Shallow hot-water ice drill: Estimation of drilling parameters and testing

摘要

Shallow hot-water systems are well-known ice-drilling devices used to create holes for temperature measurements and monitoring of glacier dynamics, basal sliding, and englacial water-pressure. A shallow hot-water ice drill system designed at Jilin University is based on a commercial high-pressure washer, Karcher HDS 6/14C, that can deliver water at a temperature in the range of 80-155 degrees C, a flow of 4-10 L/min and a pressure as high as 14 MPa. The system also includes a mast with a sheave on the top and a reel with a 100-m long rubber hose; a 2m long, 60-mm diameter drill stem; a control and measuring system; sleds; a submersible pump; a return hose; a water tank with an affiliate heating unit; and a small 2-kW generator. Theoretical estimations were performed to predict the rate of penetration and mean diameter of the melted borehole. Experiments with a shallow hot-water drill were carried out in an ice drill testing facility to determine the relationship between the rate of penetration/borehole diameter and the diameter and type of nozzle, hot water temperature, and flowrate. Under a hot water flowrate of 10 L/min with a temperature of 60 degrees C, the 1.8-mm and 2-mm nozzles created 98-114-mm diameter boreholes at a penetration rate of 34-37 m/h, while a 2.5-mm nozzle produced a 146-156-mm borehole at rate of 26 m/h. The deviation between the experimental data and theoretical estimations did not exceed 7%.