Investigation of the Effect of Nozzle on Underwater Detonation Shock Wave and Bubble Pulsation

Wang, Chuanwei; Li, Ning; Huang, Xiaolong; Wang, Chunsheng

doi:10.3390/en15093194

Cited by 3 publications

(3 citation statements)

References 26 publications

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“…Thereafter, a larger bubble with a diameter of d ≈3.5 mm exploded with a time delay (frame 6), despite it being subjected to shock compression earlier, being somewhat upstream with respect to the two bubbles that exploded earlier. Furthermore, this bubble expanded (frame 7), shrank again (frame 8) and expanded again (frames 9-11), taking the shape of a parachute (frames 12-14), and then broke up into small fragments (frames [15][16][17][18][19][20]. The processing of video records made it possible to gain information on the shockinduced motion of individual bubbles behind the traveling SW.…”

Section: Single Shock Wave Propagation In Bubbly Watermentioning

confidence: 99%

“…In [17], the results of experimental study on gas jetting by an underwater detonation tube were reported, and the mechanism of shock wave propagation and bubble deformation was discussed. The effect of the nozzle attached to a detonation tube on the underwater SW and gas detonation bubble was investigated in [18]. Three types of nozzles (converging, straight, and diverging) were examined.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Single Shock Wave Propagation In Bubbly Watermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2022

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“…Wang et al [28] reported the results of numerical simulation and experimental study on gas jetting by an underwater DT and discussed the mechanism of shock wave propagation and bubble deformation. Wang et al [29] investigated both computationally and experimentally the effect of the nozzle attached to a DT on the underwater shock wave and gas detonation bubble. Three types of nozzles (converging, straight, and diverging) were examined.…”

Section: Introductionmentioning

confidence: 99%

Pulsed Detonation Hydroramjet: Design Optimization

Фролов

Avdeev

Aksenov

et al. 2022

JMSE

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A new type of marine transportation engine, the pulsed detonation hydroramjet (PDH), which was first designed, manufactured, and tested by the present authors, has been further investigated in terms of the potential improvement of its propulsive performance. PDH is composed of a pulsed detonation tube (DT) inserted in the flow-through water guide. Thrust is developed by shock-induced pulsed water jets which are periodically emitted from the water guide nozzle. The measured values of the time-averaged thrust and specific impulse in the first operation cycle were shown to always be considerably higher than those in subsequent cycles, indicating the possibility of improving the overall thrust performance. The present manuscript is aimed at clarifying the reasons for, and eliminating, cycle-to-cycle variability during PDH operation, as well as optimization of the PDH design. An experimental model of the PDH with an optically transparent water guide was designed and manufactured. The cycle-to-cycle variability was found to be caused by the overexpansion of gaseous detonation products in the DT due to the inertia of water column in the water guide. Gas overexpansion caused the reverse flow of the gas–water mixture which filled the water guide and penetrated the DT, thus exerting a strong effect on PDH operation. To eliminate the cycle-to-cycle variability, a new PDH model was developed, manufactured, and tested. The model was equipped with a passive flap valve and active rotary valve and operated on the stochiometric propane–oxygen mixture. Its test firing showed that use of the valves made it possible to eliminate the cycle-to-cycle variability and nearly double the time-averaged thrust and specific impulse reaching 40 N and 550 s, respectively.

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Shock wave and bubble pulsation characteristics in a field generated by single underwater detonation

Wang

Huang

et al. 2022

Physics of Fluids

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To promote the development and application of underwater detonation propulsion technology, we built a single underwater detonation experimental system and established the corresponding axisymmetric five-equation model to study the characteristics of the flow field generated by a single underwater detonation. The shock wave formed by the degeneration of the detonation wave in the detonation tube interacted with the water-gas interface. Moreover, the jetting of detonated gas was blocked by water, which sharply increased the gas pressure and yielded a transmitted wave entering the water and a reflected wave returning to the tube. The transmitted wave reached a peak pressure of 16.77 MPa at 1,280 Hz. The extremely transient gas generated by detonation jetted into the water, forming bubbles with unique pulsation characteristics and completing the first pulsation cycle (28.4 ms) under the effects of the internal gas pressure and the inertia of water. In the contraction stage, the bubble changed into a complex linked annular bubble under the effects of gravity and a free surface. However, in the expansion stage, the bubble was less affected.

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Investigation of the Effect of Nozzle on Underwater Detonation Shock Wave and Bubble Pulsation

Cited by 3 publications

References 26 publications

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

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

Pulsed Detonation Hydroramjet: Design Optimization

Shock wave and bubble pulsation characteristics in a field generated by single underwater detonation

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