Effect of primary water injection angle on thermal propulsion performance of a water ramjet engine

Liu, Dechao; Li, Shulei; Xie, Gongnan

doi:10.1016/j.ast.2019.105630

Cited by 13 publications

(3 citation statements)

References 20 publications

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“…Water-breathing ramjets (ram rockets) have been studied in the past both theoretically and experimentally. Most of the theoretical works have explored the optimal performance of the motor, with a focus on using solid propellants with metal additives such as magnesium and aluminum [4][5][6][7][8]. In addition to theoretical investigations, experimental research on the combustion of various fuels with water has been conducted [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Testing of a Hybrid-Propellant Water-Breathing Ram Rocket in Underwater Cruise Conditions

Dinisman,

Eisen,

Gany

2024

JMSE

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High-speed submerged marine vehicles, such as torpedoes, traveling at velocities of an order of 100 m/s and above, require powerful propulsion to overcome the tremendous hydrodynamic drag. This paper aims to investigate a marine hybrid-propellant water-breathing ram rocket (marine ramjet or ducted rocket) under various underwater cruise conditions. At high underwater cruise speeds, the ram rocket outperforms regular rocket motors, substantially increasing its specific impulse and thrust. This investigation utilized a unique test facility capable of dynamically testing the marine ramjet. Over 20 dynamic experiments have been conducted, revealing the submerged motor characteristics at different cruise speeds, water-to-propellant mass ratios, and oxidizer-to-fuel mass ratios, thereby creating a performance map of the marine ramjet. The results were compared with static firing data and theoretical calculations, showing a good agreement with standard specific impulse improvement of about 55% compared to a regular hybrid rocket, reaching a maximum value of 380 s. The significant increase in performance demonstrates the potential of the water-breathing ramjet for propelling high-speed underwater vehicles.

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Section: Introductionmentioning

confidence: 99%

Dynamic Testing of a Hybrid-Propellant Water-Breathing Ram Rocket in Underwater Cruise Conditions

Dinisman,

Eisen,

Gany

2024

JMSE

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“…That research can serve as a convenient tool for determining the operating parameters of practical vehicles. More work on air-augmented waterjet has been conducted in the last two decades, e.g., Dynaflow's research [17][18][19], Gowing et al [20], Fu et al [21], Liu et al [22], and Zhang et al [23]. They included certain analytical aspects, numerical calculations, and experiments, typically in static systems with transparent walls allowing visualization of the flow development and phenomena.…”

Section: Introductionmentioning

confidence: 99%

Open-Sea Testing of Two-Phase Marine Ramjet Propulsion

Valensi,

Gany

2023

JMSE

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Open-sea testing of a two-phase marine ramjet vehicle has been conducted. This experimental phase was accomplished following comprehensive theoretical research. The concept of two-phase marine ramjet propulsion consists of a submerged propulsor acquiring water through an inlet due to the vehicle’s motion. Thrust is generated by injecting and dispersing air (or gas) bubbles within the water flowing through the propulsion unit channel and expelling a jet of the two-phase flow through an exit nozzle. The bubbles injected into the internal flow transmit their expansion work to the outgoing jet, resulting in an increase in the jet velocity, hence generating thrust. The article briefly describes the thrust generation concept, then it presents the overall system and thrust units attached to the test vessel, and finally, it summarizes the open-sea experimental results. Good correspondence between the theoretical prediction and actual test data is shown, revealing the feasibility of the two-phase ramjet concept at the low to intermediate cruise velocity range and a smaller relative thrust margin over the hydrodynamic resistance at the high-speed range.

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“…Aluminum has a higher heat of reaction with water, whereas magnesium is more reactive with water, which, in practice, may lead to a better reaction efficiency, compensating for its lower heat of reaction. Works performed in the field have mainly focused on different aspects of solidpropellant, water-breathing ramjets, such as evaluating optimal operating conditions and maximal theoretical performance [7][8][9][10][11], combustion properties of different propellants and fuels tailored for a water-breathing operation [1][2][3][4][5], and static firing tests [12,13] as well as other aspects [14]. Previous research conducted by these authors [15,16] suggested considering the use of a ducted, hybrid, ram-rocket-based water-breathing ramjet.…”

Section: Introductionmentioning

confidence: 99%

Examining Metal Additives in a Marine Hybrid-Propellant, Water-Breathing Ramjet

Eisen

Gany

2022

JMSE

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This research focuses on theoretically and experimentally evaluating the performance of a metallized hybrid-propellant, water-breathing ramjet. The aluminum and/or magnesium particles added to a polymeric (polyester) fuel grain are hydro-reactive, using the surrounding water as an oxidizer, in addition to a source of gas. Theoretically, the metal additives significantly increase the specific impulse of the motor, and as the percentage of the hydro-reactive ingredient increases, the theoretical performance increases as well. Additionally, aluminum is more energetic than magnesium. However, it was experimentally discovered that the addition of aluminum beyond 20% resulted in a slag formation and did not increase the specific impulse. Adding 30% of magnesium was relatively favorable to aluminum due to its better reactivity, enabling the achievement of an actual specific impulse of up to 485 s at standard conditions, approximately double the performance of common solid rockets.

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Effect of primary water injection angle on thermal propulsion performance of a water ramjet engine

Cited by 13 publications

References 20 publications

Dynamic Testing of a Hybrid-Propellant Water-Breathing Ram Rocket in Underwater Cruise Conditions

Dynamic Testing of a Hybrid-Propellant Water-Breathing Ram Rocket in Underwater Cruise Conditions

Open-Sea Testing of Two-Phase Marine Ramjet Propulsion

Examining Metal Additives in a Marine Hybrid-Propellant, Water-Breathing Ramjet

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