Pulsed Detonation Hydroramjet: Design Optimization

Фролов, С. М.; Avdeev, K. A.; Aksenov, V. S.; Фролов, Ф. С.; Садыков, И. А.; Шамшин, И. О.

doi:10.3390/jmse10091171

Cited by 4 publications

(2 citation statements)

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“…The mixture is exhausted through a nozzle generating substantially higher thrust than that of a rocket motor, mainly due to the higher jet mass flow rate. A different concept of marine ramjet, the pulse detonation hydroramjet, was recently studied by Frolov et al [27]. They presented an experimental investigation revealing positive average thrust and good performance.…”

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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Section: Introductionmentioning

confidence: 99%

Open-Sea Testing of Two-Phase Marine Ramjet Propulsion

Valensi,

Gany

2023

JMSE

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“…The performance of PDH models operating at a pulse generation frequency of up to 20 Hz was investigated in [38,39]. The time-averaged specific impulse of PDH models attained 550 s [40], which was higher than that of the most advanced liquid propellant rocket engines.…”

Section: Introductionmentioning

confidence: 99%

Interaction of Shock Waves with Water Saturated by Nonreacting or Reacting Gas Bubbles

et al. 2022

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A compressible medium represented by pure water saturated by small nonreactive or reactive gas bubbles can be used for generating a propulsive force in large-, medium-, and small-scale thrusters referred to as a pulsed detonation hydroramjet (PDH), which is a novel device for underwater propulsion. The PDH thrust is produced due to the acceleration of bubbly water (BW) in a water guide by periodic shock waves (SWs) and product gas jets generated by pulsed detonations of a fuel–oxidizer mixture. Theoretically, the PDH thrust is proportional to the operation frequency, which depends on both the SW velocity in BW and pulsed detonation frequency. The studies reported in this manuscript were aimed at exploring two possible directions of the improvement of thruster performances, namely, (1) the replacement of chemically nonreacting gas bubbles by chemically reactive ones, and (2) the increase in the pulsed detonation frequency from tens of hertz to some kilohertz. To better understand the SW-to-BW momentum transfer, the interaction of a single SW and a high-frequency (≈7 kHz) sequence of three SWs with chemically inert or active BW containing bubbles of air or stoichiometric acetylene–oxygen mixture was studied experimentally. Single SWs and SW packages were generated by burning or detonating a gaseous stoichiometric acetylene–oxygen or propane–oxygen mixture and transmitting the arising SWs to BW. The initial volume fraction of gas in BW was varied from 2% to 16% with gas bubbles 1.5–4 mm in diameter. The propagation velocity of SWs in BW ranged from 40 to 580 m/s. In experiments with single SWs in chemically active BW, a detonation-like mode of reaction front propagation (“bubbly quasidetonation”) was realized. This mode consisted of a SW followed by the front of bubble explosions and was characterized by a considerably higher propagation velocity as compared to the chemically inert BW. The latter could allow increasing the PDH operation frequency and thrust. Experiments with high-frequency SW packages showed that on the one hand, the individual SWs quickly merged, feeding each other and increasing the BW velocity, but on the other hand, the initial gas content for each successive SW decreased and, accordingly, the SW-to-BW momentum transfer worsened. Estimates showed that for a small-scale water guide 0.5 m long, the optimal pulsed detonation frequency was about 50–60 Hz.

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