Framing system for synchronously measuring multiple parameters in combustion process

Abstract

The invention discloses a framing system for synchronously measuring multiple parameters in a combustion process, and relates to the technical field of combustion process measurement. The two imaging lenses with the same specification are connected through the adapter ring to serve as a detection lens group; three dichroscopes are arranged behind the first dichroscope, a transmission signal of the first dichroscope is used for acquiring an OH-PLIF signal, and a reflection signal enters the second dichroscope; a reflection signal of the second dichroscope is used for acquiring a kerosene PLIF signal, and a transmission signal enters the third dichroscope; a reflection signal of the third dichroscope is used for acquiring a spontaneous radiation signal of a CH * group, and a transmission signal of the third dichroscope is used for acquiring a scattering signal of laser required by PIV (particle image velocimetry) detection; combustion image detection equipment is respectively arranged behind the first three signals; and a PIV image detection device is arranged behind the latter signal. Through combination of the three dichroscopes, multi-parameter synchronous measurement of OH-PLIF, kerosene PLIF, CH * group spontaneous radiation and PIV particle image velocimetry is realized.

Description

Technical Field

[0001] The invention relates to the technical field of combustion process measurement, in particular to a framing system for synchronous measurement of multiple parameters in a combustion process. Background Art

[0002] Kerosene, as a fuel with high energy density, is often used as the preferred fuel for engines such as hypersonic aircraft. The combustion process of kerosene involves complex physical and chemical processes, such as spraying, evaporation, mixing and multiphase reactions. By measuring the distribution of kerosene combustion flames, the combustion reaction area can be identified, and the flame structure, flame thickness and its propagation characteristics can be understood, which is helpful for studying the kinetic process and chemical reaction mechanism of the combustion reaction; the measurement of kerosene distribution reflects the mixing state of fuel and oxidant. By measuring the distribution of kerosene, it can be used to analyze the mixing effect, and the measurement results can provide support for the optimization of the burner; at the same time, measuring the propagation velocity helps to understand the combustion characteristics and optimize the combustion system design to achieve safe and efficient operation of the system. Therefore, the above parameters are necessary and of great significance for the measurement of kerosene combustion process.

[0003] With the continuous development of optical measurement technology, the in-depth application of optical measurements such as planar laser induced fluorescence (PLIF) and particle image velocimetry (PIV) characterizes the combustion state by measuring OH-PLIF, kerosene PLIF, spontaneous radiation of methyl radicals (CH* groups) and velocity measurement through PIV, where OH-PLIF represents the structure of the flame reaction zone, kerosene PLIF represents the degree of mixed atomization, CH* groups represent the heat release zone of the flame, and PIV represents the velocity field. The combustion process is analyzed by measuring various parameters. However, due to the use of different detection equipment between different measurement technologies, a large number of equipment are required, and it is difficult to achieve multi-parameter synchronous measurement for scenes with smaller spaces. In addition, the image data obtained by multiple detection equipment needs to be corrected according to the placement angle of the camera, which is a cumbersome process.

[0004] When performing synchronous measurement of OH-PLIF and kerosene PLIF, 283nm laser is often used as the excitation light source. 283nm laser can synchronously excite the OH signal in the flame and the unburned kerosene signal. The OH-PLIF signal is lower than 325nm, and the signal between 325nm-405nm can characterize the kerosene PLIF. The CH* group signal is between 425nm-440nm; and the scattered signal above 510nm can be used to detect the PIV signal. Therefore, 532nm or 527nm laser is generally used in PIV tests. Due to the different signal wavelength ranges of various parameters, a framing system is urgently needed to realize the synchronous measurement of the above-mentioned multiple parameters, and at the same time, it can also avoid the angle correction of the image, which is of great significance to reduce the complexity of the system. Summary of the invention

[0005] In order to overcome the shortcomings of the background technology, the present invention provides a framing system for multi-parameter synchronous measurement of combustion process, which can realize multi-parameter synchronous measurement of OH-PLIF, kerosene PLIF, CH* group spontaneous radiation and PIV particle image velocimetry by combining three dichroic mirrors.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a framing system for synchronous measurement of multiple parameters of a combustion process, comprising six imaging lenses, four detection cameras, three image intensification modules, three dichroic mirrors and four filters; wherein two of the imaging lenses have the same specifications and are connected through an adapter ring as a detection lens group, which is used to obtain detection signals of the combustion process; the three dichroic mirrors are arranged behind the detection lens group, the first dichroic mirror reflects signals above 325nm and transmits signals below 325nm, the transmission signal is used to obtain OH-PLIF signals, and the reflection signal is incident on the second dichroic mirror; the second dichroic mirror transmits signals above 405nm and reflects signals below 405nm, the reflection signal is in the range of [325nm, 405nm], which is used to obtain kerosene PLIF signals, The transmission signal is incident on the third dichroic mirror; the third dichroic mirror transmits signals above 510nm and reflects signals below 510nm, and the reflection signal is in the range of (405nm, 510nm], which is used to obtain the spontaneous radiation signal of the CH* group, and the transmission signal is used to obtain the scattering signal of the 532nm or 527nm laser required for PIV detection; combustion image detection equipment is arranged after the transmission signal of the first dichroic mirror, after the reflection signal of the second dichroic mirror, and after the reflection signal of the third dichroic mirror, respectively, and the combustion image detection equipment includes the filter, imaging lens, image enhancement module and detection camera arranged in sequence; PIV image detection equipment is arranged after the transmission signal of the third dichroic mirror, and the PIV image detection equipment includes the filter, imaging lens and detection camera arranged in sequence.

[0007] Furthermore, the positions of the corresponding detection cameras can be adjusted by arranging reflective mirrors before and after the three dichroic mirrors.

[0008] Furthermore, the three dichroic mirrors have corresponding transmission band signal transmittances and reflection band signal reflectances higher than 99%.

[0009] Furthermore, the filter arranged after the transmission signal of the first dichroic mirror is a bandpass filter with a typical measurement specification of a central wavelength of 315 nm and a half-width of 15 nm, and the corresponding imaging lens is an ultraviolet lens.

[0010] Furthermore, the filter arranged after the reflection signal of the second dichroic mirror adopts a typical measurement specification of a 325nm high-pass filter combined with a 405nm low-pass filter, and the corresponding imaging lens is an ultraviolet lens.

[0011] Furthermore, the filter arranged after the reflection signal of the third dichroic mirror is a bandpass filter with a typical measurement specification of a central wavelength of 427 nm and a half-width of 10 nm.

[0012] Furthermore, the filter arranged after the transmission signal of the third dichroic mirror is a bandpass filter with a typical measurement specification of a central wavelength of 532nm or 527nm and a half-width of 10nm according to requirements.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention can complete the selection of signals of different bands through a clever combination of three dichroic mirrors with different transmission and reflection effects, and can realize multi-parameter synchronous measurement of OH-PLIF, kerosene PLIF, CH* group spontaneous radiation and PIV particle image velocimetry, which helps to simplify the detection system, reduce the complexity of the system, and improve the detection efficiency of the signal. Moreover, there is no need to correct the placement angle of the camera to obtain the image, and the invention has good applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the framing system of the present invention.

[0015] In the figure: 1. Imaging lens; 2. Adapter ring; 3. Detection camera; 4. Image intensification module; 5. Dichroic mirror; 6. Filter; 7. Reflector. DETAILED DESCRIPTION

[0016] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0017] like Figure 1 As shown, a framing system for synchronous measurement of multiple parameters in a combustion process includes six imaging lenses 1, four detection cameras 3, three image enhancement modules 4, three dichroic mirrors 5 and four filters 6. Specifically:

[0018] The first two imaging lenses 1 have the same specifications and are connected through an adapter ring 2 as a detection lens group for obtaining detection signals of the combustion process. Since lenses of the same specifications have the same flange focal length, the first two imaging lenses 1 can be connected by using an adapter ring 2 with twice the flange focal length of the lens to ensure proportional detection of the imaging signal.

[0019] The wavelength cutoff points of the three dichroic mirrors 5 are 325nm, 405nm and 510nm respectively. The signal transmittance of each dichroic mirror 5 in the corresponding transmission band is higher than 99%, and the signal reflectance of the reflection band is higher than 99%. Among them, the first dichroic mirror 5 reflects the signal above 325nm and transmits the signal below 325nm. The transmission signal is used to obtain the OH-PLIF signal, and the reflection signal is incident on the second dichroic mirror 5; the second dichroic mirror 5 transmits the signal above 405nm and reflects the signal below 405nm. The reflection signal is in the range of [325nm, 405nm], which is used to obtain the kerosene PLIF signal, and the transmission signal is incident on the third dichroic mirror 5; the third dichroic mirror 5 transmits the signal above 510nm and reflects the signal below 510nm. The reflection signal is in the range of (405nm, 510nm], which is used to obtain the spontaneous radiation signal of the CH* group. The transmission signal is used to obtain the scattered signal of 532nm or 527nm laser for PIV detection.

[0020] In the PLIF and PIV technologies used for multi-parameter synchronous measurement, the laser often uses a combination of 283nm and 532nm (or 527nm). First, three sets of combustion image detection equipment need to be deployed, including: after the transmission signal of the first dichroic mirror 5, the first filter 6, the third imaging lens 1, the first image enhancement module 4 and the first detection camera 3 are sequentially arranged to obtain the OH-PLIF image, wherein the first filter 6 adopts a bandpass filter with a typical measurement specification of a central wavelength of 315nm and a half-width of 15nm, and the third imaging lens 1 is required to be an ultraviolet lens; after the reflection signal of the second dichroic mirror 5, the second filter 6, the fourth imaging lens 1, the second image enhancement module 4 and the first detection camera 3 are sequentially arranged. The second detection camera 3 is used to obtain the kerosene PLIF image, wherein the second filter 6 adopts a 325nm high-pass filter with a 405nm low-pass filter with typical measurement specifications, and the fourth imaging lens 1 is also required to be a UV lens; the third filter 6, the fifth imaging lens 1, the third image enhancement module 4 and the third detection camera 3 are arranged in sequence after the reflection signal of the third dichroic mirror 5 to obtain the spontaneous radiation image of the CH* group, wherein the third filter 6 adopts a bandpass filter with a typical measurement specification of a central wavelength of 427nm and a half-height width of 10nm. Secondly, it is necessary to deploy a set of PIV image detection equipment, including: a fourth filter 6, a sixth imaging lens 1 and a fourth detection camera 3 are arranged in sequence after the transmission signal of the third dichroic mirror 5 to obtain the PIV image. If a 532nm (or 527nm) laser is used for the PIV test, the fourth filter 6 adopts a bandpass filter with a typical measurement specification of a central wavelength of 532nm (or 527nm) and a half-width of 10nm.

[0021] In addition, if the space is limited, the position of each detection camera 3 can be adjusted by arranging a reflector 7 before and after the three dichroic mirrors 5, preferably a 45° reflector.

[0022] In actual use, it is necessary to build the framing system, including the following steps:

[0023] Step 1: Build the OH-PLIF signal acquisition device

[0024] The first two imaging lenses 1 of the same specification are connected by using an adapter ring 2 as a detection lens group, a first dichroic mirror 5 is placed 45 degrees behind the detection lens group, and an OH-PLIF signal detection device is built in the transmission direction of the first dichroic mirror 5, including a first filter 6, a third imaging lens 1, a first image enhancement module 4 and a first detection camera 3 arranged in sequence;

[0025] Step 2: Build the kerosene PLIF signal acquisition device

[0026] A second dichroic mirror 5 is placed at 45 degrees to the reflection direction of the first dichroic mirror 5, and a kerosene PLIF signal detection device is built in the reflection direction of the second dichroic mirror 5, including a second filter 6, a fourth imaging lens 1, a second image enhancement module 4 and a second detection camera 3 which are arranged in sequence;

[0027] Step 3: Construction of CH* group spontaneous emission and PIV signal acquisition device

[0028] A third dichroic mirror 5 is placed at 45 degrees to the transmission direction of the second dichroic mirror 5 (the second and third dichroic mirrors 5 are perpendicular to each other), and a CH* group spontaneous radiation signal detection device is built in the reflection direction of the third dichroic mirror 5, including a third filter 6, a fifth imaging lens 1, a third image enhancement module 4 and a third detection camera 3 arranged in sequence; a PIV signal detection device is built in the transmission direction of the third dichroic mirror 5, including a fourth filter 6, a sixth imaging lens 1 and a fourth detection camera 3 arranged in sequence.

[0029] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0030] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A framing system for synchronous measurement of multiple parameters in a combustion process, characterized in that: The invention comprises six imaging lenses (1), four detection cameras (3), three image enhancement modules (4), three dichroic mirrors (5) and four filters (6); wherein two of the imaging lenses (1) have the same specifications and are connected via an adapter ring (2) as a detection lens group for obtaining detection signals of a combustion process; the three dichroic mirrors (5) are arranged behind the detection lens group, wherein the first dichroic mirror (5) reflects signals above 325 nm and transmits signals below 325 nm, the transmission signal is used to obtain OH-PLIF signals, and the reflection signal is incident on the second dichroic mirror (5); the second dichroic mirror (5) transmits signals above 405 nm and reflects signals below 405 nm, the reflection signal is in the range of [325 nm, 405 nm], and is used to obtain kerosene PLIF signals, and the transmission signal is incident on the third dichroic mirror (5); the third dichroic mirror (5) transmits signals above 405 nm and reflects signals below 405 nm, the reflection signal is in the range of [325 nm, 405 nm], and is used to obtain kerosene PLIF signals, and the transmission signal is incident on the third dichroic mirror (5); The dichroic mirror (5) transmits signals above 510 nm and reflects signals below 510 nm, and the reflected signal is in the range of (405 nm, 510 nm], which is used to obtain the spontaneous radiation signal of the CH* group, and the transmitted signal is used to obtain the scattering signal of the 532 nm or 527 nm laser required for PIV detection; a combustion image detection device is arranged after the transmission signal of the first dichroic mirror (5), after the reflection signal of the second dichroic mirror (5), and after the reflection signal of the third dichroic mirror (5), respectively, and the combustion image detection device includes the filter (6), the imaging lens (1), the image enhancement module (4), and the detection camera (3) arranged in sequence; a PIV image detection device is arranged after the transmission signal of the third dichroic mirror (5), and the PIV image detection device includes the filter (6), the imaging lens (1), and the detection camera (3) arranged in sequence.

2. A framing system for synchronous measurement of multiple parameters in a combustion process according to claim 1, characterized in that: The positions of the corresponding detection cameras (3) can be adjusted by arranging reflective mirrors (7) before and after the three dichroic mirrors (5).

3. A framing system for synchronous measurement of multiple parameters in a combustion process according to claim 1 or 2, characterized in that: The three dichroic mirrors (5) have signal transmittances in the corresponding transmission bands and signal reflectances in the reflection bands that are higher than 99%.

4. A framing system for synchronous measurement of multiple parameters in a combustion process according to claim 1, characterized in that: The filter (6) arranged behind the transmission signal of the first dichroic mirror (5) is a bandpass filter with a typical measurement specification of a central wavelength of 315 nm and a half-width of 15 nm, and the corresponding imaging lens (1) is an ultraviolet lens.

5. The framing system for synchronous measurement of multiple parameters in a combustion process according to claim 1, characterized in that: The filter (6) arranged behind the reflection signal of the second dichroic mirror (5) adopts a typical measurement specification of a 325nm high-pass filter combined with a 405nm low-pass filter, and the corresponding imaging lens (1) is an ultraviolet lens.

6. A framing system for synchronous measurement of multiple parameters in a combustion process according to claim 1, characterized in that: The filter (6) arranged behind the reflection signal of the third dichroic mirror (5) is a bandpass filter with a typical measurement specification of a central wavelength of 427 nm and a half-width of 10 nm.

7. A framing system for synchronous measurement of multiple parameters in a combustion process according to claim 1, characterized in that: The filter (6) arranged after the transmission signal of the third dichroic mirror (5) is a bandpass filter with a typical measurement specification of a central wavelength of 532nm or 527nm and a half-width of 10nm according to requirements.

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