Ignition experiment observation system and use method thereof

Abstract

The invention discloses an ignition experiment observation system and a use method thereof, and relates to the technical field of fuel combustion experiments.The ignition experiment observation system comprises a shock tube, one end of the shock tube is closed, the other end of the shock tube is open, and a reaction cavity is formed in the shock tube; the visual structures are arranged on the two sides of the shock tube, and the reaction cavity can be observed through the visual structures; the light source module is arranged on one side of the shock tube, and the light source module is used for emitting light into the reaction cavity; the visual module is arranged on one side of the shock tube, the visual module and the light source module are symmetrically arranged, and the visual module is used for obtaining image information in the reaction cavity. By arranging a visual structure on the side wall of the shock tube and introducing an optical schlieren visual camera technology, image data of the ignition process in the shock tube can be completely recorded, so that the position and homogeneity of the ignition in the shock tube can be accurately judged, and required data can be provided for research on heterogeneous ignition in the shock tube.

Description

Technical Field

[0001] The present application relates to the technical field of fuel combustion experiments, and in particular to a fire experiment observation system and a method for using the same. Background Art

[0002] In actual combustion equipment such as internal combustion engines, the ignition delay time of the fuel, that is, the time it takes for the combustible mixture to reach flammable conditions and start large-scale combustion, has an important impact on the operation of the equipment.

[0003] The ignition delay time of a fuel is one of its basic properties, and its value is related to the type of fuel and environmental conditions. At present, the experimental method for measuring the ignition delay time of a fuel mainly relies on shock tubes and fast compressors, among which the shock tube experimental device is the main means of measuring the ignition delay of a fuel under medium and high temperature conditions, corresponding to a relatively short ignition delay time.

[0004] The fuel ignition delay time measurement scheme described above is mainly tested by means of a pressure sensor and a monochromator installed on the wall of the shock tube (only the side wall or the side wall + the end wall). This test is similar to a black box model and cannot effectively judge the homogeneity of the ignition process occurring in the shock tube. For the non-uniform ignition process in the shock tube, especially the transition period between homogeneous ignition and non-homogeneous ignition, the corresponding pressure signal platform period has changes, but it is not obvious. It is difficult to effectively judge whether the ignition in the shock tube only occurs near the end wall of the low-pressure section and whether it is homogeneous by relying solely on pressure and light signals, and thus it is impossible to accurately explain that the fuel ignition time measured by the shock tube at this time is valid. At the same time, since there are only pressure and light signals, it is impossible to further study the non-homogeneous ignition process in the shock tube. Summary of the invention

[0005] The present application aims to solve one of the above technical problems in the prior art. To this end, an embodiment of the present application provides a fire experiment observation system.

[0006] The embodiment of the present application also provides a method of use.

[0007] According to an embodiment of the first aspect of the present application, a fire experiment observation system is provided, comprising a shock tube, one end of the shock tube is closed and the other end is open, and a reaction chamber is arranged in the shock tube; a visualization structure, the visualization structure is arranged on both sides of the shock tube, and the reaction chamber can be observed through the visualization structure; a light source module is arranged on one side of the shock tube, and the light source module is used to emit light into the reaction chamber; a vision module is arranged on one side of the shock tube, the vision module is symmetrically arranged with the light source module, and the vision module is used to obtain image information in the reaction chamber.

[0008] The above-mentioned ignition experiment observation system has at least the following beneficial effects: when conducting a shock tube test, the light source module is powered on to emit a single wavelength of light (such as green light), and the light first enters the reaction chamber through the visualization structure, and then passes through another visualization structure to reach the visual module; at the same time, the shock wave formed by the pressure difference propagates to the shock tube reaction chamber, is reflected by the cavity wall, and then propagates in a direction away from the cavity wall. Corresponding to the incident shock wave and the reflected shock wave, the combustible mixture near the cavity wall is compressed twice. After two compressions, the combustible mixture near the cavity wall reaches the combustible condition and begins to enter the ignition chemical process. The pressure rise signal is used as a signal to trigger the visual module to start shooting and recording. The complete ignition process in the tube is recorded by the visual module. Specifically, when a fire occurs in the reaction chamber, the density in the tube changes, which will change the propagation direction of the light. Light in different directions enters the visual module and is recorded, which can make the boundary between the ignition and non-ignition areas in the tube appear and be recorded by the visual module. Based on the recorded image data, it is possible to determine whether the location of the fire in the tube is close to the end wall, whether it is a homogeneous fire, and the migration process law of the fire area formed in the tube during the fire process, which is used to study the characteristics of the heterogeneous fire process.

[0009] According to the fire experiment observation system described in the embodiment of the first aspect of the present application, a first convex lens is arranged between the light source module and the visualization structure, and the light source module is arranged at the focus of the first convex lens.

[0010] According to the fire experiment observation system described in the embodiment of the first aspect of the present application, a second convex lens is arranged between the visual module and the visualization structure.

[0011] According to the fire experiment observation system described in the embodiment of the first aspect of the present application, a light blocking member is arranged between the second convex lens and the visual module, and the light blocking member is arranged at the focus of the second convex lens.

[0012] According to the fire experiment observation system described in the embodiment of the first aspect of the present application, mounting grooves are provided on both sides of the shock tube, the mounting grooves are connected to the reaction chamber, the two ends of the mounting grooves are respectively close to the ends of the shock tube, and the visualization structure is fixed to the mounting grooves from the outside of the shock tube.

[0013] According to the fire experiment observation system described in the embodiment of the first aspect of the present application, the visualization structure includes a light-transmitting member and a pressing member, a boss is arranged in the installation groove, and the pressing member is used to press the light-transmitting member placed on the boss.

[0014] According to the fire experiment observation system described in the embodiment of the first aspect of the present application, the middle part of the clamping piece has a hollow structure, a clamping portion is provided on one side of the clamping piece, the clamping portion enters the installation groove and abuts against the light-transmitting piece, and the clamping piece is connected to the shock tube through a fastener.

[0015] According to the fire experiment observation system described in the embodiment of the first aspect of the present application, sealing gaskets are arranged between the pressing portion and the light-transmitting member and between the boss and the light-transmitting member.

[0016] According to the fire experiment observation system described in the embodiment of the first aspect of the present application, reinforcement parts are symmetrically arranged on both sides of the shock tube, and the mounting grooves are arranged on the reinforcement parts.

[0017] According to an embodiment of the second aspect of the present application, a method of use is provided, based on the fire experiment observation system described in the embodiment of the first aspect, comprising the following steps:

[0018] Adjust the positions of the light source module and the visual module so that the light source emission port of the light source module faces the camera end of the visual module, wherein both the light source module and the visual module face the visualization structure;

[0019] Adjusting the positions of the first convex lens and the light source module and placing the light source module at the focus of the first convex lens;

[0020] Adjusting the positions of the second convex lens, the light blocking member and the visual module so that the light blocking member is at the focus of the second convex lens;

[0021] Turning on the light source module, and then compressing the mixture of fuel, oxidant and diluent through the shock wave formed by the pressure difference;

[0022] The visual module is triggered by a pressure sensor disposed in the shock tube, and fuel ignition image information in the shock tube is obtained through the visual module.

[0023] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present application is further described below with reference to the accompanying drawings and embodiments;

[0025] Figure 1 The structure of the fire experiment observation system of the embodiment of the present application is shown in FIG. Figure 1 ;

[0026] Figure 2 The structure of the fire experiment observation system of the embodiment of the present application is shown in FIG. Figure 2 ;

[0027] Figure 3 The structure of the fire experiment observation system of the embodiment of the present application is shown in FIG. Figure 3 ;

[0028] Figure 4 It is a schematic diagram of the structure of the shock tube in an embodiment of the present application.

[0029] Reference numerals:

[0030] Shock tube 100, cylindrical body 110, reaction chamber 111, reinforcing portion 112, mounting groove 113, boss 114, first flange 120, second flange 130;

[0031] A first convex lens 210, a second convex lens 220;

[0032] Light blocking member 300;

[0033] Vision module 400;

[0034] Light source module 500;

[0035] Visualization structure 600 , sealing gasket 610 , light-transmitting member 620 , pressing member 630 , and fastening member 640 . DETAILED DESCRIPTION

[0036] This section will describe in detail the specific embodiments of the present application. The preferred embodiments of the present application are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present application, but it cannot be understood as a limitation on the scope of protection of the present application.

[0037] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0038] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0039] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0040] In actual combustion equipment such as internal combustion engines, the ignition delay time of the fuel, that is, the time it takes for the combustible mixture to reach the combustible conditions and start large-scale combustion, has an important impact on the operation of the equipment. For example, for a compression ignition internal combustion engine, if the ignition delay time of the fuel is long, the corresponding ignition delay period of the in-cylinder combustion will be further extended, the amount of premixed combustible mixture formed will increase, and the proportion of premixed combustion will increase, thereby affecting the engine's performance indicators such as the pressure rise rate and the maximum pressure. At the same time, for the design and development of actual combustion equipment such as internal combustion engines based on numerical simulation methods, it is necessary to establish a simulation model that couples the chemical kinetic mechanism of fuel combustion with multidimensional fluid dynamics at the current level of science and technology. For the fuel combustion chemical kinetic mechanism required to build a simulation model, the ignition delay time of the fuel is one of the main data used to fully verify and optimize the mechanism. In summary, the ignition delay time of the fuel is of great significance to the operation process of actual combustion equipment and the construction of the fuel kinetic mechanism.

[0041] The basic operating principle of the shock tube device is relatively clear. It is mainly divided into a high-pressure section and a low-pressure section, which are separated by a diaphragm in the middle. When the diaphragm ruptures, the gas in the high-pressure section rushes into the low-pressure section to form a shock wave. This shock wave that continuously propagates to the low-pressure section will compress the combustible mixture in the low-pressure section. After two compressions (two compressions of the incident shock wave and the reflected shock wave), the combustible mixture in the low-pressure section reaches the given pressure and temperature conditions. From this time on, the mixture begins the chemical preparation process until a large-scale reaction begins. The time period in between corresponds to the ignition delay time of the fuel at a given pressure and temperature.

[0042] The ideal ignition process in the shock tube occurs in the test area of ​​its low-pressure section, and is homogeneous and close to the end wall of the low-pressure section. That is, when the combustible mixture reaches the combustible condition, the chemical preparation process begins at each point in space, which then triggers the ignition. The corresponding pressure test signal has a relatively horizontal and stable plateau period. In fact, the ignition in the shock tube is not always homogeneous and is affected by various practical factors. For example, the viscosity of the gas causes the existence of a boundary layer at the inner wall of the shock tube, and the temperature inside the boundary layer is inconsistent with the temperature at the center of the tube, resulting in different ignitions at the two locations; the shock tube has been used for a long time, and there are broken particles formed by ruptured diaphragms, which will also affect the temperature distribution in the tube; the shock wave will also cause uneven temperature of the compressed combustible mixture due to uneven speed, which will cause uneven ignition. One of the more obvious characteristics of these uneven ignition processes is that the ignition process does not only occur near the end wall of the low-pressure section, but also occurs in a spatial area away from the end wall. That is, the actual ignition location is far away from the end wall, which deviates from the fact that under ideal homogeneous ignition conditions, the ignition in the shock tube only occurs near the end wall.

[0043] For the non-uniform ignition process in the shock tube, especially the transition period between homogeneous ignition and non-homogeneous ignition, the corresponding pressure signal platform period changes, but it is not obvious. It is difficult to effectively judge whether the ignition in the shock tube only occurs near the end wall of the low-pressure section and whether it is homogeneous, and it is also impossible to accurately indicate that the fuel ignition time measured by the shock tube is valid. At the same time, since there are only pressure and light signals, it is impossible to provide image data for studying the non-homogeneous ignition process in the shock tube.

[0044] For this purpose, refer to Figures 1 to 3 The embodiment of the present application provides a fire experiment observation system for observing the fire process in the test area of ​​the shock tube 100. The acquired image data can be used to determine whether the fire in the shock tube 100 occurs near the end wall and whether it is homogeneous. On the other hand, the inhomogeneous fire evolution process of the shock tube 100 can be studied based on the image data.

[0045] Specifically, the fire experiment observation system of the embodiment of the present application includes a shock tube 100 , a visualization structure 600 , a light source module 500 and a vision module 400 .

[0046] One end of the shock tube 100 is sealed and the other end is open. A reaction chamber 111 is arranged in the shock tube 100 , and the reaction chamber 111 serves as a low-pressure reaction zone of the shock tube 100 .

[0047] In the embodiment of the present application, visualization structures 600 are provided on both sides of the shock tube 100 , and the ignition condition in the reaction chamber 111 can be observed through the visualization structures 600 .

[0048] The light source module 500 is arranged on one side of the shock tube 100, and the light source module 500 is used to emit light into the reaction chamber 111; the visual module 400 is arranged on one side of the shock tube 100, and the visual module 400 and the light source module 500 are arranged symmetrically, and the visual module 400 is used to obtain image information in the reaction chamber 111.

[0049] When conducting the shock tube 100 test, the light source module 500 is powered on to emit a single-wavelength light (such as green light). The light first enters the reaction chamber 111 through the visualization structure 600, and then passes through another visualization structure 600 to reach the visual module 400; at the same time, the shock wave formed by the pressure difference propagates to the reaction chamber 111 of the shock tube 100, is reflected by the chamber wall, and then propagates in a direction away from the chamber wall. Corresponding to the incident shock wave and the reflected shock wave, the combustible mixture near the chamber wall is compressed twice. After two compressions, the combustible mixture near the chamber wall reaches the combustible condition and begins to enter the ignition chemical process. The pressure increase signal serves as a signal to trigger the visual module 400 to start shooting and recording.

[0050] The complete ignition process in the tube is recorded by the visual module 400. Specifically, when a fire occurs in the reaction chamber 111, the density in the tube changes, which in turn changes the propagation direction of the light. Lights from different directions enter the visual module 400 and are recorded, which can make the boundary between the ignition area and the non-ignition area in the tube appear and be recorded by the visual module 400. Based on the recorded image data, it can be determined whether the location of the ignition in the tube is close to the end wall, whether it is a homogeneous ignition, and the migration process law of the ignition area formed in the tube during the ignition process, which is used to study the characteristics of the non-homogeneous ignition process.

[0051] In some embodiments, a first convex lens 210 is disposed between the light source module 500 and the visualization structure 600, and the light source module 500 is disposed at the focus of the first convex lens 210. The first convex lens 210 mainly enables the light emitted by the light source module 500 to pass through the visualization structure 600 in parallel to reach the visual module 400, which facilitates the subsequent image comparison and information acquisition.

[0052] In some embodiments, a second convex lens 220 is disposed between the visual module 400 and the visualization structure 600 , and the second convex lens 220 can converge light to facilitate the shooting of the visual module 400 .

[0053] In some embodiments, a light shielding member 300 is disposed between the second convex lens 220 and the vision module 400 , and the light shielding member 300 is disposed at the focus of the second convex lens 220 . The light shielding member 300 is used to adjust the intensity of light entering the vision module 400 .

[0054] In some embodiments, mounting grooves 113 are provided on both sides of the shock tube 100, the mounting grooves 113 are connected to the reaction chamber 111, the two ends of the mounting grooves 113 are respectively close to the ends of the shock tube 100, and the visualization structure 600 is fixed to the mounting grooves 113 from the outside of the shock tube 100. This facilitates the complete observation of the fire experiment and the disassembly and assembly of the visualization structure 600.

[0055] In some specific embodiments, the shock tube 100 includes a cylindrical body 110, the middle part of the cylindrical body 110 is hollow, one end of the cylindrical body 110 is closed by a first flange 120, and the other end is open to form a reaction chamber 111, wherein a second flange 130 is provided at the open end of the cylindrical body 110, and the second flange 130 is used for installation with other components (such as a compressor or an extension tube, etc.).

[0056] It should be noted that the mounting groove 113 in the embodiment of the present application is disposed on the columnar body 110 .

[0057] The reinforcing parts 112 are symmetrically arranged on both sides of the shock tube 100, and the mounting grooves 113 are arranged on the reinforcing parts 112. Specifically, the reinforcing parts 112 are arranged on the columnar body 110, and the length of the reinforcing parts 112 is the same as the length of the columnar body 110. The reinforcing parts 112 are mainly used for structural reinforcement of the position where the mounting grooves 113 are opened on the columnar body 110.

[0058] In some embodiments, such as Figure 2 and Figure 3 As shown, the visualization structure 600 includes a light-transmitting member 620 and a pressing member 630 . A boss 114 is provided in the installation groove 113 . The pressing member 630 is used to press the light-transmitting member 620 placed on the boss 114 .

[0059] Specifically, the middle part of the clamping piece 630 has a hollow structure, and the shape of the hollow structure is similar to the shape of the mounting groove 113. The clamping piece 630 is used to press against a clamping portion on one side of the light-transmitting piece 620. The clamping portion enters the mounting groove 113 and abuts against the light-transmitting piece 620. The clamping piece 630 is connected to the shock tube 100 through the fastener 640.

[0060] In the embodiment of the present application, the fasteners 640 are bolts, and the fasteners 640 are arranged at intervals along the edge of the clamping member 630 . The fasteners 640 pass through the clamping member 630 and are threadedly connected to the columnar body 110 , thereby fixing the clamping member 630 .

[0061] In some embodiments, a sealing gasket 610 is provided between the pressing portion and the light-transmitting member 620 and between the boss 114 and the light-transmitting member 620. The sealing gasket 610 is used to improve the sealing performance of the connection between the shock tube 100 and the visualization structure 600, and at the same time, the sealing gasket 610 also prevents the light-transmitting member 620 from being crushed.

[0062] The shock tube 100 is made of stainless steel, the light-transmitting member 620 is made of quartz glass, and the sealing gasket 610 is made of polytetrafluoroethylene. The application spectrum band of quartz glass is 185 to 2500 nm. The convex lens can be made of optical glass.

[0063] The present application also provides a method for using the above-mentioned fire experiment observation system, which specifically includes the following steps:

[0064] Adjust the positions of the light source module 500 and the visual module 400 so that the light source emission port of the light source module 500 faces the camera end of the visual module 400, wherein both the light source module 500 and the visual module 400 face the visualization structure 600;

[0065] Adjust the positions of the first convex lens 210 and the light source module 500 and place the light source module 500 at the focus of the first convex lens 210;

[0066] Adjust the positions of the second convex lens 220, the light blocking member 300 and the visual module 400 so that the light blocking member 300 is at the focus of the second convex lens 220;

[0067] Turning on the light source module 500, and then compressing the mixture of fuel, oxidant and diluent through the shock wave formed by the pressure difference;

[0068] The visual module 400 is triggered by a pressure sensor disposed in the shock tube 100 , and the fuel ignition image information in the shock tube 100 is obtained through the visual module 400 .

[0069] There is no theoretical requirement for the distance between the first convex lens 210 and the second convex lens 220 and the visualization structure 600 , and the diameters of the first convex lens 210 and the second convex lens 220 are both greater than the length of the visualization structure 600 .

[0070] The light emitted from the light source module 500 (the light source module 500 of the present application may optionally use a point light source) forms parallel light after passing through the first convex lens 210. When a fire occurs in the reaction chamber 111, the density in the chamber changes, thereby changing the propagation direction of the light. The light is converged by the second convex lens 220 and the light intensity is weakened by the light blocking member 300. The light then enters the visual module 400 (the visual module 400 of the embodiment of the present application is a high-speed camera), triggering the camera function, so that the boundary between the fire area and the non-fire area in the reaction chamber 111 can be visualized and recorded.

[0071] In some embodiments, dynamic pressure sensors are installed at different positions on the side wall of the shock tube 100 along the direction of shock wave propagation, and pressure sensors and monochromators are also installed near the end wall. When conducting the shock tube 100 test, the light source module 500 is powered on to emit a single wavelength of light (such as green light); at the same time, the shock wave formed by the pressure difference propagates toward the end wall of the low-pressure section of the shock tube 100, and then is reflected by the end wall and propagates in a direction away from the end wall. Corresponding to the incident shock wave and the reflected shock wave, the combustible mixture near the end wall is compressed twice, accompanied by the increase of the pressure in the low-pressure section. After two compressions, the combustible mixture near the end wall reaches the combustible condition and begins to enter the ignition chemical process. The signal of the pressure increase is used as a signal to trigger the visual module 400 to start shooting and recording. According to the recorded image data, it can be determined whether the location of the fire in the tube is close to the end wall, whether it is a homogeneous fire, and the migration process law of the ignition area formed in the tube during the ignition process, which is used to study the characteristics of the inhomogeneous ignition process.

[0072] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present application.

Claims

1. A fire experiment observation system, characterized in that: include A shock tube, one end of which is sealed and the other end is open, and a reaction chamber is arranged in the shock tube; A visualization structure, wherein the visualization structure is disposed on both sides of the shock tube, and the reaction chamber can be observed through the visualization structure; A light source module is disposed on one side of the shock tube, and is used to emit light into the reaction chamber; A visual module is arranged at one side of the shock tube, the visual module and the light source module are arranged symmetrically, and the visual module is used to obtain image information in the reaction chamber.

2. The fire experiment observation system according to claim 1, characterized in that: A first convex lens is arranged between the light source module and the visualization structure, and the light source module is arranged at the focus of the first convex lens.

3. The fire experiment observation system according to claim 2, characterized in that: A second convex lens is arranged between the visual module and the visualization structure.

4. The fire experiment observation system according to claim 3, characterized in that: A light blocking member is arranged between the second convex lens and the visual module, and the light blocking member is arranged at the focus of the second convex lens.

5. The fire experiment observation system according to any one of claims 1 to 4, characterized in that: Mounting grooves are provided on both sides of the shock tube, the mounting grooves are connected to the reaction chamber, both ends of the mounting grooves are respectively close to the ends of the shock tube, and the visualization structure is fixed to the mounting grooves from the outside of the shock tube.

6. The fire experiment observation system according to claim 5, characterized in that: The visualization structure includes a light-transmitting member and a pressing member. A boss is arranged in the installation groove, and the pressing member is used for pressing the light-transmitting member placed on the boss.

7. The fire experiment observation system according to claim 6, characterized in that: The middle part of the clamping piece has a hollow structure, and a clamping portion is arranged on one side of the clamping piece. The clamping portion enters the mounting groove and abuts against the light-transmitting piece. The clamping piece is connected to the shock tube via a fastener.

8. The fire experiment observation system according to claim 7, characterized in that: A sealing gasket is arranged between the pressing portion and the light-transmitting member and between the boss and the light-transmitting member.

9. The fire experiment observation system according to claim 5, characterized in that: Reinforcement parts are symmetrically arranged on both sides of the shock tube, and the mounting grooves are arranged on the reinforcement parts.

10. A method of use, based on the fire experiment observation system according to any one of claims 3 to 9, characterized in that: The steps include: Adjust the positions of the light source module and the visual module so that the light source emission port of the light source module faces the camera end of the visual module, wherein both the light source module and the visual module face the visualization structure; Adjusting the positions of the first convex lens and the light source module and placing the light source module at the focus of the first convex lens; Adjusting the positions of the second convex lens, the light blocking member and the visual module so that the light blocking member is at the focus of the second convex lens; Turning on the light source module, and then compressing the mixture of fuel, oxidant and diluent through the shock wave formed by the pressure difference; The visual module is triggered by a pressure sensor disposed in the shock tube, and fuel ignition image information in the shock tube is obtained through the visual module.

Images