Coaxial cylindrical detonation driver for shock tube / wind tunnel and method thereof

Abstract

The application discloses a coaxial cylindrical detonation driving device for a shock tube / wind tunnel and a method thereof, which comprises a detonation driving section, one end of the detonation driving section being communicated with a driven section, the other end of the detonation driving section being connected with a blind plate, and a diaphragm being arranged between the detonation driving section and the driven section; the detonation driving section is inserted with a first electrode and a second electrode extending in a radial direction, and an ignition wire extending in an axial direction is electrically connected between the first electrode and the second electrode; the application further comprises a discharge system, the discharge system comprising a high-voltage capacitor, an ignition switch and a unloading switch, an ignition circuit being formed by a positive electrode of the high-voltage capacitor, the ignition switch, the first electrode, the ignition wire, the second electrode and a negative electrode of the high-voltage capacitor, an unloading circuit being formed by the positive electrode of the high-voltage capacitor, the unloading switch and the negative electrode of the high-voltage capacitor, and the ignition circuit and the unloading circuit being connected in parallel. In the application, detonation is replaced by deflagration, and there is no pressure peak in detonation, so that the combustion pressure can be 100% used for compressing test gas, and therefore the pressure of the test gas is improved.

Description

Technical Field

[0001] This invention relates to the technical field of experimental research on high-temperature high-speed gas dynamics, high-speed aircraft, etc., and more specifically, to a coaxial cylindrical deflagration drive device and method for shock tubes / wind tunnels. Background Technology

[0002] A shock tube / wind tunnel is an experimental device widely used in fields such as high-temperature, high-speed gas dynamics and high-speed aircraft. Its basic principle is that high-pressure driving gas compresses low-pressure test gas through a shock wave, bringing it to the required experimental state. For example... Figure 1 As shown, a typical shock tube / wind tunnel includes a drive section 1', a driven section 2', a nozzle 3', and a test section 4'. Before the test, the drive section 1' and the driven section 2' are separated by a diaphragm 5'. High-pressure drive gas is filled into the drive section 1', and low-pressure test gas is filled into the driven section 2'. During the test, the diaphragm 5' ruptures, the high-pressure gas expands and enters the driven section 2', and a rapidly moving shock wave is generated in the driven section 2'. If the gas after the shock wave is used directly for the test, the equipment operates in shock tube mode; if the test gas accelerated by the nozzle 3' is used for the test, the equipment operates in shock tunnel mode.

[0003] The total temperature and total pressure range of the test gas are key indicators of equipment capability, both of which depend on the driving capability of the high-pressure driving gas. Room temperature, high-pressure gases can no longer meet increasingly demanding testing requirements. Therefore, three high-performance driving technologies have been developed both domestically and internationally: piston-driven, heated light gas-driven, and detonation-driven. Among these, detonation-driven technology is characterized by low cost, simple structure, and relatively high safety, and is currently the mainstream technology in China.

[0004] The detonation-driven shock tube was first proposed by Bird in 1957. In 1981, Mr. Yu Hongru of the Institute of Mechanics, Chinese Academy of Sciences, built a 13.3m long detonation-driven shock tube, which was put into use in 1983. In 1994, the Institute of Mechanics, Chinese Academy of Sciences, developed the JF-10 detonation-driven high-enthalpy shock tunnel [see Yu Hongru, Zhao Wei, and Yuan Shengxue, Performance of Hydrogen-Oxygen Detonation-Driven Shock Tunnel - Aerodynamic Testing and Measurement Control, 1993, 7(3): 38-42]. With the help of Mr. Yu Hongru, Gronig et al. built a high-enthalpy shock tunnel (TH2-D) using reverse detonation drive at RWTH Aachen University in Germany in 1993. In 1994, NASA modified the original free piston drive design and built the Hypulse wind tunnel at GASL. This wind tunnel can operate in both reflected shock tunnel mode and expansion tube mode. [See ChueRSM, Tsai CY, Bakos RJ, Erdos JI, Rogers RC (2002) NASA's Hypulse Facility at GASL - Dual Mode, Dual Driver Reflected-Shock / Expansion Tunnel. In: Lu F, Marren D (eds), Advanced Hypersonic Test Facilities, Progress in Astronautics and Aeronautics, Vol. 198, AIAA, Chapter 3, pp29-71].

[0005] Existing document (CN102407947A) discloses a dual-drive device for detonation in a shock tunnel, comprising: a shock tunnel having a detonation driving section, one end of which is provided with a detonation unloading section, and the other end with a driven section; a first diaphragm is provided between the detonation unloading section and the detonation driving section, and a second diaphragm is provided between the driven section and the detonation driving section; a forward detonation driving ignition device is provided at a section of the detonation driving section near the detonation unloading section, and a reverse detonation driving ignition device is provided at a section of the detonation driving section near the driven section; a controllable delay triggering device is connected between the forward detonation driving ignition device and the reverse detonation driving ignition device. The method is as follows: 1) A forward detonation ignition device is installed at the end of the detonation driving section of the shock tunnel near the detonation unloading section, and a reverse detonation driving ignition device is installed at the end of the detonation driving section near the driven section; 2) Ignition is performed by the forward detonation ignition device to form a forward driving detonation wave; 3) After the forward detonation wave has propagated along the detonation driving section for a predetermined time, it is ignited by the reverse detonation driving ignition device to form a reverse driving detonation wave; 4) The reverse driving detonation wave tears the diaphragm set between the driven section and the detonation driving section. After the forward detonation wave and the reverse detonation wave intersect, a moving shock wave is formed. This moving shock wave enters the driven section to compress the test gas in the driven section.

[0006] Detonation-driven systems require the formation of an axially propagating detonation wave within the drive section. The non-uniform flow field following the detonation wave leads to the following problems with this drive technology: First, the range of detonable gas mixing ratios is much narrower than that of combustible systems, and the range of temperature and sound velocity of the drive gas is also correspondingly narrower, thus limiting the total temperature range of the test gas that detonation-driven systems can provide; Second, the effective drive pressure provided by detonation-driven systems does not exceed 40% of the equipment's pressure limit, thus limiting the total pressure range of the test gas.

[0007] To overcome the aforementioned problems of detonation-driven systems, this invention proposes a coaxial cylindrical deflagration-driven device and method for shock tubes / wind tunnels. It utilizes deflagration to generate driving gas, eliminates detonation pressure peaks, and achieves an effective driving pressure equal to 100% of the equipment's pressure limit. Furthermore, it allows for a wider range of combustible gas mixing ratios, resulting in a wider total temperature range for the test gas. This deflagration-driven technology is not easily conceived by those skilled in the art. Summary of the Invention

[0008] In view of this, the present invention provides a coaxial cylindrical deflagration drive device for shock tubes / wind tunnels, comprising:

[0009] The deflagration driving section is a straight pipe with a constant cross-section. One end of the deflagration driving section is connected to the driven section, and the other end is connected to a blind plate. A diaphragm is provided between the deflagration driving section and the driven section.

[0010] The deflagration drive section is connected to a first electrode and a second electrode that extend radially. The first electrode is located on the side of the deflagration drive section near the blind plate, and the second electrode is located on the side of the deflagration drive section near the diaphragm. An ignition wire that extends axially is electrically connected between the first electrode and the second electrode. The axial direction is the direction from the deflagration drive section to the center line of the driven section. The radial direction intersects the axial direction.

[0011] Along the axial direction, the length between the blind plate and the first electrode is L1, and the length between the second electrode and the diaphragm is L2, with the lengths of L1 and L2 both ranging from 0.5 to 20 cm.

[0012] The deflagration drive section has openings that cooperate with the first electrode and the second electrode, and the contact surfaces of the first electrode and the second electrode with the deflagration drive section are provided with sealing rings.

[0013] The deflagration drive section is filled with a combustible mixture.

[0014] It also includes a discharge system, which comprises a high-voltage capacitor, an ignition switch, and an unloading switch. The ignition circuit is formed by the positive terminal of the high-voltage capacitor, the ignition switch, the first electrode, the ignition wire, the second electrode, and the negative terminal of the high-voltage capacitor. The unloading circuit is formed by the positive terminal of the high-voltage capacitor, the unloading switch, and the negative terminal of the high-voltage capacitor. The ignition circuit and the unloading circuit are connected in parallel. The high-voltage capacitor is used to store high-voltage electricity and discharge it to the ignition wire.

[0015] Optionally, the combustible mixture includes fuel, oxidant, and inert gas, wherein the fuel is hydrogen, carbon monoxide, or alkanes, alkenes, or alkynes; the oxidant is oxygen or nitrous oxide; and the inert gas is nitrogen, rare gas, or carbon dioxide.

[0016] Optionally, the ignition wire is made of metal.

[0017] Optionally, the metal material is any one of copper, silver, nickel-chromium, tungsten, and alloys.

[0018] The present invention also provides a coaxial cylindrical deflagration driving method for shock tubes / wind tunnels, providing a deflagration driving section, wherein the deflagration driving section is a straight tube with a uniform cross section, one end of the deflagration driving section is connected to the driven section, and the other end is connected to a blind plate, and a diaphragm is provided between the deflagration driving section and the driven section.

[0019] A first electrode and a second electrode extending radially are inserted into the deflagration driving section. The first electrode is located on the side of the deflagration driving section near the blind plate, and the second electrode is located on the side of the deflagration driving section near the diaphragm. An ignition wire arranged axially is electrically connected between the first electrode and the second electrode. The axial direction is the direction from the deflagration driving section to the center line of the driven section. The radial direction intersects the axial direction.

[0020] A combustible mixture is introduced into the deflagration drive section;

[0021] A discharge system is provided, comprising a high-voltage capacitor, an ignition switch, and an unloading circuit. The ignition circuit is composed of the positive terminal of the high-voltage capacitor, the ignition switch, the first electrode, the ignition wire, the second electrode, and the negative terminal of the high-voltage capacitor. The unloading circuit is composed of the positive terminal of the high-voltage capacitor, the unloading switch, and the negative terminal of the high-voltage capacitor. The ignition circuit and the unloading circuit are connected in parallel. The ignition circuit and the unloading circuit are respectively electrically connected to the high-voltage capacitor, and the high-voltage capacitor stores high-voltage electricity.

[0022] The high-voltage capacitor discharges to the ignition wire. At the instant the ignition circuit is energized, the ignition wire heats up intensely and ignites the combustible mixture near the ignition wire within a microsecond time, forming a columnar flame surface that expands radially.

[0023] After a predetermined discharge time, the remaining charge in the high-voltage capacitor is removed using an unloading circuit.

[0024] Optionally, the predetermined discharge time is 5-30 milliseconds.

[0025] Compared with the prior art, the coaxial cylindrical deflagration driving device and method for shock tubes / wind tunnels provided by the present invention achieves at least the following beneficial effects:

[0026] On the one hand, in the existing technology, detonation drives the formation of axially propagating detonation waves in the driving section pipe. Since the extremely high pressure peak of the detonation wave cannot be fully used for driving, the effective pressure provided by detonation driving is much lower than the pressure limit of the equipment. However, in this invention, deflagration is used instead of detonation, and there is no pressure peak in detonation. The combustion pressure can be 100% used to compress the test gas, thus increasing the pressure of the test gas.

[0027] On the other hand, the mixture ratio limit of deflagration is much wider than that of detonation, and the temperature and sound speed range of the driving gas are also larger. Consequently, the total temperature range of the test gas is also larger than that driven by detonation.

[0028] Of course, any product implementing this invention does not necessarily need to achieve all of the technical effects described above at the same time.

[0029] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0031] Figure 1 This is a schematic diagram of a shock tube / wind tunnel provided in the prior art;

[0032] Figure 2 This is a schematic diagram of the structure of a coaxial cylindrical deflagration drive device for a shock tube / wind tunnel provided in an embodiment of the present invention;

[0033] Figure 3 yes Figure 2 Enlarged view of the structure at point B in the middle;

[0034] Figure 4 yes Figure 2 Enlarged view of the structure of the medium-discharge system;

[0035] Figure 5 This is a logic block diagram of a discharge system provided in an embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of a shock tube / wind tunnel provided in an embodiment of the present invention;

[0037] Figure 7 This is a flowchart of a coaxial cylindrical deflagration driving method for shock tubes / wind tunnels provided by an embodiment of the present invention. Detailed Implementation

[0038] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0039] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0040] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0041] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0043] Figure 2 This is a schematic diagram of the structure of a coaxial cylindrical deflagration drive device for a shock tube / wind tunnel provided in an embodiment of the present invention; Figure 3 yes Figure 2 Enlarged view of the structure at point B in the middle; Figure 4 yes Figure 2 Enlarged view of the structure of the medium-discharge system; Figure 5 This is a logic block diagram of a discharge system provided in an embodiment of the present invention. Figures 2-5 As shown, this embodiment provides a coaxial cylindrical deflagration drive device for shock tubes / wind tunnels, including a deflagration drive section 1, a driven section 2, a diaphragm 5 for separating the deflagration drive section 1 and the driven section 2, a blind plate 14, and a discharge system 7, wherein one end of the deflagration drive section 1 is connected to the driven section 2, and the other end is connected to the blind plate 14.

[0044] The deflagration driving section 1 is a straight pipe with a constant cross section. A first electrode 11 and a second electrode 12 extending radially Y are inserted into the deflagration driving section 1. The first electrode 11 is located on the side of the deflagration driving section close to the blind plate 14, and the second electrode 12 is located on the side of the deflagration driving section 1 close to the driven section 2. An ignition wire 13 extending axially X is electrically connected between the first electrode 11 and the second electrode 12. The axial direction X is the direction from the center line of the axis of the deflagration driving section 1 to the driven section 2, and the radial direction Y intersects with the axial direction X.

[0045] Along the axial direction X, the length between the first electrode 11 and the blind plate 14 is L1, and the length between the second electrode 12 and the diaphragm 5 is L2. The lengths of L1 and L2 are limited to 0.5cm-20cm.

[0046] The deflagration drive section 1 has an opening 8 that mates with the first electrode 11 and the second electrode 12. A sealing ring 81 is provided on the contact surface between the first electrode 11, the second electrode 12 and the opening 8.

[0047] The deflagration drive section 1 is filled with a combustible mixture;

[0048] The discharge system 7 includes a high-voltage capacitor 71, an ignition switch 720, and an unloading switch 730. The ignition circuit 72 is formed by the positive terminal of the high-voltage capacitor 71, the ignition switch 720, the first electrode 11, the ignition wire 13, the second electrode 12, and the negative terminal of the high-voltage capacitor 71. The unloading circuit 73 is formed by the positive terminal of the high-voltage capacitor 71, the unloading switch 730, and the negative terminal of the high-voltage capacitor 71. The ignition circuit 72 and the unloading circuit 73 are connected in parallel. The high-voltage capacitor 71 is used to store high-voltage electricity and discharge it to the ignition wire.

[0049] Specifically, the coaxial cylindrical deflagration drive device for shock tubes / wind tunnels includes a deflagration drive section 1 and a driven section 2. One end of the deflagration drive section 1 is connected to the driven section 2, and the other end is connected to a blind flange 14. A diaphragm 5 is installed between the deflagration drive section 1 and the driven section 2. The driven section 2 is connected to the test section 4 through a nozzle 3. The blind flange 14 is a flange cover. By using the blind flange 14 to block the end of the deflagration drive section 1, there is no need to use the traditional detonation unloading section and install a diaphragm between the detonation unloading section and the deflagration drive section. This not only helps to reduce the space occupied, but also reduces the cost.

[0050] A first electrode 11 and a second electrode 12 extending radially Y are inserted into the deflagration driving section 1. The first electrode 11 is located on the side of the deflagration driving section 1 near the blind plate 14, and the second electrode 12 is located on the side of the deflagration driving section 1 near the driven section 2. That is, the first electrode 11 and the second electrode 12 are inserted at both ends of the deflagration driving section 1. An ignition wire 13 extending axially is electrically connected between the first electrode 11 and the second electrode 12. The axial direction X is the direction from the blind plate 14 to the center line of the driven section 2. The radial direction Y intersects with the axial direction X. Optionally, the ignition wire 13 can be any metal material selected from copper, silver, nickel-chromium, tungsten and alloys. The length of the ignition wire 13 can be adjusted according to the length of the deflagration driving section 1.

[0051] The axial distance from the first electrode 11 to the blind plate 14 is L1, and the axial distance from the second electrode 12 to the diaphragm 5 is L2. If the lengths of L1 and L2 are less than 0.5cm, breakdown may occur, leading to equipment damage or endangering personnel safety. If the lengths of L1 and L2 are greater than 20cm, the combustion of the combustible mixture in the deflagration drive section 1 may be unstable. Therefore, limiting the lengths of L1 and L2 to 0.5cm-20cm not only allows the ignition wire 13 to be arranged as long as possible along the axial direction in the deflagration drive section, which can further enable the combustion of the combustible mixture in the deflagration drive section 1 to be more complete, but also avoids the distance between the first electrode 11 and the end of the deflagration drive section and between the second electrode 12 and the diaphragm 5 being too close, thereby avoiding breakdown and ensuring the safety of equipment and personnel.

[0052] Figure 3 yes Figure 2 Enlarged view of the structure at point B; where, Figure 2 The enlarged view at point C is the same as the enlarged view at point B. An opening 8 is provided on the deflagration driving section 1 to cooperate with the first electrode 11 and the second electrode 12. Figure 3In order to show the opening 8 in the figure, the diameter of the opening 8 is drawn to be larger than the actual size. The opening 8 is matched with the first electrode 11 and the second electrode 12 is matched with the opening 8. The opening 8 facilitates the insertion of the first electrode 11 and the second electrode 12 into the combustion driving section 1. In order to ensure the sealing of the deflagration driving section 1, after the first electrode 11 is inserted into the deflagration driving section 1, a sealing ring 81 is set on the contact surface of the deflagration driving section 1 where the first electrode 1 contacts the opening 8, and a sealing ring 81 is set on the contact surface of the deflagration driving section 1 where the second electrode 12 contacts the opening 8.

[0053] The deflagration drive section 1 is filled with a combustible mixture, which may include fuel, oxidant, and inert gas. The fuel is hydrogen, carbon monoxide, or alkanes, alkenes, and alkynes, or other combustible gases. The oxidant is oxygen or nitrous oxide, or other oxidizing gases. The inert gas is nitrogen, rare gases, or carbon dioxide, or other gases that do not participate in the combustion reaction. The ratio of fuel:oxidant:inert gas can be 1:1:1, 2:1:1, or 2:1:7. Of course, the ratio of fuel, oxidant, and inert gas is set according to the specific equipment and experimental requirements.

[0054] It also includes a discharge system 7, which includes a high-voltage capacitor 71, an ignition switch 720, and an unloading switch 730. The high-voltage capacitor 71 can generate a voltage of 2000V. The positive terminal of the high-voltage capacitor 71, the ignition switch 720, the first electrode 11, the ignition wire 13, the second electrode 12, and the negative terminal of the high-voltage capacitor 71 constitute an ignition circuit 72. The positive terminal of the high-voltage capacitor 71, the unloading switch 730, and the negative terminal of the high-voltage capacitor 71 constitute an unloading circuit 73. The ignition circuit 72 and the unloading circuit 73 are connected in parallel. The high-voltage capacitor 71 is used to store high-voltage electricity.

[0055] After the high-voltage capacitor 71 is charged, the ignition switch 720 is closed first. The high-voltage capacitor 71 is connected to the ignition wire 13 through the first electrode 11 and the second electrode 12 respectively, and ignition begins. After a predetermined time, the unloading switch 730 is closed to short-circuit the positive and negative terminals of the high-voltage capacitor 71. The charge in the high-voltage capacitor 71 is then instantly returned to the high-voltage capacitor 71 through the unloading circuit 73, completing the unloading. The predetermined time can be 5-30 milliseconds.

[0056] The assembly sequence of the coaxial cylindrical deflagration drive device for shock tubes / wind tunnels is as follows:

[0057] Provides deflagration drive section 1;

[0058] First, an opening 8 is provided on the deflagration driving section 1 for placing the first electrode 11 and the second electrode 12; second, a sealing ring 81 is installed on the contact surface between the first electrode 11 and the second electrode 12 and the opening 8, and the first electrode 11 and the second electrode 12 are inserted into the opening 8. The first electrode 11 is located on the side of the deflagration driving section near the blind plate 14, and the second electrode 12 is located on the side of the deflagration driving section 1 near the driven section 2; an ignition wire 13 extending along the axial direction X is connected between the first electrode 11 and the second electrode 12.

[0059] A diaphragm is installed between the deflagration driving section 1 and the driven section 2. The driven section 2 is connected to one end of the deflagration driving section 1 near the diaphragm 5, and a blind plate 14 is connected to the other end.

[0060] The deflagration drive section 1 is filled with a combustible mixture;

[0061] Connect the discharge system 7, and form an ignition circuit 72 by connecting the positive terminal of the high voltage capacitor 71, the ignition switch 720, the first electrode 11, the ignition wire 13, the second electrode 12, and the negative terminal of the high voltage capacitor 71; form an unloading circuit 73 by connecting the positive terminal of the high voltage capacitor 71, the unloading switch 730, and the negative terminal of the high voltage capacitor 71; the ignition circuit 72 and the unloading circuit 73 are connected in parallel.

[0062] Assemble the coaxial cylindrical deflagration drive device for shock tubes / wind tunnels according to the above assembly sequence. This not only allows for better insertion of the first and second electrodes and more precise placement of the ignition wire 13, but also prevents leakage of combustible mixture, ensuring personal safety, and facilitating operation.

[0063] Of course, without considering the discharge of the high-voltage capacitor to the ignition wire, the above assembly sequence can be appropriately adjusted. After installing the driven section 2 or the blind plate 14, the discharge system can be connected first, and then the combustible mixture can be filled into the deflagration drive section 1, as follows:

[0064] First, it provides the deflagration drive section 1;

[0065] Second, firstly, an opening 8 is provided on the deflagration driving section 1 for placing the first electrode 11 and the second electrode 12; secondly, a sealing ring 81 is installed on the contact surface between the first electrode 11 and the second electrode 12 and the opening 8, and the first electrode 11 and the second electrode 12 are inserted into the opening 8. The first electrode 11 is located on the side of the deflagration driving section near the blind plate 14, and the second electrode 12 is located on the side of the deflagration driving section 1 near the driven section 2; an ignition wire 13 extending along the axial direction X is connected between the first electrode 11 and the second electrode 12.

[0066] Third, a diaphragm is installed between the deflagration driving section 1 and the driven section 2. The driven section 2 is connected to one end of the deflagration driving section 1 near the diaphragm 5, and a blind plate 14 is connected to the other end.

[0067] Fourth, connect the discharge system 7, and form an ignition circuit 72 by connecting the positive terminal of the high-voltage capacitor 71, the ignition switch 720, the first electrode 11, the ignition wire 13, the second electrode 12, and the negative terminal of the high-voltage capacitor 71; form an unloading circuit 73 by connecting the positive terminal of the high-voltage capacitor 71, the unloading switch 730, and the negative terminal of the high-voltage capacitor 71; the ignition circuit 72 and the unloading circuit 73 are connected in parallel.

[0068] Fifth, the combustion-driven section 1 is filled with a combustible mixture.

[0069] It should be noted that: First, a deflagration driving section 1 is provided; second, firstly, an opening 8 is formed on the deflagration driving section 1 for placing a first electrode 11 and a second electrode 12; secondly, a sealing ring 81 is installed on the contact surface between the first electrode 11 and the second electrode 12 and the opening 8, and the first electrode 11 and the second electrode 12 are inserted into the opening 8, with the first electrode 11 located on the side of the deflagration driving section near the blind plate 14, and the second electrode 12 located on the side of the deflagration driving section 1 near the driven section 2; an ignition wire 13 extending along the axial direction X is connected between the first electrode 11 and the second electrode 12; thirdly, a diaphragm is installed between the deflagration driving section 1 and the driven section 2, with the driven section 2 connected to one end of the deflagration driving section 1 near the diaphragm 5, and the blind plate 14 connected to the other end; the assembly sequence of the above three steps is irreversible, that is, the assembly sequence cannot be reversed, otherwise it cannot be implemented.

[0070] The working principle is as follows: Within the deflagration drive section 1, there is an ignition wire 13 arranged axially (X). After the high-voltage capacitor 71 is charged, the ignition switch 720 is closed. The high-voltage capacitor 71 is connected to the ignition wire 13 through the first electrode 11 and the second electrode 12. A high voltage of several thousand to tens of thousands of volts is applied across the ignition wire 13. At the instant the ignition switch 720 is energized, the ignition wire 13 heats up intensely, igniting the combustible mixture near the ignition wire 13 within microseconds. After ignition, a columnar flame is formed and expands radially. The ignition wire 13 is made strictly coaxial with the pipe of the deflagration drive section 1 to ensure that all parts along the axial direction burn out simultaneously. Since the discharge process of the high-voltage capacitor 71 is longer than the combustion process, the remaining charge in the high-voltage capacitor 71 needs to be discharged before the combustion ends. Therefore, after a predetermined time, the unloading switch 730 is closed to short-circuit the positive and negative terminals of the high-voltage capacitor 71. The charge in the high-voltage capacitor 71 then returns to the high-voltage capacitor 71 instantly through the unloading circuit to complete the unloading, thereby preventing the combustion products near the positive terminal of the high-voltage capacitor 71 from breaking down and causing a safety accident.

[0071] It should be noted that: detonation drive requires the formation of a detonation wave propagating axially within the drive section pipe, while deflagration drive involves igniting the gas in the deflagration drive section 1 pipe simultaneously along the axial direction, completing combustion in a deflagration rather than detonation manner, and ending combustion simultaneously along the axial direction X.

[0072] The effective operating time of a shock tube / wind tunnel is typically in the range of a few milliseconds to 100 milliseconds. In order to provide accurate test conditions, it is essential to ensure that the combustible mixture in the deflagration drive section is ignited and burned out simultaneously.

[0073] As can be seen from the above embodiments, the coaxial cylindrical deflagration drive device for shock tubes / wind tunnels provided by the present invention achieves at least the following beneficial effects:

[0074] On the one hand, in the existing technology, detonation drives the formation of axially propagating detonation waves in the driving section pipe. Since the extremely high pressure peak of the detonation wave cannot be fully used for driving, the effective pressure provided by detonation driving is much lower than the pressure limit of the equipment. However, in this invention, deflagration is used instead of detonation, and there is no pressure peak in detonation. The combustion pressure can be 100% used to compress the test gas, thus increasing the pressure of the test gas.

[0075] On the other hand, the mixture ratio limit of deflagration is much wider than that of detonation, and the temperature and sound speed range of the driving gas are also larger. Consequently, the total temperature range of the test gas is also larger than that driven by detonation.

[0076] Figure 6 This is a schematic diagram of a shock tube / wind tunnel provided in an embodiment of the present invention; another embodiment of the present invention provides a shock tube / wind tunnel, including a coaxial cylindrical deflagration drive device for a shock tube / wind tunnel provided in an embodiment of the present invention.

[0077] Figure 7 This is a flowchart illustrating a coaxial cylindrical deflagration driving method for shock tubes / wind tunnels, provided by an embodiment of the present invention. (Refer to...) Figure 7 As shown, this embodiment of the invention also provides a coaxial cylindrical deflagration driving method for shock tubes / wind tunnels, providing a deflagration driving section 1, which is a straight tube with a uniform cross-section. One end of the deflagration driving section 1 is connected to the driven section 2, and the other end is connected to a blind plate 14. A diaphragm 5 is provided between the deflagration driving section 1 and the driven section 2.

[0078] A first electrode 11 and a second electrode 12 extending radially Y are inserted into the deflagration drive section 1. The first electrode 11 is located on one side of the blind plate 14, and the second electrode 12 is located on the side of the deflagration drive section 1 near the diaphragm 5. An ignition wire 13 arranged along the axial direction X is electrically connected between the first electrode 11 and the second electrode 12. The axial direction X is the direction from the center line of the deflagration drive section 1 to the driven section 2, and the radial direction X intersects the axial direction Y.

[0079] A combustible mixture is introduced into the deflagration drive section 1;

[0080] A discharge system 7 is provided, which includes a high-voltage capacitor 71, an ignition switch 720, and an unloading circuit 73. The ignition circuit 72 is composed of the positive terminal of the high-voltage capacitor, the ignition switch 720, the first electrode 11, the ignition wire 13, the second electrode 12, and the negative terminal of the high-voltage capacitor. The unloading circuit 73 is composed of the positive terminal of the high-voltage capacitor, the unloading switch 730, and the negative terminal of the high-voltage capacitor. The ignition circuit 72 and the unloading circuit 73 are connected in parallel. The ignition circuit 72 and the unloading circuit 73 are electrically connected to the high-voltage capacitor 71, respectively, and the high-voltage capacitor 71 stores high-voltage electricity.

[0081] The high-voltage capacitor 71 discharges to the ignition wire 13. At the instant the ignition circuit 72 is energized, the ignition wire 13 heats up violently and ignites the combustible mixture near the ignition wire 13 within a microsecond time, forming a columnar flame surface that expands radially.

[0082] After a predetermined discharge time, the remaining charge in the high-voltage capacitor 71 is removed using the unloading circuit 73.

[0083] Its working principle is the same as that of the coaxial cylindrical deflagration drive device used in shock tubes / wind tunnels, and will not be described in detail here.

[0084] As can be seen from the above embodiments, the coaxial cylindrical deflagration driving method for shock tubes / wind tunnels provided by the present invention achieves at least the following beneficial effects:

[0085] On the one hand, in the existing technology, detonation drives the formation of axially propagating detonation waves in the driving section pipe. Since the extremely high pressure peak of the detonation wave cannot be fully used for driving, the effective pressure provided by detonation driving is much lower than the pressure limit of the equipment. However, in this invention, deflagration is used instead of detonation, and there is no pressure peak in detonation. The combustion pressure can be 100% used to compress the test gas, thus increasing the pressure of the test gas.

[0086] On the other hand, the mixture ratio limit of deflagration is much wider than that of detonation, and the temperature and sound speed range of the driving gas are also larger. Consequently, the total temperature range of the test gas is also larger than that driven by detonation.

[0087] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A coaxial cylindrical detonation driver for a shock tube / wind tunnel, characterized by, The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel.

2. The coaxial cylindrical detonation drive for a shock tube / wind tunnel of claim 1, wherein, The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel.

3. The coaxial cylindrical detonation drive for a shock tube / wind tunnel according to any one of claims 1 and 2, characterized in that, The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel.

4. The coaxial cylindrical detonation drive for a shock tube / wind tunnel of claim 3, wherein, The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving method for a shock wave tube / wind tunnel. The application relates to a coaxial cylindrical detonation driving The discharge system comprises a high-voltage capacitor, a spark switch and a discharge loop, the spark loop is composed of the high-voltage capacitor positive pole, the spark switch, the first electrode, the spark wire, the second electrode and the high-voltage capacitor negative pole, the discharge loop is composed of the high-voltage capacitor positive pole, the discharge switch and the high-voltage capacitor negative pole, the spark loop and the discharge loop are connected in parallel, the spark loop and the discharge loop are electrically connected with the high-voltage capacitor respectively, the high-voltage capacitor stores high-voltage electricity, and the high-voltage capacitor generates a voltage of 2000V; The high-voltage capacitor is used for discharging the spark wire, the spark wire generates intense heat at the moment of the spark loop being electrified, the combustible mixture near the spark wire is ignited at the same time within the time of microsecond, a columnar flame surface is formed, and the columnar flame surface expands along the radial direction; After a predetermined discharge time, the residual charge in the high-voltage capacitor is discharged by the discharge loop.

6. The coaxial cylindrical detonation drive method for a shock tube / wind tunnel of claim 5, wherein, The predetermined discharge time is 5-30 milliseconds.

Images