Optimal Design Parameters of a Percussive Drilling System for Efficiency Improvement

Song, Chang-Heon; Chung, Jintai; Cho, Jaesang; Nam, Yoon Kwon

doi:10.1155/2018/2346598

Cited by 11 publications

(15 citation statements)

References 13 publications

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“…In a percussive drilling system, the piston directly hits the drill bit at speed v (Figure 2). For transmitted impact energy e in , the final descending speed v of the piston during impact with the drill bit can be expressed as follows [1]:…”

Section: Governing Equation For the Impact Hammermentioning

confidence: 99%

“…In this study, a new method was developed for predicting the drilling performance of a DTH hammer. A numerical model was developed that combines two previous models: Song et al's drill bit-rock interaction model [1] and hammer dynamics model [11].…”

Section: Introductionmentioning

confidence: 99%

“…e nondimensional parameter β was defined as the stiffness ratio of the rock and piston and was used to predict the effect of the rock strength on the drilling performance. erefore, the proposed model can determine the drilling efficiency [1].…”

Section: Introductionmentioning

confidence: 99%

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Prediction Model of Drilling Performance for Percussive Rock Drilling Tool

Kim

Lee

et al. 2020

Advances in Civil Engineering

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This study suggests a method for quantitatively estimating the drilling performance of the down-the-hole (DTH) hammer during percussive drilling of rock surfaces. A pneumatic dynamic model of the DTH hammer was developed that considers the mass flow rate relations representing the orifice opening areas of the air tube, the piston, and bit flushing channels. A drill bit motion model was developed to represent the dynamics of a drill bit impacted by a dropped piston and explain the impact stress propagation and rock-crushing mechanism. The rock-crushing effect of the drill button bit was measured through a piston drop test. The pneumatic hammer model and drill bit motion model were then combined in a prediction model to determine the impact efficiency according to different rock types (i.e., soft, medium-hard, and very hard). The drilling efficiency was defined as the input value of the prediction model, which was used to simulate the drilling performance of DTH hammers considering the rock type and dynamic effect of the drill bit. Finally, the simulation results were compared with the results of in situ drilling tests for verification.

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Section: Governing Equation For the Impact Hammermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Prediction Model of Drilling Performance for Percussive Rock Drilling Tool

Kim

Lee

et al. 2020

Advances in Civil Engineering

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“…The interaction between the drill bit and the worked material has also been modeled with lumped parameters modeling three-dimensional finite element methods [ 10 , 11 , 12 , 13 , 14 ]. The available studies provide useful information about the resistance during the impact and the efficiency of the energy transfer [ 15 , 16 ], but do not consider the drill bit rotation and the matching between axial and torsional vibrations, i.e., the chatter vibration phenomenon [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Measurement of Stress Waves Propagation in Percussive Drilling

Scaccabarozzi¹,

Saggin²

2021

Sensors

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This work describes the results of a test campaign aimed to measure the propagation of longitudinal, torsional, and flexural stress waves on a drill bit during percussive rock drilling. Although the stress wave propagation during percussive drilling has been extensively modeled and studied in the literature, its experimental characterization is poorly documented and generally limited to the detection of the longitudinal stress waves. The activity was performed under continuous drilling while varying three parameters, the type of concrete, the operator feeding force, and the drilling hammer rotational speed. It was found that axial stress wave frequencies and spectral amplitudes depend on the investigated parameters. Moreover, a relevant coupling between axial and torsional vibrations was evidenced, while negligible contribution was found from the bending modes. A finite element model of the drill bit and percussive element was developed to simulate the impact and the coupling between axial and torsional vibrations. A strong correlation was found between computed and measured axial stress spectra, but additional studies are required to achieve a satisfactory agreement between the measured and the simulated torque vibrations.

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“…S Yang and colleagues [17][18][19] analyzed the percussion performance of rock drill and optimized the parameters with simulation model, which was validated by the percussion performance test. C Song et al 20 optimized the design parameters of percussion system for rock drill using Taguchi method. Y Li et al, 21 J Hu and Q Hu, 22 and H Zhao et al 23 analyzed the influence of the opening at zero position of distribute valve on the internal motion law for the hydraulic rock drill.…”

Section: Introductionmentioning

confidence: 99%

Percussion characteristic analysis for hydraulic rock drill with no constant-pressurized chamber through numerical simulation and experiment

Geng

Jia

et al. 2019

Advances in Mechanical Engineering

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Considering the insufficiency of numerical study on the percussion characteristic of hydraulic rock drill, which restricts the improvement of efficiency and reliability, a coupling model including the impact piston, spool valve, impact accumulator, and connecting pipelines was established taking into account the oil compressibility, oil leakage, and pressure drop in valve ports. The rebound velocity of impact piston was calculated based on the stress wave theory. The simulation results revealed the coupling mechanism of percussion system. Pressure curves of the piston's front-chamber and rearchamber, and valve's left-chamber and right-chamber were obtained by field rock drilling test. Then, the velocity curve of impact piston was obtained after judging the striking point through the feature of rear-chamber's pressure spike, so were the rock drill's impact energy, impact frequency, and impact power. The simulation and experimental results have consistency. And, on this basis, the influence of spool valve's damping clearance (d) and pipeline diameters (d 1 , d 2) connecting the impact piston and spool valve on the percussion performance and system cavitation was researched. The results show that the larger d is better considering reversal time of spool valve, the impact frequency of rock drill, pressure fluctuation, and cavitation relief. But too large d will cause over quick impact velocity of the spool valve, which may lead to strong vibration and the damage of spool valve. The optimal value of d is 0.01 mm by comprehensive consideration. The pipeline diameters have an important influence on the pressure fluctuation and negative pressure in rear-chamber. The diameters should be larger than 18 mm to alleviate the cavitation. This article provides means for the design and research of rock drills.

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Optimal Design Parameters of a Percussive Drilling System for Efficiency Improvement

Cited by 11 publications

References 13 publications

Prediction Model of Drilling Performance for Percussive Rock Drilling Tool

Prediction Model of Drilling Performance for Percussive Rock Drilling Tool

Measurement of Stress Waves Propagation in Percussive Drilling

Percussion characteristic analysis for hydraulic rock drill with no constant-pressurized chamber through numerical simulation and experiment

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