Effects of feeding pipe diameter on the performance of a jet-driven Helmholtz oscillator generating pulsed waterjets

Deng, Li; Kang, Yong; Ding, Xiaolong; Wang, Xiaochuan; Liu, Wenchuan

doi:10.1007/s12206-017-0219-9

Cited by 26 publications

(14 citation statements)

References 36 publications

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“…Nominal pressure (MPa) 40 Burst pressure (MPa) 100 Accuracy ≤±0.5% FS Influence effects of supply (10 V) 0.05% FS Influence effects of load (kΩ) 0.05% Thermal error (10 K) ±0.5% FS Figure 2. The schematic of the experimental setup for measuring the axial pressures [28,[33][34][35].…”

Section: Bd Sensorsmentioning

confidence: 99%

“…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. In addition, the authors have already conducted a series of experiments on SRWJs, such as the effects of the nozzle inner surface roughness, feeding pipe diameter, and the area discontinuity at the nozzle inlet on the characteristics of pressure oscillations and cavitation erosion of the jet [26][27][28][29][30][31][32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

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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: Bd Sensorsmentioning

confidence: 99%

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 Helmholtz oscillator, several experiments [21][22][23][24][25] and numerical simulations [26][27][28][29][30] have been conducted to reveal the self-excited mechanism, frequency characteristics, and pressure fluctuation. The impact characteristics of the jets were quite different from those of continuous jets.…”

Section: Flow Configurationmentioning

confidence: 99%

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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“…Most recently, we studied the preferred Strouhal number used in SRWJs, and found that the optimum values are 0.315 and 0.278 respectively, corresponding to inlet pressures of 10 MPa and 20 MPa [20]. Furthermore, a series of experimental investigations on SRWJs have also been conducted, ranging from the effects of nozzle inner surface roughness to the influence of feeding pipe diameter [21][22][23][24][25][26][27][28][29]. These investigations on the mechanisms and principles of SRWJs have contributed to the understanding of the jet and improvement of the jet's performance.…”

Section: Introductionmentioning

confidence: 99%

Effects of Nozzle Exit Angle on the Pressure Characteristics of SRWJs Used for Deep-Hole Drilling

Wang

Miao

et al. 2019

Applied Sciences

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The self-resonating waterjet (SRWJ) has been applied in petroleum, natural gas, and mining engineering ever since its strong erosion ability in deep-hole drilling was recognized. Aiming at further improving the working efficiency of SRWJs, the effects of the exit angle of the organ-pipe nozzle on the axial pressure oscillations of the jet were experimentally studied. Six exit angles of θ = 0°, 30°, 45°, 60°, 75°, and 90° were employed in the experiment, and the axial pressure oscillation peak (Pmax) and amplitude (Pa) were used for characterizing the performance of SRWJs. It was found that the exit angle greatly affects the axial pressure oscillations, including the development trends against the standoff distance and the magnitudes of Pmax and Pa. Under testing with two inlet pressures, the exit angle of θ = 0° always resulted in the greatest Pmax and Pa within the range of the testing standoff distance. With the increase of standoff distance, both Pmax and Pa first increased and then decreased when the exit angle was 0°; while they kept decreasing when the exit angle was 30°, 45°, 60°, 75°, and 90°. Moreover, the exit angles of θ = 90° and 60°, corresponding to inlet pressures of Pi = 10 MPa and 20 MPa, led to both the minimum magnitudes of Pmax and Pa under the experimental conditions. The results also indicate that the exit angle affects the interactions between the nozzle lip and the jet and help provide information for improving the working efficiency of SRWJs in practical applications.

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Effects of feeding pipe diameter on the performance of a jet-driven Helmholtz oscillator generating pulsed waterjets

Cited by 26 publications

References 36 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

Effects of Nozzle Exit Angle on the Pressure Characteristics of SRWJs Used for Deep-Hole Drilling

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