A bit–rock interaction model for rotary–percussive drilling

Franca, Luiz

doi:10.1016/j.ijrmms.2011.05.007

Cited by 119 publications

(35 citation statements)

References 24 publications

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“…The single-impact energy E is of crucial importance for evaluating the performance of the fluidic hammer, as when the single-impact energy is lower than a certain value, the fluidic hammer can hardly break the corresponding rocks [36,37]. Development of fluidic hammers with great single-impact energy is the current prevailing trend [38,39].…”

Section: Performance Analysis Related To the Flow Behaviormentioning

confidence: 99%

Performance Study of a Fluidic Hammer Controlled by an Output-Fed Bistable Fluidic Oscillator

Zhang

Peng

et al. 2016

Applied Sciences

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Using a no-moving-component output-fed bistable fluidic oscillator to control fluid flows into a parallel path has been recognized for a considerable time, but as yet it is not so widely adopted as its obvious benefits would deserve. This may be attributed to the encountered problems associated with its jet behavior, complicated by its loading characteristics. In order to investigate a typical case for the application of the output-fed fluidic oscillator, this paper elaborates on the computational fluid dynamics (CFD) simulation method for studying the performance of a fluidic hammer controlled by an output-fed bistable fluidic oscillator. Given that couple mechanism exists between the flow field in the fluidic oscillator and the impact body, dynamic mesh technique and a user-defined function written in C programming language were used to update the mesh in the simulations. In terms of the evaluation of performance, the focus is on the single-impact energy and output power of the fluidic hammer in this study, to investigate the effect of different parameters of the impact body on them. Experimental tests based on the noncontact measuring method were conducted to verify the simulation results, by which the accuracy and reliability of this CFD simulation method was proved.

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Section: Performance Analysis Related To the Flow Behaviormentioning

confidence: 99%

Performance Study of a Fluidic Hammer Controlled by an Output-Fed Bistable Fluidic Oscillator

Zhang

Peng

et al. 2016

Applied Sciences

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“…The fundamental mechanisms of percussive drilling were investigated by a number of researchers including Simon [7,8], Hustrulid and Fairhurst [9][10][11][12], Lundberg [13][14][15][16][17], Franca and Weber [18,19], and the Centre for Applied Dynamics Research in Aberdeen [20][21][22][23][24][25][26]. Simon [7,8] considered the energy in the stress wave in the drill steel produced by the striker impact together with the energy required for breaking the rock and computed the efficiency of stress wave energy conversion into work done by the bit on the rock.…”

Section: Introductionmentioning

confidence: 99%

“…More recently Franca and Weber [19] conducted experimental and numerical studies of a new resonance hammer drilling model with drift and showed that the behaviour of the system may vary significantly from simple periodic regimes to chaos. Wiercigroch et al [21] presented extensive studies of ultrasonic percussive drilling with diamond-coated tools in the laboratory conditions on rocks such as sandstone, limestone, granite and basalt.…”

Section: Introductionmentioning

confidence: 99%

Modelling of high frequency vibro-impact drilling

Pavlovskaia

Hendry

Wiercigroch

2015

International Journal of Mechanical Sciences

116

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Modelling of the vibro-impact drilling system is undertaken in this study, and the results of the numerical analysis and comparison between two selected models are presented. The first one is a newly developed model of an existing experimental rig (three masses model) and the second one is a simplified low dimensional model (Pavlovskaia et al., 2001 [22]) created to describe the dynamic interaction between the drill-bit and the drilled formation. The optimal loading parameters are identified in this work based on the analysis of the system responses, and the influence of the additional degrees-offreedom on the loading optimisation strategy is investigated. Three main control parameters are considered, and they are the applied static force, and the amplitude and the frequency of the applied dynamic force.Our investigations confirm that the best progression rates are achieved when the system response is periodic and the frequency of the response is the same as the frequency of the applied dynamic force, and the value of the static force is smaller than the amplitude of the applied dynamic excitation. This result is valid for both models considered. Also in both cases, zero progression rates are obtained for lower values of the excitation amplitudes and the average progression increases with the increase in the dynamic amplitudes. Both models also predict zero progression rates at the higher excitation frequencies.Based on the analysis undertaken, it can be concluded that the low dimensional model provides good estimates of the optimal static force and the amplitude of the dynamic force, and it could be used for the operational control of the drilling system to adjust the loading parameters while drilling through different formations. The choice of the optimal frequency, however, should be made based on the predictions of the more detailed model of the drilling system as additional degrees of freedom significantly influence the structure of the internal resonances and they should be taken into account.

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“…Because of the impact loads at the bit inserts in percussion drilling are much higher than the load levels typically achieved in rotary drilling, and the total contact time of inserts with the rock is substantially less than during rotary drilling (Melaned et al, 2000), the DTH air hammer can provide high penetration rate and have been widely used in mining (Franca, 2011). In conventional DTH air hammer drilling methods, the compressed gas is pumped down into the drill pipe and out through the drill bit directly, then carrying drill cuttings into the annulus between drill pipe and borehole to return to the surface.…”

Section: Structure Design Of the Dth Air Hammermentioning

confidence: 99%

Detection Of Multilayer Cavities By Employing RC-DTH Air Hammer System And Cavity Auto Scanning Laser System

Luo

Peng

et al. 2015

Archives of Mining Sciences

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The subterrane an c avities are seriously thre atened to construction and mining safety, and it's important to obtain the exact localization and dimensions of subterranean cavities for the planning of geotechnical and mining activities. Geophysical in vestigation is an alternative method for cavity detection, but it usually failed for the uncertainly so lution of information and data obtained by Geophysical methods. Drilling is considered as the most accurate method for cavity detection. However, the conventional drilling methods can only be used for single cavity detection, and there is no effective solu tion for multilayer cavities detection have been reported. In this paper, a reverse circulation (RC) down-the-hole (DTH) air hammer system with a special structured drill bit is built and a cavity auto scanning laser system based on laser range finding technique was employed to confirm the localization and dimensions of the cavities. This RC-DTH air hammer system allows drilling through the upper cavities and putting the cavity auto scanning laser system into the cavity area through the central passage of the drill tools to protect the detection system from collapsing of borehole wall. The RC-DTH air hammer system was built, and field tests were conducted in Lanxian County Iron Ore District, which is located in Lv Liang city of Shan Xi province, the northwest of china. Field tests show that employing the RC-DTH air hammer system assisted by the cavity auto scanning laser system is an efficiency method to detect multilayer cavities.Keywords: multilayer cavities detection; RC-DTH air hammer; drill bit; cavity auto scanning laser system Podziemne wgłębienia i pustki stanowią poważne zagrożenie dla budowli oraz dla działalności górniczej; dlatego też podstawowym zagadnieniem jest ich dokładna lokalizacja i określenie wymiarów. Jest to niezbędne dla planowania prac geotechnicznych i wydobywczych. Badania geofizyczne są alternatywną metodą wykrywania podziemnych zagłębień, zazwyczaj jednak okazują się nieskuteczne ze względu na niepewność rozwiązań oraz danych uzyskiwanych za pomocą metod geofizycznych. Wykonanie odwiertu jest najdokładniejszą metodą wykrywania zagłębień i pustek, jednakże konwencjonalne metody prowadzenia wierceń pozwalają na wykrycie jednego tylko zagłębienia, nie ma też skutecznego rozwiązania kwestii istnienia zagłębień i pustek przechodzących przez liczne warstwy górotworu. W pracy omówiono zastosowanie układu młota pneumatycznego wgłębnego z odwrotnym obiegiem płuczki, wyposażonego w odpowiednie urządzenie wiertnicze, oraz układu skanera laserowego wykorzystującego technikę dalmierza do potwierdzania lokalizacji pustek i ich wymiarów. Prezentowany młot umożliwia dokonanie odwiertu w zagłębieniach i pustkach znajdujących się w warstwach wierzchnich, następnie w zagłębieniu tym umieszczane jest laserowe urządzenie skanujące powierzchnię komory wprowadzane poprzez główny kanał w urządzeniu wiertniczym, tak by zabezpieczyć skaner na wypadek osunięcia się ścian otworu. Układ składający się z młota ...

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A bit–rock interaction model for rotary–percussive drilling

Cited by 119 publications

References 24 publications

Performance Study of a Fluidic Hammer Controlled by an Output-Fed Bistable Fluidic Oscillator

Performance Study of a Fluidic Hammer Controlled by an Output-Fed Bistable Fluidic Oscillator

Modelling of high frequency vibro-impact drilling

Detection Of Multilayer Cavities By Employing RC-DTH Air Hammer System And Cavity Auto Scanning Laser System

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