Laboratory experiments and thermal calculations for the development of a next-generation glacier-ice exploration system: Development of an electro-thermal drilling device

Numerical Investigation on the Evolution of Thin Liquid Layer and Dynamic Behavior of an Electro-Thermal Drilling Probe during Close-Contact Heat Transfer

“…Figure 2 shows that the 2D axisymmetric computational domain has a length of 360 mm and width of 75 mm. We determined the geometry of the cylindrical ETDP with a flat shaped heated probe tip by referring to a previous experimental study [14]. The ETDP with a height of 160 mm and radius of 25 mm was placed within the ice region, as shown in Figure 2.…”

“…Subsequently, the ETDP pushes the thin liquid film due to its weight and can slowly move downward through the close-contact melting process. The rate of penetration (ROP), which indicates the speed at which the heated probe tip deepens the borehole, has been one of the key parameters in designing the shape and operating conditions of an ETDP [12][13][14][15]. Many researchers have analyzed the effect of factors, such as operating conditions and melting-tip shape, on the ROP.…”

“…They over-estimated the ROP by about 30% compared to the experimental results. Suto et al [14] studied the effects of the shape and material of the drill head and heater temperature on the rate of penetration via lab-scale experiments. They also estimated the total required thermal energy considering the thermal loss with various conditions through a one-dimension heat conduction problem.…”

The SUBGLACIOR drilling probe: concept and design

“…Japanese engineers have designed a thermal drilling probe that could carry in situ instruments (Suto and others, 2008). With this design, the cable is not paid out from the probe itself but is spooled on a drum at the surface.…”

Avoiding slush for hot-point drilling of glacier boreholes

“…Unfortunately though, the options for maintaining a water-filled hole are limited and all options have significant engineering constraints (Talalay, 2020). For example, borehole maintenance by a thermal source is extremely energy intensive (Suto and others, 2008), and field experience with antifreeze solutions have resulted in partial refreezing within the borehole itself as ‘slush’ which effectively freezes the hole shut (Zotikov, 1986). Thus, substantial work has been done to know the timescales for melting and subsequent freezing of water-filled boreholes (Aamot, 1968; Humphrey and Echelmeyer, 1990; Zagorodnov and others, 1994; Ulamec and others, 2007).…”