Single-pulse converging shock wave system

Abstract

The present invention provides a single-pulse converging shock wave system. The system comprises: a gas source, wherein the gas source is configured to provide a test gas; and a converging shock wave pipe, comprising: a shock wave attenuation device, wherein the test gas enters the shock wave attenuation device, then an incident shock wave is formed, the incident shock wave forms a reflected shock wave under the action of reflection, and the reflected shock wave is reflected and attenuated in the shock wave attenuation device, such that the shock wave attenuation device outputs the test gas and incident shock wave having undergone reflection and attenuation treatment; and a parameter measurement device configured to perform parameter measurement on the test gas and incident shock wave having undergone reflection and attenuation treatment, wherein parameter measurement involves at least one of pressure information, flame morphology, and combustion characteristics.

Description

Single-pulse converging shock wave system Technical Field

[0001] This disclosure relates to the field of basic reactor technology, and more specifically, to a single-pulse converging shock wave system. Background Technology

[0002] Shock tube reactors, due to their ability to provide a supercritical experimental environment that combines versatility and high efficiency, have been widely applied in various scientific fields. In combustion chemistry research, shock tubes can simulate conditions close to those of actual aero-engines, providing a key technological means for aero-fuel dynamics research. Specifically, single-pulse shock tubes absorb reflected shock waves through an unloading tank located near the diaphragm, ensuring that the reaction mixture is heated by only a single reflected shock wave. By "freezing" the reactants through reflected rarefaction waves, combined with sampling and diagnostic techniques, rich data on the distribution of substances during the research process can be obtained.

[0003] However, due to limitations in the pressure resistance of the single-pulse shock tube itself and experimental costs, its pressure level is difficult to reach the theoretical maximum value in actual experiments. Furthermore, in small-diameter shock tubes with an inner diameter of less than 10 cm, the boundary layer effect has a significant impact on temperature during sample collection, potentially leading to reduced data accuracy. Summary of the Invention

[0004] In view of this, the present disclosure provides a single-pulse converging shock wave system, comprising:

[0005] Gas source, the aforementioned gas source is configured to provide test gas;

[0006] Shock converging conduit, including:

[0007] The shock wave reduction device forms an incident shock wave after the test gas enters the shock wave reduction device. The incident shock wave forms a reflected shock wave under the action of reflection. The reflected shock wave is reflected and reduced in the shock wave reduction device, so the shock wave reduction device outputs the test gas and incident shock wave after reflection reduction.

[0008] The parameter measuring device is configured to measure parameters of the test gas and the incident shock wave after reflection reduction processing, wherein the parameter measurements include at least one of pressure information, flame morphology and combustion characteristics.

[0009] According to embodiments of this disclosure, the above-mentioned converging shock wave conduit further includes:

[0010] The test gas is driven through a diaphragm section, within which a pressure difference is created, causing the test gas to move to the shock wave reduction device under the action of the pressure difference; and / or

[0011] The driven section is configured to deliver the test gas and incident shock wave, after the aforementioned reflection reduction treatment, to the aforementioned parameter measuring device.

[0012] According to embodiments of this disclosure, the shock wave attenuation device includes:

[0013] A segmented reduction container, wherein the segmented reduction container has a receiving cavity;

[0014] The air chamber pipe runs through the segmented reduction container. The first end of the air chamber pipe is connected to the driving diaphragm section, and the second end of the air chamber pipe is connected to the driven section. Multiple reduction gaps are provided on the air chamber pipe located in the accommodating cavity.

[0015] Multiple gap-sealing structures are detachably installed on multiple of the aforementioned gap-reducing structures;

[0016] In this process, the test gas moves from the first end to the second end under the action of the pressure difference. During the movement of the gas between the reduction gap and the second end, a reflected shock wave is formed that moves toward the first end. By setting the gap sealing structure to block the number and position of the reduction gaps, the reflected shock wave that enters the receiving cavity through the unsealed reduction gaps is reflected and reduced multiple times.

[0017] According to embodiments of this disclosure, the segmented reduction container includes:

[0018] A receiving cylinder, wherein the receiving cavity is formed on one side of the receiving cylinder;

[0019] The receiving cover is sealed to the aforementioned receiving cylinder.

[0020] According to embodiments of this disclosure, the above-mentioned gap sealing structure includes:

[0021] The first sealing assembly and the second sealing assembly are installed in contact with the outer wall of the air chamber pipe when the gap is reduced, wherein the length of the first sealing assembly is greater than the length of the second sealing assembly.

[0022] The aforementioned gap reduction is completely sealed by the first sealing component and the second sealing component, or the aforementioned gap reduction is partially sealed by the first sealing component or the second sealing component.

[0023] According to embodiments of this disclosure, each of the first and second sealing components includes:

[0024] The sealing plate is configured to be inserted into the aforementioned reduction gap;

[0025] The mounting part is connected to the aforementioned sealing plate. The mounting part is configured to fit against the outer wall of the aforementioned air chamber pipe and be detachably connected to the aforementioned air chamber pipe.

[0026] According to embodiments of this disclosure, the above-mentioned converging shock wave conduit further includes:

[0027] At least one shock converging tube, wherein the shock converging tube comprises:

[0028] The first conversion tube has its input end connected to the driven section. The first conversion tube is configured to convert the incident shock wave into an oblique shock wave when the driven section receives an incident shock wave. The projection of the inner wall of the first conversion tube onto the target plane is a concave curve. The incident shock wave is formed by the test gas during the movement of the shock wave reduction device.

[0029] An inclined straight tube, the input end of which is connected to the output end of the first conversion tube, is configured to perform shock wave enhancement processing on the inclined shock wave to obtain an enhanced shock wave, wherein the projection of the inner wall of the inclined straight tube on the target plane is an inclined line segment.

[0030] The second conversion tube has its input end connected to the inclined straight tube and its output end connected to the parameter measuring device. The second conversion tube is configured to convert the enhanced shock wave into a parallel shock wave so that the parameter measuring device can measure the parameters of the parallel shock wave. The projection of the inner wall of the second conversion tube onto the target plane is a convex curve.

[0031] The concave curve, the inclined line segment, and the convex curve mentioned above are determined based on the principles of shock wave dynamics.

[0032] According to embodiments of this disclosure, the aforementioned driving diaphragm segment includes:

[0033] The test gas is transported to the diaphragm section through the drive pipeline.

[0034] The aforementioned diaphragm section is provided with a diaphragm. The aforementioned gas source supplies the aforementioned test gas to the aforementioned drive pipeline. When the preset pressure is reached, the aforementioned diaphragm ruptures to form the aforementioned pressure difference. The aforementioned test gas moves toward the aforementioned shock wave reduction device under the action of the aforementioned pressure difference.

[0035] According to embodiments of this disclosure, the above-mentioned parameter measuring device includes:

[0036] The test pipeline has an end cap at its output end and multiple test sensors installed on it.

[0037] A parameter measuring instrument is electrically connected to multiple of the aforementioned test sensors. The parameter measuring instrument is configured to process data from the aforementioned test sensors to achieve parameter measurement.

[0038] and / or

[0039] A combustion diagnostic instrument is connected to the output end of the aforementioned test pipeline. The combustion diagnostic instrument is configured to measure the flame morphology and combustion characteristics of the gas output from the aforementioned test pipeline.

[0040] According to embodiments of this disclosure, the above-described single-pulse converging shock wave system further includes:

[0041] A media supply device, comprising:

[0042] The medium conveying pipeline has one end that passes through the aforementioned end cap and the other end that is equipped with a bearing end cap. An inlet pipe for the test medium is formed on the aforementioned medium conveying pipeline.

[0043] A lead screw is installed inside the aforementioned medium conveying pipeline and is rotatably connected to the aforementioned bearing end cap.

[0044] The impeller is mounted on a lead screw outside the aforementioned medium conveying pipeline;

[0045] The piston is rotatably mounted on a lead screw inside the aforementioned medium conveying pipeline via a piston gland;

[0046] When the aforementioned rotating wheel is rotated, the lead screw causes the aforementioned gland and the aforementioned piston to move within the aforementioned medium delivery pipe. When the aforementioned piston blocks the aforementioned inlet pipe, the aforementioned test gas is supplied through the aforementioned gas source. When the aforementioned piston does not block the aforementioned inlet pipe, the aforementioned test medium is supplied through the aforementioned inlet pipe.

[0047] According to embodiments of this disclosure, the gas source includes:

[0048] The gas mixing tank contains test gas which is then transported to the converging shock wave pipeline via a gas input pipeline.

[0049] The gas distribution pipeline is provided with multiple gas distribution input terminals, through which gases of different compositions are input to the gas mixing tank or the converging shock wave pipeline to form the test gas.

[0050] According to embodiments of this disclosure, the single-pulse converging shock wave system further includes:

[0051] A vacuum extraction device is connected to the gas source and / or the driven section, and the vacuum extraction device is configured to perform vacuuming on the single-pulse converging shock wave system.

[0052] Multiple vacuum gauges are respectively installed on the aforementioned driving diaphragm section and the aforementioned driven section.

[0053] According to embodiments of this disclosure, the shock wave reduction device can perform multiple reflections to reduce the reflected shock wave generated during the movement of the test gas in the single-pulse converging shock wave system, thereby achieving absorption control of the reflected shock wave and improving the test accuracy of the single-pulse converging shock wave experiment. Attached Figure Description

[0054] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0055] Figure 1 shows a system schematic diagram of a single-pulse converging shock wave system according to an embodiment of the present disclosure;

[0056] Figure 2 shows a schematic diagram of the structure of a shock wave reduction device according to an embodiment of the present disclosure;

[0057] Figure 3 shows a schematic diagram of a shock converging tube according to an embodiment of the present disclosure;

[0058] Figure 4 shows schematic diagrams of test pipes of different sizes and their associated optical window assemblies according to embodiments of the present disclosure;

[0059] Figure 5 shows an explosion schematic diagram of a medium supply device according to an embodiment of the present disclosure;

[0060] Figure 6 shows a schematic diagram of the air intake of the air source according to an embodiment of the present disclosure;

[0061] Figure 7 shows a schematic diagram of the installation of a vacuum extraction device according to an embodiment of the present disclosure;

[0062] Figure 8 shows a physical illustration of a single-pulse converging shock wave system according to an embodiment of the present disclosure;

[0063] Figure 9 shows a schematic diagram of the repeatability test results of a single-pulse converging shock system according to an embodiment of the present disclosure.

[0064] In the above figures, the meanings of the reference numerals are as follows: 100-Gas source; 110-Gas input pipeline; 120-Gas mixing tank; 130-Gas distribution pipeline; 200-Shock wave converging pipeline; 210-Driving diaphragm section; 211-Driving pipeline; 212-Diaphragm section; 220-Shock wave reduction device; 221-Segmented reduction container; 2211-Containing cylinder; 2212-Containing cover plate; 222-Gas chamber pipeline; 2221-Reduction gap; 223-Gap sealing structure; 2231-First sealing assembly; 2232-Second sealing assembly; 230-Driven section; 240-Shock wave converging pipe; 241-First conversion pipe; 242-Slanted straight pipe; 243-Second conversion pipe; 300-Parameter measuring device; 310-Test pipeline; 320 - Parameter measuring instrument; 330 - Combustion diagnostic instrument; 400 - Medium supply device; 410 - Medium conveying pipeline; 411 - Bearing end cover; 412 - Inlet pipe; 420 - Lead screw; 430 - Rotary wheel; 440 - Piston; 500 - Vacuum extraction device; 600 - Vacuum gauge. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0066] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0067] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0068] When using expressions such as "at least one of A, B, and C," the expression should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or systems having A, B, and C. Similarly, when using expressions such as "at least one of A, B, or C," the expression should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or systems having A, B, and C.

[0069] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this disclosure.

[0070] Figure 1 shows a schematic diagram of a single-pulse converging shock wave system according to an embodiment of the present disclosure.

[0071] According to an embodiment of this disclosure, as shown in FIG1, the single-pulse converging shock wave system includes:

[0072] Gas source 100, which is configured to provide test gas;

[0073] Shock converging conduit 200, including:

[0074] Drive diaphragm section 210, and test gas moves from one end of drive diaphragm section 210 to the other end under the action of pressure difference;

[0075] Shock wave reduction device 220: After the test gas enters the shock wave reduction device, it forms an incident shock wave. The incident shock wave forms a reflected shock wave under the action of reflection. The reflected shock wave is reflected and reduced in the shock wave reduction device, so the shock wave reduction device outputs the test gas and incident shock wave after reflection reduction.

[0076] Driven section 230 is configured to provide a transport channel for the test gas and incident shock wave after reflection attenuation treatment;

[0077] The parameter measuring device 300 is configured to measure parameters of the test gas and the incident shock wave after reflection reduction processing, wherein the parameter measurement includes at least one of pressure information, flame morphology and combustion characteristics.

[0078] In one specific embodiment, when the gas source 100 provides the test gas, after reaching the preset pressure, the test gas can pass through the driving diaphragm section 210 and enter the shock wave reduction device 220. Thereafter, the shock wave reduction device 220 performs reflection reduction processing on the reflected shock wave formed by the test gas entering the shock wave reduction device 220. Then, the reflected and reduced test gas passes through the driven section 230 and enters the parameter measuring device 300 for measurement. For example, pressure data, flame morphology, and combustion characteristics can be measured. Of course, other types of parameters can also be measured, which will not be listed here.

[0079] According to embodiments of this disclosure, the shock wave attenuation device 220 can perform multiple reflections to attenuate the reflected shock wave generated during the movement of the test gas in the single-pulse converging shock wave system, thereby achieving absorption control of the reflected shock wave and improving the test accuracy of the single-pulse converging shock wave experiment.

[0080] In one specific embodiment, the single-pulse converging shock wave system may not contain the driving diaphragm section 210 and the driven section 230; it only needs to ensure that the test gas can enter the shock wave reduction device 220 under the action of the pressure difference.

[0081] Figure 2 shows a schematic diagram of the structure of a shock wave reduction device 220 according to an embodiment of the present disclosure.

[0082] According to embodiments of this disclosure, as shown in Figures 2(a) and 2(b), the shock wave attenuation device 220 includes:

[0083] The segmented reduction container 221 has a receiving cavity;

[0084] The air chamber pipe 222 passes through the segmented reduction container 221. The first end of the air chamber pipe 222 is connected to the driving diaphragm section 210, and the second end of the air chamber pipe 222 is connected to the driven section 230. Multiple reduction gaps 2221 are provided on the air chamber pipe 222 located in the accommodating cavity.

[0085] Multiple gap sealing structures 223 are detachably installed on multiple gap reduction structures 2221;

[0086] In this process, the test gas moves from the first end to the second end under the action of pressure difference. During the movement of the gas between the reduction gap 2221 and the second end, a reflected shock wave is formed that moves toward the first end. By setting the gap sealing structure 223 to block the number and position of the reduction gap 2221, the reflected shock wave that enters the containment cavity through the unsealed reduction gap 2221 is reflected and reduced multiple times.

[0087] According to embodiments of this disclosure, the shape of the gas chamber pipe 222 can be specifically configured according to experimental requirements. The gas chamber pipe 222 is connected to the segmented reduction container 221 by welding to ensure good airtightness. The gas chamber pipe 222 is connected to the main pipe of the driving diaphragm section 210 via flanges on both sides.

[0088] According to an embodiment of this disclosure, Figure 2(b) is an enlarged view of the installation of the gas chamber pipe 222 and the gap sealing structure 223. Sixteen ablation gaps 2221 are distributed in a ring on the gas chamber pipe 222, providing an effective pathway for the reflected shock wave to diffuse from the gas chamber pipe 222 into the segmented ablation container 221. The gap sealing structure 223 can be installed on the ablation gaps 2221 using hexagonal leaf screws to ensure a stable connection between the gap sealing structure 223 and the gas chamber pipe 222. By changing the number and distribution of the gap sealing structures 223, the diffusion degree of the reflected shock wave can be precisely controlled, thereby effectively suppressing and regulating the subsequent reheating effect of the shock wave.

[0089] According to an embodiment of this disclosure, after the test gas is injected into the gas source 100, the test gas flows towards the second end in the gas chamber pipe 222 due to the pressure difference at the driving diaphragm section 210. During the flow, the test gas forms a compression wave, which characterizes the flow pattern of the gas. After flowing a certain distance, a shock wave is formed between the gas reduction gap 2221 and the second end. The shock wave forms a reflected shock wave under the action of reflection and moves towards the first end in the gas chamber pipe 222. At this time, the reflected shock wave enters the receiving cavity through the unsealed reduction gap 2221. The reflected shock wave gradually attenuates in the receiving cavity through multiple reflections.

[0090] It should be noted that the number of gap reduction structures 2221 can be set according to actual needs, for example, it can be 16. At the same time, not all gap reduction structures 2221 need to be installed with gap sealing structures 223. The corresponding number of gap sealing structures 223 can be installed according to experimental needs, and the installation position can also be set according to experimental needs.

[0091] According to an embodiment of this disclosure, the air chamber conduit 222 can be connected to the driving diaphragm section 210 and the driven section 230 via a flange.

[0092] According to embodiments of this disclosure, the segmented reduction container 221 includes:

[0093] The receiving cylinder 2211 has a receiving cavity formed on one side;

[0094] The cover plate 2212 is sealed to the housing cylinder 2211.

[0095] According to the embodiments of this disclosure, the segmented shock wave reduction container 221 is designed as a detachable housing cylinder 2211 and housing cover 2212, which makes it convenient for the experimenter to install or remove the gap sealing structure 223 on the shock wave reduction gap 2221 according to the experimental requirements, thereby improving the reusability of the shock wave reduction device 220.

[0096] According to an embodiment of this disclosure, the receiving cover 2212 is sealed to the receiving cylinder 2211 by a first screw.

[0097] According to an embodiment of the present disclosure, a connecting ring is provided on one side of the opening of the receiving cylinder 2211, and the size of the receiving cover plate 2212 is larger than the size of the receiving cylinder 2211. In this case, the receiving cover plate 2212 can be connected to the receiving cylinder 2211 or the connecting ring by a first screw.

[0098] It should be noted that using the first screw for sealing connection is only one connection method; snap-fit ​​connections can also be used.

[0099] According to embodiments of this disclosure, the segmented reduction container 221 further includes:

[0100] The sealing ring and the receiving cover plate 2212 are sealed to the receiving cylinder 2211.

[0101] According to the embodiments of this disclosure, the sealing ring is used to improve the airtightness of the shock wave reduction device 220, so as to prevent gas from escaping from the gap between the receiving cylinder 2211 and the receiving cover plate 2212, thereby further improving the accuracy of the experiment.

[0102] According to an embodiment of this disclosure, the straight line containing the gap reduction 2221 forms a preset angle with the central axis of the gas chamber pipe 222. The preset angle can be set according to the actual situation and can be any angle from 0 to 90°. It is only necessary to ensure that the gap sealing structure 223 is installed after the gap reduction 2221 and fits against the outer wall of the gas chamber pipe 222 to prevent gas or reflected shock waves from escaping from the gap between the gap sealing structure 223 and the gap reduction 2221.

[0103] It should be noted that when the preset angle is 90°, the reduction gap 2221 can be a non-circular arc shape to avoid dividing the air chamber pipe 222 into two sections. When the preset angle is 0°, the reduction gap 2221 is parallel to the air chamber pipe 222. At this time, multiple reduction gaps 2221 can be evenly opened around the circumference of the air chamber pipe 222. Of course, non-uniform deployment can also achieve the reduction of reflected shock waves.

[0104] According to an embodiment of this disclosure, the gap sealing structure 223 includes:

[0105] The first sealing component 2231 and the second sealing component 2232 are installed in contact with the outer wall of the gas chamber pipe 222 when the gap 2221 is reduced. The length of the first sealing component 2231 is greater than the length of the second sealing component 2232.

[0106] The gap 2221 is completely sealed by the first sealing component 2231 and the second sealing component 2232, or the gap 2221 is partially sealed by the first sealing component 2231 or the second sealing component 2232.

[0107] According to the embodiments of this disclosure, different experiments have different requirements. In this case, on the one hand, a gap sealing structure 223 can be installed on the partially reduced gap 2221, and on the other hand, only the first sealing component 2231 or the second sealing component 2232 can be installed on the partially reduced gap 2221, so as to suit different experimental requirements.

[0108] According to another embodiment of the present disclosure, the gap sealing structure 223 includes a third sealing component, the length of which is equal to the length of the reduced gap 2221.

[0109] It should be noted that, in order to further improve the accuracy of the experiment, the gap sealing structure 223 can be designed as an n-segment sealing assembly, with different numbers of sealing assemblies installed on each reduction gap 2221, thereby more accurately controlling the number of reflected shock waves entering the containment cavity.

[0110] According to embodiments of this disclosure, each of the first blocking assembly 2231 and the second blocking assembly 2232 includes:

[0111] The sealing plate is configured to be inserted into the reduction gap 2221;

[0112] The mounting part is connected to the sealing plate. The mounting part is configured to fit against the outer wall of the air chamber pipe 222 and be detachably connected to the air chamber pipe 222.

[0113] According to an embodiment of this disclosure, the longitudinal section of the sealing plate and the mounting portion is T-shaped, wherein the contact surface between the mounting portion and the air chamber pipe 222 has a certain curvature so that the mounting portion fits tightly against the outer wall of the air chamber pipe 222.

[0114] According to an embodiment of this disclosure, when installing the sealing assembly into the reduction gap 2221, the experimenter needs to first open the segmented reduction container 221, then insert the sealing plate of the sealing assembly into the reduction gap 2221, and then use the second screw to connect the mounting part to the gas chamber pipe 222.

[0115] According to embodiments of this disclosure, in order to further improve the airtightness of the shock wave reduction device 220, a material such as a rubber gasket can be provided on the contact surface between the mounting part and the air chamber pipe 222.

[0116] It should be noted that the size of the sealing plate is as similar as possible to the size of the shock wave reduction gap 2221 in order to improve the airtightness of the shock wave reduction device 220.

[0117] According to embodiments of this disclosure, by setting multiple reduction gaps on the gas chamber pipe within the segmented reduction container, and simultaneously setting detachable gap sealing structures on some of the reduction gaps, it is convenient that during the experiment, the test gas forms a reflected shock wave as it moves from the first end to the second end under the action of a pressure difference. At this time, under the action of reflection, the reflected shock wave moves towards the first end and enters the containment cavity through the reduction gaps to perform multiple reflections and reductions on the reflected shock wave, thereby achieving absorption and control of the reflected shock wave and improving the accuracy of the experiment.

[0118] Figure 3 shows a schematic diagram of a shock converging tube 240 according to an embodiment of the present disclosure.

[0119] According to embodiments of this disclosure, the converging shock wave conduit 200 further includes:

[0120] At least one shock converging tube 240, wherein, as shown in Figure 3, the shock converging tube 240 includes:

[0121] The first conversion tube 241 has its input end connected to the driven section 230. The first conversion tube 241 is configured to convert the incident shock wave into an oblique shock wave when the driven section 230 receives an incident shock wave. The projection of the inner wall of the first conversion tube 241 onto the target plane is a concave curve. The incident shock wave is formed by the test gas during the movement of the shock wave reduction device 220.

[0122] The inclined straight tube 242 has its input end connected to the output end of the first conversion tube 241. The inclined straight tube 242 is configured to perform shock wave enhancement processing on the inclined shock wave to obtain an enhanced shock wave. The projection of the inner wall of the inclined straight tube 242 onto the target plane is an inclined line segment.

[0123] The second conversion tube 243 has its input end connected to the inclined straight tube 242 and its output end connected to the parameter measuring device 300. The second conversion tube 243 is configured to convert the enhanced shock wave into a parallel shock wave so that the parameter measuring device 300 can measure the parameters of the parallel shock wave. The projection of the inner wall of the second conversion tube 243 onto the target plane is a convex curve.

[0124] Among them, concave curves, inclined line segments, and convex curves are determined based on the principles of shock wave dynamics.

[0125] According to embodiments of this disclosure, the contraction ratio (i.e., the curvature of the concave and convex curves) plays a crucial role in the shock wave enhancement effect. A smaller contraction ratio cannot effectively enhance the shock wave, while a larger contraction ratio easily leads to the formation of converging shock waves, which causes the constant pressure zone after the reflected shock wave to shorten or even disappear. Therefore, through creative experimental work, it was found that when the angle between the inclined line segment and the central axis of the inclined straight tube 242 is 1° to 10°, a new converging shock wave can be avoided while ensuring a suitable length of the shock wave converging tube 240. Among these, a 5° angle minimizes the overall length of the shock wave converging tube 240 without forming a new converging shock wave.

[0126] According to embodiments of this disclosure, a convergence curve (i.e., a concave curve, an inclined line segment, and a convex curve) is designed based on the principle of shock wave dynamics. The existence of internal interference waves is eliminated by the mutual cancellation of shock waves-rare waves generated downstream and shock waves-shock waves generated upstream. In this way, the curve parameters of the convergence curve can be determined. Specifically, nearly 100 precise positioning points are determined by the principle of shock wave dynamics to form the above-mentioned curve.

[0127] According to embodiments of this disclosure, when parallel incident shock waves are input into the driven section 230, a portion of the incident shock waves are emitted at the concave inner wall of the first conversion tube 241, forming an oblique shock wave. This oblique shock wave then enters the inclined straight tube 242, where it interacts with the remaining incident shock wave to form an enhanced shock wave. This enhanced shock wave then enters the second conversion tube 243, where it is reflected on the convex inner wall, thus being reconverted into a parallel shock wave. After entering the test section, the parallel shock wave forms an approximately zero-dimensional homogeneous test region. This test region maintains a constant pressure for a short period, which is the most crucial testing time in the chemical shock tube. The chemical shock tube requires that the pressure in this region remain constant for a sufficient duration for pressure measurement.

[0128] According to embodiments of this disclosure, the shock wave converging device, through a first conversion tube 241, an inclined straight tube 242, and a second conversion tube 243 with different curved surface configurations, can ensure that the intensity of the converged shock wave is enhanced while maintaining a parallel shock wave output. This achieves enhanced intensity of the subsequent reflected shock wave, enabling the tested pressure information to exceed the theoretical value of a constant-diameter shock tube. Compared to related technologies, the shock wave converging device of this disclosure, while enhancing the shock wave intensity, can also ensure that the parallel shock wave forms a constant pressure zone within the test section and maintains it for a certain period of time, thereby facilitating subsequent data measurement.

[0129] In one specific embodiment, a single shock converging tube 240 can be used to achieve shock wave convergence enhancement, or multiple shock converging tubes 240 connected end to end can be used for multiple convergence enhancements.

[0130] It is important to note that when connecting the two ends, the dimensions of the connection points must be identical to avoid generating noise that could affect subsequent pressure tests as the shock wave propagates into the test section. The output size of the shock wave converging device should be smaller than the input size. For example, the input size (inner diameter) of the shock wave converging tube 240 can be 100mm to 300mm, while the output size is 50mm to 100mm.

[0131] According to embodiments of this disclosure, the driving diaphragm segment 210 includes:

[0132] Drive pipe 211, the input end of drive pipe 211 is connected to the output end of air source 100;

[0133] The diaphragm section 212 is connected at both ends to the drive pipe 211 and the drive diaphragm section 210, respectively. A diaphragm is provided on the diaphragm section 212. When the gas source 100 provides test gas and the diaphragm ruptures, the test gas moves toward the shock wave reduction device 220 under the action of the pressure difference.

[0134] According to an embodiment of this disclosure, the diaphragm section 212 is responsible for initiating the test. After the test gas enters the drive pipe 211, it forms a preset pressure, which causes the diaphragm to rupture, thereby achieving precise control over the initial rupture pressure and the test start time.

[0135] Figure 4 shows schematic diagrams of test pipes 310 of different sizes and their associated optical window assemblies according to embodiments of the present disclosure.

[0136] A schematic diagram of a single-pulse converging shock wave system.

[0137] According to embodiments of this disclosure, the parameter measuring device 300 includes:

[0138] Test pipe 310, wherein the output end of test pipe 310 is provided with an end cap, and multiple test sensors are provided on test pipe 310;

[0139] The parameter measuring instrument 320 is electrically connected to multiple test sensors and is configured to process data from the test sensors to perform parameter measurement.

[0140] and / or

[0141] Combustion diagnostic instrument 330 is connected to the output end of test pipe 310. Combustion diagnostic instrument 330 is configured to measure the flame morphology and combustion characteristics of the gas output from test pipe 310.

[0142] According to embodiments of this disclosure, test pipes 310 with different inner diameters and optical window assemblies are shown in Figure 4. The inner diameter and inner wall surface curve of the pipe are important factors affecting the shock wave morphology distribution and boundary layer growth within the test pipe 310. Figure 4(a) shows a small-diameter test pipe 310 connected to the second conversion pipe 243, with an inner diameter of 105 mm. The test pipe 310 has three sensor interfaces on its sidewall. By measuring the time it takes for the shock wave to reach each sensor, the actual shock wave velocity can be estimated. Two sets of opposing windows are provided near the end of the pipe to facilitate in-situ diagnosis and sampling analysis. Figure 4(b) shows a test pipe 310 connected to the driven section 230, with an inner diameter of 210 mm. The test pipe 310 is configured with sensor ports and opposing windows, and an additional set of windows is added to facilitate the combined application of multiple diagnostic methods.

[0143] Figure 4(c) shows the optical window assembly of test pipe 310. The stepped circular optical window is precisely aligned via the window frame and base, while the PTFE gasket ensures a tight seal between the two-phase flow single-pulse converging shock tube device and the window assembly. The curvature of the window base must match the curvature of the shock tube's inner wall. Because the curvatures of the inner walls of the two types of test pipes 310 differ, each is equipped with a dedicated window base.

[0144] According to embodiments of this disclosure, the parameter measuring instrument 320 can measure pressure and self-luminous signals, and the combustion diagnostic instrument 330 can take high-speed pictures of the burning flame to measure the shape and changes of the flame, such as measuring combustion characteristics such as pure flow combustion rate, ignition delay time, intermediate product distribution, and three-dimensional flame morphology.

[0145] Figure 5 shows an exploded schematic diagram of a medium supply device 400 according to an embodiment of the present disclosure.

[0146] According to embodiments of this disclosure, the single-pulse converging shock wave system further includes:

[0147] As shown in Figure 5, the medium supply device 400 includes:

[0148] The medium conveying pipeline 410 has an end cap at one end and a bearing end cap 411 installed at the other end. An inlet pipe 412 for the test medium is formed on the medium conveying pipeline 410.

[0149] The lead screw 420 is installed inside the medium conveying pipeline 410 and is rotatably connected to the bearing end cover 411;

[0150] The impeller 430 is mounted on the lead screw 420 outside the medium conveying pipeline 410;

[0151] Piston 440 is rotatably mounted on a lead screw inside the medium conveying pipeline 410 via a piston 440 gland;

[0152] When the rotating wheel 430 is rotated, the screw 420 causes the gland and piston 440 to move within the medium delivery pipe 410. When the piston 440 blocks the inlet pipe 412, test gas is provided through the gas source 100. When the piston 440 does not block the inlet pipe 412, test medium is provided through the inlet pipe 412.

[0153] According to embodiments of this disclosure, the test medium can refer to aerosols or other media. As shown in Figure 5, a newly designed aerosol inlet cap is designed based on the principle of large aperture and small angle, optimizing the aerosol inlet structure. When aerosol droplets enter the test pipe 310, the impact between the droplets and the inner wall of the pipe is avoided, thereby reducing the phenomenon of droplet adsorption on the wall surface. During the two-phase mixture inlet, air is simultaneously evacuated from the converging shock wave pipe 200 to ensure that the mixture forms a stable and continuous inlet state within the driving diaphragm section 210, the shock wave reduction device 220, and the driven section 230, until the aerosol fuel is evenly distributed within the pipe. This design enables accurate measurement of ignition characteristic data for complex fuel systems such as high-boiling-point, wide-range biomass aviation fuel and RP-3 kerosene, and can accurately measure the combustion characteristics of high-boiling-point, wide-range multi-component real liquid fuels.

[0154] According to embodiments of this disclosure, when it is necessary to deliver the test medium to the converging shock pipe 200, the gas source 100 can be shut off, followed by vacuuming the gas source 100. Then, the rotary wheel 430 is rotated to cause the lead screw to rotate. At this time, the gland and piston 440 move within the medium delivery pipe 410, causing the piston 440 to disengage from the inlet pipe 412, thus connecting the inlet pipe 412 with the converging shock pipe 200. The test ring can then be delivered to the converging shock pipe 200 through the inlet pipe 412. When testing of the test medium is not required, the rotary wheel 430 can be rotated to cause the piston 440 to block the inlet pipe 412.

[0155] Figure 6 shows a schematic diagram of the air intake of the air source 100 according to an embodiment of the present disclosure.

[0156] According to embodiments of this disclosure, the gas source 100 includes:

[0157] Gas input pipe 110, the first end of gas input pipe 110 is connected to drive diaphragm section 210;

[0158] Gas mixing tank 120, the output end of gas mixing tank 120 is connected to the second end of gas input pipe 110, wherein gas mixing tank 120 is filled with test gas;

[0159] and / or

[0160] The gas distribution pipe 130 has one end connected to the third end of the gas input pipe 110, and the other end of the gas distribution pipe 130 is provided with multiple gas input terminals. Gases of different compositions are input to the gas mixing tank 120, the gas input pipe 110, or the converging shock wave pipe through the multiple gas input terminals to form test gas.

[0161] According to embodiments of this disclosure, the test gas can be a flammable gas such as hydrogen or other types of non-flammable gases, such as inert gases. Multiple gas inlets can mix gases of different compositions, such as hydrogen and carbon monoxide, to form the test gas. A tee is installed on the gas inlet pipe 110, which allows the gas inlet pipe 130 and the gas mixing tank 120 to be combined, so that the experimenter can configure different test gases according to the experimental requirements.

[0162] In one specific embodiment, as shown in Figure 6, the gas source 100 has a complex structure, encompassing the supply of multiple gases. The high-pressure gas source (i.e., the test gas stored in the gas mixing tank 120) includes carbon dioxide, helium, and nitrogen, used to provide the test gas required for the driving diaphragm section 210. During the single-pulse converging shock system testing phase, the test gas for both the driving diaphragm section 210 and the driven section 230 is supplied by the air compressor of the performance calibration system. Pressure gauges (i.e., vacuum gauges 600) installed on the driving diaphragm section 210 and the driven section 230 can be used to monitor the internal pressure of each cavity of the converging shock pipe 200 in real time to ensure the accuracy of the initial conditions.

[0163] According to embodiments of this disclosure, the gas distribution pipe 130 has eight gas input terminals evenly distributed along the pipe wall, enabling the simultaneous input of multiple gases. The gases are then introduced into the gas mixing tank 120 for thorough mixing. The gas inlet is located on the gas distribution pipe 130, further enhancing the safety factor of the mixing tank. All control valves of the single-pulse converging shock wave system are integrated into the control panel for easy experimental operation. Sensor data and photomultiplier tube (PMT) signals are jointly input into the data acquisition system and connected to a computer, thereby enabling comprehensive recording and analysis of experimental data.

[0164] Figure 7 shows a schematic diagram of the installation of a vacuum extraction device 500 according to an embodiment of the present disclosure.

[0165] According to embodiments of this disclosure, the single-pulse converging shock wave system further includes:

[0166] Vacuum extraction device 500 is connected to gas source 100 and / or driven section 230, and is configured to perform vacuuming on the single-pulse converging shock wave system.

[0167] According to embodiments of this disclosure, the vacuum extraction device 500 can be divided into two stages of vacuum extraction, for example, a vacuum pump for coarse vacuum extraction and a molecular pump for precise vacuum extraction.

[0168] According to an embodiment of this disclosure, as shown in FIG7, the system ensures that the interior of the converging shock duct 200 reaches a low vacuum and high cleanliness before the start of the test, which plays an important role in reducing the interference of residual gas on subsequent tests. The driving diaphragm section 210 and the driven section 230 are connected to the vacuum extraction device 500 through a high-pressure ball valve and a piston valve 440, respectively. The gas distribution duct 130 and the gas mixing tank 120 are connected to the vacuum extraction device 500 through a pressure-resistant vacuum valve. The internal vacuum of each chamber of the two-phase flow single-pulse converging shock system is measured by different types of vacuum gauges 600 (which may be pressure gauges). For example, the driven section 230 is equipped with two high-precision vacuum gauges 600.

[0169] In one specific embodiment, the vacuum extraction device 500 employs a combined operation mode of a rotary vane vacuum pump and a molecular pump. First, the rotary vane vacuum pump is activated to ensure a low vacuum level, followed by activation of the molecular pump to achieve a higher vacuum level. Furthermore, to avoid prolonged evacuation time due to an excessively long bellows, a smooth circular tube is used along the longer evacuation path to reduce the amount of residual gas in the bellows gaps and improve the system performance of the vacuum extraction device 500.

[0170] Figure 8 shows a physical illustration of a single-pulse converging shock system according to an embodiment of the present disclosure.

[0171] According to an embodiment of this disclosure, as shown in Figure 8, the two-phase flow single-pulse converging shock wave system test bench is precisely constructed according to the initial design, equipped with a stable support and guide rail system. The entire structure is supported by a series of columns of equal height to ensure the stability of the device. The upper and lower surfaces of each column are precision machined, and the horizontal parallelism error is controlled within 2 degrees. The columns are connected to clamps via slide rails, and the clamps effectively fix the shock tube. The guide rail structure design facilitates the rapid disassembly of the double diaphragm section 212 after each experiment, significantly improving the diaphragm replacement efficiency.

[0172] Figure 9 shows a schematic diagram of the repeatability test results of a single-pulse converging shock system according to an embodiment of the present disclosure.

[0173] According to embodiments of this disclosure, Figure 9 shows the results of multiple repeatability tests conducted on a two-phase flow single-pulse converging shock system test bench, using single-diaphragm and double-diaphragm configurations to compare their reliability. The repeatability test results under the single-diaphragm configuration are shown in Figures 9(a) and 9(b). The tests were conducted at six target pressures, with each pressure point repeated ten times. Although a small number of outliers existed at each pressure level, the overall repeatability uncertainty was controlled to within approximately 5%.

[0174] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A single-pulse converging shock wave system, comprising: A gas source, configured to provide test gas; Shock converging conduit, including: The shock wave reduction device is used to generate an incident shock wave after the test gas enters the shock wave reduction device. The incident shock wave is reflected to form a reflected shock wave. The reflected shock wave is reflected and reduced in the shock wave reduction device, so the shock wave reduction device outputs the test gas and incident shock wave after reflection reduction. The parameter measuring device is configured to measure parameters of the test gas and the incident shock wave after reflection attenuation treatment, wherein the parameter measurement includes at least one of pressure information, flame morphology and combustion characteristics.

2. The system of claim 1, wherein, The converging shock wave conduit also includes: A driving diaphragm section is provided, within which the test gas creates a pressure difference, causing the test gas to move to the shock wave reduction device under the action of the pressure difference; and / or The driven section is configured to deliver the test gas and incident shock wave, after reflection reduction processing, to the parameter measuring device.

3. The system of claim 2, wherein, The shock wave attenuation device includes: A segmented reduction container, wherein the segmented reduction container has a receiving cavity; A gas chamber pipe runs through the segmented reduction container. The first end of the gas chamber pipe is connected to the driving diaphragm section, and the second end of the gas chamber pipe is connected to the driven section. Multiple reduction gaps are provided on the gas chamber pipe located in the receiving cavity. Multiple gap-sealing structures are detachably installed on multiple of the aforementioned gap-reducing structures; The test gas moves from the first end to the second end under the action of pressure difference. During the movement of the gas between the reduction gap and the second end, a reflected shock wave is formed that moves toward the first end. By setting the number and position of the reduction gaps to block the gaps, the reflected shock wave that enters the receiving cavity through the unblocked reduction gaps is reflected and reduced multiple times.

4. The system of claim 3, wherein, The segmented reduction container includes: A receiving cylinder, wherein the receiving cavity is formed on one side of the receiving cylinder; The receiving cover is sealed to the receiving cylinder.

5. The system of claim 3 or 4, wherein, The gap sealing structure includes: A first sealing assembly and a second sealing assembly are installed in contact with the outer wall of the gas chamber pipe when the gap is reduced, wherein the length of the first sealing assembly is greater than the length of the second sealing assembly; The gap is completely sealed by the first sealing component and the second sealing component, or the gap is partially sealed by the first sealing component or the second sealing component.

6. The system of claim 5, wherein, Each of the first and second blocking assemblies includes: The sealing plate is configured to be inserted into the reduction gap; The mounting part is connected to the sealing piece and is configured to fit against the outer wall of the air chamber pipe and be detachably connected to the air chamber pipe.

7. The system of claim 2, wherein, The converging shock wave conduit also includes: At least one shock converging tube, wherein the shock converging tube comprises: A first conversion tube, the input end of which is connected to the driven section, is configured to convert the incident shock wave into an oblique shock wave when the driven section receives an incident shock wave. The projection of the inner wall of the first conversion tube onto the target plane is a concave curve. The incident shock wave is formed by the test gas during the movement of the shock wave reduction device. An inclined straight tube, the input end of which is connected to the output end of the first conversion tube, is configured to perform shock wave enhancement processing on the inclined shock wave to obtain an enhanced shock wave, wherein the projection of the inner wall of the inclined straight tube on the target plane is an inclined line segment; The second conversion tube has its input end connected to the inclined straight tube and its output end connected to the parameter measuring device. The second conversion tube is configured to convert the enhanced shock wave into a parallel shock wave so that the parameter measuring device can measure the parameters of the parallel shock wave. The projection of the inner wall of the second conversion tube onto the target plane is a convex curve. The concave curve, the inclined line segment, and the convex curve are determined based on the principle of shock wave dynamics.

8. The system of claim 2, wherein, The driving diaphragm segment includes: The test gas is transported to the diaphragm section through the drive pipeline. The diaphragm section is provided with a diaphragm. The gas source supplies the test gas to the drive pipeline. When the preset pressure is reached, the diaphragm ruptures to form the pressure difference. Under the action of the pressure difference, the test gas moves toward the shock wave reduction device.

9. The system of any one of claims 1-8, wherein, The parameter measuring device includes: A test pipeline, wherein an end cap is provided at the output end of the test pipeline, and multiple test sensors are provided on the test pipeline; A parameter measuring instrument, configured to process data detected by the test sensor to measure pressure information; and / or A combustion diagnostic instrument configured to measure the flame morphology and combustion characteristics of the gas output from the test pipeline.

10. The system of claim 9, wherein, The single-pulse converging shock wave system also includes: A media supply device, comprising: A medium conveying pipeline has one end passing through the end cap and the other end equipped with a bearing end cap, and an inlet pipe for the test medium is formed on the medium conveying pipeline. A lead screw is installed inside the medium conveying pipeline and is rotatably connected to the bearing end cap; A rotating wheel is mounted on a lead screw outside the medium conveying pipeline; The piston is rotatably mounted on a lead screw inside the medium conveying pipeline via a piston gland; When the rotating wheel is rotated, the screw causes the gland and the piston to move within the medium delivery pipe. When the piston blocks the inlet pipe, the test gas is supplied through the gas source. When the piston does not block the inlet pipe, the test medium is supplied through the inlet pipe.

11. The system of any one of claims 1-10, wherein, The gas source includes: A gas mixing tank, wherein the test gas inside the gas mixing tank is delivered to the converging shock wave pipe through a gas input pipe; A gas distribution pipeline is provided with multiple gas distribution input terminals, through which gases of different compositions are input to the gas mixing tank or the converging shock wave pipeline to form the test gas.

12. The system according to any one of claims 2 to 8, further comprising: A vacuum extraction device configured to perform vacuuming on the single-pulse converging shock wave system; Multiple vacuum gauges are respectively installed on the driving diaphragm section and the driven section.

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