This study, conducted within the HOPE (Hydrogen Optimized multi-fuel Propulsion system for clean and silEnt aircraft) project, examines how kerosene-hydrogen fuel blends affect flame topology in a multi-fuel combustor designed to advance hydrogen powered aviation. High-fidelity Stress-Blended Eddy Simulations were performed to reproduce experimental testing conducted at the Delft University Sustainable Propulsion Lab, and results were compared against available experimental data to assess the flame topology across pure hydrogen, pure kerosene, and multi-fuel cases. Additionally, lower-fidelity simulations were used to evaluate combustor performance under limiting engine operating conditions, specifically a hydrogen-only take-off scenario. ... Read more

Addressing the growing environmental impact of aviation calls for systemic changes to aircraft and fuel technologies rather than incremental improvements in efficiency. Yet implementing such changes in this safety-critical and tightly regulated industry presents a significant challenge. This report proposes a dual-fuel aircraft architecture that preserves the core aircraft and airport infrastructure while advancing the transition towards hydrogen-powered aviation. The proposed aircraft retains a conventional low-wing tube-and-wing configuration and resembles modern narrow-body airliners in layout. Aimed for market entry by 2040, it accommodates 180 passengers with a maximum range of 3000 km. To enable hydrogen-kerosene operation, the design integrates a cryogenic hydrogen tank aft of the fuselage, conventional kerosene tanks within the wings, and a forward kerosene trim tank for centre of gravity control. Liquid hydrogen is fed through a dedicated conditioning system into an adapted engine that enables simultaneous dual-fuel combustion. The aircraft is designed to carry sufficient hydrogen for a round-trip mission, requiring hydrogen refuelling at a single hub airport. Tailored operational, maintenance and manufacturing concepts further support the safe and efficient introduction of hydrogen technologies into commercial aviation. At the 2000 km design range, the aircraft achieves more than 50% reduction in CO2 emissions compared to the reference Airbus A320neo, while reducing CO, soot and additional hydrocarbon-related emissions, and lowering NOx through innovations in fuel injection. Life-cycle assessment shows a 14% decrease in overall environmental impact, demonstrating that meaningful emissions reductions can be achieved without an immediate hydrogen infrastructure rollout. As this report is limited to preliminary design, future phases of development should focus on higher-fidelity simulation and experimental validation of the dual-fuel combustor and fuel system to verify and validate performance, emissions, and safety.

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Aviation is responsible for a significant share of global greenhouse gas emissions and remains one of the more challenging industries to transition to carbon-neutral operation. Research into alternative fuels and reductions in fuel consumption is therefore critical. This thesis investigates the extent to which integrating a hydrogen-fuelled Solid Oxide Fuel Cell into a CFM56-5B1 turbofan can reduce the Thrust Specific Fuel Consumption during cruise conditions. The SOFC was modelled as a 0D electrochemical component developed in OpenMDAO and integrated into pyCycle for cycle-level steady-state analysis. To assess feasibility, four heat exchanger placements were evaluated across a range of Bypass Ratio (BPR) and Jet Velocity Ratio (JVR) values. Maintaining the BPR and JVR equal to those of the baseline hydrogen-fuelled CFM56-5B1 yielded fuel consumption reductions of 12.2-16.2%, depending on heat exchanger placement. Allowing both parameters to vary produced reductions of up to 27.6% relative to the hydrogen-fuelled baseline. Total engine efficiency increased from approximately 33% for the baseline to approximately 43% for the most efficient hybrid configuration. The inter-turbine heat exchanger placement was found to be thermodynamically optimal, while positioning the heat exchanger downstream of the cathode exhaust achieved the second-highest efficiency with potential benefits in terms of system weight and compactness. The maximum power output of the fuel cell stack is fundamentally limited by the available cooling capacity of the cathode airflow in this type of SOFC integrated type. Several hybrid architectures also operated at lower combustion chamber temperatures than the baseline engine, offering the additional benefit of reduced NOx emissions. ... Read more

The sustainability issue has intensified interest in low-carbon alternatives to conventional hydrocarbon fuels for transport and power, where combustion is still expected to play a role. Ammonia is a promising carbon-free energy carrier, but it is difficult to ignite and exhibits slow early flame propagation, limitations that become more severe at low temperature and high pressure. Experimental data in this combined regime remain scarce, motivating this work to establish a validated basis for assessing ammonia and ammonia–hydrogen combustion under subzero conditions.

A custom constant-volume chamber was designed, commissioned, and validated for controlled subzero operation, with pressure-based diagnostics used to infer laminar burning velocity during early spherical flame growth. Results show that lowering the initial temperature from room temperature to \SI{-50}{\degree C} produces a strong penalty in neat-ammonia burning velocity across the investigated equivalence ratios, pushing the flame into a regime where losses and stretch effects become increasingly influential and ignition robustness is reduced. Hydrogen blending at \SI{-50}{\degree C} provides a marked performance recovery, with 20% and 30% H$_2$ producing substantial increases in burning velocity and restoring behaviour comparable to neat ammonia at room temperature near stoichiometric conditions. Minimum ignition energy could not be quantified reliably due to electrical signal variability, but ignition threshold settings indicate a strong increase in ignition difficulty as temperature decreases. Overall, the results show that subzero temperatures penalise neat-ammonia early combustion more strongly than predicted by kinetic models, while modest hydrogen enrichment can recover performance and improve robustness under cold-start-relevant conditions. ... Read more

Additive Manufacturing (AM) has become the standard for the production of liquid propellant rocket engines, including the Throttleable Liquid Propulsion Demonstrator (TLPD) developed by the Łukasiewicz Research Network – Institute of Aviation. The aim of this thesis is twofold. The first goal is to calibrate a nonlinear material model of AM CuCrZr alloy based on experimental tests. The second goal is to perform a thermostructural analysis of the TLPD2 combustion chamber using that material model. Multiple types of tests were conducted, and manual calibration of the model achieved high accuracy. The model was applied to the FEM analysis of the TLPD2 chamber, showing elastic operation and no lifetime concerns. An additional analysis with increased pressure loads was conducted to compare the new material model with the old model based only on tensile tests. Large differences between the two models are present when plastic deformation occurs.

Related dataset 4TU.ResearchData: https://doi.org/10.4121/9072efcd-23ff-40bb-9b52-c490c28797cc
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This research, conducted in collaboration with Isar Aerospace SE, presents a heat transfer analysis on a single-element LOx/Propane subscale rocket combustor with reactive-film cooling. The work aims to firstly reconstruct the time/space-resolved wall heat flux distribution using an inverse method, and secondly to analyze how operating parameters influence the thermal loads.
A series of hot-fire experiments were conducted in a capacitively and film-cooled copper subscale chamber, instrumented with thermocouples in multiple axial and azimuthal locations to capture the thermal response. A solver called Roq¤FITT was used to compute the heat flux profiles from temperature measurements, by coupling a transient conduction model with an iterative Jacobian-based optimization loop.
The analysis was focused on the throat region, where thermal stress peaks, and relied on visual graphs and statistical tools. Although a strong collinearity between chamber pressure and film ratio emerged, highlighting the limitation of the experimental set-up to fully isolate the contribution of all variables, meaningful trends emerged. Among them are correlations between heat loads and both chamber pressure and pressure instabilities, as well as an optimal film ratio configuration with minimized heat flux.
By computing the wall heat flux from internal temperature measurements, the study provides thermal insight into combustion-driven heat loading without the need to directly model the complex chemical and turbulent flow dynamics occurring inside the chamber. The obtained results form a valuable foundation for further design decisions on regeneratively cooled chambers and multi-element injector configurations, using the innovative LOx/Propane propellant combination. ... Read more

With the rapid growing aviation industry and the high amount of produced greenhouse gases, the search in more sustainable propulsion methods continues. A possible solution is the use of hydrogen fuel cells, significantly reducing the production of NOx and CO2. Although several studies are being performed for the performance and applications of the fuel cell, for which the Airbus ZEROe program is one of them, the additional air supply system lacks research. Due to the specific operating conditions of the fuel cell and the large difference between ambient conditions, the air supply system should be analysed with care as it can require a lot of energy over an entire flight. This thesis focuses on developing a model capable of analysing the performance of the air supply system, using the Airbus ZEROe fuel cell as a reference. Furthermore, different architectures have been compared in order to analyse the effect of different components. A model has been developed capable of sizing and analysing the performance for different air supply architectures. The compressor, turbine, and heat exchangers have beenmodelled such that they provide a physical representation of what is happening inside the air supply system. Furthermore, as the model requires geometrical parameters as an input, it can be easily adapted to optimise these components for different design conditions. Therefore, the model has been used to optimise four different architectures, consisting of a variation between single or double stage compressors and the inclusion of a recuperator. The optimisation has been performed for several design conditions, analysing not only the effect for different flight conditions but also the altitude, fuel cell pressure, and air mass flow. For the optimisation, it has been found that the architecture resulting in the lowest power required has a single stage compressor and a recuperator, having a power required of 77.5 kW for cruise. However, the addition of the recuperator adds a significant amount of mass, as the total air supply system mass is estimated around 315 kg. Compared to an architecture without the recuperator (168 kg) this is a significant difference. However, the power required for this architecture is significantly higher, with a value of 100 kW. Overall it was found that although adding mass, the recuperator significantly reduces the power required. Next to the recuperator, the addition of a second stage compressor has been analysed as well. Although adding mass, it has been seen that for the higher mass flow and pressure ratio cases, such as top of climb, the double stage compressor performs better than the single stage compressor, although this difference is not as large as for the addition of the recuperator. Apart from the optimisation, the off-design performance has been analysed as well for the four different architectures, taking the cruise-, takeoffand top of climb optimised architectures as a base. It was found that the off-design performance for the different architectures is mostly limited by the choice in design point. The main component that was affected the most by this is the turbine, as a turbine bypass valve is required. The turbine bypass valve regulates the mass flow passing through the turbine, controlling the expansion ratio for a fixed shaft speed. It has been observed that the valve is required for architectures that are optimised for high pressure ratios and low mass flows, as the valve was seen opened for lower pressure ratios and higher mass flows. Although the bypass valve is required, it was observed that the performance of these architectures was always better than an architecture that did not require the turbine bypass valve, such as those optimised for takeoff. Additionally, limiting operating conditions have been identified through off-design analysis. The most critical case for sizing the heat exchangers is the hot day scenario at the top of climb. Due to the high pressure ratio and the resulting high compressor outlet temperature, adequate cooling is required to achieve the necessary fuel cell temperature. It was found that, for other optimised points, architectures with a recuperator face more challenges in this regard compared to those without a recuperator, mainly because of their smaller liquid heat exchangers. Other identified limiting conditions include low mass flow operating points for the compressor, lower-than-design expansion ratios, and higher mass flows for the turbine. These conditions necessitate the addition of bypass valves to ensure proper operation. ... Read more

The decarbonization of gas turbine technology requires combustion systems capable of operating with hydrogen and hydrogen–natural gas blends while maintaining low NOx emissions. Hydrogen combustion increases flame temperature and reactivity, which might increase thermal NO formation through the Zeldovich mechanism and increase the flashback risk. Steam dilution is a promising strategy to mitigate NOx and improve flashback resistance without major hardware modifications, yet its performance in partially premixed, swirl-stabilized flames with different fuel composition, steam delivery strategy, and operating conditions is not yet fully understood.

This thesis investigates the effect of steam injection on NO emissions in lean premixed CH4/H2 flames using a swirl-stabilized vertical combustor operating at 7–11 kW. Four experimental series were conducted to isolate the influence of (i) thermal load, (ii) H2 blend fraction, (iii) steam injection amount, and (iv) injection location (side vs. axial). Emissions were measured using an ABB AO2000 gas analyzer, and the results are reported as raw, 15% O2 normalized and mass- & energy-based emission indices (EINO). Flame structure was characterized using DSLR imaging and OH∗ chemiluminescence. A simplified analytical estimate based on thermal NO scaling was developed to contextualize the measurements.


Steam injection consistently reduced NO under all operating conditions. Measured reductions ranged from 30–40% at moderate steam loadings (17.7 g/min) to 45–55% under higher steam addition (24.4 g/min), in close agreement with the simplified thermal prediction. NO reductions exceeded 80% in high methane fraction blends in lean conditions but approached local quench limits, as indicated by elevated CO and unburned CH4 measured at the exhaust. High hydrogen blend fraction flames produced higher absolute NO but tolerated steam injection without evident oxidation penalties. Axial steam injection provided more uniform premixing than side injection and maintained stable operation across all H2 blends, achieving comparable or improved NO reduction without CO rise. Flame Imaging revealed that steam addition cools and weakens the flame core, producing annular reaction zones consistent with reduced peak temperatures and suppressed radical pools.


The results demonstrate that steam injection is an effective NO control strategy for hydrogen partially- premixed combustion. Its effectiveness depends on injection strategy, blend ratio, and operating power. A more uniform steam–air partial-premixing have a more favorable effect on NO reduction and stability. The findings provide design guidance for implementing steam dilution in practical low-NOx hydrogen combustion systems and highlight directions for future work, including high-pressure testing and resolved diagnostics of radical fields and local temperature ... Read more

Human civilization must transition tomore sustainable energy sources to meet the goals of the Paris Agreement, which aims to limit the global temperature increase to well below 2 ◦C above pre-industrial levels. However, hard to abate sectors such as aviation and heavy industries will continue to rely on combustion for the foreseeable future. For these industries, the development and deployment of alternative fuels are essential. One of the most promising alternative fuels is hydrogen (H2), primarily because it enables carbonfree combustion. Nevertheless, significant challenges remain regarding its production, storage, and transportation, leading to uncertainties in its large-scale availability. As a result, there is growing interest in fuel-flexible combustion systems that can operate efficiently on traditional carbon-based fuels, hydrogen, or any mixture of the two, while maintaining combustion stability and lowemissions across the full fuel range. Hydrogen differs significantly from carbon-based fuels such as methane (CH4) in its combustion characteristics. It has a much higher flame speed and higher adiabatic flame temperature at the same equivalence ratio. These properties can pose serious design challenges such as increased risk of flashback and elevated NOx emissions.

In swirl-stabilized combustion, injecting non-swirled air axially on the centreline can be a very efficient way to stabilize flames with high hydrogen content. This work investigates the emissions and flame stability of a fuel flexible swirl-stabilized combustor that can operate on fuel mixtures ranging from 100% CH4 to 100% H2. In this set-up, fuel is injected in a jet in cross-flow configuration just downstream of the swirler exit. A mixing tube is placed between the injection point and the combustion chamber to allow for fuel-air mixing. The objective of this thesis is to identify the dominant parameters that govern emissions and stability in fuel-flexible combustion systems. To support this aim, several research questions are formulated and addressed in dedicated chapters…
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This study investigates the use of a non-pre-mixed resonance igniter for liquid propellant rocket engines, using oxygen and methane. Resonance heating at varying nozzle gap spacing for both oxygen and nitrogen is investigated both experimentally and numerically. High frequency microphone data is used to experimentally determine the operating mode of the igniter. Temperature measured on the outside of the resonator tip is used to evaluate heating performance at specific set points. The Open Source CFD software SU2 is used to create a numerical model, capable of accurately predicting the switch in igniter operating point, as well as the operational parameters leading to the highest rates of thermo-acoustic heating. Ignition attempts show that the separate injection of methane into the combustion chamber causes severe disruption of resonance heating, preventing the mixture from igniting. ... Read more

This master thesis explores the potential of hydrogen-enriched fuel blends in improving the performance and reducing emissions of lean premixed swirl-stabilized combustors in the aerospace sector. As industries face increased pressure to decarbonize amidst global energy crises and climate change, alternative fuels like hydrogen are being considered due to their lower carbon emissions compared to traditional hydrocarbon fuels.

By employing a high-speed solenoid flow valve to induce controlled fluctuations in the air-fuel mixture, the study investigates how these changes influence the overall behavior of the combustion process. The experimental setup for this thesis involved a swirl-stabilized multi-fuel combustor at the TU Delft Sustainable Propulsion Lab, capable of operating with methane and up to 100% hydrogen enrichment. The experimental analysis used a range of techniques, including Particle Image Velocimetry, SPOD and various acoustic and pressure measurements, to examine the impacts on the combustor’s operation across different power settings and levels of hydrogen enrichment.

The findings reveal that adjusting the equivalence ratio through precise airflow modulation can significantly alter the unsteady combustion dynamics. Notably, this modulation enhances the stability of the flame by dampening the damaging thermoacoustic instabilities commonly associated with lean premixed combustors. Additionally, the research demonstrates that these adjustments can lead to changes in emission levels, notably in how nitrogen oxides and carbon dioxide are produced under varying conditions of hydrogen content and power settings.

A comprehensive numerical model was also developed to support and extend the experimental results, providing insights into the potential scalability and application of these findings to larger, real-world combustion systems. This model underscores the practical implications of the experimental findings, suggesting that such controlled fluctuations can be a viable method to optimize the design and operation of next-generation combustors. ... Read more

The demand for commercial aviation is growing at an annual rate of 4%, posing significant environmental challenges. Large-capacity aircraft designed for long ranges are often used on short-to-medium range routes, leading to inefficient fuel consumption and higher emissions. With a future market need for aircraft seating 211 to 300 passengers, there is a clear gap for such a passenger airliner. This report examines the feasibility of the X-300 EcoFlyer, a proposed short-to-medium range aircraft with reduced environmental impact. Designed to carry 300 passengers over 3000 km, the X-300 aims to achieve 25% lower CO2 emissions, 50% lower NOx emissions, and 20% lower noise emissions compared to the Airbus A320neo. The study covers aircraft functions, system design, performance analysis, manufacturing, sustainability, operations, logistics, business viability, and technical risks. The findings confirm the X-300 EcoFlyer's potential to meet future demands with lower environmental impact. Innovations include a noise-shielding fuselage, a water-injected turbofan engine, in-wheel electrical taxing, and an electrical environmental control system. Overall, the X-300 EcoFlyer represents a promising solution to the challenges facing the future of high-capacity air transport. ... Read more

This report discusses urban air quality measurements carried out in a park in Aigaleo (Athens), located adjacent to a busy road. The measurements were taken using the Sniffer4D Mini 2 sensor box with a drone to investigate how Urban Air Mobility can aid in measuring urban air quality. CO, NO₂, O₃, SO2, PM_2.5 and PM₁₀ concentrations were recorded through point measurements at varying locations, altitudes and times. Several validation measurements were carried out, showing that temperature heavily influenced the outcome of the recordings. Due to the high number of variables, no conclusion has been found on the wind effect. During rush hour, NO₂ and CO concentrations were highest close to the traffic; however, NO₂ concentration showed non-linear behaviour with increase in altitude when further from the traffic or out of rush hour. SO₂ concentration always decreased with an increase in altitude; highest concentrations were observed further from the busy road. Highest O₃ concentrations were obtained in the afternoon at higher altitudes, due to its reaction under sunlight. PM_2.5 and PM₁₀ concentrations had a high variability due to environmental conditions. Additionally, continuous measurements were carried out, in which the drone flew a path through several locations and altitudes. The results from these were interpolated to enable the detection of areas with higher concentrations of air pollutants. ... Read more

The growing demand in the aviation industry after the COVID-19 pandemic and the anthropogenic effects on the climate require the aviation sector to identify suitable solutions to continue operating while reducing its impact on the environment. Among the challenges faced by the aviation sector, the reduction of non-CO2 emissions is of particular interest. The use of alternative carbon-free fuels such as hydrogen poses challenges. Compared to conventional fuels, the increased flame temperature of hydrogen flames leads to higher NOx emissions while the increase in flame speed presents difficulties to stabilize the flame
and prevent flashback.

Numerical investigations have assessed the thermal and chemical effects as a result of the injection of water droplets in a hydrogen flame. The present investigation aims to assess the interaction of water droplets on premixed methane and hydrogen flames to determine if they can impart flame stretch. The effect is novel and would represent a third effect in addition to the thermal and chemical ones.

Identifying off-the-shelf atomizers is challenging and the two available and suitable atomizers at the time of the execution of the thesis are selected. The first atomizer is a pressure swirl nozzle and is integrated in a swirl-stabilized flame set-up. The second atomizer is an ultrasonic atomizer and is integrated in laminar premixed methane and hydrogen flames set-ups. The pressure swirl atomizer is integrated with a pressurization system to impose a pressure differential across the nozzle, where the pressure is converted into kinetic energy. Moreover, a 3D printed holder is manufactured to enclose the ultrasonic atomizer.

A thermodynamic model is developed to determine the equilibrium temperature of the products arising from the combustion of an adiabatic flame mixing with the injected water. The model allows to determine the non-dimensional fraction of fuel to water content for each operating condition.

The selected flames are a turbulent partially premixed swirl-stabilized flame and a set of laminar premixed flames. The laminar premixed flames include bunsen flames, plate-stabilized and V-shaped flames. The operating conditions of the flames are determined to characterize the interaction between water droplets and the considered flames. The selection of laminar bunsen flames allows to assume that the baseline configuration is unstretched, while the plate-stabilized flames allow to approach a configuration where the flame is already strained and finally the V-shaped flame allows to achieve a configuration where the
flame front is more accessible compared to the bunsen flame and the plate-stabilized flames. Moreover, the swirl-stabilized flame allows to verify the injection of water droplets in a confined environment in order to assess if the interaction with the water droplets is sufficient to perform measurement of NOx emissions using an exhaust gas analzyer. Additionally, the effects of flame stretch according to theory are reflected in the test point selection.

OH*chemiluminescence average images on the laminar premixed hydrogen flames show that the fluid dynamic interaction between water droplets and the flame surface is limited due to the relatively small size of the hydrogen flame, which must be stabilized using a smaller burner due to enhanced fuel reactivity. The difference between dry and wet conditions shows a change in signal intensity without affecting the flame position. Plate-stabilized flames allow to reduce the dependency of the interaction on the flame size and therefore are more suitable to perform investigations on the interaction between water droplets and hydrogen flames.
The comparison of OH-PLIF and OH* chemiluminescence images allows to state the former technique allows to identify the region where the water droplets interact with the reaction zone, while the latter allows to identify and isolate the effects on the flame front. ... Read more

Hydrogen, as a carbon-free fuel, offers a promising solution to reduce CO2 emissions in pursuit of cleaner combustion technologies. However, its combustion poses challenges, including increased NOx production due to high adiabatic flame temperatures, along with risks of flashback and thermo-diffusive instabilities. One approach to addressing these challenges is Moderate or Intense Low-Oxygen Dilution (MILD) combustion, which significantly lowers NOx emissions by reducing reaction temperatures. Techniques like exhaust gas recirculation (EGR) can further support this process. Additionally, blending hydrogen with other fuels, such as ammonia and methane, improves flame stability, safety, and flame speed.

This thesis is part of the ACHIEVE project (Advancing the Combustion of Hydrogen-Ammonia Blends for Improved Emissions and Stability), funded by the European Union under the Horizon European Research and Innovation Actions in collaboration with the Clean Hydrogen Partnership. The project aims to advance Technology Readiness Level 4 technologies that reduce pollutants in unconventional hydrogen blends, such as mixtures of NH3, CH4, and H2. The combustion characteristics of these unconventional blends are studied numerically and experimentally in high-stability combustors, with a focus on MILD combustion and the effects of exhaust gas recirculation.

Aligned with these goals, the TU Delft Enclosed-Jet-in-Hot-Coflow (EJHC) burner, designed for MILD combustion, is used to experimentally investigate premixed and non-premixed methane-hydrogen and pure hydrogen flames. The research examines flame morphology, temperature, emissions profiles, and the effects of exhaust gas recirculation on NOx emissions. This serves as a foundational step for future research into ammonia-hydrogen blends. The burner features a central flame auto-ignited by a hot vitiated coflow produced by a secondary burner. Design modifications were implemented to improve coflow uniformity near the jet exit.

The research involved two experimental campaigns. The first, conducted under cold flow conditions using Particle Image Velocimetry (PIV), assessed coflow uniformity at different inlet velocities. The second campaign focused on reactive flow experiments, using thermocouples, chemiluminescence, and gas analyzers to study methane-air coflow and methane-hydrogen blends in premixed and non-premixed conditions. Hydrogen concentration was varied from 0% to 100%, with different power ratios between the central jet and coflow.
The study showed that using a perforated plate as a secondary burner enhanced coflow uniformity, with PIV results showing reduced radial variations of the vertical velocity component. Thermocouple measurements confirmed a uniform temperature profile.
Flame lift-off height and shape in both premixed and non-premixed conditions were influenced by jet velocity, laminar flame speed, and hydrogen content. Hydrogen addition reduced lift-off height. In premixed conditions, flames were compact and narrow, while in diffusion conditions, higher hydrogen content increased mixing with the coflow at greater radial distances. NO emissions remained stable in premixed cases but were affected by coflow composition in diffusion flames, with lower oxygen levels enhancing NO reburning.

This study provides a versatile system for investigating exhaust gas recirculation and hydrogen blends over a wide range of power and equivalence ratios. It lays the foundation for future studies on ammonia-hydrogen combustion.
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