Abstract
ABSTRACTIce-core drilling to depths of 200–300 m is an important part of research studies concerned with paleoclimate reconstruction and anthropogenic climate change. However, conventional drilling methods face difficulties due to firn permeability. We have developed an electromechanical ice-core drill with air reverse circulation at the hole bottom. We believe that the new drilling system will recover ice cores faster than shallow auger drills, with high efficiency and low energy consumption. The theoretically estimated up-hole speed of the airflow should be not <7.7 m s−1 to allow proper removal of ice cuttings from the borehole bottom. The computer simulation and test results showed that the design of the new ice-coring drill is feasible. The maximum allowed penetration rate depends by square law on airflow.
Highlights
Ice-core drilling through snow/firn layers and solid ice to depths of 200–300 m is an important part of the International Partnerships on Ice Coring Sciences spatial 2000-year array (IPICS ‘2k Array’)
It was decided to: research air reverse circulation in theoretical terms; set up an air reverse circulation test stand to acquire some of the data required from the experiment in order to prove that the air can form reverse circulation and readily suck ice cuttings into the chip chamber; use the fluid dynamics software ‘Fluent 15’, which is a general finite element analysis software developed by the ANSYS company, to verify the parameters obtained from the theoretical calculation; and carry out the overall simulated field trial after laboratory testing
Our study demonstrates that near-bottom air reverse circulation should theoretically be a sound option for polar ice-core drilling
Summary
Ice-core drilling through snow/firn layers and solid ice to depths of 200–300 m is an important part of the International Partnerships on Ice Coring Sciences spatial 2000-year array (IPICS ‘2k Array’). Wang and others (2017) suggested using conventional reverse-circulation drilling technology with dual-wall drill rods in which compressed air flows downward through the annular space of the double-wall drill pipes and the inner tubes provide a continuous pathway for the chips and cores from the coring head to the surface. All these drill rigs are still bulky, consume a lot of power and need a powerful air compressor to create enough air pressure for ice cuttings removal. Simplification of some components (cable termination, instrumentation section) and the use of lightweight materials can significantly reduce the weight (
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