Characterization of ammonia spray combustion and mixture formation under high-pressure, direct injection conditions

Scharl, Valentin; Lackovic, Tomislav; Sattelmayer, Thomas

doi:10.1016/j.fuel.2022.126454

Cited by 40 publications

(10 citation statements)

References 37 publications

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“…Despite the poor compression ignition performance of ammonia, the ignition energy supplied by a small amount of diesel injected in advance could better satisfy the pressure requirements. Although the flame speed of ammonia was slower than that of diesel, , the intense turbulent flow in the cylinder and the higher atomization rate of ammonia after spraying into the cylinder compared to diesel , allow for the formation of mixed combustible gas to occur more quickly. Therefore, the mixing rate of gas in the cylinder predominates over the combustion rate.…”

Section: Resultsmentioning

confidence: 99%

Simulation Research on the Injection Strategy of a Diesel-Ammonia Dual-Fuel Marine Engine

et al. 2023

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Currently, most ships still rely on fossil fuels as the main source for marine engines. However, diesel as a fuel for marine engines is no longer sufficient to meet the economic requirements of shipping and emission restrictions imposed by regulations as a result of the depletion of fossil fuels and the pollution generated by their burning. This research examined the viability of employing hydrogen-carrying fuel ammonia (NH 3 ) in marine engines to develop a low-carbon combustion technology, to address the carbon emission problem of marine diesel engines. The results demonstrate that a greater proportion of ignition fuel must be injected into the burning of ammonia due to its higher ignition energy requirements. And ammonia has a high evaporation rate, so it is important to properly extend the injection duration to lower the combustion rate and keep the maximum explosion pressure in the cylinder under control. If the injection duration of the original engine's diesel mode is maintained in dual-fuel mode, the explosion pressure in the cylinder can increase by more than 5 MPa, exceeding the limit of the original engine. However, by extending the original engine duration, the maximum explosion pressure returned to the original engine level. The starting point of the in-cylinder combustion can be efficiently regulated by changing the injection timing. Under typical injection intervals, the heat released rate (HRR) curve shifted with ammonia injection time, and rough combustion occurred only when the injection interval between the ignition fuel and ammonia was too short. According to the simulation, with all other conditions held constant, the optimal fuel injection strategy maintains the in-cylinder pressure of the engine at the diesel engine's original level in the dual-fuel mode. Additionally, it reduced carbon emissions by over 90% and NOx emissions by approximately 70% compared with the original diesel engine.

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Section: Resultsmentioning

confidence: 99%

Simulation Research on the Injection Strategy of a Diesel-Ammonia Dual-Fuel Marine Engine

et al. 2023

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“…However, it is important to note that the actuator's output is influenced by the working environment temperature and the set speed. Taking the REXA hydraulic actuator as an example, the thrust force of the actuator was FIGURE 8 The relationship between temperature and speed to actuator output directly measured through mechanical testing, obtaining the relationship between temperature and the actuator's output force under varying ambient temperatures and different set maximum speeds, as shown in Figure 8.…”

Section: Results and Discussion Of Adjusting Calorific Value Process ...mentioning

confidence: 99%

“…The fuel's calorific value, composition, temperature, and pressure can lead to systematic issues. During the initial stage of IGCC system debugging, gas turbines often encounter problems with calorific value control, resulting in shutdowns [6].To adapt to different gas turbine operating conditions, it is necessary to adjust the syngas' calorific value within a certain range using a specific method to ensure stable combustion of the gas turbine [7,8]. Currently, the main method of adjusting the calorific value involves adding saturated steam or nitrogen to the fuel.…”

Section: Introductionmentioning

confidence: 99%

Fuel calorific value control process analysis and research based on IGCC power plant

Ding,

Chen,

Tao

2023

IET Renewable Power Gen

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The stability of the equipment has been more and more important with the continuous development of IGCC (Integrated Gasification Combined Cycle) technology. The control of the calorific value of the fuel gas of the gas turbine is one of the most important factors for the stable operation of the gas turbine. There are many variables in the calorific value of IGCC fuels that will cause unstable fuel combustion conditions and low thermal efficiency. In terms of process equipment, process conditions, instrument control calculation, and logic adjustment, this paper studies the automatic adjustment system of the calorific value of syngas for IGCC gas turbine fuel. The calorific value of the syngas can be automatically adjusted under different working conditions of the gas turbine. It helps the stable combustion of the gas turbine to form a perfect, efficient, reliable calorific value control system.

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“…They found that the interaction angle between the diesel jet and liquid ammonia jet strongly affected the ignition delay and heat release rate of ammonia combustion. The visualized experiment demonstrated more information on the spray and flame characteristics [36]. They also revealed that the instability of ammonia flame is mainly caused by the difficulty of achieving a good quality of the fuel-air mixture.…”

Section: Introductionmentioning

confidence: 87%

Experimental Investigation of High-Pressure Liquid Ammonia Injection under Non-Flash Boiling and Flash Boiling Conditions

Fang

Zhang

et al. 2023

Energies

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Liquid ammonia is an ideal zero-carbon fuel for internal combustion engines. High-pressure injection is a key technology in organizing ammonia combustion. Characteristics of high-pressure liquid ammonia injection is lack of research. Spray behaviors are likely to change when a high-pressure diesel injector uses liquid ammonia as its fuel. This study uses high-speed imaging with a DBI method to investigate the liquid penetration, width, and spray tip velocity of high-pressure liquid ammonia injection up to 100 MPa. Non-flash and flash boiling conditions were included in the experimental conditions. Simulation was also used to evaluate the results. In non-flash boiling conditions, the Hiroyasu model provided better accuracy than the Siebers model. In flash boiling conditions, a phenomenon was found that liquid penetration and spray tip velocity were strongly suppressed in the initial stage of the injection process, this being the “spray resistance phenomenon”. The “spray resistance phenomenon” was observed when ambient pressure was below 0.7 MPa during 0–0.05 ms ASOI and was highly related to the superheated degree. The shape of near-nozzle sprays abruptly changed at 0.05 ms ASOI, indicating that strong cavitation inside the nozzle caused by needle lift effects is the key reason for the “spray resistance phenomenon”.

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Characterization of ammonia spray combustion and mixture formation under high-pressure, direct injection conditions

Cited by 40 publications

References 37 publications

Simulation Research on the Injection Strategy of a Diesel-Ammonia Dual-Fuel Marine Engine

Simulation Research on the Injection Strategy of a Diesel-Ammonia Dual-Fuel Marine Engine

Fuel calorific value control process analysis and research based on IGCC power plant

Experimental Investigation of High-Pressure Liquid Ammonia Injection under Non-Flash Boiling and Flash Boiling Conditions

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