A freezing and thawing cycle device for a ring-shaped rock sample considering temperature gradient influence

Abstract

The application discloses a device for freeze-thaw cycle of circular rock sample considering temperature gradient influence, which is composed of a freeze-thaw box main body, a circular rock sample, a support frame, a wind speed classifier, an air compressor, a guide pipe, a temperature control machine, a flow rate valve, a flowmeter, a thermometer, an L-shaped guide pipe, a baffle, an air outlet pipe, an air outlet valve, an air inlet hole, an air outlet hole and a sample hole.

Description

Technical Field

[0001] This invention belongs to the field of rock testing technology, specifically a freeze-thaw cycle device for circular rock samples that can take into account the influence of temperature gradients. Background Technology

[0002] Energy extraction in western China has gradually become a hot topic. Since most of western my country is a cold region, rocks are affected by freeze-thaw cycles. Under the influence of moisture migration and frost heave, the number and growth of internal fissures and pores in the rock mass continuously develop, leading to the deterioration of the rock mass properties. During coal mining, the shaft walls are exposed to the outside environment. The rock in the vertical shaft walls is affected by freeze-thaw cycles, weakening its mechanical properties and reducing its safety. Different air velocity and temperature at different depths within the shaft wall create temperature gradients, resulting in varying freeze-thaw rates at different locations within the shaft.

[0003] Patent CN116148306A discloses a bidirectional freezing test device and a method for adjusting bidirectional freezing test parameters. Utilizing a test chamber, temperature sensing module, air-cooling module, refrigeration module, moisture sensing module, spray pipes, water supply module, and control module, the cooling method more closely resembles natural environmental cooling. Simultaneously, it ensures more uniform cooling and water replenishment, achieving a bidirectional freezing-unidirectional thawing process with a temperature gradient, thereby improving the accuracy and reliability of the test. Patent CN112834559A discloses a rock freeze-thaw cycle test device that considers temperature gradients. Components include a water temperature control system, a constant temperature water bath, a flow meter, a water pump, valves, a temperature sensor, a temperature monitoring system, a top temperature source, a top temperature control system, a bottom temperature source, a bottom temperature control system, a heat conduction device, a rock sample, a permeable filter, an insulated chamber body, and partitions. This device considers temperature gradients during the freeze-thaw cycle, achieving stratified freeze-thaw of the rock.

[0004] The aforementioned patent only considers the use of water temperature and flow rate for freeze-thaw cycles, and its applicability to circular rock samples is poor. It does not consider the air temperature and flow rate of the well wall in actual operation. Therefore, it is necessary to design a device that utilizes air temperature and flow rate to generate a temperature gradient in the circular rock sample, thereby controlling the freeze-thaw rate at different locations of the circular rock sample. Summary of the Invention

[0005] The purpose of this invention is to provide a freeze-thaw cycle device for circular rock samples that takes into account the influence of temperature gradients. Using this device, a temperature gradient can be generated in the circular rock sample during the freeze-thaw process, allowing control of the freeze-thaw rate at different locations on the sample. This device has advantages such as simple structure and ease of operation.

[0006] To achieve the above objectives, the device is implemented through the following scheme:

[0007] This device consists of a freeze-thaw chamber, a circular rock sample, a support frame, an anemometer, an air compressor, a conduit, a temperature controller, a flow valve, a flow meter, a thermometer, an L-shaped conduit, a baffle, an air outlet pipe, an air outlet valve, an air inlet, an air outlet, and a sample hole. The freeze-thaw cycle system comprises a freeze-thaw chamber, a ring-shaped rock sample, baffles, air inlets, air outlets, and a sample hole. Within this system, two baffles are positioned inside the freeze-thaw chamber, the ring-shaped rock sample is placed inside, a sample hole is located at the front of the chamber, three air inlets are located on the left side, one air inlet is located at the rear, and three air outlets are located on the right side. An air compressor, duct, temperature controller, flow valve, flow meter, thermometer, and L-shaped duct constitute an airflow control system. In this system, the air compressor and temperature controller are connected via a duct. The L-shaped duct is equipped with a flow valve, flow meter, and thermometer, and is mounted above the temperature controller. The airflow control system is connected to the freeze-thaw cycle system via the L-shaped duct and the air inlets. An air outlet system comprises an air outlet pipe and an air outlet valve. The air outlet valve is located above the air outlet pipe, and the air outlet system is connected to the freeze-thaw cycle system via the air outlet pipe and the air outlet holes. In the above-mentioned parts, the air inlet, air outlet and sample hole are all circular; the duct, L-shaped duct and air outlet pipe are made of PVC material; the support frame, anemometer and baffle are made of aluminum alloy; the flow valve and air outlet valve are made of stainless steel; the freeze-thaw chamber body, air compressor and temperature controller are made of low temperature resistant material; the anemometer is equipped with three different numbers of rotating fan blades.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0009] By coordinating the air compressor, duct, temperature controller, flow valve, flow meter, thermometer, L-shaped duct, baffle, air outlet pipe, and air outlet valve, the gas temperature and flow rate at three locations within the freeze-thaw chamber can be controlled to be different. Inside the annular rock sample, an air velocity classifier is used to achieve different air flow rates within the annular sample. Since the different gas temperatures and flow rates affect the freeze-thaw rate of the rock, a temperature gradient is generated inside and outside the annular sample, thereby controlling the freeze-thaw rate at different locations within the annular rock sample and achieving the goal of considering the temperature gradient during the freeze-thaw cycle of the annular rock sample. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0011] The invention will now be further described with reference to the accompanying drawings.

[0012] Figure 1 This is a schematic diagram of the main structure of the device of the present invention;

[0013] Figure 2 This is a schematic diagram of the left side of the device of the present invention;

[0014] Figure 3 This is a top view of the device of the present invention;

[0015] Figure 4 This is a schematic diagram of the airflow control system of the present invention;

[0016] Figure 5 This is a schematic diagram of the wind speed classifier of the device of the present invention;

[0017] Figure 6 This is a schematic diagram of the interior of the freeze-thaw chamber of the device of the present invention;

[0018] Figure 7 This is a schematic diagram of the inner baffle of the freeze-thaw chamber of the device of the present invention;

[0019] The following are the labels in the diagram: 1- Freeze-thaw chamber body, 2- Circular rock sample, 3- Support frame, 4- Anemometer, 5- Air compressor, 6- Conduit, 7- Temperature controller, 8- Flow valve, 9- Flow meter, 10- Thermometer, 11- L-shaped conduit, 12- Air outlet pipe, 13- Air outlet valve, 14- Baffle, 15- Air inlet, 16- Air outlet, 17- Sample hole. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example:

[0022] For example Figures 1 to 7As shown, an apparatus for freeze-thaw cycles of a circular rock sample that can take into account the influence of temperature gradients consists of a freeze-thaw chamber body 1, a circular rock sample 2, a support frame 3, an anemometer 4, an air compressor 5, a conduit 6, a temperature controller 7, a flow valve 8, a flow meter 9, a thermometer 10, an L-shaped conduit 11, an air outlet pipe 12, an air outlet valve 13, a baffle 14, an air inlet 15, an air outlet 16, and a sample hole 17. The freeze-thaw cycle system consists of a freeze-thaw chamber body 1, a circular rock sample 2, baffles 14, air inlets 15, air outlets 16, and sample holes 17. Within the freeze-thaw cycle system, two baffles 14 are positioned inside the freeze-thaw chamber body 1, and the circular rock sample 2 is placed inside the freeze-thaw chamber body 1. A sample hole 17 is located at the front of the freeze-thaw chamber body 1, three air inlets 15 are located on the left side, one air inlet 15 is located at the rear side, and three air outlets 16 are located on the right side. The system also includes an air compressor 5, a duct 6, a temperature controller 7, a flow rate valve 8, a flow meter 9, a thermometer 10, and an L-shaped duct 11. An airflow control system is formed. In the airflow control system, the air compressor 5 and the temperature controller 7 are connected through the conduit 6. The L-shaped conduit 11 is equipped with a flow valve 8, a flow meter 9, and a thermometer 10. The L-shaped conduit 11 is installed above the temperature controller 7. The airflow control system is connected to the freeze-thaw cycle system through the connection of the L-shaped conduit 11 and the air inlet 15. The air outlet duct 12 and the air outlet valve 13 form the air outlet system. In the air outlet system, the air outlet valve 13 is arranged above the air outlet duct 12. The air outlet system is connected to the freeze-thaw cycle system through the connection of the air outlet duct 12 and the air outlet 16. In the above-mentioned parts, the air inlet 15, air outlet 16 and sample hole 17 are all circular; the conduit 6, L-shaped conduit 11 and air outlet pipe 12 are made of PVC material; the support frame 3, wind speed classifier 4 and baffle 14 are made of aluminum alloy; the flow rate valve 8 and air outlet valve 13 are made of stainless steel; the freeze-thaw chamber body, air compressor and temperature controller are made of low temperature resistant material; three different numbers of rotating fan blades are installed on the wind speed classifier 4.

[0023] The specific steps are as follows:

[0024] Step 1, Preparation Stage: First, the circular rock sample 2 is placed inside the freeze-thaw chamber body 1 through the sample hole 17; second, the anemometer 4 is arranged in the circular rock sample 2 and fixed by the support frame 3; the air compressor 5, duct 6, temperature controller 7, flow valve 8, flow meter 9, thermometer 10, and L-shaped duct 11 are arranged according to... Figure 4 The gas flow rate and temperature control system is installed, and the four airflow control systems are connected to the freeze-thaw chamber body 1 through the air inlet 15. Finally, the air outlet pipe 12 and the air outlet valve 13 are combined to form the air outlet system, and the three air outlet systems are connected to the freeze-thaw chamber body 1 through the air outlet 16.

[0025] The second step is sample freezing: First, turn on the air compressor 5 and the temperature controller 7; second, open the flow rate valve 8 to allow air to pass through the L-shaped duct 11. The air temperature and flow rate can be displayed by the flow meter 9 and the thermometer 10, respectively; then, adjust the temperature controller 7 and the flow rate valve 8 according to the experimental requirements to make the air flow rate and temperature reach the experimental conditions required for freezing the ring rock sample 2; the three airflow control systems connected to the left side of the freeze-thaw chamber body 1 are set to the air temperature and flow rate respectively, and the airflow control system connected to the rear side of the freeze-thaw chamber body 1 is adjusted by the temperature controller 7 and the flow rate valve 8. After the airflow temperature and speed reach the experimental conditions, the airflow is introduced into the ring rock sample 2. The number and speed of the rotating fan blades in the wind speed classifier 4 control the airflow speed at different positions inside the ring rock sample 2; finally, open the air outlet valve 13 in the air outlet system to stabilize the airflow speed inside the freeze-thaw chamber body 1, and the sample begins to freeze.

[0026] The third step is sample melting: First, adjust the temperature controller 7 and flow rate valve 8 according to the experimental requirements to make the air flow rate and temperature reach the experimental conditions required for melting the ring rock sample 2; second, set the air temperature and flow rate required for melting the ring rock sample 2 respectively for the three airflow control systems connected to the left side of the freeze-thaw chamber body 1; finally, the airflow control system connected to the rear side of the freeze-thaw chamber body 1 adjusts the temperature controller 7 and flow rate valve 8, and after the airflow temperature and speed reach the experimental conditions, introduce the airflow into the ring rock sample 2. The wind speed classifier 4 controls the airflow rate at different positions inside the ring rock sample 2, and the sample begins to melt.

[0027] Fourth, after one freeze-thaw cycle is completed, repeat steps two and three to begin the second freeze-thaw cycle.

[0028] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0029] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for freeze-thaw cycles of a circular rock sample considering the influence of temperature gradient, comprising a freeze-thaw chamber body (1), a circular rock sample (2), a support frame (3), an anemometer (4), an air compressor (5), a duct (6), a temperature controller (7), a flow valve (8), a flow meter (9), a thermometer (10), an L-shaped duct (11), an air outlet pipe (12), an air outlet valve (13), a baffle (14), an air inlet (15), an air outlet (16), and a sample hole (17), characterized in that: The freeze-thaw chamber body (1), the circular rock sample (2), the baffle (14), the air inlet (15), the air outlet (16), and the sample hole (17) constitute a freeze-thaw circulation system. In the freeze-thaw circulation system, two baffles (14) are arranged inside the freeze-thaw chamber body (1), the circular rock sample (2) is placed inside the freeze-thaw chamber body (1), a sample hole (17) is arranged in front of the freeze-thaw chamber body (1), three air inlets (15) are arranged on the left side, one air inlet (15) is arranged on the rear side, and three air outlets (16) are arranged on the right side. The air compressor (5), the duct (6), the temperature controller (7), the flow valve (8), the flow meter (9), the thermometer (10), and the L-shaped duct (11) constitute an airflow control system. In the airflow control system, the air... The compressor (5) and the temperature controller (7) are connected by a conduit (6). A flow rate valve (8), a flow meter (9), and a thermometer (10) are arranged on the L-shaped conduit (11). The L-shaped conduit (11) is installed above the temperature controller (7). The airflow control system is connected to the freeze-thaw cycle system through the combination of the L-shaped conduit (11) and the air inlet (15). The air outlet pipe (12) and the air outlet valve (13) form the air outlet system. In the air outlet system, the air outlet valve (13) is arranged above the air outlet pipe (12). The air outlet system is connected to the freeze-thaw cycle system through the combination of the air outlet pipe (12) and the air outlet (16). By utilizing the air temperature and flow rate, a temperature gradient is generated in the circular rock sample, which can control the freeze-thaw rate at different locations of the circular rock sample.

2. The apparatus for freeze-thaw cycles of a circular rock sample considering the influence of temperature gradients according to claim 1, characterized in that: The air inlet (15), air outlet (16), and sample hole (17) are all circular.

3. The apparatus for freeze-thaw cycles of a circular rock sample considering the influence of temperature gradients according to claim 1, characterized in that: The duct (6), L-shaped duct (11) and air outlet duct (12) are made of PVC material; the support frame (3), wind speed classifier (4) and baffle (14) are made of aluminum alloy; the flow rate valve (8) and air outlet valve (13) are made of stainless steel; the freeze-thaw chamber body (1), air compressor (5) and temperature controller (7) are made of low temperature resistant material.

4. The apparatus for freeze-thaw cycles of a circular rock sample considering the influence of temperature gradients according to claim 1, characterized in that: The wind speed classifier (4) is equipped with three different numbers of rotating fan blades.

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