Apparatus and method for simultaneous imaging of flame structure, flow field structure and flow field velocity

Abstract

The application provides a device and method for synchronous imaging of flame structure, flow field structure and flow field velocity, which comprises generating 283.55nm laser and 355nm laser, transmitting and integrating the two lasers into sheet laser, and then making the sheet laser incident to a flame region of hydrocarbon fuel combustion in a combustion chamber; imaging a first fluorescent signal generated by exciting CH2O in the flame by the 355nm laser to obtain a transient structure of a preheating zone of the flame; imaging a second fluorescent signal generated by exciting OH in the flame by the 283.55nm laser to obtain a transient structure of a burned zone of the flame; and imaging a flow field structure of the flame region by using pulse schlieren and imaging a flow field velocity distribution of the flame region by using schlieren velocity measurement. The application realizes synchronous high-time-resolution imaging of flame multi-zone structure, schlieren and schlieren velocity measurement.

Description

Technical Field

[0001] This invention mainly relates to the field of flame chemical reaction and turbulent flow field research technology, and in particular to a device and method for simultaneous imaging of flame structure, flow field structure and flow field velocity. Background Technology

[0002] Turbulent combustion is a phenomenon in which flame chemical reactions and turbulent flow fields are coupled. Current imaging schemes for turbulent combustion can only achieve simultaneous imaging of a single flame structure (or component) and schlieren. Imaging a single flame structure, a single flow field, or a single flow field velocity cannot provide sufficient information or richer information about flame structure and flow field velocity, which is not conducive to the study of turbulence-flame interaction. Summary of the Invention

[0003] In view of the technical problems existing in the prior art, the present invention proposes a device and method for simultaneous imaging of flame structure, flow field structure and flow field velocity.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] On one hand, the present invention provides a device for simultaneous imaging of flame structure, flow field structure, and flow field velocity, comprising:

[0006] A 283.55nm laser generation unit is used to generate 283.55nm laser light.

[0007] A 355nm laser generation unit is used to generate 355nm laser light.

[0008] A sheet laser generating unit is used to transmit or shape a 283.55nm or 355nm laser into a sheet laser and then incident it into the flame area of ​​hydrocarbon fuel combustion in the combustion chamber.

[0009] The first imaging unit is used to image the first fluorescence signal generated by the CH2O component of the flame excited by the 355nm laser, and to image the instantaneous structure of the flame preheating zone.

[0010] The second imaging unit is used to image the second fluorescence signal generated by the flame component OH excited by the 283.55nm laser, and to image the instantaneous structure of the flame-burned zone.

[0011] The schlieren imaging unit emits schlieren light into the flame region, uses pulsed schlieren imaging to visualize the flow field structure of the flame region, and uses schlieren velocimetry to visualize the flow field velocity distribution of the flame region.

[0012] Furthermore, the present invention also includes an image processing unit that obtains an instantaneous structure image of the flame heat release zone based on the product of the instantaneous structure image of the flame preheating zone and the instantaneous structure image of the flame burned zone.

[0013] Furthermore, the schlieren imaging unit of the present invention includes a high-energy pulsed light source, a condenser lens, a first plane mirror, a first concave mirror, a second concave mirror, a second plane mirror, a knife edge, a semi-transparent beam splitter, a first schlieren camera, and a second schlieren camera. The high-energy pulsed light source is used to generate schlieren light. The light output from the high-energy pulsed light source is focused by the condenser lens and then guided by the first plane mirror to the first concave mirror. The light is then paralleled by the first concave mirror and passes through the flame region. After passing through the flame region, it is incident parallel to the second concave mirror on the other side of the flame region. After passing through the second concave mirror and the second plane mirror, it is focused to the knife edge position. The schlieren light passes through the semi-transparent beam splitter and forms two beams that enter the first schlieren camera and the second schlieren camera respectively. By controlling the working time of the high-energy pulsed light source and the exposure gate width of the two schlieren cameras, the shooting interval of the two schlieren cameras can be adjusted. Since the interval is known, the instantaneous flow field structure of the flame region can be imaged using pulse schlieren imaging, and the flow field velocity distribution of the flame region can be imaged using schlieren velocimetry. Furthermore, the direction of the schlieren incident flame region is perpendicular to the direction of the sheet laser incident flame region.

[0014] Furthermore, in this invention, the working timing of the high-energy pulse light source and the two schlieren cameras in the 283.55nm laser generation unit, 355nm laser generation unit, first imaging unit, second imaging unit, and schlieren imaging unit is controlled to ensure that the imaging of the two schlieren cameras in the first imaging unit, second imaging unit, and schlieren imaging unit does not interfere with each other.

[0015] Furthermore, the 283.55nm laser generation unit in this invention includes a first Nd:YAG laser and a dye laser, wherein the first Nd:YAG laser pumps the dye laser to generate 283.55nm laser.

[0016] Furthermore, the 355nm laser generation unit in this invention includes a second Nd:YAG laser, which generates 355nm laser by means of the second Nd:YAG laser and frequency third harmonic technology.

[0017] Furthermore, in this invention, the first imaging unit includes a first enhanced camera, with a CH2O PLIF filter disposed in front of the lens of the first enhanced camera; the second imaging unit includes a second enhanced camera, with an OH PLIF filter disposed in front of the lens of the first enhanced camera. Even further, to avoid interference between the two enhanced cameras (OH PLIF and CH2O PLIF) on schlieren imaging, tilt-shift imaging technology is specifically employed. Specifically, a tilt-shift adapter is installed between the enhanced camera and its lens in the first imaging unit and / or the second imaging unit, enabling the acquisition of a clearly focused flame fluorescence image under tilted shooting conditions.

[0018] Furthermore, the laser sheet light generation unit of the present invention includes an optical path steering and transmission device, a beam combining device, and an optical sheet shaping device. The 283.55nm laser and the 355nm laser are steered and transmitted by the optical path steering and transmission device, and the beam combining device merges the transmission paths of the two laser beams into the same transmission path for transmission. The optical sheet shaping device includes a concave cylindrical mirror and a convex spherical mirror, and the two laser beams are shaped into a sheet-like laser by the concave cylindrical mirror and the convex spherical mirror.

[0019] On the other hand, the present invention provides a method for simultaneous imaging of flame structure, flow field structure, and flow field velocity, including:

[0020] Generates 283.55nm and 355nm lasers;

[0021] The 283.55nm and 355nm lasers are transmitted and shaped into sheet-like lasers before being incident on the flame area of ​​hydrocarbon fuel combustion in the combustion chamber.

[0022] The first fluorescence signal generated by the CH2O component of the flame excited by a 355nm laser was imaged to obtain the instantaneous structure of the flame preheating zone.

[0023] The second fluorescence signal generated by the flame component OH excited by the 283.55nm laser was imaged to obtain the instantaneous structure of the flame-burned zone;

[0024] The flow field structure in the flame region is imaged using pulse schlieren imaging, and the flow velocity distribution in the flame region is imaged using schlieren velocimetry.

[0025] Furthermore, the above-mentioned method for simultaneous imaging of flame structure, flow field structure, and flow field velocity also includes obtaining an instantaneous structure image of the flame heat release zone based on the product of the instantaneous structure image of the flame preheating zone and the instantaneous structure image of the flame burned zone.

[0026] Turbulent combustion is a phenomenon in which flame chemical reactions and turbulent flow fields are coupled. Imaging a single flame structure, flow field, or flow velocity is insufficient to provide enough information, hindering the study of turbulence-flame interactions. This invention enables simultaneous imaging of multi-zone flame structure, flow field structure, and flow velocity, which is of great significance for the diagnostic research of turbulent combustion. Compared with existing technologies, the technical advantages of this invention are specifically manifested in:

[0027] This invention enables simultaneous imaging of flame CH2O components, flame OH components, flame heat release zone structure, flow field structure, and flow field velocity.

[0028] Furthermore, this invention uses tilt-shift technology to achieve simultaneous imaging of schlieren, CH2O PLIF, and OH PLIF, solving the interference problem between schlieren imaging and flame component imaging systems while maintaining clear focus.

[0029] This invention uses a high-energy pulsed schlieren light source with precise and controllable emission time, which solves the problem of schlieren light interference CH2OPLIF and OH PLIF. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a structure according to an embodiment of the present invention;

[0032] Numbering on the map:

[0033] 1. First Nd:YAG laser; 2. Dye laser; 3. Second Nd:YAG laser; 4. First mirror; 5. Dichroic mirror; 6. Second mirror; 7. Third mirror; 8. Concave cylindrical mirror; 9. Aperture; 10. Convex spherical mirror; 11. Flame region; 12. First enhanced camera; 13. First enhanced camera lens; 14. First tilt-shift adapter; 15. CH2O PLIF filter; 16. Second enhanced camera; 17. Second enhanced camera lens; 18. Second tilt-shift adapter; 19. OH PLIF filter; 20. High-energy pulsed light source; 21. Condensing lens; 22. Slit; 23. First plane mirror; 24. First concave mirror; 25. Second concave mirror; 26. Second plane mirror; 27. Knife edge; 28. Semi-transparent and semi-reflective beam splitter; 29. ​​First schlieren camera; 30. Second schlieren camera. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] In one embodiment, to achieve high-time-resolution synchronous imaging of the flame structure, flow field structure, and flow field velocity in a combustion field, an apparatus for synchronous imaging of the flame structure, flow field structure, and flow field velocity is provided, comprising:

[0036] A 283.55nm laser generation unit is used to generate 283.55nm laser light.

[0037] A 355nm laser generation unit is used to generate 355nm laser light.

[0038] A sheet laser generating unit is used to transmit or shape a 283.55nm or 355nm laser into a sheet laser and then incident it into the flame area of ​​hydrocarbon fuel combustion in the combustion chamber.

[0039] The first imaging unit is used to image the first fluorescence signal generated by the CH2O component of the flame excited by the 355nm laser, and to image the instantaneous structure of the flame preheating zone.

[0040] The second imaging unit is used to image the second fluorescence signal generated by the flame component OH excited by the 283.55nm laser, and to image the instantaneous structure of the flame-burned zone.

[0041] The schlieren imaging unit emits schlieren light into the flame region, uses pulsed schlieren imaging to visualize the flow field structure of the flame region, and uses schlieren velocimetry to visualize the flow field velocity distribution of the flame region.

[0042] In the above embodiments, CH2O PLIF and OH PLIF technologies are used to simultaneously image the instantaneous multi-zone structure of the flame. CH2O PLIF images the instantaneous structure of the flame preheating zone, and OH PLIF images the instantaneous structure of the flame burned zone. The product of the CH2O PLIF-imaged instantaneous structure of the flame preheating zone and the OH PLIF-imaged instantaneous structure of the flame burned zone yields the instantaneous structure image of the flame heat release zone. This invention uses pulse schlieren technology to image the instantaneous flow field structure of the flame region and uses schlieren velocimetry to provide the two-dimensional velocity distribution of the instantaneous flow field in the flame region.

[0043] Reference Figure 1One embodiment provides a device for synchronous imaging of flame structure, flow field structure, and flow field velocity, comprising a first Nd:YAG laser 1, a dye laser 2, a second Nd:YAG laser 3, a first reflector 4, a dichroic mirror 5, a second reflector 6, a third reflector 7, a concave cylindrical mirror 8, an aperture 9, a convex spherical mirror 10, a first enhanced camera 12, a first enhanced camera lens 13, a first tilt-shift adapter 14, a CH2O PLIF filter 15, a second enhanced camera 16, a second enhanced camera lens 17, a second tilt-shift adapter 18, an OH PLIF filter 19, a high-energy pulsed light source 20, a focusing lens 21, a slit 22, a first plane reflector 23, a first concave reflector 24, a second concave reflector 25, a second plane reflector 26, a knife edge 27, a semi-transparent and semi-reflective beam splitter 28, a first schlieren camera 29, and a second schlieren camera 30.

[0044] The first Nd:YAG laser 1 and the dye laser 2 form a 283.55nm laser generation unit. Specifically, the first Nd:YAG laser 1 pumps the dye laser 2 to generate 283.55nm laser light for OH PLIF imaging. The 355nm laser generation unit includes a second Nd:YAG laser 3, which generates 355nm laser light using frequency third harmonic technology for CH2O PLIF imaging.

[0045] The 283.55nm and 355nm lasers are redirected and transmitted via an optical path redirection and transmission device, and then combined into a single transmission path by a beam combiner. The optical sheet shaping device includes a concave cylindrical mirror and a convex spherical mirror, which shape the two laser beams into a sheet-like laser beam. Figure 1 As shown, a first reflector 4 is positioned along the laser transmission path of the 283.55nm laser, and a dichroic mirror 5 is positioned along the reflection direction of the first reflector 4. A dichroic mirror 5 is also positioned along the laser transmission path of the 355nm laser. At the dichroic mirror 5, the transmission paths of the two laser beams merge into a single transmission path. Multiple reflectors are sequentially positioned along the subsequent transmission path, such as... Figure 1 The system includes a second reflector 6 and a third reflector 7. A series of reflectors direct and transmit the laser beam to a light-shaping device above the flame region 11. The light-shaping device includes a concave cylindrical mirror 8 and a convex spherical mirror 10. The laser beam incident on the concave cylindrical mirror 8 is shaped into a sheet-like laser beam after passing through an aperture 9 and the convex spherical mirror 10, and then directly incident on the flame region 11 in the combustion chamber where hydrocarbon fuels are burning.

[0046] The first imaging unit includes a first enhanced camera 12, with a CH2O PLIF filter 15 disposed in front of the first enhanced camera lens 13; the second imaging unit includes a second enhanced camera 16, with an OH PLIF filter 19 disposed in front of the second enhanced camera lens 17. Furthermore, to avoid interference between the two enhanced cameras (OH PLIF and CH2O PLIF) on schlieren imaging, tilt-shift imaging technology is employed. Specifically, a first tilt-shift adapter 14 is installed between the first enhanced camera 12 and the first enhanced camera lens 13, and a second tilt-shift adapter 18 is installed between the second enhanced camera 16 and the second enhanced camera lens 17, so that both enhanced cameras can obtain clearly focused flame fluorescence images under tilted shooting conditions.

[0047] like Figure 1 As shown, the schlieren imaging unit in this embodiment includes a high-energy pulsed light source 20, a focusing lens 21, a slit 22, a first planar reflector 23, a first concave reflector 24, a second concave reflector 25, a second planar reflector 26, a knife edge 27, a semi-transparent and semi-reflective beam splitter 28, a first schlieren camera 29, and a second schlieren camera 30. The high-energy pulsed light source 20 is used to generate schlieren light. The light output from the high-energy pulsed light source 20 is focused by the focusing lens 21, passes through the slit 22, and is guided by the first planar reflector 23 to the first concave reflector 24. The first concave reflector 24 forms parallel light that passes through the flame region 11, wherein the direction of the schlieren light incident on the flame region 11 is perpendicular to the direction of the sheet laser incident on the flame region.

[0048] The schlieren light, after passing through the flame region 11, is incident parallel to the second concave mirror 25 on the other side of the flame region 11. After passing through the second concave mirror 25 and the second planar mirror 26 in sequence, it is focused to the knife edge 27. The schlieren light then passes through a semi-transparent beam splitter 28, forming two beams that enter the first schlieren camera 29 and the second schlieren camera 30 respectively. By controlling the working time of the high-energy pulse light source 20 and the exposure gate width of the two schlieren cameras, the shooting interval of the two schlieren cameras can be adjusted. Since the interval is known, the instantaneous flow field structure of the flame region can be imaged using pulse schlieren imaging, and the flow field velocity distribution of the flame region can be imaged using schlieren velocimetry. Furthermore, the direction of the schlieren light incident on the flame region is perpendicular to the direction of the sheet laser incident on the flame region.

[0049] The operating timing of the lasers in the 283.55nm and 355nm laser generation units, the first enhanced camera, the second enhanced camera, the high-energy pulsed light source, and the two schlieren cameras is precisely controlled by multiple digital delay generators to ensure that the imaging of the first enhanced camera, the second enhanced camera, and the two schlieren cameras does not interfere with each other. In one embodiment, and not generally proposed, the exposure gate width of the two enhanced cameras is approximately 100ns, and the exposure gate width of the two schlieren cameras is approximately 300ns, meaning the total imaging time for the four images is approximately 800ns. Compared to most combustion phenomena, this exposure time is very short, and the flow field can be considered to be in a frozen state, thus achieving synchronous visualization of the flame preheating zone, flame heat release zone, flame combustion zone, flow field structure, and flow field velocity.

[0050] In another embodiment, a method for simultaneous imaging of flame structure, flow field structure, and flow field velocity is proposed, comprising:

[0051] Generates 283.55nm and 355nm lasers;

[0052] The 283.55nm and 355nm lasers are transmitted and shaped into sheet-like lasers before being incident on the flame area of ​​hydrocarbon fuel combustion in the combustion chamber.

[0053] The first fluorescence signal generated by the CH2O component of the flame excited by a 355nm laser was imaged to obtain the instantaneous structure of the flame preheating zone.

[0054] The second fluorescence signal generated by the flame component OH excited by the 283.55nm laser was imaged to obtain the instantaneous structure of the flame-burned zone;

[0055] The flow field structure in the flame region is imaged using pulse schlieren imaging, and the flow velocity distribution in the flame region is imaged using schlieren velocimetry.

[0056] Furthermore, in one embodiment, the synchronous imaging method based on the above-mentioned flame structure, flow field structure, and flow field velocity further includes obtaining an instantaneous structure image of the flame heat release zone based on the product of the instantaneous structure image of the flame preheating zone and the instantaneous structure image of the flame burned zone.

[0057] The specific implementation methods or hardware structures of each step in the above method can be implemented based on the corresponding designs in the device for synchronous imaging of flame structure, flow field structure and flow field velocity provided in any of the above embodiments, and will not be elaborated here.

[0058] The embodiments of the present invention differ from existing devices or methods that only image a single flame structure (or component). The present invention enables instantaneous imaging of multiple flame regions (including CH2O components, OH components, and the flame heat release zone). Furthermore, unlike existing technologies that can only achieve simultaneous imaging of a single flame structure (or component) and schlieren, and cannot provide richer flame structure and flow field velocity information, the embodiments of the present invention achieve simultaneous high-time-resolution imaging of multiple flame regions, schlieren, and schlieren velocity measurement.

[0059] Matters not covered in this invention are common knowledge.

[0060] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0061] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for simultaneous imaging of flame structure, flow field structure, and flow field velocity, characterized in that, include: A 283.55nm laser generation unit is used to generate 283.55nm laser light. A 355nm laser generation unit is used to generate 355nm laser light. A sheet laser generating unit is used to transmit or shape a 283.55nm or 355nm laser into a sheet laser and then incident it into the flame area of ​​hydrocarbon fuel combustion in the combustion chamber. The first imaging unit is used to image the first fluorescence signal generated by the CH2O component of the flame excited by the 355nm laser, and to image the instantaneous structure of the flame preheating zone. The second imaging unit is used to image the second fluorescence signal generated by the flame component OH excited by the 283.55 nm laser, and to image the instantaneous structure of the flame-burned zone. A schlieren imaging unit emits schlieren light incident on the flame region, using pulsed schlieren imaging to visualize the flow field structure of the flame region and schlieren velocimetry to visualize the flow field velocity distribution of the flame region. The schlieren imaging unit includes a high-energy pulsed light source, a focusing lens, a first planar reflector, a first concave reflector, a second concave reflector, a second planar reflector, a knife edge, a semi-transparent beam splitter, a first schlieren camera, and a second schlieren camera. The high-energy pulsed light source generates schlieren light. The light output from the high-energy pulsed light source is focused by the focusing lens and then guided by the first planar reflector to the first concave reflector, and then... Parallel light from a surface mirror passes through the flame region and is incident parallel to a second concave mirror on the other side of the flame region. After passing through the second concave mirror and the second surface mirror, the light is focused onto the knife edge. The schlieren light passes through a semi-transparent beam splitter, forming two beams that enter the first and second schlieren cameras respectively. By controlling the working time of the high-energy pulse light source and the exposure gate width of the two schlieren cameras, the shooting interval of the two schlieren cameras can be adjusted. Since the interval is known, the instantaneous flow field structure of the flame region can be imaged using pulse schlieren imaging, and the flow field velocity distribution of the flame region can be imaged using schlieren velocimetry. The image processing unit obtains the instantaneous structure image of the flame heat release zone based on the product of the instantaneous structure image of the flame preheating zone and the instantaneous structure image of the flame already burned zone.

2. The device for synchronous imaging of flame structure, flow field structure, and flow field velocity according to claim 1, characterized in that, The direction of the schlieren incident flame region is perpendicular to the direction of the sheet laser incident flame region.

3. The device for simultaneous imaging of flame structure, flow field structure, and flow field velocity according to claim 1, characterized in that, The timing of the high-energy pulsed light source and the two schlieren cameras in the 283.55nm laser generation unit, 355nm laser generation unit, first imaging unit, second imaging unit, and schlieren imaging unit is controlled to ensure that the imaging of the two schlieren cameras in the first imaging unit, second imaging unit, and schlieren imaging unit does not interfere with each other.

4. The apparatus for synchronous imaging of flame structure, flow field structure, and flow field velocity according to claim 1, 2, or 3, characterized in that, The 283.55nm laser generation unit includes a first Nd:YAG laser and a dye laser. The first Nd:YAG laser pumps the dye laser to generate 283.55nm laser light.

5. The apparatus for synchronous imaging of flame structure, flow field structure, and flow field velocity according to claim 4, characterized in that, The 355nm laser generation unit includes a second Nd:YAG laser, which generates 355nm laser light through the second Nd:YAG laser and frequency third harmonic technology.

6. The apparatus for synchronous imaging of flame structure, flow field structure, and flow field velocity according to claim 1, characterized in that, The first imaging unit includes a first enhanced camera, and a CH2OPLIF filter is disposed in front of the lens of the first enhanced camera; the second imaging unit includes a second enhanced camera, and an OH PLIF filter is disposed in front of the lens of the first enhanced camera.

7. The apparatus for synchronous imaging of flame structure, flow field structure, and flow field velocity according to claim 6, characterized in that, A tilt-shift adapter is installed between the enhanced camera and its lens in the first imaging unit and / or the second imaging unit.

8. The apparatus for synchronous imaging of flame structure, flow field structure, and flow field velocity according to claim 1, 2, 3, 5, 6, or 7, characterized in that, The laser sheet light generation unit includes an optical path steering and transmission device, a beam combining device, and an optical sheet shaping device. The 283.55nm laser and the 355nm laser are steered and transmitted by the optical path steering and transmission device. The beam combining device merges the transmission paths of the two laser beams into the same transmission path for transmission. The optical sheet shaping device includes a concave cylindrical mirror and a convex spherical mirror. The two laser beams are shaped into a sheet-like laser by the concave cylindrical mirror and the convex spherical mirror.

9. A method for simultaneous imaging of flame structure, flow field structure, and flow field velocity, characterized in that, Based on the device for synchronous imaging of flame structure, flow field structure, and flow field velocity as described in claim 1, including: Generates 283.55nm and 355nm lasers; The 283.55nm and 355nm lasers are transmitted and shaped into sheet-like lasers before being incident on the flame area of ​​hydrocarbon fuel combustion in the combustion chamber. The first fluorescence signal generated by the CH2O component of the flame excited by a 355nm laser was imaged to obtain the instantaneous structure of the flame preheating zone. The second fluorescence signal generated by the flame component OH excited by the 283.55 nm laser was imaged to obtain the instantaneous structure of the flame-burned zone; Emitting schlieren light incident on the flame region, using pulse schlieren imaging to image the flow field structure of the flame region, and using schlieren velocimetry to image the flow field velocity distribution of the flame region; The instantaneous structure image of the flame heat release zone is obtained by multiplying the instantaneous structure image of the flame preheating zone and the instantaneous structure image of the flame burned zone.

Images