Multi-parameter adjustable injection type ice layer hot water drill bit based on modular design

Abstract

The invention belongs to the technical field of polar region ice layer drilling, hot water drilling serves as an ice layer drilling method with the highest drilling speed at present and has become an important technical means for ice layer and under-ice environment detection, however, only part of heat energy of high-temperature jet flow is transmitted to an ice layer for drilling and broaching, heat loss exists, and drilling efficiency is high. The invention provides a multi-parameter adjustable injection type ice layer hot water drill bit based on modular design, which is characterized in that a reducing nozzle, a drill bit main body and a mixing pipe are located at coaxial positions, and different combination modes of the reducing nozzle and the mixing pipe which are selectable in multiple specifications support dynamic combination of key parameters such as a throat nozzle distance, an area ratio and a mixing pipe contraction angle; by introducing the jet pump structure, recycling and heat exchange strengthening of low-temperature hot water heat energy are achieved, the heat energy utilization rate of the low-temperature hot water is remarkably increased, full-static structural design is adopted, no moving part exists, and the continuous drilling machine has the advantages of being high in structural reliability, low in maintenance cost and the like and is suitable for continuous drilling operation in the fields of polar region ice layer exploration and glacier research.

Description

Technical Field

[0001] The present invention belongs to the technical field of polar ice layer drilling, and more specifically, relates to an ejector-type ice layer hot water drill bit with multi-parameter adjustable based on modular design. Background Art

[0002] In polar scientific expeditions and glacier research, how to efficiently drill into glaciers and obtain polar ice cores is crucial. Currently, there are mainly three methods for ice layer drilling: hot water drilling, thermal melting drilling, and mechanical drilling. Among them, hot water drilling has gradually become the primary choice of drilling method because it neither has the pollution problem caused by mechanical drilling fluids nor has the problem that the thermal melting drill is easily adhered to the surface by particle sediments, reducing the drilling efficiency. As the current fastest drilling speed ice layer drilling method, hot water drilling has become an important technical means for ice layer and sub-ice environment detection. The hot water drilling technology is powered by a high-pressure pump and provides heat through a heater. The high-temperature and high-speed hot water jet formed through the drill bit nozzle cuts and melts the ice layer, thereby realizing the rapid drilling of the ice layer. Although the development of existing hot water drill systems in the world is relatively mature and can achieve rapid drilling of ice layers with a thickness of up to 3000 meters, this technology in China has not yet been developed maturely. Only about 70% of the heat carried by the high-temperature jet is used to melt the ice layer to form a borehole. This is mainly because only a part of the thermal energy of the high-temperature jet is transferred to the ice layer for drilling and reaming, and the other part remains at the bottom of the hole in the form of low-temperature hot water and is dissipated during the process of returning to the surface through the recovery water pipe. Therefore, designing a device that can reduce the heat loss during the return journey of the recovery water pipe and realize the recycling of the heat of low-temperature hot water is of great significance for the development of hot water drills. Summary of the Invention

[0003] Based on the above background, the present invention provides an ejector-type ice layer hot water drill bit with multi-parameter adjustable based on modular design, aiming to strengthen the convective heat transfer effect at the bottom of the hole, enable the heat of the high-temperature jet to be efficiently transferred to the ice layer, and improve the energy utilization rate, drilling rate, and hole diameter uniformity. Based on the ejector-type ice layer hot water drill, a modular design is carried out, and the key parameters of the drill bit are quickly adjusted according to specific application scenarios to achieve the optimal drilling efficiency. Compared with the currently widely used hot water jet drilling method, the present invention has the advantages of adjustable design parameters, high drilling rate, good hole diameter uniformity, and high heat utilization rate, and is particularly suitable for solving the problems of low thermal efficiency, poor hole diameter uniformity, and poor vertical drilling stability of traditional hot water drill bits.

[0004] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0005] A multi-parameter adjustable ejector type ice layer hot water drill bit, comprising a drill bit body, several reducing nozzles with different inner diameters and a mixing tube. The reducing nozzles, the drill bit body and the mixing tube are in a coaxial position. The water inlet end of the reducing nozzle is connected to the water outlet of the upstream high-temperature hot water pipeline, and the outer diameter of the reducing nozzle matches the inner diameter of the water inlet end of the drill bit body. The tapered water outlet end of the reducing nozzle is placed inside the drill bit body; the water inlet end of the mixing tube is connected to the water outlet end of the drill bit body, and the outer diameter of the water inlet end of the mixing tube matches the inner diameter of the water outlet end of the drill bit body.

[0006] Furthermore, the drill bit body is an integral structure. An inhalation chamber and several ejector tubes are arranged inside the drill bit body. The inlet of the inhalation chamber is connected to the reducing nozzle, and the water outlet end of the reducing nozzle is located inside the inhalation chamber. The outlet of the inhalation chamber is connected to the water inlet end of the mixing tube; the ejector tubes are symmetrically distributed in a circumferential array around the inhalation chamber, and the ejector tubes penetrate from the outer wall of the drill bit body to the inhalation chamber.

[0007] Furthermore, the included angle between the axis of the ejector tube and the axis of the drill bit body is 0° to 90°, and the number of ejector tubes is at least 2.

[0008] Furthermore, the internal flow channel of the reducing nozzle is successively a nozzle constant cross-section flow channel and a nozzle reducing flow channel along the water flow direction. The nozzle constant cross-section flow channel is located upstream, and the tapered water outlet end located downstream is the nozzle reducing flow channel.

[0009] Furthermore, the tapered water outlet end of the reducing nozzle is threadedly connected to the drill bit body, and the insertion depth of the reducing nozzle inside the drill bit body is adjusted by the thread depth.

[0010] Furthermore, the internal flow channel of the mixing tube is a mixing tube constant cross-section flow channel or a mixing tube reducing flow channel along the flow direction, and the water inlet end of the mixing tube is flush with the water outlet end of the inhalation chamber of the drill bit body.

[0011] Furthermore, the distance between the tapered water outlet end of the reducing nozzle and the water inlet end of the mixing tube, i.e., the throat-to-nozzle distance, is 0.1 to 10 times the inner diameter of the water inlet end of the mixing tube.

[0012] In summary, the present invention has the following beneficial effects:

[0013] (1) High thermal efficiency and fast drilling speed. The present invention innovates by introducing a jet pump structure, optimizes the bottom hole flow field distribution, realizes the recovery and utilization of low-temperature hot water heat energy and heat transfer enhancement, and significantly improves the heat energy utilization rate of low-temperature hot water. At the same time, secondary heat loss is reduced, and the drilling speed is significantly increased compared with traditional drill bits.

[0014] (2) Modular design and rapid parameter adjustment. The present invention adopts a split combination building block type component structure, and different combination methods of reducing nozzles and mixing tubes with multiple specifications support the dynamic combination of key parameters such as throat-to-nozzle distance, area ratio, and mixing tube contraction angle.

[0015] (3) Fully static fluid drive, zero mechanical moving parts. The present invention does not require a drill bit rotation mechanism, breaking through the limitation of traditional drill bits relying on rotation mechanisms, and achieving drilling completely relying on jet dynamics effects. It is applicable to a wide range of operating conditions and works stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional schematic diagram and assembly diagram of a multi-parameter adjustable ejector-type ice layer hot water drill bit based on modular design.

[0017] Figure 2 It is a sectional view of a multi-parameter adjustable ejector-type ice layer hot water drill bit based on modular design.

[0018] Figure 3 It is a schematic diagram of the drilling principle.

[0019] Figure 4 It is a comparison diagram of the return water temperature in experimental tests.

[0020] Figure 5 It is a comparison diagram of the drilling speed in experimental tests.

[0021] In the figure, 1 - converging nozzle, 2 - drill bit body, 3 - mixing tube, 4 - suction chamber, 5 - ejector tube, 6 - equal cross-section flow channel of the nozzle, 7 - converging flow channel of the nozzle, 8 - equal cross-section flow channel of the mixing tube, 9 - converging flow channel of the mixing tube. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will be further described in detail below with reference to the accompanying drawings.

[0023] It should be noted that for the convenience of description, the descriptions of directions in the following text are consistent with the directions of the accompanying drawings themselves, but do not limit the structure of the present invention.

[0024] Such as Figures 1 to 5As shown in the figure, the present invention discloses a multi-parameter adjustable ejector type ice layer hot water drill bit, which includes a drill bit body 2, a number of convergent nozzles 1 with different inner diameters, and a mixing tube 3. The convergent nozzles 1, the drill bit body 2, and the mixing tube 3 are in a coaxial position. By selecting convergent nozzles 12 and mixing tubes 3 with different inner diameters, different specifications of combined installation can be achieved, enabling quick adjustment of three key parameters of the drill bit, namely the nozzle diameter, the throat-nozzle distance, and the mixing tube diameter, to achieve the optimal drilling efficiency. The present invention adopts a fully static structure design without moving parts, having advantages such as high structural reliability and low maintenance cost, and is applicable to continuous drilling operations in fields such as polar ice layer exploration and glacier research. Among them, the throat-nozzle distance is the distance from the outlet of the nozzle 1 to the inlet of the mixing tube 3. The water inlet end of the convergent nozzle 1 is connected to the water outlet of the upstream high-temperature hot water pipeline, and the outer diameter of the convergent nozzle 1 matches the inner diameter of the water inlet end of the drill bit body 2. The tapered water outlet end of the convergent nozzle 1 is placed inside the drill bit body 2; the water inlet end of the mixing tube 3 is connected to the water outlet end of the drill bit body 2, and the outer diameter of the water inlet end of the mixing tube 3 matches the inner diameter of the water outlet end of the drill bit body 2.

[0025] The drill bit body 2 is an integral structure. Inside the drill bit body 2, a suction chamber 4 and a number of ejector tubes 5 are provided. The inlet of the suction chamber 4 is connected to the convergent nozzle 1, and the water outlet end of the convergent nozzle 1 is located inside the suction chamber 4. The outlet of the suction chamber 4 is connected to the water inlet end of the mixing tube 3; the ejector tubes 5 are symmetrically distributed in a circumferential array around the suction chamber 4, and the ejector tubes 5 penetrate from the outer wall of the drill bit body 2 to the suction chamber 4. The included angle between the axis of the ejector tube 5 and the axis of the drill bit body 2 is 0° to 90°, and the number of ejector tubes 2 is at least 2. A jet pump is a device that uses the kinetic energy of a high-speed fluid (working fluid) to suck or transport another fluid (the fluid to be sucked). The present invention adopts the jet pump structure flow channel and realizes the cascade utilization of the waste heat of the low-temperature return water at the bottom of the hole through the ejector type heat recovery mechanism, which can significantly improve the drilling speed and thermal efficiency compared with traditional hot water drills.

[0026] The internal flow channel of the convergent nozzle 1 is successively a nozzle constant cross-section flow channel 6 and a nozzle convergent flow channel 7 along the water flow direction. The nozzle constant cross-section flow channel 6 is located upstream, and the tapered water outlet end located downstream is the nozzle convergent flow channel 7. The tapered water outlet end of the convergent nozzle 1 is threadedly connected to the drill bit body 2, and the insertion depth of the convergent nozzle 1 inside the drill bit body 2 is adjusted by the thread depth, and the adjustment of the throat-nozzle distance can also be achieved.

[0027] The internal flow channel of the mixing tube 3 is a mixing tube constant cross-section flow channel 8 or a mixing tube convergent flow channel 9 along the flow direction. The water inlet end of the mixing tube 3 is flush with the water outlet end of the suction chamber 4 of the drill bit body 2. The distance between the tapered water outlet end of the convergent nozzle 1 and the water inlet end of the mixing tube 3 is 0.1 to 10 times the inner diameter of the water inlet end of the mixing tube 3.

[0028] Embodiment:

[0029] The present invention verifies the principle of the feasibility of the ejector-type ice-layer hot water drill bit through experimental tests. The drilling principle is as follows: Figure 3 As shown in the figure. The mainstream high-temperature hot water forms a high-speed jet after passing through a converging nozzle under the action of an external pump. A negative pressure area is formed in the suction chamber 4 of the drill bit body 2. The low-temperature return water after melting the ice at the bottom of the drill hole is sucked into the suction chamber 4 through the ejector pipe 5 under the action of the pressure difference. The low-temperature hot water and the high-temperature hot water are evenly mixed in the mixing pipe 3 and then form a jet to impact the ice layer. The drill bit continuously dives under its own weight to complete the drilling process.

[0030] A comparative experiment on ice layer drilling was carried out using a single-hole conical nozzle drill bit and an ejector-type ice-layer hot water drill bit with the same nozzle outlet diameter. The comparison of the return water temperature drawn from the ice hole is shown in Figure 4 . In the experiment, the temperature of the mainstream high-temperature hot water is 60 °C, and the flow rate is 70 L / h. The temperature of the experimental ice column is -20 °C, with a height of 900 mm and a diameter of 150 mm. As shown in Figure 4 the figure, it takes 340 s for the single-hole conical nozzle drill bit to drill through the entire ice column, while the ejector-type ice-layer hot water drill bit of the present invention takes 290 s, and the drilling rate is increased by 15%. In the comparison of the return water temperature, the present invention is significantly lower than that of the single-hole conical nozzle drill bit, indicating that more heat is used for melting ice and drilling holes, and the thermal energy utilization rate is increased by 23.4%, proving that the negative pressure ejector structure of the present invention effectively reduces heat loss.

[0031] Based on Figure 4 the experimental results shown in the figure, Figure 5 Figure shows the comparison of the drilling speeds of a single-hole conical nozzle drill bit (non-ejector condition) and an ejector-type ice-layer hot water drill bit (ejector condition) at different flow rates. In the flow rate range of 60 - 110 L / h, the ejector-type drill bit has better flow rate response characteristics compared with the traditional structure. The improvement amplitude of the drilling speed increases with the increase of the flow rate, increasing from 9.6% to 21%, and reaching the highest gain at 110 L / h. The present invention can realize the recovery and utilization of the thermal energy of low-temperature hot water and the enhancement of heat transfer. The thermal energy utilization rate of low-temperature hot water is significantly improved; at the same time, the secondary heat loss is reduced, and the drilling speed is significantly increased compared with the traditional drill bit.

[0032] The experimental data proves the optimization effect of the ejector structure of the present invention on the ice layer drilling performance. The present invention forms a dynamically adjustable drilling system through a triple cooperative mechanism of controlling the jet velocity by a converging nozzle, adjusting the return water suction volume by an ejector pipe, and strengthening the heat and mass transfer by a mixing pipe, providing a new type of technical equipment for polar drilling engineering.

[0033] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A multi-parameter adjustable jet-type ice layer hot water drill bit, characterized in that: The invention comprises a drill bit body (2), a plurality of gradually converging nozzles (1) with different inner diameters, and a mixing tube (3); the gradually converging nozzle (1), the drill bit body (2), and the mixing tube (3) are in a coaxial position; the water inlet end of the gradually converging nozzle (1) is connected to the water outlet of an upstream high-temperature hot water pipeline, and the outer diameter of the gradually converging nozzle (1) matches the inner diameter of the water inlet end of the drill bit body (2); the conical water outlet end of the gradually converging nozzle (1) is placed in the drill bit body (2); the water inlet end of the mixing tube (3) is connected to the water outlet end of the drill bit body (2), and the outer diameter of the water inlet end of the mixing tube (3) matches the inner diameter of the water outlet end of the drill bit body (2).

2. The multi-parameter adjustable jet-type ice layer hot water drill bit according to claim 1 is characterized in that: The drill bit body (2) is an integrated structure, wherein a suction chamber (4) and a plurality of ejector tubes (5) are arranged inside the drill bit body (2), wherein the inlet of the suction chamber (4) is connected to a gradually converging nozzle (1), wherein the outlet end of the gradually converging nozzle (1) is located inside the suction chamber (4), and the outlet of the suction chamber (4) is connected to the inlet end of the mixing tube (3); the ejector tubes (5) are symmetrically distributed around the suction chamber (4) in a circular array, and the ejector tubes (5) penetrate from the outer wall of the drill bit body (2) to the suction chamber (4).

3. The multi-parameter adjustable jet-type ice layer hot water drill bit according to claim 2 is characterized in that: The included angle between the axis of the ejector tube (5) and the axis of the drill bit body (2) is 0° to 90°, and the number of ejector tubes (2) is at least 2.

4. The multi-parameter adjustable jet-type ice layer hot water drill bit according to claim 1, characterized in that: The internal flow channel of the tapered nozzle (1) is a nozzle constant cross-section flow channel (6) and a nozzle tapered flow channel (7) in sequence along the water flow direction; the nozzle constant cross-section flow channel (6) is located upstream, and the tapered water outlet end located downstream is the nozzle tapered flow channel (7).

5. The multi-parameter adjustable jet-type ice layer hot water drill bit according to claim 1 is characterized in that: The conical water outlet end of the tapered nozzle (1) is connected to the drill bit body (2) by means of threads, and the insertion depth of the tapered nozzle (1) in the drill bit body (2) is adjusted by the depth of the threads.

6. The multi-parameter adjustable jet-type ice layer hot water drill bit according to claim 1, characterized in that: The internal flow channel of the mixing tube (3) is a mixing tube constant cross-section flow channel (8) or a mixing tube tapered flow channel (9) along the flow direction, and the water inlet end of the mixing tube (3) is kept flush with the water outlet end of the suction chamber (4) of the drill bit body (2).

7. The multi-parameter adjustable jet-type ice layer hot water drill bit according to claim 1, characterized in that: The distance between the conical water outlet end of the gradually converging nozzle (1) and the water inlet end of the mixing tube (3), i.e., the throat-to-mouth distance, is 0.1 to 10 times the inner diameter of the water inlet end of the mixing tube (3).

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