Water-based monopropellant fuel droplet combustion behavior three-dimensional diagnosis device

Abstract

The invention provides a water-based single-component fuel droplet combustion behavior three-dimensional diagnosis device, and relates to the technical field of combustion diagnos.The water-based single-component fuel droplet combustion behavior three-dimensional diagnosis device comprises a fuel dripping system, a data acquisition system and a temperature control system.Single droplet dripping is controlled by the fuel dripping system, and the temperature of a metal plate is controlled by the temperature control system; when water-based single-component fuel liquid drops are dropwise added to a metal plate and are heated and ignited, temperature changes in the whole process are recorded by a thermocouple of a data acquisition system, a high-speed camera shoots and records liquid drop combustion images, an infrared spectrometer acquires infrared spectrums of combustion gas products in real time, and the infrared spectrums of the combustion gas products are calculated. The real-time acquisition of the temperature change, the combustion image and the infrared spectrum of the combustion gas product in the combustion process of the water-based single-component fuel liquid drop is realized.

Description

Technical Field

[0001] This invention relates to the field of combustion diagnostics technology, and more specifically, to a three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets. It is a multi-parameter synchronous sampling device for droplet combustion that integrates microsecond-level time-resolved temperature measurement, image acquisition, and infrared spectral acquisition and analysis, and is suitable for studying the combustion characteristics of single droplets under normal pressure. Background Technology

[0002] A fuel droplet combustion behavior diagnostic device is a device that can simultaneously acquire images, temperature, and infrared spectral signals of combustion products during droplet combustion. Since the droplet combustion process lasts only a few seconds, the time resolution for image, temperature, and infrared spectrum acquisition must be at the millisecond level. By comprehensively analyzing the combustion images, temperature, and infrared spectral data of water-based monocomponent fuel droplets from various formulations using this device, the minimum ignition temperature of the corresponding fuel formulation, as well as the ignition response delay time (i.e., the time from droplet contact with the hot metal plate to the droplet generating a flame), combustion time (the time from the appearance of the flame blade to its extinguishing), and types of combustion products at different temperatures can be obtained.

[0003] Water-based monocomponent fuel is a novel high-energy monocomponent fuel containing energetic ionic liquids. It features high energy density, rapid and stable decomposition, no solid residue after combustion, clean fuel, low fuel characteristic signal, and low toxicity. Water-based monocomponent fuel typically consists of an oxidant, a propellant, water as a solvent, and additives, and can sustain combustion in oxygen-free environments such as space or underwater. Common oxidant components include hydroxylamine nitrate (HAN), ammonium dinitrate (ADN), and hydrogen peroxide (H2O2); common propellants include triethanolamine nitrate (TEAN), N,N-diethylhydroxylamine nitrate (DEHAN), hydrazine nitrate (HN), ethylhydrazine nitrate (EHN), hydroxyethylhydrazine nitrate (HEHN), ammonium nitrate (AN), ammonia (AH), and methanol (MeOH); surfactants include sodium dodecylbenzenesulfonate (SDBS), sodium dodecyl sulfate (SDS), hexadecyltrimethylammonium bromide (CTAB), and sodium allyl sulfonate (ALS); and common additives include nitrogen-containing heterocyclic organic base pH adjusters. Typical water-based monocomponent fuels include AF-M315E (main components are 44.5% HAN, 44.5% HEHN, and 11% water), SHP-163 (main components are 73.6% HAN, 16.3% methanol, 3.9% AN, and 6.2% water), and ADN-LMP103S (main components are 63% ADN, 18.4% methanol, and 18.6% ammonia solution).

[0004] In contrast, the most typical oil-based monocomponent fuel is OTTO-II type fuel, whose main components are 76% propylene glycol dinitrate (PGDN, as an energy agent), 22.5% dibutyl sebacate (DBS, as a diluent), and 1.5% 2-nitroaniline (2-NPA, as a stabilizer). The single-droplet combustion of oil-based monocomponent fuels is similar to that of ordinary oil-based fuels (gasoline, diesel), primarily involving gas-phase combustion. During combustion, the droplet surface first vaporizes to generate gas, which then burns on the droplet surface. As combustion progresses, the droplet gradually shrinks. Therefore, oil-based monocomponent fuels are generally easy to ignite and have relatively stable combustion.

[0005] In contrast, water-based monocomponent fuels, due to their water solvent, generate a large amount of water vapor on the droplet surface upon heating. Since water vapor is non-combustible and water has a high latent heat of vaporization, a single droplet needs to absorb a significant amount of heat before combustion. As the water-based monocomponent fuel droplet evaporates and concentrates, the entire droplet absorbs heat and heats up. When the temperature reaches the decomposition temperature, the entire liquid decomposes instantaneously, releasing a large amount of heat. Therefore, the droplet combustion mechanism of water-based monocomponent fuels differs fundamentally from that of oil-based monocomponent fuels. Because water vaporization involves rapid heat absorption and release, water-based monocomponent fuels are more difficult to ignite and sustain. Therefore, studying the evaporation-concentration-decomposition-combustion process of water-based monocomponent fuel droplets is of great significance for their engineering applications.

[0006] However, there are currently few reports on devices for diagnosing the combustion behavior of droplet fuels. Ao Wen et al. from Northwestern Polytechnical University reported a high-temperature, high-pressure, multi-atmosphere single-droplet combustion test device (CN113391022A). This device mainly provides the atmosphere and high pressure, igniting single droplets through an automatic droplet generation device and a U-shaped ignition plate, but lacks real-time acquisition equipment for temperature, images, and infrared spectra. Huang Ronghua et al. from Huazhong University of Science and Technology reported a three-dimensional reconstruction method and experimental device for flame temperature in single-droplet combustion (CN110608889B). This device uses spark plug ignition, a fiber optic imaging bundle, an optical lens system, and a high-speed camera to primarily acquire images and temperature information; it uses spark ignition, a blackbody furnace to calibrate the temperature, and an algorithm to reconstruct the three-dimensional flame temperature field.

[0007] However, existing devices for diagnosing the combustion behavior of droplet fuels lack the ability to simultaneously acquire temperature, images, and infrared spectra in real time with millisecond-level time resolution. They cannot accurately capture key parameters of the transient combustion process (such as minimum ignition temperature, ignition response delay, and combustion time), and they lack sufficient measurement of species information of combustion products. In particular, they are unable to meet the requirements for formulation screening and optimization of water-based monocomponent fuels (which do not require an external oxygen source). Summary of the Invention

[0008] To address the aforementioned technical problems of droplet fuel combustion behavior diagnostic devices lacking millisecond-level temporal resolution for simultaneous real-time acquisition of temperature, image, and infrared spectra, thus failing to accurately capture key parameters of the transient combustion process and providing insufficient measurement of combustion product species information, this invention provides a three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets. This invention mainly consists of a fuel dripping system, a data acquisition system, and a temperature control system. It can perform real-time acquisition and recording of temperature changes, combustion images, and infrared spectra of combustion gas products during the few seconds it takes for water-based monocomponent fuel droplets to be heated and ignited.

[0009] The technical means employed in this invention are as follows: A three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets includes a fuel dripping system, a data acquisition system, and a temperature control system. The fuel dripping system controls the single-droplet addition, while the temperature control system controls the temperature of a metal plate. When the water-based monocomponent fuel droplets are added to the metal plate, they are heated and ignited. The temperature changes throughout the process are recorded by thermocouples in the data acquisition system, the droplet combustion images are captured by a high-speed camera, and the infrared spectra of the combustion gas products are acquired in real time by an infrared spectrometer. This enables real-time acquisition of temperature changes, combustion images, and the infrared spectra of combustion gas products during the combustion process of the water-based monocomponent fuel droplets.

[0010] Furthermore, the fuel dripping system includes a fixed bracket, a clamp, and a syringe. The syringe is fixed to the fixed bracket by the clamp. The angle between the syringe and the vertical direction is less than 15°, and the distance between the syringe tip and the metal plate is 1cm to 10cm.

[0011] Furthermore, the temperature control system includes an electric heating furnace, a metal plate, and a temperature measuring thermocouple. The electric heating furnace is positioned below the metal plate to heat it. The thermocouple is a type K armored thermocouple with a diameter ≤0.5mm. The measuring end of the thermocouple is fixed to the center of the metal plate by forming a spherical structure through laser welding. The thermocouple is configured to collect temperature data at a frequency of ≥500Hz and transmit it to a computer via direct storage access.

[0012] Furthermore, the data acquisition system includes an infrared spectrometer, a high-speed camera, and a temperature acquisition module. The high-speed camera is fixed on the fixed bracket to record images of droplet combustion. The high-speed camera has a shooting frequency of ≥500Hz and an image size of ≥640×480.

[0013] Furthermore, the sampling resolution of the infrared spectrometer is ≥1 cm. -1 .

[0014] Furthermore, the temperature acquisition module is fixed on the fixed bracket and connected to the thermocouple. The computer is connected to the infrared spectrometer, the high-speed camera, and the temperature acquisition module respectively, for recording and storing data.

[0015] Furthermore, the device also includes a spotlight and a lifting platform. The spotlight is rotatably mounted on a fixed bracket to provide supplemental lighting for the high-speed camera. The electric heating furnace is located above the lifting platform. When the temperature of the metal plate reaches a preset value, the electric heating furnace is moved away by the lifting platform to avoid the influence of the high-temperature heating wire on the metal plate.

[0016] Furthermore, the water-based monocomponent fuel is mainly composed of an oxidant, a propellant, and water as a solvent.

[0017] Furthermore, the oxidant is one or more of hydroxylamine nitrate, dinitramide ammonium, and hydrogen peroxide.

[0018] Further, the combustion agent is one or more mixtures selected from triethanolamine nitrate, N,N-diethylhydroxylamine nitrate, hydrazine nitrate, ethylhydrazine nitrate, hydroxyethylhydrazine nitrate, ammonium nitrate, hydrazine, and methanol.

[0019] Compared with the prior art, the present invention has the following advantages: This invention relates to a diagnostic device for the droplet combustion behavior of water-based monocomponent fuels, designed to address the droplet combustion characteristics of these fuels. Besides acquiring temperature and image information with millisecond-level time resolution, it also acquires infrared spectral information to measure combustion product species. Furthermore, taking advantage of the characteristics of water-based monocomponent fuels (which require no external oxygen source), this device can calculate the minimum ignition temperature, ignition response delay time at different temperatures, combustion time, and combustion product types of different water-based monocomponent fuel formulations based on images acquired by a high-speed camera and the acquisition frequency.

[0020] The device of this invention has the ability to simultaneously acquire images, temperatures, and infrared signals of single-droplet combustion of water-based monocomponent fuels. Furthermore, by analyzing the image signals, it can measure parameters crucial for screening water-based monocomponent fuel formulations, such as ignition response time and droplet combustion cycle. By analyzing the temperature curves, water-based monocomponent fuel formulations that easily achieve self-sustaining combustion can be screened. By analyzing the combustion products, the oxygen-fuel ratio of the water-based monocomponent fuel formulation can be optimized. Attached Figure Description

[0021] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A schematic diagram of a three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets.

[0023] Figure 2 Images were acquired during the ignition and combustion cycle of water-based monocomponent fuel droplets, with an acquisition frequency of 2000 Hz.

[0024] Figure 3 This is a graph showing the temperature variation during the combustion cycle of the water-based single-component fuel droplets of the present invention.

[0025] Figure 4 The infrared spectra of the combustion products of water-based monocomponent fuel droplets are shown in (a) as the background signal; (b) as a typical infrared spectrum of water-based monocomponent fuel; and (c) as an infrared spectrum of another water-based monocomponent fuel formulation.

[0026] In the diagram: 1. Infrared spectrometer; 2. Fixed bracket; 3. Lifting platform; 4. Electric heating furnace; 5. Metal plate; 6. Thermocouple; 7. Spotlight; 8. Syringe; 9. Temperature acquisition module; 10. High-speed camera; 11. Computer. Detailed Implementation

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0031] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0032] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0033] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0034] like Figure 1 As shown, the present invention provides a three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets, which consists of three parts: a water-based monocomponent fuel dripping system, a heating and temperature control system, and a data acquisition system. The device can collect and record in real time the temperature changes, combustion images, and spectra of combustion gas products during the combustion process within a few seconds when the water-based monocomponent fuel droplets are heated and ignited.

[0035] Figure 1 This is a schematic diagram of a three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets. The device includes: an infrared spectrometer 1, capable of acquiring infrared spectra of combustion gas products in microseconds; a fixed bracket 2, used to secure a spotlight 7, syringe 8, metal plate 5, and high-speed camera 10; a lifting platform 3, used to remove the electric heating furnace 4 when the temperature of the metal plate 5 reaches a preset value, preventing the high-temperature heating wires from affecting the metal plate 5; the electric heating furnace 4, used to control the heating of the metal plate 5 to a specified temperature; the metal plate 5, used to heat and ignite the fuel droplets; a thermocouple 6, fixed in the center of the metal plate 5, used to collect temperature information during the fuel droplet combustion process; a spotlight 7, used to provide supplementary lighting for the high-speed camera 10; a syringe 8, used to control the individual drops of fuel added to the metal plate 5; a temperature recording module 9, used to store and record the temperature information of the thermocouple 6; a high-speed camera 10, used to capture images of the fuel droplet combustion; and a computer 11, used to control the infrared spectrometer 1, the high-speed camera 10, and the temperature recording module 9.

[0036] The data acquisition system can simultaneously acquire three signals: temperature, image, and infrared spectrum. Thermocouple 6 is a type K armored thermocouple 6; combustion image is captured by a high-speed camera 10; and infrared spectrum is captured by a time-resolved infrared spectrometer 1. The sampling frequencies for temperature, combustion image, and infrared spectrum are all ≥500Hz; the high-speed camera 10 has a frequency ≥500Hz and an image size ≥640×480; the infrared spectrometer 1 has a sampling resolution ≥1cm. -1 .

[0037] The fuel dripping system consists of a fixed bracket 2, a clamp, and a syringe 8, which can adjust the dripping position, angle, and height; the angle between the syringe 8 and the vertical direction is <15°; the distance between the syringe tip and the metal plate 5 is 1cm~10cm.

[0038] The temperature control system consists of an electric heating furnace 4, a metal plate 5, and a temperature measuring thermocouple 6. The temperature control accuracy is not less than ±0.5℃. The thermocouple 6 is a K-type armored thermocouple with a diameter of less than or equal to 0.5mm. Its measuring end is formed into a spherical structure by laser welding and fixed to the center of the metal plate 5. It is configured to collect temperature data at a frequency of ≥500Hz and transmit it to the storage computer 11 through direct memory access (DMA).

[0039] Water-based single-component fuel mainly consists of an oxidant, a propellant, and water as a solvent. The oxidant is one or more of hydroxylamine nitrate, ammonium dinitrate, and hydrogen peroxide; the propellant is one or more of triethanolamine nitrate, N,N-diethylhydroxylamine nitrate, hydrazine nitrate, ethylhydrazine nitrate, hydroxyethylhydrazine nitrate, ammonium nitrate, hydrazine, and methanol.

[0040] Example 1 like Figure 1-4 As shown, this invention provides a three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets. First, an electric heating furnace 4 heats a metal plate 5 to the required temperature. Then, a lifting platform 3 lowers the electric heating furnace away from the metal plate 5 to avoid the influence of the high-temperature heating element on ignition. Next, water-based monocomponent fuel is added dropwise to the surface of the metal plate 5 using a syringe 8, while simultaneously acquiring data on temperature, high-speed imaging, and infrared spectroscopy. The ignition response time and combustion time of the water-based fuel at different temperatures are calculated using the high-speed imaging images; the types of combustion products are determined using the infrared spectroscopy.

[0041] Figure 2 The image shows a high-speed camera image of a water-based monocomponent fuel, with a sampling frequency of 2000 Hz. It can be seen that after the fuel droplets contact the metal plate 5, the droplets first heat up, then the water evaporates, and the droplets concentrate and become smaller. The flame appears at 9258 ms. Therefore, the ignition response time of the water-based monocomponent fuel of this formulation is 9258 ms.

[0042] Figure 3 The figure shows the temperature curve corresponding to the combustion process of water-based monocomponent fuel droplets. As can be seen from the figure, the initial temperature (i.e., ignition temperature) of metal plate 5 is also 300.0℃. After the droplets come into contact with metal plate 5, there is a significant cooling behavior. The lowest temperature of metal plate 5 reaches 279.7℃, and the temperature drops by 20℃. Subsequently, the water-based monocomponent fuel begins to partially decompose and release heat, and the temperature rises slightly. At 9361ms, the droplets are ignited, and the temperature of metal plate 5 rises rapidly to a maximum of 655.4℃, and then falls back quickly.

[0043] Figure 4 This is the infrared spectrum of the combustion products of water-based monocomponent fuel droplets. Figure 4 (a) is the background signal at 3200cm. -1 Up to 3600cm -1 Within the range, there is a broad and strong hydroxyl association peak, which is the OH stretching vibration peak, at 1600 cm⁻¹. -1 -1700cm -1 The moderate-intensity peaks are visible, representing the bending vibration peaks of the OH group; these two OH peaks correspond to water vapor in the air. At 2350 cm⁻¹ -1 The C=O symmetric stretching vibration peak can be observed at 667 cm⁻¹. -1 We can see the C=O asymmetric stretching vibration peaks; these correspond to CO2 gas in the air.

[0044] Figure 4 (b) is a typical infrared spectrum of a water-based single-component fuel. The spectrum shows that at 3200 cm⁻¹... -1 Up to 3600cm -1 Range of hydroxyl association peak and 1600 cm -1 -1700cm -1 The bending vibration peak of OH is slightly enhanced; these two OH peaks correspond to water vapor in the droplet combustion products; at 2334 cm⁻¹ -1 2353cm -1 The C=O symmetric stretching vibration peak can be observed at 668 cm⁻¹. -1 We can observe the C=O asymmetric stretching vibration peaks; these peaks are significantly enhanced, corresponding to the CO2 gas produced by the combustion of fuel droplets; at 2117 cm⁻¹... -1 and 2166cm -1 At 3016 cm⁻¹, a relatively strong C=O stretching vibration peak appeared, corresponding to CO in the droplet combustion products; at 3016 cm⁻¹... -1 The peak at 1304 cm⁻¹ represents the CH stretching vibration peak. -1The peak at this location corresponds to the CH bending vibration, which is a CH4 gaseous product. The above analysis shows that although water vapor and CO2 are present in the background air, the peak intensities corresponding to water vapor and CO2 increase significantly after fuel combustion, indicating the presence of these two gaseous products in the combustion products. Furthermore, characteristic peaks for CO and CH4 were observed, confirming that these gases are also included in the combustion products.

[0045] Figure 4 (c) is the infrared spectrum of another water-based single-component fuel formulation. From the figure, it can be seen that at 3200 cm⁻¹... -1 Up to 3600cm -1 Range of hydroxyl association peak and 1600 cm -1 -1700cm -1 The bending vibration peaks of OH are slightly different from those at these two locations, which correspond to water vapor in the droplet combustion products; at 2340 cm⁻¹ -1 2361cm -1 The peak is a C=O symmetrical stretching vibration peak at 670 cm⁻¹. -1 These are C=O asymmetric stretching vibration peaks, and these peaks are significantly enhanced, corresponding to CO2 gas produced by the combustion of fuel droplets; at 2234 cm⁻¹ -1 2210cm -1 The peak represents the antisymmetric stretching vibration of the NNO bond; 1298 cm⁻¹ -1 1268cm -1 The peaks represent the symmetrical stretching vibrations of N2O, confirming the presence of N2O gaseous products in the droplet combustion products.

[0046] From the above Figures 2-4 As can be seen, the device of the present invention has the ability to simultaneously acquire images, temperatures, and infrared signals of single-droplet combustion of water-based monocomponent fuels. Furthermore, by analyzing the image signals, it can measure parameters crucial for screening water-based monocomponent fuel formulations, such as ignition response time and droplet combustion cycle. By analyzing the temperature curves, water-based monocomponent fuel formulations that easily achieve self-sustaining combustion can be screened. By analyzing the combustion products, the oxygen-fuel ratio of the water-based monocomponent fuel formulation can be optimized. In summary, the device of the present invention can optimize the design of water-based monocomponent fuel formulations from multiple aspects.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A three-dimensional diagnostic device for the combustion behavior of water-based single-component fuel droplets, characterized in that, The system includes a fuel dripping system, a data acquisition system, and a temperature control system. The fuel dripping system controls the single-droplet addition, while the temperature control system controls the temperature of the metal plate. When water-based monocomponent fuel droplets are added to the metal plate, they are heated and ignited. The temperature changes throughout the process are recorded by thermocouples in the data acquisition system, images of the droplet combustion are captured by a high-speed camera, and the infrared spectra of the combustion gas products are acquired in real time by an infrared spectrometer. This enables real-time acquisition of temperature changes, combustion images, and the infrared spectra of combustion gas products during the combustion process of water-based monocomponent fuel droplets.

2. The three-dimensional diagnostic device for the combustion behavior of water-based single-component fuel droplets according to claim 1, characterized in that, The fuel dripping system includes a fixed bracket, a clamp, and a syringe. The syringe is fixed to the fixed bracket by the clamp. The angle between the syringe and the vertical direction is less than 15°, and the distance between the syringe tip and the metal plate is 1cm to 10cm.

3. The three-dimensional diagnostic device for the combustion behavior of water-based single-component fuel droplets according to claim 1, characterized in that, The temperature control system includes an electric heating furnace, a metal plate, and a temperature measuring thermocouple. The electric heating furnace is located below the metal plate to heat the metal plate. The thermocouple is a type K armored thermocouple with a diameter ≤0.5mm. The measuring end of the thermocouple is fixed to the center of the metal plate by forming a spherical structure through laser welding. The thermocouple is configured to collect temperature data at a frequency of ≥500Hz and transmit it to a computer through direct storage access.

4. The three-dimensional diagnostic device for the combustion behavior of water-based single-component fuel droplets according to claim 2, characterized in that, The data acquisition system includes an infrared spectrometer, a high-speed camera, and a temperature acquisition module. The high-speed camera is fixed on the fixed bracket to record images of droplet combustion. The high-speed camera has a shooting frequency of ≥500Hz and an image size of ≥640×480.

5. The three-dimensional diagnostic device for the combustion behavior of water-based single-component fuel droplets according to claim 4, characterized in that, The sampling resolution of the infrared spectrometer is ≥1cm. -1 .

6. The three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets according to claim 4, characterized in that, The temperature acquisition module is fixed on the fixed bracket and connected to the thermocouple. The computer is connected to the infrared spectrometer, the high-speed camera and the temperature acquisition module respectively, for recording and storing data.

7. The three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets according to claim 4, characterized in that, The device also includes spotlights and a lifting platform. The spotlights are rotatably mounted on a fixed bracket to provide supplemental lighting for the high-speed camera. The electric heating furnace is located above the lifting platform. When the temperature of the metal plate reaches a preset value, the electric heating furnace is moved away by the lifting platform to avoid the high-temperature heating wires affecting the metal plate.

8. The three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets according to claim 1, characterized in that, The water-based single-component fuel mainly consists of an oxidant, a fuel, and water as a solvent.

9. The three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets according to claim 8, characterized in that, The oxidant is one or more of hydroxylamine nitrate, ammonium dinitrate, and hydrogen peroxide.

10. The three-dimensional diagnostic device for the combustion behavior of water-based monocomponent fuel droplets according to claim 8, characterized in that, The propellant is one or a mixture of triethanolamine nitrate, N,N-diethylhydroxylamine nitrate, hydrazine nitrate, ethylhydrazine nitrate, hydroxyethylhydrazine nitrate, ammonium nitrate, hydrazine, and methanol.

Images