat to obtain a supersonic airflow; wherein, the diameter of the first throat is determined based on a preset Mach number; the preset Mach number is the Mach number of the target Ludwig tube wind tunnel determined based on simulation requirements.

[0024] Step S12: Determine whether the target ratio corresponding to the first stable segment and the first throat is within the target range; the first cross-sectional area of ​​the first stable segment is greater than the second cross-sectional area of ​​the first throat; the target ratio is the ratio between the second cross-sectional area and the first cross-sectional area.

[0025] In this embodiment, the first stabilizing section needs to resist the impact of the supersonic flow generated by the first throat, and at the same time, it also needs to reduce the supersonic airflow to subsonic airflow. Figure 3This is a schematic diagram of a first stable section structure provided in this embodiment. The first stable section needs to be equipped with a sintered mesh assembly including a sintered mesh, a grid-shaped support frame, and a honeycomb unit. The sintered mesh is arranged at the front end of the support frame. Figure 4 This is a schematic diagram of a sintered mesh support frame provided in this embodiment, wherein, Figure 4 (a) is a front view of a sintered mesh support frame; Figure 4 (b) in the figure is a rear view of a sintered mesh support frame; Figure 4 Image (c) is a cross-sectional view of a sintered wire mesh support frame. The positions of the sintered wire mesh assembly and the honeycomb unit can be adjusted by a sleeve. The sintered wire mesh assembly can effectively block airflow, reducing supersonic airflow to subsonic airflow and improving the uniformity of the flow. Specifically, the first stabilizing section includes a sintered wire mesh assembly, a honeycomb unit, and a sleeve for adjusting the positions of the sintered wire mesh assembly and the honeycomb unit. The sintered wire mesh assembly is a component constructed using a metal wire mesh and a grid-shaped support frame. The front end of the grid-shaped support frame is flat, and the rear end is wedge-shaped.

[0026] It is understandable that the target ratio between the first cross-sectional area and the second cross-sectional area is determined using the average Mach number and specific heat ratio of the first stable segment, and the corresponding formula is as follows: ; in, This is the second cross-sectional area corresponding to the first throat. This refers to the first cross-sectional area corresponding to the first stable segment; The average Mach number of the first stable segment; The target ratio is the specific heat ratio of the experimental gas. After obtaining the target ratio, it is determined whether the target ratio is within the target range. If the first cross-sectional area corresponding to the first stable section is too small, it will easily lead to fluid viscosity and boundary layer effects, making it difficult to start the first throat. If the first cross-sectional area is too large, it will not only increase the total pressure loss, but also increase the airflow impact faced by the first stable section, thus requiring higher structural strength from the rectifier components. In one specific embodiment, the target ratio is greater than 1.39 and less than 5.37. Due to the transonic shock wave oscillation problem at a speed of 1.2, the average Mach number of the first stable section is estimated as 1.5, and appropriate boundary layer correction is performed to obtain the target ratio of 1.39. The maximum value of the target ratio is estimated as an average Mach number of 3, resulting in 5.37. The target range can also be adjusted according to the actual situation. Specifically, determining whether the target ratio corresponding to the first stable segment and the first throat is within the target range includes: using the average Mach number and specific heat ratio of the first stable segment to determine the target ratio between the first cross-sectional area and the second cross-sectional area, and determining whether the target ratio is within the target range.

[0027] Step S13: If the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stabilizing section, and the subsonic airflow is transmitted to the second stabilizing section to obtain decelerated airflow; the diameter of the second stabilizing section is larger than the diameter of the first stabilizing section.

[0028] In this embodiment, if the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stabilization section, and the subsonic airflow is transmitted to the transition section. In the transition section, the subsonic airflow is expanded using a preset expansion method to obtain expanded airflow. The expanded airflow is then transmitted to the second stabilization section. The second stabilization section has the same rectification principle as the traditional stabilization section. The function of the second stabilization section is to increase the diameter of the stabilization section so as to match the target nozzle inlet with a low Mach number. The expanded airflow is decelerated using the second stabilization section to improve the rectification effect.

[0029] Specifically, the target Ludwig tube wind tunnel also includes a transition section; correspondingly, if the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stabilizing section, and the subsonic airflow is transmitted to the second stabilizing section to obtain a decelerated airflow, including: if the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stabilizing section, and the subsonic airflow is transmitted to the transition section connecting the first stabilizing section and the second stabilizing section to expand the subsonic airflow using the transition section to obtain an expanded airflow; the expanded airflow is transmitted to the second stabilizing section to decelerate the expanded airflow using the second stabilizing section to obtain a decelerated airflow.

[0030] Step S14: The decelerated airflow is input into the target nozzle through the second throat, and the decelerated airflow is accelerated by the target nozzle to obtain a target low Mach number flow field that meets the target conditions; the target nozzle is a nozzle with an exit Mach number lower than a preset Mach number; the diameter of the second throat is larger than the diameter of the first throat.

[0031] In this embodiment, after obtaining the decelerated airflow, it is input into the target nozzle through the second throat. In one specific implementation, the diameter of the first throat is 0.13m, the diameter of the second throat is 0.287m, the inner diameter of the first stabilizing section is 0.3m, and the inner diameter of the second stabilizing section is 0.6m; the above values ​​can also be adjusted according to the actual situation. Specifically, the target Ludwig tube wind tunnel is also equipped with an experimental section, a diffusion section, and a vacuum tank; correspondingly, after accelerating the decelerated airflow using the target nozzle to obtain a target low Mach number flow field that meets the target conditions, the process further includes: storing the target low Mach number flow field in the experimental section to obtain experimental data corresponding to the target low Mach number flow field and obtain the experimental airflow; decelerating and depressurizing the experimental airflow using the diffusion section to obtain a depressurized airflow, and inputting the depressurized airflow into the vacuum tank.

[0032] As can be seen from the above, this application converts compressed air into supersonic airflow through a first throat, pre-checking whether the target ratio between the cross-sectional area of ​​the first stabilizing section and the cross-sectional area of ​​the first throat is within the target range to avoid airflow anomalies caused by an excessively large or small ratio, and the cross-sectional area of ​​the first stabilizing section is larger than that of the first throat; then, the decelerated airflow is obtained through two stabilizing sections, wherein the diameter of the second stabilizing section is larger than that of the first stabilizing section; the decelerated airflow is converted into a target low Mach number flow field through the second stabilizing section and a target nozzle with an exit Mach number lower than a preset Mach number. In this way, by replacing the low Mach number nozzle and adding a matching second-stage stabilizing section, the high-speed wind tunnel can be extended from the basic Mach number to a low Mach number, and the flow field pulsation at the outlet of the stabilizing section can be reduced, thereby improving the flow field quality of the experimental section.

[0033] Accordingly, see Figure 5 As shown, this application also provides a Ludwig tube high-speed wind tunnel extension low Mach number device, applied to a target Ludwig tube wind tunnel; the target Ludwig tube wind tunnel includes a gas storage section, a quick-opening valve, a first throat, a first stabilizing section, a second stabilizing section, a second throat, and a target nozzle; wherein, the device includes: The high-pressure air conversion module 11 is used to compress air to obtain high-pressure air and inject the high-pressure air into the air storage section. After the target Ludwig tube wind tunnel is started, the high-pressure air is released by a quick-opening valve and transmitted to the first throat, so as to convert the high-pressure air into supersonic airflow based on the first throat. The target ratio judgment module 12 is used to determine whether the target ratio corresponding to the first stable segment and the first throat is within the target range; the first cross-sectional area of ​​the first stable segment is greater than the second cross-sectional area of ​​the first throat; the target ratio is the ratio between the second cross-sectional area and the first cross-sectional area. The airflow transmission module 13 is used to convert the supersonic airflow into subsonic airflow using the first stabilization section if the target ratio is within the target range, and then transmit the subsonic airflow to the second stabilization section to obtain decelerated airflow; the diameter of the second stabilization section is larger than the diameter of the first stabilization section. The target flow field determination module 14 is used to input the decelerated airflow into the target nozzle through the second throat, and to accelerate the decelerated airflow through the target nozzle to obtain a target low Mach number flow field that meets the target conditions; the target nozzle is a nozzle with an exit Mach number lower than a preset Mach number; the diameter of the second throat is larger than the diameter of the first throat.

[0034] In some specific embodiments, the high-pressure air conversion module 11 may specifically include: An air sealing unit is used to compress air to a high-pressure state using a preset compression device to obtain high-pressure air, and then inject the high-pressure air into the air storage section for sealing. An air transmission unit is used to release and transmit the high-pressure air to the first throat through a quick-opening valve connected to the air storage section after the target Ludwig tube wind tunnel is started. An air acceleration unit is used to accelerate the high-pressure air using the first throat to obtain a supersonic airflow.

[0035] In some specific embodiments, the first stabilizing section includes a sintered mesh assembly, a honeycomb unit, and a sleeve for adjusting the position of the sintered mesh assembly and the honeycomb unit.

[0036] In some specific embodiments, the target ratio determination module 12 may specifically include: The target ratio determination unit is used to determine the target ratio between the first cross-sectional area and the second cross-sectional area using the average Mach number and specific heat ratio of the first stable segment, and to determine whether the target ratio is within the target range.

[0037] In some specific embodiments, the target Ludwig tube wind tunnel is also provided with a transition section; Accordingly, the airflow transmission module 13 may specifically include: An airflow expansion unit is used to convert the supersonic airflow into a subsonic airflow using the first stabilizing section if the target ratio is within the target range, and to transmit the subsonic airflow to the transition section connecting the first stabilizing section and the second stabilizing section, so as to expand the subsonic airflow using the transition section to obtain the expanded airflow. An airflow deceleration unit is used to transmit the expanded airflow to the second stabilization section, so as to decelerate the expanded airflow using the second stabilization section to obtain a decelerated airflow.

[0038] In some specific embodiments, the target Ludwig tube wind tunnel is also equipped with an experimental section, a diffusion section, and a vacuum tank; Accordingly, the Ludwig tube high-speed wind tunnel extension low Mach number device may further include: The experimental data acquisition unit is used to store the target low Mach number flow field in the experimental section, so as to use the experimental section to acquire the experimental data corresponding to the target low Mach number flow field and obtain the airflow after the experiment. The airflow depressurization unit is used to decelerate and depressurize the post-experiment airflow using the diffusion section to obtain depressurized airflow, and then input the depressurized airflow into the vacuum tank.

[0039] Furthermore, embodiments of this application also disclose an electronic device, Figure 6 This is a structural diagram of an electronic device 20 according to an exemplary embodiment. The content of the diagram should not be construed as limiting the scope of this application. The electronic device 20 may specifically include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. The memory 22 stores a computer program, which is loaded and executed by the processor 21 to implement the relevant steps in the Ludwig tube high-speed wind tunnel extension low Mach number method disclosed in any of the foregoing embodiments. Alternatively, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0040] In this embodiment, the power supply 23 is used to provide operating voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and external devices, and the communication protocol it follows can be any communication protocol applicable to the technical solution of this application, and is not specifically limited here; the input / output interface 25 is used to acquire external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs, and is not specifically limited here.

[0041] In addition, the memory 22, as a carrier for resource storage, can be a read-only memory, random access memory, disk or optical disk, etc. The resources stored thereon can include operating system 221, computer program 222, etc., and the storage method can be temporary storage or permanent storage.

[0042] The operating system 221 is used to manage and control the various hardware devices on the electronic device 20 and the computer program 222, which may be Windows Server, Netware, Unix, Linux, etc. In addition to including a computer program capable of performing the Ludwig tube high-speed wind tunnel extension low Mach number method disclosed in any of the foregoing embodiments, the computer program 222 may further include computer programs capable of performing other specific tasks.

[0043] Furthermore, this application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, it implements the aforementioned method for extending a Ludwig tube high-speed wind tunnel to a low Mach number. Specific steps of this method can be found in the corresponding content disclosed in the foregoing embodiments, and will not be repeated here.

[0044] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0045] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0046] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0047] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for extending a high-speed wind tunnel with a low Mach number using a Ludwig tube, characterized in that, The method is applied to a target Ludwig pipe wind tunnel; the target Ludwig pipe wind tunnel includes a gas storage section, a quick-opening valve, a first throat, a first stabilizing section, a second stabilizing section, a second throat, and a target nozzle; wherein, the method includes: High-pressure air is obtained by compressing air and injecting it into the storage section. After the target Ludwig tube wind tunnel is started, the high-pressure air is released by a quick-opening valve and transmitted to the first throat, so as to convert the high-pressure air into a supersonic airflow based on the first throat. Determine whether the target ratio corresponding to the first stable segment and the first throat is within the target range; the first cross-sectional area of ​​the first stable segment is greater than the second cross-sectional area of ​​the first throat; the target ratio is the ratio between the second cross-sectional area and the first cross-sectional area; If the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stabilization section, and the subsonic airflow is transmitted to the second stabilization section to obtain decelerated airflow; the diameter of the second stabilization section is larger than the diameter of the first stabilization section. The decelerated airflow is input into the target nozzle through the second throat, and the target nozzle accelerates the decelerated airflow to obtain a target low Mach number flow field that meets the target conditions; the target nozzle is a nozzle with an exit Mach number lower than a preset Mach number; the diameter of the second throat is larger than the diameter of the first throat.

2. The method for extending a high-speed wind tunnel to a low Mach number using a Ludwig tube according to claim 1, characterized in that, The process involves compressing air to obtain high-pressure air, injecting the high-pressure air into the storage section, and after starting the target Ludwig pipe wind tunnel, releasing the high-pressure air using a quick-opening valve and transmitting it to the first throat, so as to convert the high-pressure air into a supersonic airflow based on the first throat, including: Air is compressed to a high pressure state using a pre-set compression device to obtain high-pressure air, which is then injected into the air storage section for sealing. After the target Ludwig tube wind tunnel is started, the high-pressure air is released and transmitted to the first throat using a quick-opening valve connected to the gas storage section. The high-pressure air is accelerated using the first throat to obtain a supersonic airflow; The diameter of the first throat is determined based on a preset Mach number; the preset Mach number is the Mach number of the target Ludwig tube wind tunnel determined based on simulation requirements.

3. The method for extending a high-speed wind tunnel to a low Mach number using a Ludwig tube according to claim 1, characterized in that, The first stabilizing section includes a sintered mesh assembly, a honeycomb unit, and a sleeve for adjusting the position of the sintered mesh assembly and the honeycomb unit; The sintered mesh assembly is a component constructed using a metal wire mesh and a grid-shaped support frame; the front end of the grid-shaped support frame is flat, and the rear end is wedge-shaped.

4. The method for extending a high-speed wind tunnel to a low Mach number using a Ludwig tube according to claim 1, characterized in that, The step of determining whether the target ratio corresponding to the first stable segment and the first throat is within the target range includes: The target ratio between the first cross-sectional area and the second cross-sectional area is determined using the average Mach number and specific heat ratio of the first stable segment, and it is determined whether the target ratio is within the target range.

5. The method for extending a high-speed wind tunnel to a low Mach number using a Ludwig tube according to claim 1, characterized in that, The target Ludwig tube wind tunnel also includes a transition section; Accordingly, if the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stabilization section, and the subsonic airflow is transmitted to the second stabilization section to obtain decelerated airflow, including: If the target ratio is within the target range, the supersonic airflow is converted into subsonic airflow using the first stable section, and the subsonic airflow is transmitted to the transition section connecting the first stable section and the second stable section, so as to expand the subsonic airflow using the transition section to obtain the expanded airflow. The expanded airflow is transmitted to the second stabilization section to decelerate the expanded airflow and obtain a decelerated airflow.

6. The method for extending a high-speed wind tunnel to a low Mach number using a Ludwig tube according to claim 1, characterized in that, The step of inputting the decelerated airflow into the target nozzle through the second throat, and accelerating the decelerated airflow through the target nozzle to obtain a target low Mach number flow field that meets the target conditions, includes: The decelerated airflow is guided into the target nozzle by the second throat, and the target nozzle is used to accelerate the decelerated airflow to obtain a target low Mach number flow field with a Mach number lower than the target value.

7. The method for extending a high-speed wind tunnel to a low Mach number using a Ludwig tube according to claim 1, characterized in that, The target Ludwig tube wind tunnel is also equipped with an experimental section, a diffusion section, and a vacuum chamber. Accordingly, after accelerating the decelerated airflow using the target nozzle to obtain a target low Mach number flow field that meets the target conditions, the process further includes: The target low Mach number flow field is stored in the experimental section to obtain the experimental data corresponding to the target low Mach number flow field and to obtain the airflow after the experiment. The gas flow after the experiment is decelerated and depressurized using a diffuser section to obtain a depressurized gas flow, which is then input into a vacuum tank.

8. A Ludwig tube high-speed wind tunnel extension low Mach number device, characterized in that, Applied to a target Ludwig pipe wind tunnel; the target Ludwig pipe wind tunnel includes a gas storage section, a quick-opening valve, a first throat, a first stabilizing section, a second stabilizing section, a second throat, and a target nozzle; wherein, the device includes: The high-pressure air conversion module is used to compress air to obtain high-pressure air and inject the high-pressure air into the air storage section. After the target Ludwig tube wind tunnel is started, the high-pressure air is released by a quick-opening valve and transmitted to the first throat, so as to convert the high-pressure air into supersonic airflow based on the first throat. The target ratio judgment module is used to determine whether the target ratio corresponding to the first stable segment and the first throat is within the target range; the first cross-sectional area of ​​the first stable segment is greater than the second cross-sectional area of ​​the first throat; the target ratio is the ratio between the second cross-sectional area and the first cross-sectional area; An airflow transmission module is used to convert the supersonic airflow into subsonic airflow using the first stabilization section if the target ratio is within the target range, and then transmit the subsonic airflow to the second stabilization section to obtain decelerated airflow; the diameter of the second stabilization section is larger than the diameter of the first stabilization section. The target flow field determination module is used to input the decelerated airflow into the target nozzle through the second throat, and to accelerate the decelerated airflow through the target nozzle to obtain a target low Mach number flow field that meets the target conditions; the target nozzle is a nozzle with an exit Mach number lower than a preset Mach number; the diameter of the second throat is larger than the diameter of the first throat.

9. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor for executing the computer program to implement the Ludwig tube high-speed wind tunnel extension low Mach number method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, Used to store a computer program, wherein the computer program, when executed by a processor, implements the Ludwig tube high-speed wind tunnel extension low Mach number method as described in any one of claims 1 to 7.

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