A test device and method for studying the heat transfer efficiency of air source heat exchange chamber in high ground temperature tunnel

Abstract

The present invention provides a test device and method for studying the heat transfer efficiency of an air source heat exchange chamber in a high geothermal tunnel, comprising an insulation test box, a heat exchange mechanism, a chamber plugging assembly and a heating plate. The insulation test box is filled with a tunnel model, and the tunnel model is provided with a chamber, one end of the chamber is provided with a heat exchange mechanism, and the other end is provided with a chamber plugging assembly, the chamber plugging assembly comprises a support assembly, a heat-resistant airbag, a solenoid valve and an air pressure source, the support assembly is arranged in the chamber, at least two heat-resistant airbags are connected through the solenoid valve, and one of the heat-resistant airbags is connected to the support assembly and connected to the air pressure source. By introducing positive pressure into the heat-resistant airbag, the heat-resistant airbag expands to change the size of the chamber, and then the influence of the chamber size on the heat exchange efficiency is explored by controlling variables, and the temporal and spatial evolution law of the chamber temperature field and the change mechanism of the surrounding rock heat storage performance are explored, so as to provide a basis and basis for optimizing the design of the air source heat exchange chamber and improving the utilization rate of geothermal energy.

Description

Technical Field

[0001] The invention relates to the field of chamber heat exchange efficiency testing, and in particular to a test device and method for studying the heat transfer efficiency of an air source heat exchange chamber in a high geothermal tunnel. Background Art

[0002] There are more and more high-geotemperature tunnels in my country. While facing the high-temperature construction environment, thermal energy is also an environmentally friendly, stable and clean energy. It can be directly used for anti-freezing of tunnel entrances in cold regions, effectively solving the problem of tunnel frost damage.

[0003] Publication No. CN113339873 A proposes an air source heat pump heat chamber for the cold and frost protection system of high geothermal tunnels in cold regions, that is, a heat chamber is built at a location where the surrounding rock temperature of the tunnel is relatively high, and the air source heat pump is used to absorb the heat of the air for antifreeze at the tunnel entrance. However, the multi-body coupling heat transfer mechanism of the air source heat exchange chamber is still unclear, and the changing characteristics of the surrounding rock heat storage performance during the air source heat pump heat extraction process are still unclear, which makes the chamber design and heat pump power selection unreasonable, and to a certain extent limits the application and development of the air source heat exchange chamber.

[0004] In view of the defect that the multi-body coupling heat transfer mechanism of the air source heat exchange chamber in the above-mentioned prior art is still unclear, the publication number CN107014974B provides a simulation experimental device for an enhanced geothermal system and a method for testing the heat extraction rate of the reservoir of the enhanced geothermal system using the device. This prior art can simulate the influence of the well layout on the heat extraction efficiency and stable production time by adjusting the opening and closing of the heat exchange chamber entrance and exit; by changing the rock block combination and the distribution of the proppant, it can simulate the influence of different fracturing methods, crack width, number of cracks, and crack network morphology on the heat extraction efficiency and stable production time. Although this prior art explores the heat exchange efficiency by controlling variables, the influence of the size of the chamber on the heat exchange efficiency cannot be explored. Summary of the invention

[0005] The purpose of the present invention is to provide a test device and method for studying the heat transfer efficiency of an air source heat exchange chamber in a high geothermal tunnel, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A test device for studying the heat transfer efficiency of an air source heat exchange chamber in a high geothermal tunnel comprises a heat preservation test box, a heat exchange mechanism, a chamber plugging assembly and a heating plate. The heat preservation test box is filled with a tunnel model, and the tunnel model is provided with a chamber. The heat preservation test box is provided with a heating plate, wherein:

[0008] A heat exchange mechanism is provided at one end of the chamber, and a chamber sealing assembly is provided at the other end. The chamber sealing assembly includes a support assembly, a heat-resistant airbag, a solenoid valve and an air pressure source. The support assembly is arranged in the chamber, at least two of the heat-resistant airbags are connected through the solenoid valve, and one of the heat-resistant airbags is connected to the support assembly and connected to the air pressure source.

[0009] Preferably, the support assembly includes a support frame, a slider, a screw rod, a threaded sleeve and a connecting rod. The slider is cooperated with three guide rails arranged at equal angles on the support frame. The screw rod is rotatably installed on the support frame. The threaded sleeve is sleeved on the screw rod and forms a threaded connection pair with the screw rod. The slider is hinged with a connecting rod, and the other end of the connecting rod is hinged to the threaded sleeve.

[0010] Preferably, the air pressure source is composed of a telescopic hose and an air pump, one end of the telescopic hose is connected to the heat-resistant airbag, and the other end is connected to the air pump.

[0011] Preferably, a heat insulation plate is provided at the end of the chamber.

[0012] Preferably, the heat exchange mechanism includes a heat exchanger, a water tank, a water pipe and a constant flow pump. The heat exchanger is arranged in the chamber, and the water tank is connected to the heat exchanger through two water pipes. The water pipes pass through the insulation board. A constant flow pump is provided between one of the water pipes and the water tank, and a temperature sensor is provided on the water pipe.

[0013] Preferably, a partition is provided in the middle of the water tank, wherein the partition divides the water tank into a water storage chamber and a reflux chamber, wherein the constant flow pump is connected to the water storage chamber.

[0014] Preferably, temperature sensors are provided in both the chamber and the tunnel model.

[0015] An experimental method for studying the heat transfer efficiency of an air source heat exchange chamber in a high ground temperature tunnel comprises the following steps:

[0016] S1, filling the insulation test box with similar materials to surrounding rocks, and then constructing a tunnel model. When filling the similar materials to surrounding rocks, bury the heating plate and the temperature sensor at the preset position, and construct the chamber at the designed position;

[0017] S2, a heat exchange mechanism is arranged on one side of the chamber, and a chamber plugging assembly is arranged on the other side;

[0018] S3, heating the tunnel model using a heating plate;

[0019] S4, exchanging the heat in the chamber through a heat exchange mechanism;

[0020] S5, after the heat exchange in S4 is completed, the heat exchange efficiency of the chamber is calculated by the temperature difference of the water pipes on both sides, and then the heat exchange is stopped. Then, positive pressure is pumped into the heat-resistant airbag to expand it, thereby changing the size of the chamber, and then S4 is repeated to obtain the heat exchange efficiency after the size of the chamber is changed.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention introduces positive pressure into the heat-resistant airbag, which expands and changes the size of the chamber. The influence of the chamber size on the heat exchange efficiency is explored by controlling variables, and the spatiotemporal evolution law of the chamber temperature field and the mechanism of change of the surrounding rock heat storage performance are explored, providing a basis and basis for optimizing the design of air source heat exchange chambers and improving the utilization rate of geothermal energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 It is a front view of the chamber plugging assembly in the present invention;

[0025] Figure 3 is a three-dimensional schematic diagram of the support assembly in the present invention;

[0026] Figure 4 is a cross-sectional view of the heat-resistant airbag of the present invention;

[0027] Figure 5 It is a three-dimensional schematic diagram of the heat exchange mechanism in the present invention.

[0028] In the figure: 1 insulation test box, 2 heat exchange mechanism, 3 chamber plugging assembly, 4 heating plate, 5 insulation board, 6 temperature sensor, 21 heat exchanger, 22 water tank, 23 water pipe, 24 constant flow pump, 231 temperature sensor, 31 support assembly, 32 heat-resistant air bag, 33 solenoid valve, 34 telescopic hose, 35 air pump, 311 support frame, 312 slider, 313 screw rod, 314 threaded sleeve, 315 connecting rod. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example:

[0031] See also Figures 1 to 5 , the present invention provides a technical solution:

[0032] A test device for studying the heat transfer efficiency of an air source heat exchange chamber in a high ground temperature tunnel comprises a heat preservation test box 1, a heat exchange mechanism 2, a chamber plugging component 3 and a heating plate 4, wherein:

[0033] The insulation test box 1 is filled with a tunnel model, and the tunnel model is provided with a chamber. A heating plate 4 is provided in the insulation test box 1, and the heating plate 4 is preferably an electric heating plate;

[0034] A heat exchange mechanism 2 is provided at one end of the cavern, and a cavern sealing assembly 3 is provided at the other end. The cavern sealing assembly 3 includes a support assembly 31, a heat-resistant airbag 32, a solenoid valve 33 and an air pressure source. The support assembly 31 is arranged in the cavern, and at least two heat-resistant airbags 32 are connected through the solenoid valve 33, and one of the heat-resistant airbags 32 is connected to the support assembly 31 and connected to the air pressure source, wherein the airbag 32 is in a folded state when not inflated, and then it will expand when the airbag 32 is filled with positive pressure, thereby filling the cavern to achieve the effect of changing the size of the cavern. The solenoid valve 33 is electrically connected to a control switch, and then the solenoid valve 33 is opened or closed by the control switch, and the opening and closing of the solenoid valve 33 is a well-known technical means for those skilled in the art, and its switching principle will not be repeated here.

[0035] As a preferred embodiment, the support assembly 31 includes a support frame 311, a slider 312, a screw rod 313, a threaded sleeve 314 and a connecting rod 315. The slider 312 is matched with three guide rails arranged at equal angles on the support frame 311. The screw rod 313 is rotatably installed on the support frame 311. The threaded sleeve 314 is sleeved on the screw rod 313 and forms a threaded connection pair with the screw rod 313. The connecting rod 315 is hinged on the slider 312, and the other end of the connecting rod 315 is hinged to the threaded sleeve 314. By rotating the screw rod 313, the threaded sleeve 314 moves toward or away from the support frame 311, and then the connecting rod 315 pushes the slider 312 to slide, so that the end of the slider 312 can fit on the inner wall of the chamber to achieve the supporting effect, and the support assembly 31 is limited by a threaded connection pair to facilitate the displacement of the support assembly 31, so that when the airbag 32 is fully expanded or cannot reach the predetermined position of the chamber after expansion, it can be displaced by the support assembly 31. Of course, the limiting method of the support assembly 31 and the chamber disclosed in this embodiment is not the only limiting method, and a spring can also be set between the support frame 311 and the slider 312, and the slider 312 is directly pulled when displacement is required, and the spring automatically rebounds after the displacement is completed, so that the end of the slider 312 fits on the inside of the chamber.

[0036] As a preferred embodiment, the air pressure source is composed of a telescopic hose 34 and an air pump 35. One end of the telescopic hose 34 is connected to the heat-resistant airbag 32, and the other end is connected to the air pump 35. The arrangement of the telescopic hose 34 prevents the air pump 35 from being synchronously displaced when the airbag 32 is displaced.

[0037] As a preferred embodiment, a heat insulation plate 5 is provided at the end of the chamber.

[0038] As a preferred embodiment, the heat exchange mechanism 2 includes a heat exchanger 21, a water tank 22, a water pipe 23 and a constant flow pump 24. The heat exchanger 21 is arranged in the chamber, and the water tank 22 is connected to the heat exchanger 21 through two water pipes 23. The water pipes 23 pass through the heat insulation board 5. A constant flow pump 24 is arranged between one of the water pipes 23 and the water tank 22. Both water pipes 23 are provided with temperature sensors 231. Then, the temperature of the cold water and the temperature of the hot water after the heat exchange can be measured by the temperature sensor 231, and then the efficiency of the heat exchange can be obtained. The heat exchanger 21 is a heat exchange component with a cavity structure inside. When the cold water flows into the heat exchanger 21, it is heated by contacting with the hot air, thereby achieving the effect of heat exchange.

[0039] As a preferred embodiment, a partition is provided in the middle of the water tank 22, wherein the partition divides the water tank 22 into a water storage chamber and a reflux chamber, wherein the constant flow pump 24 is connected to the water storage chamber.

[0040] As a preferred embodiment, both the chamber and the tunnel model are provided with temperature sensors 6. The temperature sensors 6 can detect the temperature gradient inside the chamber and the tunnel model in real time.

[0041] An experimental method for studying the heat transfer efficiency of an air source heat exchange chamber in a high ground temperature tunnel comprises the following steps:

[0042] S1, filling the insulation test box 1 with surrounding rock similar materials, and then constructing a tunnel model. When filling the surrounding rock similar materials, bury the heating plate 4 and the temperature sensor 6 at a preset position, and construct a chamber at a designed position;

[0043] S2, a heat exchange mechanism 2 is arranged on one side of the chamber, and a chamber plugging assembly 3 is arranged on the other side;

[0044] S3, heating the tunnel model using the heating plate 4;

[0045] S4, the heat in the chamber is exchanged out through the heat exchange mechanism 2; specifically, the cold constant flow of the water storage chamber is pumped into the heat exchanger 21 through the constant flow pump 24, and then the heat inside the chamber is transferred to the cold water by the heat exchanger 21, and then the heated water flows back to the reflux chamber.

[0046] S5, after the heat exchange in S4 is completed, the heat exchange efficiency of the chamber is calculated by the temperature difference of the water pipes 23 on both sides, and then the heat exchange is stopped, and then the size of the chamber is changed by pumping positive pressure into the heat-resistant airbag 32 to expand it, and then S4 is repeated to obtain the heat exchange efficiency after the size of the chamber is changed. The heat exchange efficiency is reflected according to the temperature of the hot water exchanged and the calorific value contained. Since both water pipes 23 are provided with temperature sensors 231, the temperature of the cold water and the temperature of the hot water after the heat exchange can be measured by the temperature sensor 231, and then the heat exchange efficiency can be obtained.

[0047] The size of the chamber is specifically changed by introducing positive pressure into the airbag 32 connected thereto through the air pressure source, so that the airbag 32 expands and fills the chamber. When the size of the chamber needs to be further changed, the solenoid valve 33 is opened, and when the air pressure source continues to introduce positive pressure, another airbag 32 also expands. By directly moving the position of the support assembly 31, the position of the entire chamber plugging assembly 3 is changed to ensure that the size of the chamber reaches the preset size of the experiment.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A test device for studying the heat transfer efficiency of an air source heat exchange chamber in a high ground temperature tunnel, comprising a heat preservation test box (1), a heat exchange mechanism (2), a chamber plugging assembly (3) and a heating plate (4), wherein the heat preservation test box (1) is filled with a tunnel model, and the tunnel model is provided with a chamber, and the heat preservation test box (1) is provided with a heating plate (4), characterized in that: A heat exchange mechanism (2) is provided at one end of the chamber, and a chamber sealing assembly (3) is provided at the other end. The chamber sealing assembly (3) comprises a support assembly (31), a heat-resistant airbag (32), a solenoid valve (33) and an air pressure source. The support assembly (31) is arranged in the chamber, at least two of the heat-resistant airbags (32) are connected via the solenoid valve (33), and one of the heat-resistant airbags (32) is connected to the support assembly (31) and is connected to the air pressure source.

2. According to claim 1, a test device for studying the heat transfer efficiency of the air source heat exchange chamber in a high ground temperature tunnel is characterized by: The support assembly (31) comprises a support frame (311), a slider (312), a screw rod (313), a threaded sleeve (314) and a connecting rod (315); the slider (312) is matched in three guide rails arranged at equal angles on the support frame (311); the screw rod (313) is rotatably mounted on the support frame (311); the threaded sleeve (314) is sleeved on the screw rod (313) and forms a threaded connection pair with the screw rod (313); the connecting rod (315) is hinged on the slider (312), and the other end of the connecting rod (315) is hinged to the threaded sleeve (314).

3. The test device for studying the heat transfer efficiency of the air source heat exchange chamber in a high geothermal tunnel according to claim 1, characterized in that: The air pressure source is composed of a telescopic hose (34) and an air pump (35). One end of the telescopic hose (34) is connected to the heat-resistant air bag (32), and the other end is connected to the air pump (35).

4. The test device for studying the heat transfer efficiency of the air source heat exchange chamber in a high ground temperature tunnel according to claim 1, characterized in that: A heat insulation board (5) is provided at the end of the chamber.

5. The test device for studying the heat transfer efficiency of the air source heat exchange chamber in a high ground temperature tunnel according to claim 4, characterized in that: The heat exchange mechanism (2) comprises a heat exchanger (21), a water tank (22), a water pipe (23) and a constant flow pump (24); the heat exchanger (21) is arranged in a chamber, and the water tank (22) is connected to the heat exchanger (21) through two water pipes (23); the water pipes (23) pass through the heat insulation board (5); a constant flow pump (24) is arranged between one of the water pipes (23) and the water tank (22); and temperature sensors (231) are arranged on both water pipes (23).

6. The test device for studying the heat transfer efficiency of the air source heat exchange chamber in a high ground temperature tunnel according to claim 5, characterized in that: A partition is provided in the middle of the water tank (22), wherein the partition divides the water tank (22) into a water storage chamber and a reflux chamber, wherein the constant flow pump (24) is in communication with the water storage chamber.

7. The test device for studying the heat transfer efficiency of the air source heat exchange chamber in a high ground temperature tunnel according to claim 1, characterized in that: Temperature sensors (6) are provided in the chamber and the tunnel model.

8. An experimental method for studying the heat transfer efficiency of an air source heat exchange chamber in a high ground temperature tunnel according to claim 1, characterized in that: The following steps are involved: S1, filling the insulation test box (1) with surrounding rock-similar materials, and then constructing a tunnel model. When filling the surrounding rock-similar materials, the heating plate (4) and the temperature sensor (6) are buried at a preset position, and a chamber is constructed at a designed position; S2, a heat exchange mechanism (2) is arranged on one side of the chamber, and a chamber plugging assembly (3) is arranged on the other side; S3, heating the tunnel model using a heating plate (4); S4, exchanging the heat in the chamber through the heat exchange mechanism (2); S5, after the heat exchange in S4 is completed, the heat exchange efficiency of the chamber is calculated by the temperature difference of the water pipes (23) on both sides, and then the heat exchange is stopped. Then, positive pressure is pumped into the heat-resistant air bag (32) to expand it, thereby changing the size of the chamber, and then S4 is repeated to obtain the heat exchange efficiency after the size of the chamber is changed.

Images