Swirl flow fluid burner based on non-equilibrium plasma chemical reaction power

Abstract

The application discloses a swirl fluid combustor based on non-equilibrium plasma chemical reaction power, and relates to the technical field of combustion equipment. The application comprises the following steps: constructing a non-equilibrium plasma DBD activation combustion experiment system; adjusting the swirl angle through a variable-angle blade type swirl generator; measuring the OH, NH* free radical fluorescence signal intensity and distribution by using a laser-induced fluorescence excitation unit and an ICCD imaging camera; detecting NO x emission concentration by using a flue gas analyzer; constructing a ChemPlasKin and Cantera two-stage simulation model, and bidirectional closed-loop verification with experimental data. The application adopts the above combustor to improve the hydrogen / ammonia combustion performance and effectively reduce the NO x emission (DBD=8kV, φ =0.7, the angle is from 80° to 20°, and the NO x emission is reduced by 74%. The results have important guiding significance for the NO x emission control and prediction of zero-carbon combustion equipment such as an aero-engine and a gas turbine.

Description

Technical Field

[0001] This invention relates to the field of combustion equipment technology, and in particular to a swirling fluid burner based on non-equilibrium plasma chemical reaction dynamics. Background Technology

[0002] To address climate change caused by greenhouse gas emissions, the international community has reached a series of consensuses on accelerating energy structure transformation. my country's "Regulations on the Certification of Civil Aviation Products and Components" (CCAR-34) aligns with international airworthiness requirements. GB 13271-2014 "Emission Standard of Air Pollutants for Boilers" and GB 13223-2011 "Emission Standard of Air Pollutants for Thermal Power Plants" stipulate that the NOx emission limit for both gas-fired boilers and gas turbine units shall not exceed 50 mg / m³. 3 At the international level, the European Union issued the Industrial Emissions Directive (IED 2.0), which sets a medium-term target of reducing net greenhouse gas emissions by 90% from 1990 levels by 2040; the U.S. National Aeronautics and Space Administration (NASA) has also clearly stated its strategic goal of achieving net-zero emissions in the aviation sector by 2050.

[0003] Meanwhile, the global clean ammonia market is experiencing explosive growth. According to industry research reports, the global clean ammonia and synthetic fuel market size was approximately US$24.5 billion in 2025 and is projected to grow to US$98.55 billion by 2032, representing a compound annual growth rate of 22.0%. Against this backdrop, ammonia (NH3) and hydrogen (H2) have attracted widespread attention as zero-carbon fuels. Mixing ammonia and hydrogen in a certain proportion forms the NH3 / H2 binary fuel. However, systematic research on this binary fuel under controlled combustion conditions is currently very limited, particularly regarding NO under different swirl intensities, equivalence ratios, and plasma-assisted combustion conditions. x Quantitative data on the generation patterns are extremely scarce in publicly available literature. Regarding the NH3 / H2 binary fuel system, previous work has almost entirely focused on the control effects of scalar parameters such as equivalence ratio, pressure, inlet temperature, and premixing degree. However, a systematic understanding of the mechanism behind swirl intensity, a core vector parameter that determines flow field structure, mixing characteristics, and flame residence time, remains lacking. The few studies involving swirl only use swirl number as an auxiliary variable for macroscopic emission comparisons, and their analytical depth stops at "swirl can reduce NO." x The qualitative description of NO fails to distinguish the relative contribution evolution of fuel-based NO and thermal NO at different swirl numbers, and also fails to establish a quantitative correlation between swirl changes and competition for key elementary reaction pathways. A deeper problem lies in the fact that changes in swirl angle fundamentally reshape the flame topology, transforming it from an attached flame to a raised flame, and from combustion to conventional diffusion combustion. This topological transformation is accompanied by the spatial redistribution of key free radicals such as OH, NH2, and NHI, and it is precisely this redistribution that determines the NO...x The core competing pathways are the inverse relationship between NH2 + NO ⇔ NNH + OH (promoting NO reduction) and NH + NO ⇔ N2O + H (promoting NO formation). However, to date, few published studies have revealed, from the perspective of elementary reaction kinetics, how swirling-induced flow field distortion intervenes in the threshold of the aforementioned competing reactions by altering local strain rates and residence time in the recirculation zone. Even more regrettably, while a few CFD studies have attempted to incorporate the swirling effect, their simplified combustion models fail to capture the impact of swirling breaking vortices on flame stretching and local quenching, and cannot distinguish the essential differences in turbulent-chemical interactions under the extreme conditions of weak and strong swirling. It can be said that the mechanism by which the swirling angle regulates the NO formation pathway in the NH3 / H2 flame remains a "black box"—lacking both systematic experimental data calibration and reliable numerical model description. This has become the most critical knowledge gap restricting the engineering design of low-emission burners for this fuel system.

[0004] In simulation studies, most current work uses zero-dimensional homogeneous reaction kinetics software such as Cantera for combustion mechanism analysis, which can predict ignition delay, laminar flame velocity, and NO₂ well. x While these methods can simulate emission trends, they inherently assume a homogeneous reaction system and fail to capture the effects of strongly anisotropic turbulence, recirculation structure, and flame folds on the flow-chemical reaction coupling within the swirling field. A few studies have attempted to combine Cantera with CFD, simulating the flow field and emission characteristics of swirling combustors by coupling chemical solvers with Reynolds-averaged Navier-Stokes (RANS) or Large Eddy Simulation (LES). However, such couplings often employ simplified or reduced-order chemical models, and the description of plasma activation effects is still in its early stages. Regarding the coupling simulation of non-equilibrium plasma chemical dynamics with swirling combustion, although there are international advancements such as the development of zero-dimensional plasma-gas dynamics solvers like ChemPlasKin, and a unified framework coupling Boltzmann equation solvers with reactive flow CFD, their applications are primarily focused on ignition and combustion mechanisms under homogeneous mixtures or simple geometric conditions. There are no publicly reported studies coupling DBD non-equilibrium plasma pre-activation, detailed free radical generation paths, and the three-dimensional flow field of the swirling combustor. This gap is precisely what this paper aims to fill.

[0005] In summary, there is an urgent need to investigate the synergistic effect of DBD nonequilibrium plasma and swirl angle on NO in the NH3 / H2 binary fuel system. xThe influence mechanism of the generation path is revealed by focusing on the coupling mechanism between plasma dissociating fuel molecules through high-energy electron collisions and regulating the competition of OH / NH2 free radicals, and the swirling field changing the flame topology and residence time of active particles. The ChemPlasKin-Cantera two-stage coupled simulation method is developed to fill the gap in the coupled simulation of non-equilibrium plasma activation and three-dimensional swirling combustion field. Summary of the Invention

[0006] The purpose of this invention is to provide a swirling fluid burner based on non-equilibrium plasma chemical reaction dynamics, thereby solving the problems existing in the prior art.

[0007] To achieve the above objectives, this invention provides a swirling fluid burner based on non-equilibrium plasma chemical reaction dynamics, including a mixed gas input unit. The mixed gas generated by the mixed gas input unit is transported to a dielectric barrier discharge reactor, where non-equilibrium plasma is generated to activate the mixed gas. The top outlet of the dielectric barrier discharge reactor is sealed and connected to a swirling combustion unit, which is used to convert the axial flow of the activated mixed gas into swirling flow, forming a strong swirling field for combustion. A laser-induced fluorescence excitation unit is provided on one side of the swirling combustion unit, with its emitting end facing the swirling combustion unit. It emits a laser beam of a specific wavelength to excite OH free radicals in the flame of the swirling combustion unit to generate characteristic fluorescence signals. An imaging camera and a flue gas analyzer are provided on the other side of the swirling combustion unit. The lens of the imaging camera is facing the swirling combustion unit to detect the fluorescence signal of OH free radicals and to image them. The signal output terminals of the flue gas analyzer, the dielectric barrier discharge reactor, and the imaging camera are all electrically connected to the signal input terminal of an experimental data acquisition computer.

[0008] Preferably, the mixed gas input unit includes a hydrogen cylinder, an ammonia cylinder, and an air cylinder. The outlets of the hydrogen cylinder, ammonia cylinder, and air cylinder are respectively connected to a hydrogen mass flow controller, an ammonia mass flow controller, and an air mass flow controller. The outlets of the hydrogen mass flow controller, ammonia mass flow controller, and air mass flow controller are sealed and connected to the bottom air inlet of the dielectric barrier discharge reactor through a gas manifold.

[0009] Preferably, the dielectric barrier discharge reactor adopts a coaxial dielectric barrier discharge structure, which contains a quartz dielectric tube. The outer wall of the quartz dielectric tube is covered with a high-voltage electrode, and a low-voltage electrode is coaxially arranged inside. The high-voltage electrode and the low-voltage electrode form an alternating electric field under the drive of the plasma excitation power supply, thereby generating non-equilibrium plasma, and realizing the activation treatment of the mixed gas through high-energy electron collision.

[0010] Preferably, the high-voltage electrode is electrically connected to the high-voltage output terminal of the plasma excitation power supply, the low-voltage electrode is electrically connected to the low-voltage terminal and the ground terminal of the plasma excitation power supply, and the signal output terminal of the plasma excitation power supply is electrically connected to a discharge parameter monitoring oscilloscope for real-time monitoring of the discharge voltage and current waveforms of the plasma excitation power supply.

[0011] Preferably, the swirl combustion unit includes a swirl burner, a swirl generator, and a main combustion chamber. The inlet of the swirl burner is sealed and connected to the top outlet of the dielectric barrier discharge reactor, and the nozzle of the swirl burner extends into the interior of the main combustion chamber to deliver the activated swirl mixed gas to the main combustion chamber. The swirl generator is fixedly integrated in the internal airflow channel of the swirl burner to apply tangential momentum to the activated mixed gas, converting axial flow into swirl flow and forming a strong swirl field. The main combustion chamber provides a sealed and stable reaction space for the combustion reaction.

[0012] Preferably, the side wall of the main combustion chamber is provided with an optical observation window to provide an optical path for laser incident and fluorescence signal acquisition. The exhaust port of the main combustion chamber is sealed and connected to the sampling end of the flue gas analyzer to detect the concentration of nitrogen oxides in the exhaust gas at the exhaust port of the main combustion chamber in real time.

[0013] Preferably, the laser-induced fluorescence excitation unit includes a YAG exciter, a dye laser, and an optical focusing lens group. The output optical paths of the YAG exciter and the dye laser are arranged coaxially with the optical focusing lens group after optical path adjustment. The YAG exciter, the dye laser, and the optical focusing lens group work together to form a laser-induced fluorescence excitation source, emitting a laser beam of a specific wavelength to excite OH free radicals in the flame region of the main combustion chamber to generate characteristic fluorescence signals. The laser beam enters the flame core region inside the main combustion chamber through the optical observation window.

[0014] Preferably, the imaging camera is an ICCD imaging camera, which is positioned directly opposite the optical observation window, and the lens axis of the ICCD imaging camera intersects perpendicularly with the laser incident light path in the core region of the flame.

[0015] Preferably, the signal output terminal of the flue gas analyzer, the operating condition signal output terminal of the plasma excitation power supply, and the image signal output terminal of the ICCD imaging camera are all electrically connected to the signal input terminal of the experimental data acquisition computer. The experimental data acquisition computer is used to synchronously acquire and store nitrogen oxide concentration, plasma discharge operating condition parameters, and OH free radical fluorescence image parameter data, providing complete experimental data support for combustion mechanism analysis and model verification.

[0016] Therefore, the present invention employs the above-mentioned swirling fluid burner based on non-equilibrium plasma chemical reaction dynamics, which has the following beneficial effects: (1) Improved combustion performance: The combustion performance of hydrogen / ammonia fuel was significantly improved through the synergistic effect of non-equilibrium plasma and swirling flow field; (2) Effective reduction of nitrogen oxide emissions: By regulating the competitive pathways of OH radicals and NH2 radicals, combined with the swirling-induced double-flame structure, effective reduction of nitrogen oxide emissions was achieved; (3) Accurate prediction of combustion process under plasma action was achieved by using the coupled simulation method of Chemplaskin and Cantera; (4) An equivalent substitution relationship between plasma discharge voltage and hydrogen mixing ratio in improving combustion intensity was discovered, providing a new path for efficient combustion under low hydrogen mixing ratio conditions; (5) Real-time, in-situ observation of key active free radicals during combustion was achieved through the OH-PLIF laser-induced fluorescence system.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the swirling fluid burner based on non-equilibrium plasma chemical reaction dynamics of the present invention; Figure 2 This is a schematic diagram of the dielectric barrier discharge reactor of the present invention; Figure 3 This is a schematic diagram of the vortex generator of the present invention; Figure 4 This is a technical roadmap of an embodiment of the present invention; Figure 5 This is a flowchart of the two-stage simulation using Chemplaskin and Cantera in an embodiment of the present invention. Figure 6 Embodiment NO of the present invention x A comparison of experimental and simulation results showing the evolution of plasma voltage variation; Figure 7 The diagram shows the experimental evolution of free radicals as a function of plasma voltage in an embodiment of the present invention, where (a) represents OH and (b) represents NH2. Figure 8 This is a chemical reaction pathway analysis diagram of OH free radicals as a function of plasma voltage in an embodiment of the present invention; Figure 9 This is a chemical reaction pathway analysis diagram of NH2 free radicals as a function of plasma voltage in an embodiment of the present invention; Figure label: 1. Hydrogen cylinder; 2. Ammonia cylinder; 3. Air cylinder; 4. Hydrogen mass flow controller; 5. Ammonia mass flow controller; 6. Air mass flow controller; 7. Gas manifold; 8. Dielectric barrier discharge reactor; 9. Quartz dielectric tube; 10. High-voltage electrode; 11. Low-voltage electrode; 12. Plasma excitation power supply; 13. Discharge parameter monitoring oscilloscope; 14. Swirl burner; 15. Swirl generator; 16. Main combustion chamber; 17. Optical observation window; 18. YAG exciter; 19. Dye laser; 20. Optical focusing lens group; 21. ICCD imaging camera; 22. Flue gas analyzer; 23. Experimental data acquisition computer. Detailed Implementation

[0019] The following detailed description of embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0020] Please see Figures 1-3 The swirling fluid burner based on non-equilibrium plasma chemical reaction dynamics includes a hydrogen cylinder 1, an ammonia cylinder 2, and an air cylinder 3. The outlet of the hydrogen cylinder 1 is sealed to the inlet of the hydrogen mass flow controller 4, the outlet of the ammonia cylinder 2 is sealed to the inlet of the ammonia mass flow controller 5, and the outlet of the air cylinder 3 is sealed to the inlet of the air mass flow controller 6. The outlets of the hydrogen mass flow controller 4, the ammonia mass flow controller 5, and the air mass flow controller 6 are all connected to the inlet of the gas manifold 7, and the outlet of the gas manifold 7 is sealed to the bottom air inlet of the dielectric barrier discharge reactor 8.

[0021] The dielectric barrier discharge reactor 8 adopts a coaxial dielectric barrier discharge structure, with a quartz dielectric tube 9 inside. The outer wall of the quartz dielectric tube 9 is covered with a high-voltage electrode 10, and a low-voltage electrode 11 is coaxially arranged inside. Driven by the plasma excitation power supply 12, the high-voltage electrode 10 and the low-voltage electrode 11 form an alternating electric field, thereby generating non-equilibrium plasma, which is used for the activation treatment of the mixed gas through high-energy electron collisions. The high-voltage electrode 10 is electrically connected to the high-voltage output terminal of the plasma excitation power supply 12, and the low-voltage electrode 11 is electrically connected to the low-voltage terminal and ground terminal of the plasma excitation power supply 12. Furthermore, a discharge parameter monitoring oscilloscope 13 is electrically connected to the signal output terminal of the plasma excitation power supply 12 for real-time monitoring of the discharge voltage and current waveforms of the plasma excitation power supply 12.

[0022] The top outlet of the dielectric barrier discharge reactor 8 is sealed and connected to the inlet of the swirl burner 14, and the nozzle of the swirl burner 14 extends into the interior of the main combustion chamber 16 to deliver the activated swirl mixture to the main combustion chamber 16. The swirl generator 15 is fixedly integrated into the internal airflow channel of the swirl burner 14. The main combustion chamber 16 provides a sealed and stable reaction space for the combustion reaction. An optical observation window 17 is provided on the side wall of the main combustion chamber 16, and the outlet of the main combustion chamber 16 is sealed and connected to the sampling end of the flue gas analyzer 22.

[0023] The output light paths of the YAG exciter 18 and the dye laser 19 are arranged coaxially with the optical focusing lens group 20 after optical path adjustment. The laser beam enters the flame core region inside the main combustion chamber 16 through the optical observation window 17. The ICCD imaging camera 21 is positioned directly opposite the optical observation window 17, and the lens axis of the ICCD imaging camera 21 intersects the laser incident light path perpendicularly in the flame core region.

[0024] The signal output terminal of the flue gas analyzer 22, the operating condition signal output terminal of the plasma excitation power supply 12, and the image signal output terminal of the ICCD imaging camera 21 are all electrically connected to the signal input terminal of the experimental data acquisition computer 23.

[0025] The working process of the above burner is as follows: Hydrogen cylinder 1, ammonia cylinder 2, and air cylinder 3 are used to store hydrogen fuel, ammonia fuel, and combustion air, respectively, providing fuel and oxidant sources for the combustion reaction. Hydrogen mass flow controller 4, ammonia mass flow controller 5, and air mass flow controller 6 are used to precisely regulate the supply flow rates of hydrogen, ammonia, and air, achieving a quantitative ratio of the three gases according to a preset hydrogen mixing volume ratio and combustion equivalence ratio, ensuring the uniformity and stability of the premixed gas components. Gas manifold 7 is used to transport the premixed hydrogen, ammonia, and air to the dielectric barrier discharge reactor 8, providing a stable and uniform mixed gas medium for plasma activation treatment.

[0026] The dielectric barrier discharge reactor 8 employs a coaxial dielectric barrier discharge structure, with a quartz dielectric tube 9 serving as the insulating dielectric layer to confine the discharge channel, prevent arc generation, and maintain a stable non-equilibrium plasma generation state. The high-voltage electrode 10 and the low-voltage electrode 11, driven by the plasma excitation power supply 12, form an alternating electric field, thereby generating non-equilibrium plasma. High-energy electron collisions activate the mixed gas. The discharge parameter monitoring oscilloscope 13 is used to monitor the discharge voltage and current waveforms of the plasma excitation power supply 12 in real time, ensuring the stability and controllability of the plasma excitation process.

[0027] The swirl generator 15 applies tangential momentum to the plasma-activated gas mixture, converting axial flow into swirling flow and creating a strong swirling field. This enhances the turbulent mixing of fuel and oxidant and prolongs the residence time of active particles in the combustion zone. The swirl burner 14 delivers the activated swirling gas mixture to the main combustion chamber 16, achieving stable swirling combustion. The main combustion chamber 16 provides a sealed and stable reaction space for the combustion reaction, ensuring a smooth combustion process. The optical observation window 17 provides an optical path for laser incident and fluorescence signal acquisition, while maintaining the stability of the combustion flow field and preventing external airflow from disturbing the combustion process.

[0028] The YAG exciter 18, dye laser 19, and optical focusing lens group 20 work together to form a laser-induced fluorescence excitation source, emitting a laser beam of a specific wavelength to excite OH free radicals in the flame region to generate characteristic fluorescence signals. The ICCD imaging camera 21 is used to collect the fluorescence signals of OH free radicals and image them, realizing in-situ detection of the two-dimensional distribution of OH free radicals in the flame region, and intuitively reflecting the enhancement effect of plasma activation and swirling combustion.

[0029] The flue gas analyzer 22 is used to detect the concentration of nitrogen oxides in the exhaust gas at the outlet of the main combustion chamber 16 in real time, realizing the quantitative detection of combustion pollutant emissions. The experimental data acquisition computer 23 is used to simultaneously acquire and store nitrogen oxide concentration data, plasma discharge condition parameters, and OH free radical fluorescence image data, providing complete experimental data support for combustion mechanism analysis and model verification.

[0030] Based on such Figure 4 The technical approach shown employs a closed-loop research framework of experimental diagnosis, numerical simulation, and bidirectional verification to validate the core innovation of the aforementioned burner: achieving deep synergistic coupling between precise control of swirling fluid dynamics and DBD non-equilibrium plasma chemical kinetics activation, effectively overcoming the insufficient combustion efficiency of hydrogen / ammonia binary fuel mixtures and NO... xThis addresses the existing technological bottlenecks of difficulty in pollutant suppression and low accuracy in non-equilibrium combustion mechanism simulation. The entire technical approach consists of three core modules: experimental research, numerical simulation, and coupled verification. It includes seven progressively key implementation steps, forming a complete closed-loop technical system. These steps sequentially complete pre-plasma molecular activation, swirling flow field-enhanced combustion, in-situ diagnosis of combustion parameters, plasma microdynamics simulation, combustion free radical mechanism deduction, macroscopic combustion characteristic analysis, and iterative correction of experimental and simulation results. Each step is progressive, mutually supportive, and optimized in a closed loop. The experimental research focuses on actual combustion physics processes. By precisely controlling DBD plasma discharge parameters and swirling structure parameters, a standardized premixed combustion experimental platform is built. High-precision testing equipment is used to obtain real experimental data on combustion characteristics, free radical evolution, and pollutant emissions. The numerical simulation module innovatively adopts a two-stage simulation architecture using Chemplaskin and Cantera, overcoming the limitations of traditional models in characterizing plasma non-equilibrium dynamics and compensating for the difficulty of capturing microscopic transient reaction mechanisms in physical experiments. This invention constructs a closed-loop optimization mechanism of "experimental calibration simulation and simulation-guided experiment" through bidirectional verification of experimental and simulation data and iterative model optimization, aiming to improve combustion performance and reduce NO. x Regarding emission suppression and energy conservation and emission reduction goals, the following content systematically elaborates on the core technical solution and multi-field synergistic mechanism of the present invention, providing reliable technical support for the engineering implementation of zero-carbon fuel burners.

[0031] I. Experimental Research This research section corresponds to Figure 4 The experimental steps 1-3 of the technical route involve three progressive experimental procedures: plasma pre-molecular activation, multi-condition swirling combustion construction, and in-situ diagnosis of combustion characteristic parameters. Based on... Figure 1 The burner shown was used in experiments and integrates four functional units: precise fuel supply, DBD non-equilibrium plasma activation, controllable swirling combustion, and multi-parameter detection and data acquisition. All parts are sealed and interconnected, enabling precise mixing of hydrogen / ammonia / air premixed fuels, plasma molecular activation, controllable swirling combustion, and simultaneous acquisition of combustion parameters across the entire combustion domain. The core control component uses a variable-angle blade swirling generator 15, which can gradient-adjust the swirling intensity to construct a controllable structured combustion flow field. Relying on the multi-field coupling mechanism of plasma chemical activation and swirling fluid optimization, it effectively overcomes the shortcomings of traditional hydrogen-ammonia fuel combustion, such as insufficient activation, weak flow field controllability, and limited experimental conditions. It provides a standardized and reproducible experimental basis for exploring coupled combustion characteristics, analyzing microscopic mechanisms, and calibrating simulation models.

[0032] Step 1: Construction based on non-equilibrium plasma excitation and realization of molecular activation principles.

[0033] This step is performed on a burner experimental platform, with the dielectric barrier discharge (DBD) plasma excitation device operated by the experimenter. First, a premixed gas of ammonia, hydrogen, and air is introduced into the premixing chamber through the mixed gas input unit at a preset hydrogen mixing volume ratio. Then, the DBD plasma excitation device is activated, applying a high-voltage alternating current (discharge voltage 0-16kV, discharge frequency 5kHz), generating a dielectric barrier discharge between the high-voltage electrode 10 and the ground electrode, producing non-equilibrium plasma. High-energy electrons (energy range 1-10eV) in the plasma undergo inelastic collisions with N2, O2, and NH3 molecules, elevating the molecules from the ground state to the excited state through vibrational and electronic excitation processes. The electronic energy balance of this process can be described by the following equation: ; in, For electron density, The average electron energy, For electron drift velocity, The electric field provides power input to electrons. This refers to the energy loss of electrons due to inelastic collisions. Let be the electron energy flux. This equation quantitatively describes the source (work done by the electric field) and destination (collision loss and heat dissipation) of electron energy, where The term is contributed by the following key inelastic collision response, namely, the interaction between macroscopic energy loss and microscopic elementary reactions. These items are physically linked and together constitute a complete description from energy balance to reaction dynamics.

[0034] Key responses include: ; ; ; ; ; ; ; ; Vibrational excited state Energy is transferred to the NH3 molecule through VV energy transfer and VT relaxation processes, promoting its dissociation to generate NH2 radicals; electronically excited state and As an energy carrier, it undergoes energy transfer reactions with ground-state molecules, further generating active free radicals such as O and H, providing active boundary conditions for subsequent combustion reactions, and reducing ignition temperature and activation energy.

[0035] Step 2: Implementation of hydrogen / ammonia swirl combustion fluid dynamics and premixed combustion principle.

[0036] This step, based on the principles of enhanced swirling fluid dynamics and the stoichiometric ratio of hydrogen / ammonia premixed combustion, completes fuel supply, mixture preparation, and swirling combustion condition construction. Using ammonia mass flow controller 5, hydrogen mass flow controller 4, and air mass flow controller 6, the volumetric flow rates of the three gases are precisely controlled according to the principle of fluid mass conservation. The hydrogen blending volume ratio is set to 30%, and the combustion equivalence ratio to be 0.4-1.2. The three gases are introduced into the premixing chamber according to the specified ratio. Through the turbulent structure within the chamber, a uniform hydrogen / ammonia-air premixed gas is formed, eliminating combustion fluctuations caused by uneven local fuel concentration and ensuring the stoichiometric stability of the combustion reaction. The premixed gas flows axially along the burner body to the swirling generator 15 region. The swirling generator 15 applies tangential momentum to the airflow, converting the axial flow into a strong swirling field combining axial and swirling directions. The swirling intensity is determined by the swirling number... Quantitative characterization was performed on the blade-type axial vortex generator 15 used in this embodiment. With blade installation angle The (swirl angle) satisfies the following relationship: ; in, For the hub radius, The outer radius of the blade. Let be the wheel hub ratio. When the wheel hub ratio is small, the above formula can be simplified to: The swirl angle in this invention The angle can be adjusted within the range of 20°-80°, corresponding to the number of swirls. The range is approximately 0.24-3.78. For industrial / gas turbine applications, a range of 30°-45° is preferred. =0.4-0.7), achieving a balance between stable combustion, mixing, and flameout risks; the aim is to ensure the flow field is in a strongly swirling state, thereby generating a central recirculation zone sufficient to prolong the residence time of active particles and enhance mixing. A stable central recirculation zone can be formed within this swirling number range, NO x Both CO emissions are at low levels. Simultaneously, by leveraging the central backflow effect, the residence time of active free radicals and unburned fuel in the combustion zone is extended, optimizing the spatiotemporal distribution conditions of the combustion reaction. This provides a stable reaction flow field for plasma-activated fuel molecules, achieving spatial coupling between swirling hydrodynamic control and plasma chemical excitation.

[0037] The gas motion within the swirling flow field follows the Reynolds-averaged Navier-Stokes equations, taking the axial momentum equation as an example: ; in, 、 The axial and radial Reynolds average velocities are respectively. It is the effective viscosity coefficient (including molecular viscosity and turbulent eddy viscosity). Radial coordinates, For gas density, For axial coordinates, The symbol is for partial differentials. The axial momentum equation is the source term, representing the volume force effect exerted by the swirl blades on the airflow. This equation accurately describes the velocity field distribution of the gas inside the swirl burner and serves as the theoretical basis for quantitatively designing the geometry of the swirl generator 15 and simulating and predicting the mixing uniformity and recirculation zone location.

[0038] Step 3: Application of the principles of in-situ diagnosis and physicochemical characterization of key combustion parameters.

[0039] This step is based on the principles of thermodynamic temperature measurement, flue gas chemical detection, and laser-induced fluorescence / chemiluminescence optical diagnosis to collect and quantitatively characterize the core parameters of the combustion process in situ.

[0040] (1) Temperature field and NO x Emissions measurement High-precision thermocouples were inserted at different axial and radial positions in the combustion zone. Combustion temperature field data were collected based on the thermodynamic equilibrium heat transfer principle. The regulation law of combustion temperature distribution by the synergistic effect of swirling flow and plasma was analyzed to suppress the formation of local high-temperature zones and reduce NO. x generate.

[0041] A flue gas sampling probe is placed 150 mm downstream of the burner outlet to continuously extract combustion exhaust gas. NO is then detected using an electrochemical flue gas analyzer (such as the Madur GA-21 model). x Concentration. Its principle is controlled potential electrolysis: NO x When gas passes through the sensor's sensitive electrode, an electrochemical oxidation-reduction reaction occurs, and the resulting current signal follows Faraday's law in relation to the gas concentration. ； in, For the number of electrons, It is Faraday's constant. The diffusion coefficient (m) 2 / s), NO x Concentration (mol / m3 The measurement results were standardized and calibrated based on a 15% oxygen concentration to eliminate the interference of operating conditions on emission data.

[0042] (2) PLIF measurement of OH free radicals The OH-PLIF laser-induced fluorescence system was used to react with OH free radicals using a laser at a wavelength of 283.55 nm. The characteristic absorption peak of the transition undergoes resonant excitation, causing OH radicals to generate characteristic fluorescence signals (detection band 307nm±10nm). The fluorescence signal intensity is positively correlated with the radical concentration. Fluorescence images are acquired and reconstructed using an ICCD imaging camera 21, enabling quantitative measurement of the two-dimensional concentration distribution of OH radicals within the flame region. This directly reflects the enhancement level of plasma on the combustion core radicals and the intensity of the combustion reaction. (Fluorescence signal intensity) The quantitative relationship between the concentration of the OH free radical to be measured and the concentration of the OH free radical is given by the following formula: ; in, This is a system constant (including optical collection efficiency, ICCD gain, etc.). For laser intensity, The number density of OH free radicals. The fluorescence quantum efficiency is related to temperature and pressure. This equation establishes a bridge between the measurable signal and the concentration to be measured; by calibrating the coefficients, the absolute OH concentration in the flame core region can be inverted from the image.

[0043] (3) Chemiluminescence measurement of NH2 free radicals Simultaneously, NH2 radicals were measured using the NH2* chemiluminescence method: NH2* (electronically excited state NH2) spontaneously generates a chemiluminescence signal during combustion, with a detection wavelength of approximately 630 nm ± 10 nm (corresponding to the ⁻¹⁰ nm of NH2). 2 A1→X̃ 2 The spatial distribution and intensity evolution of NH2 radicals were obtained by capturing data (gate width 250 μs) of the B1 transition band using an ICCD camera equipped with a 630 nm bandpass filter. NH2 radicals are a precursor to NO. x The core participant in the reduction pathway (NH2+NO⇔N2+H2O) has a concentration evolution pattern that directly characterizes the regulatory effect of plasma excitation on pollutant suppression.

[0044] II. Simulation Research This simulation study corresponds to Figure 4 Technical route steps 4-6, relying on Figure 5 A two-stage simulation architecture is used to conduct multi-scale combustion engine analysis. Figure 5It clearly presents the complete calculation process and data transfer logic of plasma dynamics preprocessing, combustion dynamics postprocessing, and model iteration verification.

[0045] The preprocessing stage is based on the Chemplaskin platform. It matches the discharge parameters calibrated in the experiment with the fuel component boundary, solves the Boltzmann equation to obtain electronic dynamic parameters, quantifies the evolution law of excited state of fuel and oxidant molecules, and outputs the concentration of key active free radicals, providing accurate non-equilibrium activation initial conditions for combustion simulation.

[0046] In the post-processing stage, the preprocessing results are imported into the Cantera platform, coupled with a high-precision ammonia-hydrogen combustion mechanism, to simultaneously complete the analysis of microscopic free radical reaction pathways and the calculation of macroscopic combustion characteristics, accurately evaluating combustion performance and NO. x Emission performance. Simultaneously, this architecture integrates an experimental benchmarking and iteration mechanism, correcting simulation mechanism parameters using measured data to control the overall model error within a certain range. This coupling mode overcomes the computational limitations of single simulation tools, achieving cross-scale linkage analysis of nanosecond-level plasma microdynamics and millisecond-level macroscopic combustion reactions, significantly improving the simulation accuracy of the hydrogen / ammonia binary coupled combustion mechanism.

[0047] After being calibrated with experimental data, the model has generalization prediction capabilities and can be directly used to predict combustion performance and emission characteristics under different operating conditions and fuel ratios without recalibration. It can be directly adopted by those skilled in the art as a virtual simulation design tool for hydrogen / ammonia burners.

[0048] Step 4: Simulation of plasma micro-reaction dynamics based on Chemplaskin.

[0049] This step involves using the Chemplaskin software to construct a plasma-fuel coupled reaction model based on the principle of non-equilibrium plasma chemical reaction kinetics modeling, revealing the mechanism of plasma excitation and dissociation of fuel molecules at the microscopic level.

[0050] Based on the fundamental reaction mechanism of hydrogen / ammonia-air combustion, and superimposed with plasma-specific reactive mechanisms, this study simulates the elementary reactions between high-energy electrons and N2, NH3, and O2 molecules by inputting core parameters such as discharge voltage, discharge frequency, and electron energy distribution function. In terms of electron collision excitation, high-energy electrons can excite N2 to A2. 3 Σ u + An electronically excited state (threshold energy approximately 6.2 eV) or a vibrationally excited state v=1-8 (threshold energy approximately 0.29 eV) can excite O2 to a... 1The Δg electronically excited state (threshold energy approximately 0.98 eV) allows high-energy electrons to directly break chemical bonds, dissociating NH3 into NH2 and H (threshold energy approximately 4.7 eV), H2O into OH and H (threshold energy approximately 5.1 eV), and O2 into two O atoms (threshold energy approximately 5.58 eV). In terms of electron collisional ionization, high-energy electrons can react with N2 and O2 to produce N2. + O2 + And secondary electrons.

[0051] Chemplaskin obtains the electron energy distribution function by solving the Boltzmann equation, accurately calculates the proportion of electrons with different energies, and then accurately quantifies the rates of the above-mentioned excitation, dissociation and ionization reactions, providing accurate non-equilibrium initial boundary conditions for subsequent combustion simulation.

[0052] Chemplaskin obtained the electron energy distribution function by solving the Boltzmann equation: ; in, For acceleration, For the velocity space gradient, Let be the electron energy distribution function. For collision terms. Solving the Boltzmann equation to obtain the electron energy distribution function (EEDF) is the key to distinguishing the simulation of this invention from traditional methods. Traditional methods usually assume the Maxwell distribution, but the EEDF in non-equilibrium plasma deviates significantly from the Maxwell distribution. It is necessary to accurately calculate the proportion of electrons with different energies by solving the Boltzmann equation in order to accurately calculate the rates of subsequent excitation and dissociation reactions.

[0053] Excited-state species are interconnected through energy transfer: N2(A 3 Σ u + Metastable excited-state molecules such as NH3 and H2O can act as energy carriers, transferring energy to fuel molecules like NH3 and H2O through collisions with ground-state molecules, promoting their dissociation to generate reactive free radicals such as NH2 and OH. Simultaneously, the O atoms generated from the collisions of high-energy electrons with O2 can further react with H2O to generate OH. These energy transfer reactions between excited-state species and ground-state molecules constitute a complete reaction network for plasma activation.

[0054] Chemplaskin simulations can quantify the generation rates and concentration evolution of excited-state species such as N2, O, and H*, as well as active free radicals such as OH and NH2. From the perspective of quantum chemistry and reaction kinetics, this elucidates the microscopic mechanism by which plasma activates fuel molecules through electron energy transfer, providing accurate non-equilibrium initial boundary conditions for subsequent combustion simulations and compensating for the shortcomings of traditional combustion simulation models in describing the principles of non-equilibrium plasma electrochemical effects.

[0055] Step 5: Simulation of the microscopic evolution dynamics of combustion radicals based on Cantera.

[0056] This step involves using a computer to construct a combustion reaction model based on the detailed chemical reaction kinetics of hydrogen / ammonia combustion and the free radical competition reaction mechanism. Cantera software is an object-oriented, open-source chemical kinetics computational toolkit that supports the numerical solution of rigid ordinary differential equations. It can accurately simulate homogeneous reactions, heterogeneous reactions, and chemical reactions involved in combustion, and is widely used in combustion mechanism analysis, reaction pathway analysis, and sensitivity analysis. The excited-state species and active free radical concentrations output by Chemplaskin are used as initial input conditions, and the Okafor mechanism is imported as the core reaction framework (this mechanism has been systematically verified specifically for the ammonia-hydrogen-air combustion system, including NH3 oxidation, H2 oxidation, and NO...). x (A complete elementary reaction network of generation and reduction).

[0057] The mole fractions and formation rates of key species such as OH, NH2, and NO were calculated through simulation. According to the definition in the Cantera official manual, the net formation rate of the components is given by the following formula: ; in, 、 For the first In the first reaction The stoichiometric coefficients of the products and reactants. For the first The equation for the rate of change of an elementary reaction (i.e., the net rate of change of reaction extent) is based on a matrix of reaction stoichiometric coefficients: when the reaction... When the forward and reverse reaction rates are known, the species The net production rate is equal to the sum of the products of the differences in the stoichiometric coefficients of the reactants and products in all reactions, multiplied by the corresponding reaction rates. This equation is implemented internally in Cantera using the `getNetProductionRates` method of the `ReactionStoichMgr` class, which can accurately calculate the contribution of each elementary reaction to the net production rate of a specific chemical component. This can be achieved by comparing the contributions of different reaction steps. Values ​​identify the dominant reaction pathway.

[0058] There is a close kinetic relationship between excited-state species and key combustion radicals: O atoms (threshold energy approximately 5.58 eV) generated from collisions between high-energy electrons and O2 can react with H2 to form O + H2 ⇔ OH + H, generating OH radicals; simultaneously, NH2 radicals generated from the dissociation of NH3 by electron collisions are key participants in the NOx reduction pathway (NH2 + NO ⇔ N2 + H2O). Furthermore, N2(A 3 Σ u + The energy transfer reaction between excited-state molecules such as NH3 and ground-state molecules can further promote the formation of NH2. The energy transfer reactions between these excited-state species and ground-state molecules constitute the physicochemical link between the Chemplaskin pretreatment and the Cantera posttreatment.

[0059] Simultaneously, reaction sensitivity analysis is performed by perturbing the elementary reaction rate constant (usually taken as...). =1%), calculate the normalized sensitivity coefficient of the target output variable (such as NO emission concentration) to each elementary reaction, and its mathematical definition is: ; in, For the first The reaction rate constant of each reaction For the target amount (e.g., species mole fraction or flame velocity), a positive sensitivity coefficient indicates that the reaction promotes the formation of the target amount, while a negative sensitivity coefficient indicates an inhibitory effect. This method quantifies the influence of each reaction on the concentration of the target species, revealing the combustion acceleration pathway dominated by OH radicals under plasma excitation (e.g., H + O2 ⇔ O + OH) and the NO combustion acceleration pathway dominated by NH2 radicals. x The microscopic competition mechanism of reduction pathways (such as NH2+NO⇔N2+H2O) clarifies the intrinsic relationship between free radical evolution and combustion performance and pollutant generation, providing microscopic theoretical support for the optimization of combustion parameters.

[0060] Step 6: Dynamic analysis of macroscopic characteristics of swirling combustion based on Cantera.

[0061] This step involves constructing a one-dimensional laminar premixed flame model in Cantera software based on the principles of premixed flame propagation dynamics and the macroscopic mechanism of swirling-combustion coupling. The hydrodynamic effects, such as enhanced mixing and prolonged residence time, brought about by the swirling field are transformed into model boundary conditions. The macroscopic combustion characteristics under the synergistic effect of swirling and plasma are then simulated and analyzed. In Cantera's one-dimensional flame model, the energy equation describes the heat balance within the flame, and its conservation form is as follows: ; in, For isobaric specific heat capacity, For axial velocity, For temperature, For axial coordinates, Thermal conductivity, For the first Diffusion mass flux of the components For the first The specific heat capacity of the components, For the first Specific enthalpy of the components For the first The molecular weight of each component; the left side of the equation represents heat transport caused by convection, and the three terms on the right side represent heat diffusion caused by heat conduction, enthalpy flux caused by component diffusion, and heat released by chemical reaction, respectively.

[0062] By calculating key macroscopic parameters such as ignition delay time, flame surface density, and combustion temperature distribution through modeling, the study fully reveals the synergistic effect of plasma chemical excitation and swirling fluid regulation in improving hydrogen / ammonia combustion performance and suppressing NO. x The generated overall mechanism provides numerical basis for determining the optimal operating parameters.

[0063] III. Experiment-Simulation Two-Way Closed-Loop Verification Step 7: Experiment-Simulation Multi-Dimensional Coupling Verification and Model Mechanism Correction.

[0064] This step, based on the principles of reaction kinetic parameter correction and multi-physics coupling matching, compares experimentally measured data with simulation results to complete model verification and parameter correction. First, it compares the simulated OH radical concentration distribution and combustion temperature field data with experimentally measured data to verify the consistency between the trends of radical evolution and temperature distribution. If discrepancies exist, the electron collision reaction rate constant in the plasma reactant mechanism is corrected to optimize the simulation accuracy of the plasma molecular activation mechanism. Then, it compares the simulated and experimentally measured NOx emission concentrations. The model correction process minimizes the objective function through an optimization algorithm. ; in, Let be the parameter vector to be corrected. , The first Simulated and experimental values ​​of each observation. To measure the uncertainty of the experiment, This represents the total number of observations. This equation provides a quantitative evaluation index for model correction, and through iterative adjustments, the weighted sum of squared residuals between simulation and experiment converges to a minimum threshold. Through multiple rounds of iterative correction, the simulation model is made to fully match the experimental results in terms of physical mechanisms, chemical laws, and kinetic trends, ensuring that the established model can truly reflect the core principles of plasma-swirling co-combustion and provide a reliable theoretical model for technological engineering applications.

[0065] At the experimental level, the activation of non-equilibrium plasma chemical reaction kinetics combines non-equilibrium plasma excitation with swirling combustion: the swirling field can enhance the macroscopic mixing of hydrogen / ammonia fuel and air, prolong the residence time of active particles in the combustion zone, and allow for more complete fuel combustion; the non-equilibrium plasma, through high-energy electron collisions, directly dissociates fuel and oxidant molecules, generating a large number of OH radicals to accelerate the combustion chain reaction, while simultaneously generating NH2 radicals to participate in NO. x Reduction, simultaneously achieving a significant improvement in combustion performance and NO reduction at the chemical kinetics level. x Effective inhibition of combustion and synergy between the two technologies achieve highly efficient and low-pollution combustion of hydrogen / ammonia, breaking the traditional limitations in combustion performance and NO emission control. x The bottleneck of emissions being difficult to balance.

[0066] With a 40° swirl angle and equivalent ratio φ Taking the 1.2 operating condition as an example, after applying 16kV DBD plasma excitation, NO x The emission concentration decreased significantly from 1350 ppm to 900 ppm, a reduction of 450 ppm; simultaneously, the net increase in OH radicals was 2 counts, and the net increase in NH2 radicals was 3 counts, confirming that plasma excitation can significantly reduce NO emissions under conditions of slightly enhanced combustion activity. x Highly efficient suppression.

[0067] At the simulation level, a two-stage simulation method combining Chemplaskin and Cantera is proposed: first, Chemplaskin is used to accurately calculate plasma excited-state species and electron energy distribution, solving the problem of non-equilibrium plasma dynamics modeling; then, the results are imported into Cantera to accurately simulate the evolution of combustion free radicals, macroscopic combustion characteristics, and NO. x The generation law overcomes the limitation of traditional models in coupling plasma effects, providing precise theoretical support for the optimization of swirling and plasma parameters, and achieving closed-loop verification between experiments and simulations. Experimental verification shows that NO... xThe concentration prediction error is less than 3%, achieving high-precision closed-loop verification between experiments and simulations.

[0068] Looking ahead to future applications, the results of this invention can be widely applied to aero-engine power plants, distributed gas turbine power generation systems, and industrial heating boilers.

[0069] Based on the above experiments, the experimental and simulation results are as follows: (1) Physical control of low-angle swirling flow field to achieve NO x Suppressing pollutants at their source.

[0070] like Figure 6 As shown, the equivalence ratio is illustrated. φ =1.2, swirl angle: 20°-80°, NO x Comparison of experimental and simulation results on the evolution of plasma voltage variation.

[0071] Using the 8kV critical voltage range as a unified reference, quantitative data from multi-gradient swirling flow conditions clearly confirm this control law: NO under a small 20° swirling flow condition x Emissions are only 950 ppm, NO under 80° large-angle swirl conditions x Emissions can reach approximately 1650 ppm, representing an increase of about 73.6% compared to a 20° swirl angle and about 10.0% compared to a 60° swirl angle, fully demonstrating the positive effect of low-angle swirls on NO. x The highly efficient suppression of pollutants and the differential control of the swirl angle have a significant impact on the emission performance of hydrogen / ammonia binary fuel combustion.

[0072] Its mechanism lies in the fact that a low swirl angle can create a central recirculation zone of moderate size and compact structure, effectively converging the core combustion area and compressing the local high-temperature reaction zone, thus blocking thermal NO from its source. x The invention optimizes the formation conditions of NOx by extending the residence time of reactive free radicals such as OH and NH2 in the core combustion region, thus maintaining the reduction advantage of NH2 free radicals. However, high swirl angles can easily lead to problems such as flow field disturbance, dispersion in the combustion reaction zone, and local high-temperature accumulation, significantly exacerbating the formation and accumulation of thermal NOx. Therefore, this invention preferably uses a low swirl angle to simultaneously achieve stable combustion and source suppression of pollutants from the perspective of physical flow field.

[0073] (2) DBD non-equilibrium plasma critical voltage excitation to achieve high-pressure and efficient NO reduction x .

[0074] like Figure 6 As shown, at a fixed 40° commonly used engineering vortex angle, φ =1.2 NO3- of hydrogen / ammonia binary fuel combustion system under fuel-rich conditions xEmissions exhibit a differentiated evolution pattern with increasing DBD discharge voltage, showing stability at low voltages and a sharp drop at medium and high voltages. The plasma excitation effect demonstrates a clear voltage-critical activation characteristic. In the 0-8kV low-voltage range, the DBD plasma excitation intensity is weak, and NO emissions... x Emissions remained stable at around 1350 ppm, with almost no emission reduction effect; when the discharge voltage exceeded the 8kV critical activation range, NO... x Emissions plummeted to 1030 ppm, and the emission reduction effect continued to strengthen as the voltage increased to 16 kV.

[0075] like Figure 7 As shown, at a fixed 40° commonly used engineering vortex angle, φ =1.2 Under fuel-rich conditions, OH and NH2 radicals exhibited differentiated evolution characteristics with increasing DBD discharge voltage, showing a stable low-voltage state and a sudden drop at medium to high voltage, further verifying the accuracy of the experiments and simulations. Below the critical voltage of 8kV, the electron energy density was low, and the excited-state species population was extremely low, resulting in very weak net growth of both OH and NH2 radicals, making it difficult to change the original combustion reaction equilibrium. When the voltage exceeded the critical 8kV threshold, the plasma excitation intensity increased in a gradient manner, leading to a large enrichment of excited-state species. OH radicals increased from 14 to 16 counts, a net increase of approximately 2 counts, while NH2 radicals increased from 31 to 34 counts, a net increase of approximately 3 counts. The growth rate of NH2 was significantly higher than that of OH. NH2 radicals efficiently suppressed NO through the dominant reaction NH2 + NO ⇔ N2 + H2O. x The reduction effect of NO is significantly stronger than that of OH. Therefore, in this embodiment, the discharge voltage is preferably controlled above the critical activation range of 8-16kV. Relying on the non-equilibrium plasma energy level excitation and free radical precise control mechanism, NO can be generated under medium and high voltage conditions. x Highly efficient suppression.

[0076] (3) The experimental data and simulation mechanism are matched with high precision.

[0077] like Figure 6 As shown, NO under different swirl angles x The experimental data on emissions varying with voltage showed a high degree of agreement with the simulation prediction results, verifying the prediction accuracy of the two-stage simulation model of this invention. Combined with... Figure 7 , Figure 8 , Figure 9Radical reaction pathway analysis (ROP) reveals the underlying mechanism. The main pathway for OH radical generation is H + O₂ ⇔ O + OH, which is the core step in the combustion chain branching and directly determines flame propagation and reaction intensity. The main pathway for OH radical consumption is OH + NH₃ ⇔ H₂O + NH₂, followed by OH + H₂ ⇔ H₂O + H and OH + OH ⇔ H₂O + O. As the DBD voltage increases from 8kV to 16kV, the reaction rates of all OH-related elementary elements accelerate synchronously, with the main generation pathway H + O₂ ⇔ O + OH showing the largest increase, resulting in a net increase of approximately 2 counts in the steady-state OH concentration. The increase in OH concentration directly enhances the combustion chain branching reaction rate, accelerates the fuel oxidation and exothermic process, increases flame propagation speed, shortens ignition delay time, and improves combustion completeness, macroscopically manifesting as a significant improvement in combustion performance. The core supply of NH2 radicals comes from the reverse reaction of NH2 + H ⇔ H2 + NH, while the forward consumption pathways include H + H2NO ⇔ OH + NH2 and NH2 + NO ⇔ N2 + H2O. With increased voltage, the rates of all NH2-related reactions significantly increase, resulting in a net increase of approximately 3 counts of NH2, with NH2 + NO ⇔ N2 + H2O being the primary source of NO. x The core denitrification reaction of reduction exhibits a particularly significant rate increase. High-concentration NH2 radicals efficiently consume NO through this reaction, effectively offsetting the thermal NO reduction induced by the increased OH concentration. x Generative effect.

[0078] In summary, under 8-16kV high-voltage operating conditions, increased OH concentration enhances the combustion chain reaction and combustion performance, while increased NH2 concentration dominates NO production. x The restoration path, through synergy, achieves a balance between "efficiency enhancement" and "emission reduction." The aforementioned free radical evolution law and... Figure 6 The macroscopic experimental data are completely consistent, which fully verifies that the Chemplaskin-Cantera simulation model of this invention can accurately characterize the non-equilibrium reaction characteristics and free radical game mechanism of plasma, and the simulation mechanism and experimental results are highly matched.

[0079] This invention achieves efficient and stable combustion of hydrogen / ammonia and NO through a synergistic coupling scheme combining controllable angle swirling flow field regulation with DBD non-equilibrium plasma excitation. x Synergistic emission reduction of pollutants. The low-swirl structure can optimize the combustion flow field and compress the high-temperature reaction zone, inhibiting pollutant generation at the source from a physical level; the gradient high-pressure DBD plasma can reconstruct the OH / NH2 free radical game mechanism, enhance the NO reduction denitrification reaction, and significantly improve the emission reduction effect. At the same time, the self-developed Chemplaskin-Cantera two-stage simulation model has high accuracy, strong adaptability to operating conditions, and good generalization ability. It can be widely adapted to different combustion conditions and engineering scenarios, providing reliable technical support for the optimization of low-pollution combustion parameters of hydrogen / ammonia.

[0080] Therefore, this invention employs the aforementioned swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics. Through the synergistic coupling of non-equilibrium plasma chemical kinetic excitation and swirling fluid kinetic regulation, it fundamentally improves hydrogen / ammonia combustion performance and reduces NO. x emission.

[0081] 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 preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An experimental method for a swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics, characterized in that, The swirling fluid burner includes a mixed gas input unit, which delivers the mixed gas to a dielectric barrier discharge reactor. The mixed gas is activated by generating non-equilibrium plasma. A swirling combustion unit is sealed to the top outlet of the dielectric barrier discharge reactor, converting the axial flow of the activated mixed gas into a swirling flow to form a strong swirling field for combustion. A laser-induced fluorescence excitation unit is located on one side of the swirling combustion unit, with its emitter facing the swirling combustion unit. It emits a specific wavelength laser beam to excite OH radicals within the flame of the swirling combustion unit, generating characteristic fluorescence signals. An imaging camera and a flue gas analyzer are located on the other side of the swirling combustion unit. The lens of the imaging camera faces the swirling combustion unit to detect and image the fluorescence signals of OH radicals. The signal output terminals of the flue gas analyzer, the dielectric barrier discharge reactor, and the imaging camera are all electrically connected to the signal input terminal of the experimental data acquisition computer. The experimental method specifically includes the following steps: S1. A premixed gas of NH3, H2 and air is introduced into the dielectric barrier discharge reactor according to the preset hydrogen mixing volume ratio and combustion equivalence ratio. The plasma excitation power supply is started and a high-voltage alternating current is applied. A dielectric barrier discharge is generated between the high-voltage electrode and the low-voltage electrode, generating non-equilibrium plasma. High-energy electrons undergo inelastic collisions with N2, O2, NH3, and H2O molecules. Through vibrational excitation, electronic excitation, dissociation, and ionization processes, excited-state species and active free radicals are generated, completing the activation treatment of the mixed gas. S2. The flow rates of H2, NH3, and air are adjusted using hydrogen, ammonia, and air mass flow controllers, respectively, setting the hydrogen blending volume ratio to 30% and the combustion equivalence ratio to 0.4-1.

2. Under the same discharge voltage and swirl angle conditions, the three gases are introduced into the premixing chamber according to their proportions. The gases are thoroughly mixed by the turbulent structure within the chamber to form a uniform hydrogen / ammonia-air premixed gas. The premixed gas enters the swirl burner, where a variable-angle blade swirl generator applies tangential momentum, converting the axial flow into a strong swirling field combining axial and swirl directions. The swirl intensity is determined by the swirl number... The quantitative characterization used a bladed axial vortex generator, adjusting the blade installation angle. Within the range of 20°-80°, the corresponding swirl number , The range is 0.24-3.78; S3. The combustion temperature field is measured using thermocouples; NOx concentration is detected using a flue gas analyzer 150 mm downstream of the burner outlet, and standardized based on a 15% oxygen concentration; an OH-PLIF laser-induced fluorescence system is used to excite OH free radicals with a 283.55 nm wavelength laser. The transition was detected by fluorescence signal, and the two-dimensional distribution of OH radicals was acquired by ICCD imaging camera; simultaneously, the spatial distribution and intensity evolution of NH2 radicals were acquired by NH2* chemiluminescence method. S4. Input the experimentally calibrated discharge voltage, discharge frequency, and N2 / O2 / NH3 / H2 gas composition. Solve the Boltzmann equation based on the ChemPlasKin platform to obtain the electron energy distribution function (EEDF), electron temperature, electron density, and electron collision reaction rate. Calculate electron collision excitation, dissociation, and ionization reactions, quantify the generation rate and concentration evolution of excited-state species and active free radicals, and output the non-equilibrium activation initial conditions. S5. Import the excited-state species and active free radical concentrations output from S4 into the Cantera platform, couple them with the Okafor ammonia-hydrogen combustion mechanism, and calculate the mole fraction, net formation rate, reaction pathway, and sensitivity coefficient of key species such as OH, NH2, and NO. By coupling electron collision reactions with combustion elementary reactions, an evolution equation for the composition of matter under a reduced electric field intensity is established, and the net formation rate of the components is given by the following equation: ； in, 、 For the first In the first reaction The stoichiometric coefficients of the products and reactants. For the first The elementary reaction rates are used to calculate the normalized sensitivity coefficients of the target output variable to each elementary reaction by perturbing the elementary reaction rate constants. The mathematical definition of these coefficients is as follows: ； in, For the first The reaction rate constant of each reaction For the target amount, a positive sensitivity coefficient indicates that the reaction promotes the production of the target amount, while a negative sensitivity coefficient indicates an inhibitory effect. S6. Construct a one-dimensional laminar premixed flame model in the Cantera platform, transforming the hydrodynamic effects of the swirling field into model boundary conditions, and calculate ignition delay time, flame areal density, combustion temperature distribution, and NOx emissions; fully reveal the synergistic effect of plasma chemical excitation and swirling fluid regulation in improving hydrogen / ammonia combustion performance and suppressing NOx emissions. x The overall mechanism of action of generation; S7. Compare the experimentally measured OH / NH2 radical concentration distribution, combustion temperature field, and NOx emissions from S3 with the simulation results from S4-S6. First, verify the trend of radical evolution and temperature distribution using the OH radical concentration distribution and combustion temperature field, and verify the consistency between the trends of radical evolution and temperature distribution. If the deviation exceeds the set threshold, correct the electron collision reaction rate constant in the ChemPlasKin plasma reactant mechanism or the Cantera combustion mechanism parameters. The model correction process minimizes the objective function through an optimization algorithm. ； in, Let be the parameter vector to be corrected. , The first Simulated and experimental values ​​of each observation. To measure the uncertainty of the experiment, This represents the total number of observations. Through iterative adjustments, the weighted sum of squared residuals from simulation and experiment converges to a minimum threshold.

2. The experimental method for a swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics according to claim 1, characterized in that: The mixed gas input unit includes a hydrogen cylinder, an ammonia cylinder, and an air cylinder. The outlets of the hydrogen cylinder, ammonia cylinder, and air cylinder are respectively connected to a hydrogen mass flow controller, an ammonia mass flow controller, and an air mass flow controller. The outlets of the hydrogen mass flow controller, ammonia mass flow controller, and air mass flow controller are sealed and connected to the bottom air inlet of the dielectric barrier discharge reactor through a gas manifold.

3. The experimental method for a swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics according to claim 1, characterized in that: The dielectric barrier discharge reactor adopts a coaxial dielectric barrier discharge structure, which contains a quartz dielectric tube. The outer wall of the quartz dielectric tube is covered with a high-voltage electrode, and a low-voltage electrode is coaxially arranged inside. The high-voltage electrode and the low-voltage electrode form an alternating electric field under the drive of the plasma excitation power supply, thereby generating non-equilibrium plasma. The activation treatment of the mixed gas is achieved through high-energy electron collision.

4. The experimental method for a swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics according to claim 3, characterized in that: The high-voltage electrode is electrically connected to the high-voltage output terminal of the plasma excitation power supply, and the low-voltage electrode is electrically connected to the low-voltage terminal and ground terminal of the plasma excitation power supply. The signal output terminal of the plasma excitation power supply is electrically connected to a discharge parameter monitoring oscilloscope for real-time monitoring of the discharge voltage and current waveforms of the plasma excitation power supply.

5. The experimental method for a swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics according to claim 1, characterized in that: The swirl combustion unit includes a swirl burner, a swirl generator, and a main combustion chamber. The inlet of the swirl burner is sealed and connected to the top outlet of the dielectric barrier discharge reactor, and the nozzle of the swirl burner extends into the interior of the main combustion chamber to deliver the activated swirl mixed gas to the main combustion chamber. The swirl generator is fixedly integrated in the internal airflow channel of the swirl burner to apply tangential momentum to the activated mixed gas, converting axial flow into swirl flow and forming a strong swirl field. The main combustion chamber provides a sealed and stable reaction space for the combustion reaction.

6. The experimental method for a swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics according to claim 5, characterized in that: An optical observation window is provided on the side wall of the main combustion chamber to provide an optical path for laser incident and fluorescence signal acquisition. The exhaust port of the main combustion chamber is sealed and connected to the sampling end of the flue gas analyzer to detect the concentration of nitrogen oxides in the exhaust gas at the exhaust port of the main combustion chamber in real time.

7. The experimental method for a swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics according to claim 6, characterized in that: The laser-induced fluorescence excitation unit includes a YAG exciter, a dye laser, and an optical focusing lens group. The output optical paths of the YAG exciter and the dye laser are arranged coaxially with the optical focusing lens group after optical path adjustment. The YAG exciter, the dye laser, and the optical focusing lens group work together to form a laser-induced fluorescence excitation source, which emits a laser beam of a specific wavelength to excite OH free radicals in the flame region of the main combustion chamber to generate characteristic fluorescence signals. The laser beam enters the flame core region inside the main combustion chamber through the optical observation window.

8. The experimental method for a swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics according to claim 7, characterized in that, The imaging camera is an ICCD imaging camera, which is positioned directly opposite the optical observation window, and the lens axis of the ICCD imaging camera intersects perpendicularly with the laser incident light path in the core region of the flame.

9. The experimental method for a swirling fluid burner based on non-equilibrium plasma chemical reaction kinetics according to claim 4, characterized in that: The signal output terminals of the flue gas analyzer, the operating condition signal output terminal of the plasma excitation power supply, and the image signal output terminal of the ICCD imaging camera are all electrically connected to the signal input terminal of the experimental data acquisition computer. The experimental data acquisition computer is used to synchronously acquire and store nitrogen oxide concentration, plasma discharge operating condition parameters, and OH free radical fluorescence image parameter data, providing complete experimental data support for combustion mechanism analysis and model verification.

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