Recent developments in technological innovations in scramjet engines: A review

Kumar, S. Lakshmana; Pandey, Krishna Murari; Sharma, K. K.

doi:10.1016/j.matpr.2020.12.1086

Cited by 14 publications

(6 citation statements)

References 70 publications

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“…Ramjets are most efficient around the Mach 3 mark, after which, disassociation causes efficiency to drop off [49]. Numerous challenges are presented when running scramjets at hypersonic speeds, such as maintaining efficient combustion when the air passing through the engine is extremely pressurised and contained in the combustor for only a few milliseconds.…”

Section: Fuel Efficiency With Regards To Engine Efficiencymentioning

confidence: 99%

Assessing the Sustainability of Liquid Hydrogen for Future Hypersonic Aerospace Flight

et al. 2022

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This study explored the applications of liquid hydrogen (LH2) in aerospace projects, followed by an investigation into the efficiency of ramjets, scramjets, and turbojets for hypersonic flight and the impact of grey, blue, and green hydrogen as an alternative to JP-7 and JP-8 (kerosene fuel). The advantage of LH2 as a propellant in the space sector has emerged from the relatively high energy density of hydrogen per unit volume, enabling it to store more energy compared to conventional fuels. Hydrogen also has the potential to decarbonise space flight as combustion of LH2 fuel produces zero carbon emissions. However, hydrogen is commonly found in hydrocarbons and water and thus it needs to be extracted from these molecular compounds before use. Only by considering the entire lifecycle of LH2 including the production phase can its sustainability be understood. The results of this study compared the predicted Life Cycle Assessment (LCA) emissions of the production of LH2 using grey, blue, and green hydrogen for 2030 with conventional fuel (JP-7 and JP-8) and revealed that the total carbon emissions over the lifecycle of LH2 were greater than kerosene-derived fuels.

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Section: Fuel Efficiency With Regards To Engine Efficiencymentioning

confidence: 99%

Assessing the Sustainability of Liquid Hydrogen for Future Hypersonic Aerospace Flight

et al. 2022

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“…There are also continued combustion of gas and dissociation and recombination reactions of the components in the nozzle [2], while the vibrational energy of the gas is excited at high temperatures, and these phenomena indicate that the flow in the nozzle has thermochemical non-equilibrium effects. Among them, the chemical reactions and vibrational energy changes will affect the scramjet propulsive efficiency [3]. Hence, the study of thermochemical non-equilibrium effects is essential for complex flows in the high Mach number nozzle.…”

Section: Introductionmentioning

confidence: 99%

Influence of thermochemical non-equilibrium effects on non-uniform entrance scramjet nozzle

Wang,

Zhuo,

Ren

2024

J. Phys.: Conf. Ser.

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The high Mach number scramjet nozzle flow has prominent non-uniform characteristics and high-temperature non-equilibrium effects. Thus, the thermochemical non-equilibrium gas model was developed for simulating flows in the non-uniform and uniform entrance of a Mach 10 hydrocarbon fuel scramjet nozzle. The results show that the non-uniform entrance has a higher non-uniform degree in the flow-field compared to the uniform entrance. Additionally, the expansion degree inside the nozzle is greater and the thermal non-equilibrium effects downstream of the nozzle exit are stronger. The non-uniform entrance condition has a more intense chemical reaction near the nozzle exit but has less impact on the flow parameters. For the nozzle performance, under the influence of the non-uniform entrance, the greater gas expansion degree inside the nozzle results in a lower pressure acting on the upper wall, and then the nozzle thrust decreases by 1.68%. Hence, the structural design and performance optimization of the high Mach number scramjet nozzle must consider entrance non-uniform characteristics and thermochemical non-equilibrium effects.

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“…They have been widely used in fields such as space shuttles, high-speed weapons, and wide-speed-range vehicles [3], and comprise one of the most efficient and promising propulsion systems [4][5][6]. When a scramjet engine operates normally, air enters the engine at extremely high speeds, and the time for fuel injection, fuel/air mixing, and combustion in the combustion chamber is only a few milliseconds [7]. It is very difficult to maintain a stable flame, so a rational flame stabilization scheme is essential.…”

Section: Introductionmentioning

confidence: 99%

Parametric Study of Flow and Combustion Characteristic in a Cavitied Scramjet with Multi-Position Injection

Xi,

Liu,

Shao

et al. 2024

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This study focuses on the three-dimensional flow and combustion characteristics of a cavitied scramjet engine with multi-position injection. A single-equation large eddy simulation (LES) turbulence model is employed, with a detailed reaction mechanism for hydrogen combustion, as described by Jachimowski. The combustion characteristics of hydrogen in the scramjet combustion chamber are analyzed. Based on the combustion chamber model, the influence of different equivalence ratios, injection timing, injection positions, and injection pressures on the flame formation and propagation process are compared. The results indicate that within a certain range, an increase in the equivalence ratio enhances the combustion intensity and chamber pressure. In the case of multi-position injection, the order of injection from different nozzles has little effect on the final flame stabilization mode and pressure distribution. The opposite-side distribution of nozzles can effectively improve the fuel efficiency and the internal pressure. Furthermore, when the nozzles are closely placed in the opposite-side distribution, the combustion efficiency increases, although this leads to a higher total pressure loss. In scenarios where the fuel injection duration is short, an increase in the injection pressure at the upstream nozzles of the cavity results in a higher local equivalence ratio, as well as reduced fuel mixing and ignition time.

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Recent developments in technological innovations in scramjet engines: A review

Cited by 14 publications

References 70 publications

Assessing the Sustainability of Liquid Hydrogen for Future Hypersonic Aerospace Flight

Assessing the Sustainability of Liquid Hydrogen for Future Hypersonic Aerospace Flight

Influence of thermochemical non-equilibrium effects on non-uniform entrance scramjet nozzle

Parametric Study of Flow and Combustion Characteristic in a Cavitied Scramjet with Multi-Position Injection

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