Experimental and computational studies of shock wave-to-bubbly water momentum transfer

Фролов, С. М.; Avdeev, K. A.; Aksenov, V. S.; Борисов, А. А.; Фролов, Ф. С.; Шамшин, И. О.; Tukhvatullina, R. R.; Basara, Branislav; Edelbauer, Wilfried; Pachler, K.G.R.

doi:10.1016/j.ijmultiphaseflow.2017.01.016

Cited by 26 publications

(7 citation statements)

References 46 publications

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“…More specific studies on the transformation of the momentum into a shock wave to a bubbly liquid are presented in [6]. The photographs presented in the cited work indicate a fairly uniform distribution of bubbles in the liquid volume, which indicates the possibility of comparison with the theoretical results of this work.…”

Section: Introductionmentioning

confidence: 75%

Unsteady flow of bubble liquid in hydraulic systems of aircraft and helicopters

Lukianov,

Pavlova

2024

aktt

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The subject of this work is the phenomenon of a water hammer in a liquid that contains a small volume of gas bubbles. Historically, this phenomenon began to be studied as the dynamics of gas bubbles (Rayleigh-Pleset equation). Today, thanks to progress in computer technology, this phenomenon is studied at the level of bubble deformation during hydraulic shock. Another approach is to consider the dynamics of a multiphase (two-phase) medium in the form of a bubbly liquid. After several assumptions, the main one being a relatively small gas content in the liquid, the model consists of two differential equations with respect to the shock wave propagation speed and the resulting pressure perturbations. The specified system of equations differs from the corresponding classical water hammer equations: they consider the convection of the velocity field. In addition, the friction of the liquid against the wall according to the Weisbach-Darcy model is considered. Because of the small content of gas bubbles, the Weissbach-Darcy friction is approximated in the same way as in a homogeneous liquid, i.e., in a certain sense, greater than the real friction. Maybe that is why more or less physical results are obtained only for small values of the dimensionless parameter responsible for the friction of the liquid against the wall. It concerns the non-contradiction of the assumptions and the results obtained on their basis. Thus, in the front region of the shock pulse, where the pressure increases, the radial velocity of the bubbles is negative; however, for relatively large values of the friction parameter, the maximum pressure disturbance moves from the center of the shock pulse. This contradicts the assumption about compression: after passing the maximum pressure, gas bubbles expand due to a decrease in pressure. The graphical dependence obtained in this study are compared with the results related to a homogeneous liquid. They agree, but the shock pulse in a bubbly liquid is not as concentrated in space as that in a homogeneous liquid. Its length is 10-12 times greater than the corresponding value in a homogeneous liquid. Research methods are purely theoretical. The well-known bubble liquid model is used as a single-speed model continuum. Differential equations are solved analytically, approximately (series expansion), and numerically. In addition, the original approach of obtaining an analytical solution of an autonomous system is used-finding the function of pressure disturbances from the velocity of propagation of the shock pulse (and vice versa). Conclusions. A simple one-dimensional hydraulic model of shock wave (impulse) propagation in a bubbly liquid is proposed. In contrast to classical ideas (solutions) about a water hammer, which consists of two waves of opposite directions of propagation, a shock pulse is a region of pressure disturbances in which the speed of motion of fluid particles is also variable – from the maximum value to almost zero.

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Section: Introductionmentioning

confidence: 75%

Unsteady flow of bubble liquid in hydraulic systems of aircraft and helicopters

Lukianov,

Pavlova

2024

aktt

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“…Thirdly, with an increase in α, the SW amplitudes in the SW package decrease, which is consistent with the decrease in the propagation velocity of its leading front noted above (see Table 1). High-speed video filming makes it possible to measure the penetration depth of gaseous detonation products, L p , and the velocity of BW behind the SW package, u cs , by tracking the motion of the contact surface "detonation products-BW" [35]. Table 2 shows the measured depths of product gas jets and the contact surface velocities at different distances (20 mm (u sc,20-mm ), 40 mm (u sc,40-mm ), and 60 mm (u sc,60-mm )) from the cutoff of acceptor detonation tubes, which was determined from video frames.…”

Section: Shock Wave Package Propagation In Bubbly Watermentioning

confidence: 99%

“…The results of experiments show that the use of high-frequency SW pulses in the PDH is pointless because the interference of pulses impairs the SW-to-BW momentum transfer. For efficient operation of the PDH, it is necessary to maintain the required SW intensity and the required level of volumetric gas content (≈20-25% [35]) in its water guide. The SW intensity is mainly determined by the fuel mixture used.…”

Section: Shock Wave Package Propagation In Bubbly Watermentioning

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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“…Shock wave pressure is widely used in explosive power tests, medical treatment, combustion engine development and material impact studies [1][2][3]. It can be measured by using pres sure sensors according to certain requirements.…”

Section: Introductionmentioning

confidence: 99%

A fast estimation of shock wave pressure based on trend identification

Yao

Wang

Wang³

et al. 2018

Meas. Sci. Technol.

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In this paper, a fast method based on trend identification is proposed to accurately estimate the shock wave pressure in a dynamic measurement. Firstly, the collected output signal of the pressure sensor is reconstructed by discrete cosine transform (DCT) to reduce the computational complexity for the subsequent steps. Secondly, the empirical mode decomposition (EMD) is applied to decompose the reconstructed signal into several components with different frequency-bands, and the last few low-frequency components are chosen to recover the trend of the reconstructed signal. In the meantime, the optimal component number is determined based on the correlation coefficient and the normalized Euclidean distance between the trend and the reconstructed signal. Thirdly, with the areas under the gradient curve of the trend signal, the stable interval that produces the minimum can be easily identified. As a result, the stable value of the output signal is achieved in this interval. Finally, the shock wave pressure can be estimated according to the stable value of the output signal and the sensitivity of the sensor in the dynamic measurement. A series of shock wave pressure measurements are carried out with a shock tube system to validate the performance of this method. The experimental results show that the proposed method works well in shock wave pressure estimation. Furthermore, comparative experiments also demonstrate the superiority of the proposed method over the existing approaches in both estimation accuracy and computational efficiency.

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Experimental and computational studies of shock wave-to-bubbly water momentum transfer

Cited by 26 publications

References 46 publications

Unsteady flow of bubble liquid in hydraulic systems of aircraft and helicopters

Unsteady flow of bubble liquid in hydraulic systems of aircraft and helicopters

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

A fast estimation of shock wave pressure based on trend identification

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