Gas phase jet flow flame combustion and diagnosis experiment device and method

Abstract

The invention relates to the technical field of online combustion flame diagnosis, and discloses a gas phase jet flow flame combustion and diagnosis experiment device and method.The gas phase jet flow flame combustion and diagnosis experiment device comprises a schlieren light source unit, a laser emission unit, a light splitting plain film, a schlieren detection unit and a fluorescence collection unit, and the light splitting plain film is used for splitting schlieren light and fluorescence light. In-situ observation characterization is carried out on the gas phase jet flow flame by coupling schlieren, autofluorescence and laser-induced fluorescence methods, synchronous measurement of laser-induced fluorescence and schlieren and synchronous measurement of flame autofluorescence and schlieren can be realized, and the method is particularly suitable for in-situ observation characterization and diagnosis of flame with an asymmetric structure.

Description

Technical Field

[0001] The invention relates to the technical field of on-line combustion flame diagnosis, and discloses a gas phase jet flame combustion and diagnosis experimental device and method. Background Art

[0002] Currently, researchers have conducted experimental studies on aircraft engine combustion flames using in-situ methods, but related research still has shortcomings and needs further improvement. For example:

[0003] The patent "A laser-induced fluorescence focused schlieren system" can perform two-dimensional visualization of the hypersonic combustion flow field, but cannot reveal the distribution of intermediate components;

[0004] The patent "Measurement system and combustion diagnosis method based on tunable diode laser absorption spectroscopy" can judge the combustion state in the combustion chamber of a ramjet engine by measuring the absorption rate of components.

[0005] In addition, relevant researchers have also conducted in-situ diagnosis of combustion flames in their research papers, coupling the use of methods such as schlieren and laser-induced fluorescence. However, their research usually places schlieren and laser-induced fluorescence in two different directions, that is, schlieren and fluorescence observations are performed in two intersecting directions, which is acceptable for axisymmetric flames; but for asymmetric burners (such as multi-jet burners with multiple combustion nozzles arranged in a straight line when studying the interaction between flames), it is difficult to obtain flame information in the same direction at the same time. Summary of the invention

[0006] The purpose of the present invention is to provide a gas-phase jet flame combustion and diagnosis experimental device and method, which can realize the synchronous measurement of laser-induced fluorescence and schlieren, as well as the synchronous measurement of flame spontaneous fluorescence and schlieren, and is particularly suitable for in-situ observation, characterization and diagnosis of flames with asymmetric structures.

[0007] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0008] A gas phase jet flame combustion and diagnosis experimental device, comprising:

[0009] A schlieren light source unit, the schlieren light source unit is used to emit light to the burning flame, irradiating the flame to generate schlieren;

[0010] A laser emitting unit, the laser emitting unit is used to emit a laser signal to the burning flame to induce the flame to generate fluorescence;

[0011] A spectroscopic plate, the spectroscopic plate is used to split the schlieren light and the fluorescent light; the schlieren light is a schlieren signal generated by the schlieren light source unit irradiating the flame; the fluorescent light includes a first fluorescent signal induced by the laser and a second fluorescent signal spontaneously generated by the flame;

[0012] A schlieren detection unit, the schlieren detection unit is used to collect the schlieren signal after the spectral splitting by the spectral splitting plate;

[0013] The fluorescence collection unit is used to receive the first fluorescence signal and the second fluorescence signal after being split by the spectroscopic plate.

[0014] Furthermore, the light from the schlieren light source unit acting on the flame is perpendicular to the laser light acting on the flame.

[0015] Furthermore, the spectroscopic plate is an optical device having a transmittance higher than 80% for ultraviolet light at 308 nm and a transmittance lower than 0.1% for visible light at 520 nm.

[0016] Furthermore, the fluorescence collection unit includes an ultraviolet objective lens, an image intensifier and a first camera; the ultraviolet objective lens is used to collect the fluorescence light passing through the spectroscopic plate, and the image intensifier is used to synchronize and amplify the fluorescence light collected by the ultraviolet objective lens, and transmit the synchronized and amplified signal to the first camera.

[0017] Furthermore, the schlieren detection unit includes a blade and a second camera, and a first convex lens is provided on the optical signal transmission path between the blade and the beam splitter plate.

[0018] Furthermore, the laser emitting unit includes a nanosecond pulse laser, a first reflector, a second reflector, a dye laser, a third reflector, a fourth reflector, a convex spherical lens, and a plano-concave cylindrical lens, which are arranged in sequence along a laser transmission path; the pump light provided by the nanosecond pulse laser is guided to the dye laser via the first reflector and the second reflector to form a tunable laser for a laser induced fluorescence method; the tunable laser emitted by the dye laser is guided via the third reflector and the fourth reflector, and is converted into a sheet light source via the convex spherical lens and the plano-concave cylindrical lens to act on the flame to induce fluorescence of flame components.

[0019] Furthermore, the Schlieren light source unit includes an LED point light source, a second convex lens, and a fifth reflector; it is used to collimate the light emitted by the LED point light source through the second convex lens and reflect it onto the flame through the fifth reflector, and the Schlieren signal generated by the Schlieren light source unit irradiating the flame is reflected by the fifth reflector to the spectroscopic plate.

[0020] Furthermore, it also includes a third camera, which is used to directly collect the flame luminescence morphology.

[0021] Furthermore, it also includes a control and acquisition subsystem, which is used to control the schlieren light source unit and the laser emission unit to generate corresponding optical signals, and control the schlieren detection unit and the fluorescence acquisition unit to collect and transmit corresponding optical signals.

[0022] In order to achieve the above technical effects, the present invention also provides a gas-phase jet flame combustion and diagnosis experimental method, which is based on the gas-phase jet flame combustion and diagnosis experimental device, and includes:

[0023] The schlieren light source unit is used to emit light to the burning flame to irradiate the flame to produce schlieren, and the laser emission unit is used to emit a laser signal to the burning flame to induce the flame to produce fluorescence;

[0024] A spectroscopic plate is used to split the schlieren light and the fluorescent light; the fluorescent light includes a first fluorescent signal induced by the laser and a second fluorescent signal spontaneously generated by the flame;

[0025] The schlieren detection unit is used to collect the schlieren signal after the spectral splitting by the spectral splitting plate; and the fluorescence collection unit is used to receive the first fluorescence signal and the second fluorescence signal after the spectral splitting by the spectral splitting plate.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention couples the use of schlieren, autofluorescence, and laser-induced fluorescence methods to perform in-situ observation and characterization of gas jet flames, and can achieve synchronous measurement of laser-induced fluorescence and schlieren, as well as synchronous measurement of flame autofluorescence and schlieren, and is particularly suitable for in-situ observation, characterization, and diagnosis of flames with asymmetric structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the gas phase jet flame combustion and diagnosis experimental device in Example 1 or 2;

[0028] Figure 2 Schematic diagram of the structure of the overall experimental device in Example 1 or 2

[0029] Figure 3 is a schematic structural diagram of the liquid fuel supply subsystem in Example 2;

[0030] Figure 4 is the autofluorescence image of the propane multi-jet flame in Example 2;

[0031] Figure 5 is a schlieren image of the propane multi-jet flame in Example 2;

[0032] Among them, 1. Combustion and detection subsystem; 101. Burner; 1011. Fuel jet tube; 1012. Heating rod; 1013. Burner cover; 1014. Sintering plate; 102. LED point light source; 103. Second convex lens; 104. Fifth reflector; 105. Spectral plate; 106. First convex lens; 107. Blade; 108. Second camera; 109. Nanosecond pulse laser; 110. First reflector; 111. Second reflector; 112. Dye laser; 113. Third reflector; 114. Fourth reflector; 115. Convex spherical lens; 116. Plano-concave cylindrical lens; 117. UV objective lens; 118. Image intensifier; 119. First camera; 120. Third camera; 2. Fuel supply subsystem; 3. Air supply subsystem; 4. Control and acquisition subsystem. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with the embodiments and drawings. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0034] Example 1

[0035] See also Figure 1 and Figure 2 , a gas phase jet flame combustion and diagnosis experimental device, comprising:

[0036] A schlieren light source unit, the schlieren light source unit is used to emit light to the burning flame, irradiating the flame to generate schlieren;

[0037] A laser emitting unit, the laser emitting unit is used to emit a laser signal to the burning flame to induce the flame to generate fluorescence;

[0038] A spectroscopic plate 105, wherein the spectroscopic plate 105 is used to split the schlieren light and the fluorescent light; the schlieren light is a schlieren signal generated by the schlieren light source unit irradiating the flame; the fluorescent light includes a first fluorescent signal induced by the laser and a second fluorescent signal spontaneously generated by the flame;

[0039] A schlieren detection unit, the schlieren detection unit is used to collect the schlieren signal after the spectral splitting by the spectral splitter plate 105;

[0040] The fluorescence collection unit is used to receive the first fluorescence signal and the second fluorescence signal after being split by the splitter plate 105 .

[0041] In this embodiment, by coupling the use of schlieren, autofluorescence, and laser-induced fluorescence methods to perform in-situ observation and characterization of the gas jet flame, it is possible to achieve synchronous measurement of laser-induced fluorescence and schlieren, as well as synchronous measurement of flame autofluorescence and schlieren, which is particularly suitable for in-situ observation, characterization, and diagnosis of flames with asymmetric structures.

[0042] In the present embodiment, the light of the schlieren light source unit acting on the flame is perpendicular to the laser light acting on the flame. Since the propagation directions of the first fluorescence signal and the second fluorescence signal are perpendicular to the laser, and the propagation direction of the schlieren signal is perpendicular to the light of the schlieren light source unit, it is possible to achieve the same-direction and synchronous measurement of laser-induced fluorescence and schlieren, as well as the same-direction and synchronous measurement of flame spontaneous fluorescence and schlieren. This is particularly suitable for in-situ observation, characterization and diagnosis of flames with asymmetric structures (such as multi-jet burners, etc.).

[0043] The spontaneous fluorescence of the flame intermediate components and the fluorescence of the flame components induced by the laser are mainly in the ultraviolet light band; therefore, the spectroscopic plate 105 in this embodiment uses an optical device with a transmittance of more than 80% for ultraviolet 308nm light and a transmittance of less than 0.1% at visible light 520nm, such as ZWB3 glass, to achieve simultaneous observation of flame pattern and fluorescence.

[0044] In this embodiment, the fluorescence collection unit includes an ultraviolet objective lens 117, an image intensifier 118 and a first camera 119; the ultraviolet objective lens 117 is used to collect the fluorescent light passing through the spectroscopic plate 105, and the image intensifier 118 is used to synchronize and amplify the fluorescent light collected by the ultraviolet objective lens 117, and transmit the synchronized and amplified signal to the first camera 119 (such as an industrial camera).

[0045] In this embodiment, the schlieren detection unit includes a blade 107 and a second camera 108 (such as an industrial camera). A first convex lens 106 is provided on the optical signal transmission path between the blade 107 and the beam splitter plate 105; the blade 107 is used to block direct light and retain schlieren refracted light.

[0046] In this embodiment, the laser emitting unit includes a nanosecond pulse laser 109, a first reflector 110, a second reflector 111, a dye laser 112, a third reflector 113, a fourth reflector 114, a convex spherical lens 115, and a plano-concave cylindrical lens 116, which are arranged in sequence along the laser transmission path; the pump light provided by the nanosecond pulse laser is guided to the dye laser via the first reflector and the second reflector to form a tunable laser for the laser induced fluorescence method; the laser light emitted by the dye laser 112 is guided via the third reflector 113 and the fourth reflector 114, and is converted into a sheet light source via the convex spherical lens 115 and the plano-concave cylindrical lens 116 to act on the flame to induce the fluorescence of the flame components.

[0047] In this embodiment, the Schlieren light source unit includes an LED point light source 102, a second convex lens 103, and a fifth reflector 104; it is used to collimate the light emitted by the LED point light source 102 through the second convex lens 103 and reflect it onto the flame through the fifth reflector 104, and the fifth reflector 104 reflects the Schlieren signal generated by the Schlieren light source unit irradiating the flame to the beam splitter 105.

[0048] In addition, the gas phase jet flame combustion and diagnosis experimental device in this embodiment also includes a control and acquisition subsystem, which is used to control the schlieren light source unit and the laser emission unit to generate corresponding optical signals, and control the schlieren detection unit and the fluorescence acquisition unit to collect and transmit corresponding optical signals.

[0049] Based on the same inventive concept, this embodiment also provides a gas-phase jet flame combustion and diagnosis experimental method, which is based on the gas-phase jet flame combustion and diagnosis experimental device, and includes:

[0050] The schlieren light source unit is used to emit light to the burning flame to irradiate the flame to produce schlieren, and the laser emission unit is used to emit a laser signal to the burning flame to induce the flame to produce fluorescence;

[0051] The schlieren light and the fluorescent light are split by using a beam splitter plate 105; the schlieren light includes a schlieren signal generated by the schlieren light source unit irradiating the flame; the fluorescent light includes a first fluorescent signal induced by the laser and a second fluorescent signal spontaneously generated by the flame;

[0052] The schlieren detection unit is used to collect the schlieren signal after the spectral splitting by the spectral splitter 105 ; and the fluorescence collection unit is used to receive the first fluorescence signal and the second fluorescence signal after the spectral splitting by the spectral splitter 105 .

[0053] Example 2

[0054] like Figure 1-Figure 3 As shown, this embodiment takes the combustion flame of liquid fuel as an example to explain in detail the gas phase jet flame combustion and diagnosis experimental device and method of the present invention. The overall experimental device can be divided into a combustion detection subsystem 1, a liquid fuel supply subsystem 2, an air supply subsystem 3, and a control acquisition subsystem 4.

[0055] The combustion detection subsystem 1 is as follows Figure 2 As shown, it is mainly used for flame combustion and its detection, including:

[0056] Burner 101, LED point light source 102, convex lens 103, fifth reflector 104, spectroscopic plate 105, convex lens 106, blade 107, second camera 108, nanosecond pulse laser 109, first reflector 110, second reflector 111, dye laser 112, third reflector 113, fourth reflector 114, convex spherical lens 115, plano-concave cylindrical lens 116, ultraviolet objective lens 117, image intensifier 118, first camera 119, third camera 120. The third camera 120 is used to directly collect the luminous morphology of the flame.

[0057] like Figure 3 As shown, the burner 101 can be used for burning gaseous fuel and liquid fuel, and includes components of a fuel jet pipe 1011, a heating rod 1012, a burner cover 1013, and a sintering plate 1014. The heating rod 1012 is used to heat the burner and preheat the air to prevent fuel condensation.

[0058] The beam splitter plate 105 realizes the coupling of the fluorescent light path and the schlieren light path, and has the characteristics of high transmittance in the ultraviolet band and high reflectivity in the visible light band.

[0059] The combustion detection subsystem 1 in this embodiment has two detection modes, wherein:

[0060] In the first detection mode, laser-induced fluorescence and schlieren are measured synchronously in the same direction: the schlieren light emitted by the LED point light source 102, collimated by the convex lens 103, and reflected by the fifth reflector 104 is reflected at the spectroscopic plate 105 to the first convex lens 106 and the second camera 108 for schlieren detection; the laser emitted by the dye laser 112 is converted into a sheet light source through the reflection guide path of the third reflector 113 and the fourth reflector 114, the convex spherical lens 115, and the plano-concave cylindrical lens 116 and acts on the flame, inducing the fluorescence of the flame components, which is mainly in the ultraviolet light band; the fluorescence passes through the spectroscopic plate 105, is collected by the ultraviolet objective lens 117, synchronized and amplified by the image intensifier 118, and collected by the first camera 119.

[0061] In the second detection mode, the spontaneous fluorescence and schlieren are measured synchronously in the same direction: the schlieren are still measured in the same way as the first detection mode; the spontaneous fluorescence of the intermediate components of the flame is mainly ultraviolet light, and the fluorescence passes through the spectroscopic plate 105, is collected by the ultraviolet objective lens 117, synchronized and amplified by the image intensifier 118, and is collected by the first camera 119.

[0062] The liquid fuel supply subsystem 2 in this embodiment is used to realize liquid fuel supply, atomization, and vaporization, and includes a mass flow meter, a pressure gauge, a float flow meter, a liquid injection pump, a three-way joint, a vaporizer, and a pyrolysis furnace. The liquid fuel is stably supplied by the injection pump at a set flow rate, mixed with the nitrogen carrier gas supplied by the mass flow meter at the three-way joint, and the gas-liquid mixed gas is transported to the vaporizer.

[0063] The vaporizer structure is used to realize the vaporization of liquid fuel, and is provided with components such as a sealed furnace tube, a microporous atomizing tube, etc. The gas-liquid mixture from the three-way joint is sprayed out through the microporous atomizing tube to form tiny droplets, which are stably vaporized inside the sealed furnace tube to realize the vaporization supply of liquid fuel in large flow.

[0064] The air supply subsystem 3 of this embodiment is used for air supply and flow control, and the air source can be switched to a compressed air cylinder or an air compressor; it includes an air cylinder, a mass flow meter, an air compressor, a cold dryer, a pressure regulating valve, a regulating valve, a Roots flowmeter, a pressure gauge, and a float flowmeter.

[0065] The control and acquisition subsystem 4 is used to respectively exchange signals and data with the combustion detection subsystem 1, the liquid fuel supply subsystem 2, and the air supply subsystem 3 to achieve signal synchronization control and image acquisition, including a digital delay generator, etc.

[0066] The process of the gas phase jet flame diagnosis method in this embodiment is as follows:

[0067] The first step is to optimize the Schlieren light path, mainly optimizing the positions and angles of the LED point light source 102, the convex lens 103, the fifth reflector 104, the beam splitter plate 105, the convex lens 106, the blade 107, and the second camera 108 to achieve normal Schlieren imaging;

[0068] The second step is to optimize the autofluorescence optical path, mainly optimizing the positions and angles of the ultraviolet objective lens 117, the image intensifier 118, and the first camera 119, so as to achieve normal imaging of the autofluorescence of the intermediate components of the flame;

[0069] The third step is to optimize the laser induced fluorescence optical path, mainly optimizing the positions and directions of the third reflector 113, the fourth reflector 114, the convex spherical lens 115, and the plano-concave cylindrical lens 116 to form a good light sheet, and the light sheet is in a reasonable position;

[0070] The fourth step is the synchronous control and acquisition settings, which mainly sets the time resolution control parameters of the control acquisition subsystem 4, such as delay, pulse width, trigger, etc., to achieve the timing control of the industrial camera and image intensifier 118;

[0071] The fifth step is to set the temperature control of the vaporizer, pyrolysis furnace, and burner to achieve reasonable control of the temperature of the vaporizer, pyrolysis furnace, and burner heating rod 1012 to avoid condensation of liquid fuel;

[0072] The sixth step is to set the air and liquid flow rates;

[0073] The seventh step is the first detection mode acquisition;

[0074] The eighth step is the second detection mode acquisition;

[0075] Set the flame to different working conditions, repeat steps 6 to 8, and realize the synchronous collection of laser-induced fluorescence and schlieren, and the synchronous collection of spontaneous fluorescence and schlieren.

[0076] In one embodiment of the present patent, the spectroscopic plate 105 is made of ZWB3 glass, which has a transmittance higher than 80% at ultraviolet 308nm and a transmittance lower than 0.1% at visible light 520nm.

[0077] In one embodiment of the present invention, the propane flame is subjected to the same-direction and synchronous measurement of the autofluorescence and the schlieren, i.e. the first detection mode. The results are as follows: Figure 4 , Figure 5 As shown, Figure 4 This is the autofluorescence image of the propane multi-jet flame. Figure 5 This is a schlieren image of a propane multi-jet flame; the flame is a three-jet flame of propane, which can be used to study the interaction between jet flames. The patented experimental device can be used to observe and characterize the changes in the jet flames.

[0078] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas phase jet flame combustion and diagnostic experimental device, characterized in that: include: A schlieren light source unit, the schlieren light source unit is used to emit light to the burning flame, irradiating the flame to generate schlieren; A laser emitting unit, the laser emitting unit is used to emit a laser signal to the burning flame to induce the flame to generate fluorescence; A spectroscopic plate, the spectroscopic plate is used to split the schlieren light and the fluorescent light; the schlieren light is a schlieren signal generated by the schlieren light source unit irradiating the flame; the fluorescent light includes a first fluorescent signal induced by the laser and a second fluorescent signal spontaneously generated by the flame; A schlieren detection unit, the schlieren detection unit is used to collect the schlieren signal after the spectral splitting by the spectral splitting plate; The fluorescence collection unit is used to receive the first fluorescence signal and the second fluorescence signal after being split by the spectroscopic plate.

2. The gas phase jet flame combustion and diagnosis experimental device according to claim 1 is characterized in that: The light of the schlieren light source unit acting on the flame is perpendicular to the laser light acting on the flame.

3. The gas phase jet flame combustion and diagnosis experimental device according to claim 2 is characterized in that: The spectroscopic plate is an optical device having a transmittance higher than 80% for ultraviolet light of 308 nm and a transmittance lower than 0.1% for visible light of 520 nm.

4. The gas phase jet flame combustion and diagnosis experimental device according to claim 3 is characterized in that: The fluorescence collection unit includes an ultraviolet objective lens, an image intensifier and a first camera; the ultraviolet objective lens is used to collect the fluorescence light passing through the spectroscopic plate, and the image intensifier is used to synchronize and amplify the fluorescence light collected by the ultraviolet objective lens, and transmit the synchronized and amplified signal to the first camera.

5. The gas phase jet flame combustion and diagnosis experimental device according to claim 3 is characterized in that: The schlieren detection unit comprises a blade and a second camera, and a first convex lens is arranged on the optical signal transmission path between the blade and the beam splitter plate.

6. The gas phase jet flame combustion and diagnosis experimental device according to claim 3 is characterized in that: The laser emitting unit comprises a nanosecond pulse laser, a first reflector, a second reflector, a dye laser, a third reflector, a fourth reflector, a convex spherical lens, and a plano-concave cylindrical lens which are sequentially arranged along a laser transmission path; the pump light provided by the nanosecond pulse laser is guided to the dye laser via the first reflector and the second reflector to form a tunable laser for a laser induced fluorescence method; the tunable laser emitted by the dye laser is guided via the third reflector and the fourth reflector to a path, and is converted into a sheet light source via the convex spherical lens and the plano-concave cylindrical lens to act on a flame to induce fluorescence of flame components.

7. The gas phase jet flame combustion and diagnosis experimental device according to claim 3 is characterized in that: The Schlieren light source unit comprises an LED point light source, a second convex lens and a fifth reflector; the unit is used to collimate the light emitted by the LED point light source through the second convex lens and reflect the light through the fifth reflector onto the flame, and the fifth reflector reflects the Schlieren signal generated by the Schlieren light source unit irradiating the flame onto the beam splitter.

8. The gas phase jet flame combustion and diagnosis experimental device according to claim 1 is characterized in that: It also includes a third camera, which is used to directly collect the flame luminescence morphology.

9. The gas phase jet flame combustion and diagnosis experimental device according to any one of claims 1 to 8, characterized in that: It also includes a control and acquisition subsystem, which is used to control the schlieren light source unit and the laser emission unit to generate corresponding optical signals, and control the schlieren detection unit and the fluorescence acquisition unit to collect and transmit corresponding optical signals.

10. A gas phase jet flame combustion and diagnosis experimental method, the method is based on the gas phase jet flame combustion and diagnosis experimental device according to claim 1, characterized in that: include: The schlieren light source unit is used to emit light to the burning flame to irradiate the flame to produce schlieren, and the laser emission unit is used to emit a laser signal to the burning flame to induce the flame to produce fluorescence; A spectroscopic plate is used to split the schlieren light and the fluorescent light; the fluorescent light includes a first fluorescent signal induced by the laser and a second fluorescent signal spontaneously generated by the flame; The schlieren detection unit is used to collect the schlieren signal after the spectral splitting by the spectral splitting plate; and the fluorescence collection unit is used to receive the first fluorescence signal and the second fluorescence signal after the spectral splitting by the spectral splitting plate.

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