Theory calculation and testing of air injection parameters in ice core drilling with air reverse circulation

Cao, Pinlu; Liu, Miaomiao; Chen, Zhuo; Chen, Baoyi; Zhao, Qing

doi:10.1016/j.polar.2018.06.005

Cited by 12 publications

(7 citation statements)

References 10 publications

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“…Swirling flows bring about very strong suction forces toward rock cuttings. We ever designed a drill bit with a guide vane built in [6]. Our preliminary numerical simulations verified the role of swirling flows in improving the reverse circulation within drill bits [6].…”

Section: Introductionmentioning

confidence: 81%

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Experimental and Numerical Analysis of Flow Behavior for Reverse Circulation Drill Bit with Inserted Swirl Vanes

Yang¹,

Jiang²,

et al. 2022

Geofluids

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A swirling drill bit designed with an integrated vane swirler was developed to improve reverse circulation in down-the-hole hammer drilling. Its entrainment effect and influential factors were investigated by CFD simulation and experimental tests. The numerical results exhibit reasonable agreement with the experimental data, with a maximum error of 13.68%. In addition, the structural parameters of the swirler were shown to have an important effect on the reverse circulation performance of the drill bit, including the helical angle and number of spiral blades, swirler outlet area, and the flushing nozzles. The optimal parameters for the swirling drill bit without flushing nozzles include a helical angle of 60°, four spiral blades, and the area ratio of 2, while it is about 30°, 3, and 3 for the drill bit with flushing nozzles. Moreover, the entrainment ratio of the drill bit without flushing nozzles can be improved by nearly two times compared with one with flushing nozzles under the same conditions.

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Section: Introductionmentioning

confidence: 81%

“…A swirling flow can be generated by many kinds of swirl generator [6], such as guiding vanes, tangential intake swirler, annular swirler, rotating mechanical devices, and honeycomb generator. Extensive experimental, analytical, and numerical studies that focus on swirling flows have been published in literature [7].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Analysis of Flow Behavior for Reverse Circulation Drill Bit with Inserted Swirl Vanes

Yang¹,

Jiang²,

et al. 2022

Geofluids

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“…It can provide a rich paleo-environmental archive for numerous types of studies including understanding the mechanism of global climate change, learning about the evolution of the earth's glaciology and determining the resilience of life forms exposed to extreme conditions. Sampling from these zones is also important to provide scientists with information regarding the ice-sheet/bedrock interaction and how this zone influences the overlying ice-sheet dynamics (Popp and others, 2014a; Cao and others, 2018). However, the ice located in this zone is extremely difficult to drill with electromechanical drills because the in situ temperature of the ice is close to or at its pressure melting point, which is a so-called warm ice problem.…”

Section: Introductionmentioning

confidence: 99%

Anti-icing performance of hydrophobic material used for electromechanical drill applied in ice core drilling

et al. 2020

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Using an anti-icing coating to prevent ice accretion on the drill surface is a feasible solution to address the drilling difficulties in warm ice. In this study, four types of commercially available hydrophobic coating materials were tested to evaluate their water repellency and anti-icing properties, namely, a mixture of silica and fluorocarbon resin with polytrifluoroethylene, modified Teflon, silica-based emulsion and an acrylic-based copolymer. Their water contact angles are ~107°, 101°, 114° and 95°, respectively. All these hydrophobic coatings can significantly reduce the strength of the ice adhesion within a temperature range of −10 to −30°C on a planar or curved surface. The coating of an acrylic-based copolymer, in particular, can reduce the average tensile strength and the shear strength of the ice adhesion by 87.08 and 97.11% on planar surfaces at −30°C, and by 98.06 and 96.15% on a curved surface, respectively. The main challenge in the practical application of these coatings is their durability. An acrylic-based copolymer coating will lose its water repellency performance after 140 cycles of abrasion. The shear strength of ice adhered on curved surfaces coated with this material will approach that achieved on uncoated surfaces after 11 cycles of icing and de-icing tests.

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“…High-pressure air coming from air compressors flows through a dual-channel swivel and the annular space in double-wall drill pipes, and enters into a reverse circulation drill bit. After entraining the ice chips at the bottom of the borehole, the compressed air is directed into the central space of the double-wall drill pipes, and then carried with ice cores and chips up to the surface (Cao and others, 2018a). The main advantage of this method is that ice cores and ice chips can be continuously returned to the surface as drilling proceeds, and core barrel retrieval is not needed after each run, which saves considerable time.…”

Section: Introductionmentioning

confidence: 99%

“…The second is whether the reverse circulation can be effectively formed with the appearance of ice cores. In the work by Wang and others (2017) and Cao and others (2018a), the minimum air volume flow rate and the pressure drop needed to convey ice cores were studied. The results show that the air injection parameters required in ice core drilling are much lower than that of conventional rock drilling if the diameter and the length of the ice core are set as 60 and 250 mm, respectively.…”

Section: Introductionmentioning

confidence: 99%

Orthogonal experimental research on the structural parameters of a novel drill bit used for ice core drilling with air reverse circulation

et al. 2019

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A new type of ice core drill bit, designed with a vane swirler, was developed for ice core drilling with air reverse circulation. An orthogonal experimental design method was employed to investigate the effects of the swirler structure parameters on the reverse circulation performance of the drill bit including helical angle, number of blades, blade length and blade central angle, etc. The entrainment ratio was used to evaluate the reverse circulation effectiveness of the drill bit. The results show that the helical angle is the dominant factor regardless of whether or not the flushing nozzles are part of the design of the drill bit. The number of blades is the least important factor for the drill bit designed with the flushing nozzles (referred to as drill bit I), while the outlet area of the swirling slot is the least influential factor for the drill bit without flushing nozzles (referred to as drill bit П). In addition, the appearance of the ice core has a certain effect on the air reverse circulation for both drill bits. Within the ranges of this study, the optimal structure of the drill bit was determined based on the range analysis of the orthogonal design.

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Theory calculation and testing of air injection parameters in ice core drilling with air reverse circulation

Cited by 12 publications

References 10 publications

Experimental and Numerical Analysis of Flow Behavior for Reverse Circulation Drill Bit with Inserted Swirl Vanes

Experimental and Numerical Analysis of Flow Behavior for Reverse Circulation Drill Bit with Inserted Swirl Vanes

Anti-icing performance of hydrophobic material used for electromechanical drill applied in ice core drilling

Orthogonal experimental research on the structural parameters of a novel drill bit used for ice core drilling with air reverse circulation

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