Experimental and theoretical analysis on chamber pressure of a self-resonating cavitation waterjet

Liu, Wenchuan; Kang, Yong; Zhang, Mingxing; Wang, Xiaochuan; Deng, Li; Xie, Lu

doi:10.1016/j.oceaneng.2018.01.019

Cited by 32 publications

(20 citation statements)

References 17 publications

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“…Peng et al [23] established a mathematic model to study the cavitation bubble size in the flow fields of SRWJs. Besides, Liu et al [24] carried out an experiment to study the pressure characteristics of SRWJs with the use of Hilbert-Huang transform method. Ding et al [25] took advantage of SRWJs to improve the mechanical properties of the aluminum alloy and claimed that the hardness and residual stress could be increased by 61.69% and 148%, respectively.…”

Section: Introductionmentioning

confidence: 99%

The Effects of the Downstream Contraction Ratio of Organ-Pipe Nozzle on the Pressure Oscillations of Self-Resonating Waterjets

et al. 2018

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Self-resonating waterjets (SRWJs) are being widely used in the fields of energy exploitation, due to the significantly increased penetration rate of roller bits in deep-hole drilling. To further improve the impact and erosion abilities of SRWJs, the effects of the downstream contraction ratio of organ-pipe nozzle on the axial pressure oscillations were experimentally studied. The axial pressure oscillation peak and amplitude were used to evaluate the effects under two inlet pressures and various standoff distances. The results show that the downstream contraction ratio can affect the development trends of the pressure oscillations and determines the values of the peaks and amplitudes. Under the experimental conditions, 2.5 is the ratio that leads to the maximum peaks and amplitudes at almost all the testing standoff distances, while the ratio of 2 always results in the minimum ones. The development trend of the pressure oscillation peak for the ratio of 3.5 has a great change at an inlet pressure of 20 MPa. Generally, the relative pressure oscillations are more violent at an inlet pressure of 10 MPa, which is regardless of the contraction ratio. This study helps provide a guideline for determining the physical parameters required in the fabrication of organ-pipe nozzles used for deep-hole drilling.

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Section: Introductionmentioning

confidence: 99%

The Effects of the Downstream Contraction Ratio of Organ-Pipe Nozzle on the Pressure Oscillations of Self-Resonating Waterjets

et al. 2018

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“…As for the oscillator used in the present study, the upstream nozzle diameter was d1 = 2.6 mm, which was much smaller than that in the literature [29]. With the decrease of nozzle structure parameters, the Reynolds number of jet flow increase under the same operating pressure.…”

Section: Frequency Spectrumsmentioning

confidence: 71%

“…The same nozzle parameters as in the literature were selected for calculation, and the pressure fluctuation at the nozzle outlet was obtained. Figure 4 shows the marginal spectrums obtained at nozzle outlet compared with the experiment results measured by Liu et al [29]. If we choose the frequency at which the spectrum is the highest as the true value of fp, it is fp = 0.49 Hz for the LES case and fp = 0.42 Hz for the experiment.…”

Section: Validationmentioning

confidence: 97%

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Large Eddy Simulation of Self-Excited Oscillation Pulsed Jet (SEOPJ) Induced by a Helmholtz Oscillator in Underground Mining

Fang

Zhang

et al. 2019

Energies

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Pulsed waterjet can break rocks effectively by taking advantage of the water hammer effect, and is thus widely used in mining, petroleum, and natural gas fields. With the aim to further clarify the flow field characteristics of pulsed jets induced by a Helmholtz oscillator, large eddy simulation was conducted under different operating pressures. The velocity distribution, mean flow field, and the coherent structure were examined using the oscillators of different cavity lengths and diameters. The results clearly showed that the major frequency of jet pulsation gradually increased with the increase of operating pressure. A stable periodic velocity core was formed at the outlet of the Helmholtz oscillator, while the external flow field was subjected to periodic impact. As a result, the ambient fluid was strongly entrained into the jet beam. With the increase of the cavity length, the length of the core segment decreased while the energy loss caused by the cavity increased, which was also accompanied by a rapid attenuation of the axial velocity at the jet outlet. The coherent structure of the jet in the oscillator with small cavity diameter was more disordered near the nozzle outlet, and the vortex scale was larger. The effect of cavity diameter can be reflected in the feedback modulation of the jet in the cavity. Compared with the conical nozzle, the length of the core section of the jet was shorter, but the jet had better bunching, a smaller diffusion angle, and better mixing performance. These results provide a further understanding of the characteristics of pulsed water jet for better utilizations in the fields of energy exploitation. a self-propelled water-jet drilling nozzle to drill three-type boreholes to improve gas extraction and drilling experiments were conducted to optimize the nozzle configuration. As a generator of SEOPJ, attention has been paid to the Helmholtz oscillator and extensive research has been done by . The unsteady flow phenomenon in SEOPJ is combined with various theories such as fluid dynamics, fluid resonance, and hydroelasticity, which makes it difficult to measure the flow patterns and vortex structures. In particular, an experimental study was conducted to characterize the discrete model by the change of cavity length and to give stable working regions under various parameters [7]. The identification of the complex mechanism responsible for this phenomenon is difficult because it is the result of multiple factors and data acquisition of all the instantaneous fields simultaneously is unavailable under the existing measurement techniques [8].Energies 2019, 12, x FOR PEER REVIEW 3 of 21 be distinguished. The research results can be used as the theoretical basis for selection and design of SEOPJ nozzles in underground mining.

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“…The results show that the downstream contraction ratio can affect the development trends of the pressure oscillations and determines the values of the peaks and amplitudes. Liu et al [19,20] investigated the turbulence flow past a 120 • impinging edge Helmholtz nozzle, a modified theoretical model accompanied by numerical simulation was proposed to obtain the range of the oscillation frequency and was verified using experimental results.…”

Section: Introductionmentioning

confidence: 99%

Impact Performance of Helmholtz Self-Excited Oscillation Waterjets Used for Underground Mining

Fang

Gao²,

Xia

et al. 2019

Applied Sciences

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Featured Application: The paper will provide nozzle selection basis and impact mechanism of Helmholtz self-excited oscillation waterjets used for underground mining.Abstract: Pulsed waterjets are widely used in exploitation of fossil fuels for their high efficiency.With the aim to further clarify the impact performance of Helmholtz self-excited oscillation waterjets (HSEOW), numerical and experimental studies were conducted. The morphological characteristics of the erosion surfaces between conical and HSEOW nozzles were compared and the cavitation evolution was obtained. Results show that the cavitation damage caused by the HSEOW nozzle on the specimen was mainly caused by the jet cavitation cloud under submerged conditions. The cavitation effect produced by the HSEOW nozzle had a much greater destructive effect than that of a conical nozzle. The mass loss caused by HSEOW nozzles increased first with the increase of standoff distance, then decreased rapidly after reaching the maximum value. Moreover, the density of holes and the damage intensity weakened with the increase of radial distance. A dimensionless cavity length of 2 and a dimensionless cavity diameter of 8 was the optimal structure that led to maximum mass loss. These results provide a further understanding of cavitation mechanism which leads to the impact performance of pulsed water jets and optimal working parameters in the field of energy exploitation.

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Experimental and theoretical analysis on chamber pressure of a self-resonating cavitation waterjet

Cited by 32 publications

References 17 publications

The Effects of the Downstream Contraction Ratio of Organ-Pipe Nozzle on the Pressure Oscillations of Self-Resonating Waterjets

The Effects of the Downstream Contraction Ratio of Organ-Pipe Nozzle on the Pressure Oscillations of Self-Resonating Waterjets

Large Eddy Simulation of Self-Excited Oscillation Pulsed Jet (SEOPJ) Induced by a Helmholtz Oscillator in Underground Mining

Impact Performance of Helmholtz Self-Excited Oscillation Waterjets Used for Underground Mining

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