CN115468978B - Method for testing heat transfer property of high-temperature hot-water tunnel concrete material - Google Patents
Method for testing heat transfer property of high-temperature hot-water tunnel concrete material Download PDFInfo
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- 238000012360 testing method Methods 0.000 title claims abstract description 194
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- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000002937 thermal insulation foam Substances 0.000 claims description 8
- 229920001169 thermoplastic Polymers 0.000 claims description 7
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- 238000000465 moulding Methods 0.000 claims description 5
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- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
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- 238000009529 body temperature measurement Methods 0.000 description 2
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- 229910000838 Al alloy Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
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- 229910052802 copper Inorganic materials 0.000 description 1
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- G01N25/00—Investigating or analyzing materials by the use of thermal means
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Abstract
The invention discloses a method for testing heat transfer property of a high-temperature hot water tunnel concrete material, which comprises the following steps: s1: installing a test device; s2: manufacturing a concrete test piece, arranging temperature measuring points in the concrete test piece, and arranging heat flow sensors on the upper and lower surfaces of the concrete test piece; s3: the temperature and heat flow sensors of all measuring points are connected with a data acquisition instrument, and acquisition frequency is set; placing the concrete test piece with the mould at a reserved position of a water bath box, and continuously collecting data until the data of each measuring point tend to be stable, and collecting to obtain temperature and thermoelectric potential data; s4: and (3) calculating various parameters of heat transfer property of the high-temperature tunnel concrete material in the high-temperature hot water according to the data acquired in the step (S3). The method is suitable for testing and evaluating the heat transfer performance between different mediums such as surrounding rock of a high-temperature hot water tunnel, concrete material, air in the tunnel and the like in the temperature range of 30-150 ℃, and provides a calculation basis for the design of a high-temperature tunnel concrete supporting structure system.
Description
Technical Field
The invention relates to the field of concrete materials, in particular to a method for testing heat transfer property of a high-temperature hot water tunnel concrete material.
Background
When the tunnel is built, the tunnel can pass through a high-ground-temperature stratum caused by underground hot water, and the temperature is sometimes up to 90 ℃ and above, so that great difficulty is caused to engineering construction and operation. In order to ensure the smooth construction and normal operation of engineering, the tunnel concrete material is required to have good heat insulation, and meanwhile, the transfer rule of heat among different mediums such as surrounding rock, concrete material, air in a hole and the like in the existing high-temperature hot water tunnel environment is also required to be known so as to provide theoretical basic data for the design of a high-temperature tunnel supporting structure system. The parameters for representing the heat transfer performance of different materials mainly comprise the heat convection coefficient and the heat conduction coefficient. Up to now, there is no method for evaluating heat transfer related parameters between different mediums such as surrounding rock-concrete material-air in a hole of an existing hot water tunnel.
A test method for the thermal conductivity coefficient of the concrete is provided in the test method standard (GBT 50081-2019) for the physical and mechanical properties of the concrete. The method is an indoor test method, and the specific method comprises the following steps: and pouring concrete according to a certain size, molding and curing the concrete to a specified age, testing the temperatures of two sides of a test piece in special instruments and equipment, and determining the heat conductivity coefficient of the concrete through formula calculation. The method has the following problems in the aspect of evaluating the heat transfer performance of the high-ground-temperature tunnel concrete material:
(1) The heat conduction performance of the concrete material at different moments in the early-age process from construction pouring, setting and hardening to 1 day, 3 days and the like cannot be tested, so that guidance cannot be provided for measures such as construction cooling of a high-temperature tunnel, temperature gradient distribution of different depth parts of a concrete supporting structure cannot be described, and a theoretical basis cannot be provided for design and optimization of the mixing ratio of the concrete material of the high-temperature tunnel.
(2) The method can only test and obtain the heat conductivity coefficient of the concrete, and can not obtain the heat convection coefficient of the contact surface between the high-temperature hot water and the concrete material and between the concrete material and the air in the hole, so that the method can not be used for evaluating the heat transfer property between different mediums such as surrounding rocks of a high-temperature hot water tunnel, the concrete material, the air in the hole and the like.
(3) The test requires special instruments and equipment, cannot simulate the working condition that one side of the concrete test piece is liquid water and the other side of the concrete test piece is air, and can only test the environment condition that both sides of the concrete test piece are air, which is not in accordance with the actual conditions of tunnel construction and operation.
(4) The instrument and equipment used in the method are not suitable for the water environment condition of the ultra-high temperature water with the temperature of 90 ℃ or above.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a method for testing the heat transfer performance of surrounding rock-concrete material-air in a tunnel of a high-temperature hot water tunnel, which can simulate the actual environmental conditions and the construction process of the tunnel and is convenient to operate, and provides theoretical support for the design of a supporting structure system of the high-temperature tunnel, and guides and ensures the smooth construction and normal operation of the engineering.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
the method comprises the following steps:
s1: installing a test device;
The test device comprises a probe type temperature sensor, ceramic fiber cloth, a high-temperature-resistant heat-insulation foam board, a waterproof board, heat conduction water, a waterproof board placing rack, a concrete test piece placing rack, a concrete test mold, a water bath box, a limiting piece, a heat flow sensor, a patch type temperature sensor and a water temperature sensor; the waterproof board placing frame, the waterproof board, the ceramic fiber cloth and the high-temperature-resistant heat-insulation foam board are provided with reserved openings for installing a concrete test mould; a plurality of test mold preformed holes are formed in the bottom of the concrete test mold;
S2: manufacturing a concrete test piece, arranging a plurality of thin-wall metal pipes in the concrete test piece, fixing probe type temperature sensors in the thin-wall metal pipes, respectively arranging patch type temperature sensors on the upper surface and the lower surface of the concrete test piece, and respectively arranging heat flow sensors on the upper surface and the lower surface of the concrete test piece;
Fixing a patch type temperature sensor and a heat flow sensor at the bottom of a concrete test mould in advance, filling concrete mixture into the concrete test mould with a test mould preformed hole at the bottom, and then placing the concrete test mould filled with the concrete mixture on a vibrating table for vibrating and forming; after vibration molding, removing the concrete test piece with the mold from the vibration table, and arranging a thin-wall metal pipe and a probe type temperature sensor in the concrete test piece and arranging a rest patch type temperature sensor and a heat flow sensor;
S3: the probe type temperature sensor, the patch type temperature sensor and the heat flow sensor of each measuring point are connected with a data acquisition instrument, and the acquisition frequency is set; placing the concrete test piece with the die at a reserved position of a water bath box, after setting a heat conduction water temperature value, starting a heating device in the water bath box to heat water to the set heat conduction water temperature value T w, recording the ambient air temperature T a, and then carrying out uninterrupted data acquisition until the change of the data of each measuring point tends to be stable; collecting and obtaining the contact interface temperature T s1 of the bottom of the concrete sample and hot water, the contact interface temperature T s2 of the surface of the concrete sample and air, the thermoelectric potential E 1 of the surface of the concrete sample and the thermoelectric potential E 2 of the bottom surface of the concrete sample;
S4: according to the data collected in the step S3, calculating various parameters of heat transmissibility of the high-temperature tunnel concrete material in the high-temperature hot water;
Calculating the heat flux density q of the concrete material:
q＝Kr·|E1-E2|
Wherein q is the heat flux density of the concrete material, the unit is W/m 2;Kr, the resolution of a heat flux sensor is W/(m 2 mV);
calculating a convection heat exchange coefficient h 1 of the contact interface surface of the bottom of the concrete test piece and hot water:
In the formula, h 1 is the convective heat transfer coefficient of the surface of the contact interface between the bottom of the concrete test piece and hot water, and the unit is W/(m 2. K);
calculating a convective heat transfer coefficient h 2 of the surface of the concrete test piece and the surface of the air contact interface:
In the formula, h 2 is the convective heat transfer coefficient of the surface of the concrete test piece and the surface of the air contact interface, and the unit is W/(m 2. K);
Calculating the heat conductivity coefficient lambda of the concrete material:
Wherein, lambda is the thermal conductivity coefficient of the concrete material, and the unit is W/(m.K); delta-thickness of concrete material, unit m;
Meanwhile, according to temperature data obtained by probe type temperature sensors embedded in different depths of the interior of the concrete test piece, the temperature gradient distribution of the interior of the concrete test piece is obtained.
Further, the step S1 further includes the following steps:
S11: during installation, firstly placing the concrete test piece placing frame in a water bath box, then adjusting the heat conduction water level to the position of 2-3cm above the concrete test piece placing frame, and then placing the waterproof board placing frame on the concrete test piece placing frame;
S12: sequentially paving a waterproof board with reserved openings, ceramic fiber cloth and a high-temperature-resistant heat-insulating foam board on the upper part of a waterproof board placing frame; the waterproof board is provided with a reserved opening for placing a concrete test piece, and the reserved opening is attached to the outer portion of the concrete test piece.
Further, the heating device in the water bath box is an electric heating rod or a heating pipe, and the water bath box is also provided with a water inlet and a water outlet.
Further, a plurality of thin-wall metal pipes with different lengths are arranged in the concrete test piece, the bottoms of the thin-wall metal pipes are pre-buried in different depths of each measuring point of the concrete test piece, and the probe type temperature sensor extends into the bottoms of the thin-wall metal pipes to be in contact with the concrete through holes in the thin-wall metal pipes.
Further, the heat flow sensor at the bottom of the concrete test piece is bonded through a high-temperature-resistant insulating adhesive, and the heat flow sensor on the upper surface of the concrete test piece is bonded through vaseline.
Further, the concrete test piece placing rack is a hollowed-out plate or a net rack; the concrete test mould is a thermoplastic test mould, and a plurality of test mould preformed holes are arranged at the bottom of the thermoplastic test mould.
The beneficial effects of the invention are as follows:
(1) The invention can obtain the heat conduction performance of the concrete material at different moments in the early age process from construction pouring, setting and hardening to 1 day, 3 days and the like, thereby providing guidance for measures such as high-temperature tunnel construction cooling and the like, also explaining the temperature gradient distribution of different depth parts of the concrete supporting structure, and providing theoretical basis for the design and optimization of the mixing ratio of the concrete material of the high-temperature tunnel.
(2) The method of the invention can not only test and obtain the heat conductivity coefficient of the concrete, but also obtain the heat convection coefficient of the contact surface between the high-temperature hot water and the concrete material and between the concrete material and the air in the hole, thereby being used for evaluating the heat transfer property between different mediums such as surrounding rocks of the tunnel with the high-temperature hot water, the concrete material, the air in the hole and the like.
(3) The invention can simulate the working condition that one side of the concrete test piece is liquid water and the other side is air, and is more in line with the actual conditions of tunnel construction and operation.
(4) The method is suitable for testing and evaluating the heat transfer performance between different mediums such as surrounding rock of a high-temperature hot water tunnel, concrete material, air in the tunnel and the like in the temperature range of 30-150 ℃, and can provide a calculation basis for the design of a high-temperature tunnel concrete supporting structure system.
Drawings
FIG. 1 is a schematic view of the structure of the test device of the present invention;
FIG. 2 is a schematic view of the waterproof board rack of the present invention;
FIG. 3 is a schematic diagram of the installation of a patch type temperature sensor;
FIG. 4 is a schematic view of the installation of a thermal flow sensor;
fig. 5 is a flow chart of the heat transfer test of the high-temperature hot water tunnel concrete material of the invention.
The main component symbols in the drawings are described as follows:
1. A probe type temperature sensor; 2. ceramic fiber cloth; 3. high temperature resistant and heat insulating foam board; 4. a waterproof board; 5. a concrete test piece; 6. conducting hot water; 7. a waterproof board placing rack; 8. a concrete test piece placing rack; 9. testing concrete; 10. a water bath tank; 11. a test mold reserved hole; 12. a limiting piece; 13. a heat flow sensor; 14. a patch type temperature sensor; 15. a water temperature sensor; 16. thin-walled metal tubing.
Detailed Description
The following description of the embodiments of the present invention is provided to facilitate understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and all the inventions which make use of the inventive concept are protected by the spirit and scope of the present invention as defined and defined in the appended claims to those skilled in the art.
As shown in fig. 1,2, 3 and 4, a test apparatus for testing a heat transfer method of a concrete material of a high-temperature hot water tunnel, as shown in fig. 1, is a schematic structural view of the test apparatus. The test device for testing the heat transfer property of the high-water-temperature tunnel concrete material comprises a probe type temperature sensor 1, ceramic fiber cloth 2, a high-temperature-resistant heat-insulation foam board 3, a waterproof board 4, heat conduction water 6, a waterproof board placing rack 7, a concrete test piece placing rack 8, a concrete test mold 9, a water bath 10, a limiting piece 12, a heat flow sensor 13, a patch type temperature sensor 14 and a water temperature sensor 15; reserved openings for installing a concrete test mold 9 are formed in the waterproof board placing frame 7, the waterproof board 4, the ceramic fiber cloth 2 and the high-temperature-resistant heat-insulation foam board 3; a plurality of test mold reserved holes 11 are arranged at the bottom of the concrete test mold 9; a plurality of thin-walled metal tubes 16 are provided at different depths within the concrete test piece. The concrete test piece placing rack 8 is a hollowed-out plate or a net rack; the concrete test mould 9 is a thermoplastic test mould, and a plurality of test mould preformed holes 11 are arranged at the bottom of the thermoplastic test mould.
The heat flow sensor 13 measures the temperature range of-50 ℃ to 150 ℃ with the accuracy of +/-0.2 ℃ and has the main functions of: and measuring and calculating the heat flux density of the concrete test piece. The probe type temperature sensor 1 and the patch type temperature sensor 14 are used for measuring the temperature range of-60 ℃ to 250 ℃, the precision is +/-0.4 ℃, the acquisition frequency is 30 s/time, and the main functions are as follows: the temperature of each measuring point is displayed and recorded in real time, the measuring frequency can be regulated and controlled, and the data can be recorded. Ceramic fiber cloth 2, the main functions: is a heat-insulating material, and reduces the heat loss of a heat source. High temperature resistant thermal insulation foam board 3, main function: high-temperature-resistant heat preservation and heat insulation prevent heat from being dissipated from the periphery of the concrete test piece, and ensure heat transfer from the bottom of the concrete test piece to the surface of the concrete test piece to the maximum extent. Waterproof board 4, main functions: preventing water vapor from overflowing to influence the temperature measurement precision of the surface of the concrete test piece. The thickness of the concrete test piece 5 can be determined according to the tunnel engineering requirement, and the length and the width are suitable for eliminating the influence of the peripheral boundary. And the heat conduction water 6 simulates an environmental heat source of the high-temperature hot water tunnel. The waterproof board placing frame 7, waterproof board placing frame 7 should be higher than the hot water surface by a certain height, and main functions are: the water vapor contacts, condenses and liquefies, so that the water vapor overflow in the device is prevented from influencing the temperature measurement precision of the concrete test piece; is used for laying a waterproof board 4, ceramic fiber cloth 2 and a high-temperature-resistant heat-insulating foam board 3. The concrete sample rack 8 is made of metal, such as stainless steel, and has good bearing capacity. The concrete sample rack 8 is a steel grating, and hollow holes are formed in the steel grating, and the steel grating can also be a hollow plate or a net rack. And a hole is reserved at the bottom of the concrete test mould 9 to enable the bottom surface of the test piece to be in contact with heat conduction water, and the concrete test mould 9 is preferably a thermoplastic test mould. The bottom of the concrete test mould 9 is provided with a plurality of test mould preformed holes 11. The inner wall of the water bath 10 is preferably 700mm multiplied by 500mm multiplied by 1100mm (length multiplied by width multiplied by height), the temperature control range is 20-150 ℃, and the main functions are as follows: heating the water in the tank to a set temperature and providing a stable heat source. And a limiting piece 12 for supporting the concrete test piece placing frame 8 is further arranged on the inner wall of the water bath 10, and the limiting piece 12 is used for supporting and fixing the concrete test piece placing frame 8. The water temperature sensor 15 measures the temperature range of-50 ℃ to 150 ℃ with the accuracy of +/-0.2 ℃, and the water temperature sensor 15 is used for measuring the temperature of the heat conducting water. The inner side pipe diameter of the thin-wall metal pipe 16 is slightly larger than the outer diameter of the probe type temperature sensor 1, the thin-wall metal pipe 16 is used for guaranteeing the depth and the position of a probe type temperature sensor probe, and the thin-wall metal pipe 16 is preferably made of metal materials such as copper, copper alloy, aluminum alloy, stainless steel and the like.
The method for testing the heat transfer property of the high-temperature hot water tunnel concrete material comprises the following steps:
s1: installing a test device;
s11: during installation, the concrete test piece placing frame 8 is placed in the water bath 10, then the liquid level of the heat conducting water 6 is adjusted to the position 2-3cm above the concrete test piece placing frame 8, and then the waterproof board placing frame 7 is placed on the concrete test piece placing frame 8;
S12: sequentially paving a waterproof board 4 with reserved openings, ceramic fiber cloth 2 and a high-temperature-resistant heat-insulation foam board 3 on the upper part of a waterproof board placing frame 7; the waterproof board 4 is provided with a reserved opening for placing the concrete test piece 5, and the reserved opening is attached to the outside of the concrete test piece 5;
S2: manufacturing a concrete test piece 5, arranging a plurality of thin-wall metal pipes 16 in the concrete test piece 5, fixing the probe type temperature sensor 1 at the bottom of the thin-wall metal pipes 16, arranging patch type temperature sensors 14 on the upper surface and the lower surface of the concrete test piece 5, and arranging heat flow sensors 13 on the upper surface and the lower surface of the concrete test piece 5 respectively; the bottom of the concrete test piece 5 contacted with the heat conduction water 6 and the upper surface of the concrete test piece 5 contacted with the air are respectively provided with a patch type temperature sensor 14, and the inside of the concrete test piece is provided with a plurality of probe type temperature sensors 1 with different depths;
Fixing a patch type temperature sensor 14 and a heat flow sensor 13 at the bottom of a concrete test mould 9 in advance, filling concrete mixture into the concrete test mould 9 with a test mould preformed hole at the bottom, and then placing the concrete test mould 9 filled with the concrete mixture on a vibrating table for vibrating and forming; after vibration molding, the concrete test piece 5 with the mold is taken off from the vibration table, and the arrangement of the thin-wall metal tube 16 and the probe type temperature sensor 1 in the concrete test piece 5 and the arrangement of the rest of the patch type temperature sensor 14 and the heat flow sensor 13 are carried out.
According to the concrete mixture related test rules, mixing the concrete mixture according to the designed mixing ratio, and testing the workability of the mixture, loading the concrete mixture into a concrete test mold 9 with a test mold preformed hole 11 at the bottom, and selecting concrete test molds 9 with different sizes according to the test requirements, such as a cubic test mold with side length of 100, 150 or 200 mm; then placing a concrete test mould 9 filled with concrete mixture on a vibrating table for vibrating and forming; after vibration molding, the concrete test piece 5 with the mold is taken down from the vibration table, and the arrangement of the thin-wall metal tube 16, the probe type temperature sensor 1, the patch type temperature sensor 14 and the heat flow sensor 13 in the concrete test piece is carried out;
temperature measuring point part: arranging temperature measuring points on the bottom of the concrete test mould 9 contacted with the heat conducting water 6 and the upper surface contacted with air, and arranging probe type temperature sensors in the middle part of the concrete test piece 5 and other parts with different depths;
The temperature measuring point arrangement method comprises the following steps: the concrete test piece 5 is internally provided with a plurality of thin-wall metal pipes 16 with different lengths, the bottoms of the thin-wall metal pipes 16 are pre-buried at different depths of each measuring point of the concrete test piece 5, and the probe type temperature sensor 1 extends into the bottoms of the thin-wall metal pipes 16 to be in contact with concrete through holes in the thin-wall metal pipes 16. The patch type temperature sensor 14 is adopted at the upper and lower interfaces of the concrete test piece 5, the patch type temperature sensor 14 can be directly arranged on the upper surface of the concrete test piece 5, and when the patch type temperature sensor 14 is arranged on the lower surface, the patch type temperature sensor 14 can be stuck to the bottom of a concrete test mold by using a high-temperature-resistant insulating adhesive before the concrete mixture is poured into the concrete test mold 9.
Heat flow sensor 13 arrangement method: before the concrete mixture is put into the mould, the heat flow sensor 13 is stuck to the bottom of the test mould by using a high-temperature-resistant insulating adhesive, and after the mixture is put into the mould for vibration forming, the other heat flow sensor 13 is stuck to the upper surface of the concrete test piece by using vaseline.
S3: the probe type temperature sensor 1, the patch type temperature sensor 14 and the heat flow sensor 13 of each measuring point are connected with a data acquisition instrument, and the acquisition frequency is set; placing a concrete test piece with a die at a reserved position of a water bath box, after setting a temperature value of heat conducting water 6, starting a heating device in the water bath box 10 to heat the water to the set temperature value T w of the heat conducting water, recording the temperature T a of ambient air, and then carrying out uninterrupted data acquisition until the data change of each measuring point is stable; collecting and obtaining the contact interface temperature T s1 of the bottom of the concrete sample and hot water, the contact interface temperature T s2 of the surface of the concrete sample and air, the thermoelectric potential E 1 of the surface of the concrete sample and the thermoelectric potential E 2 of the bottom surface of the concrete sample; the heating device in the water bath 10 is an electric heating rod or a heating pipe, a water temperature sensor 15 for detecting the water temperature of the heat conduction water is also arranged in the water bath 10, and a water inlet and a water outlet are also arranged on the water bath 10;
S4: according to the data collected in the step S3, calculating various parameters of heat transmissibility of the high-temperature tunnel concrete material in the high-temperature hot water;
Calculating the heat flux density q of the concrete material:
q＝Kr·|E1-E2|
wherein q is the heat flux density of the concrete material, the unit W/m 2;Kr is the resolution of a heat flux sensor, W/(m 2.mV);E1) is the surface thermoelectric potential of the concrete test piece, the unit mV is E 2 is the bottom thermoelectric potential of the concrete test piece, and the unit mV is the thermal potential of the bottom surface of the concrete test piece;
calculating a convection heat exchange coefficient h 1 of the contact interface surface of the bottom of the concrete test piece and hot water:
In the formula, h 1 is the convection heat exchange coefficient of the surface of the contact interface between the bottom of the concrete test piece and hot water, the unit W/(m 2.K);Tw is the temperature of the hot water, the unit K; T s1 is the temperature of the contact interface between the bottom of the concrete test piece and the hot water, the unit K;
calculating a convective heat transfer coefficient h 2 of the surface of the concrete test piece and the surface of the air contact interface:
in the formula, h 2 is the convective heat transfer coefficient of the surface of the concrete test piece and the surface of the air contact interface, the unit W/(m 2.K);Ts2 is the temperature of the surface of the concrete test piece and the surface of the air contact interface, the unit K is the temperature of T a is the temperature of the ambient air, and the unit K is the temperature of the ambient air;
Calculating the heat conductivity coefficient lambda of the concrete material:
wherein, lambda is the thermal conductivity coefficient of the concrete material, and the unit is W/(m.K); delta-thickness of concrete material, unit m.
Meanwhile, according to the temperature data obtained by the probe type temperature sensors 1 embedded in the concrete test piece 5 at different depths, the temperature gradient distribution in the concrete test piece 5 can be obtained.
As shown in fig. 5, a flow chart of the heat transfer test of the high-temperature hot-water tunnel concrete material.
Claims (6)
1. A method for testing heat transfer properties of a high temperature hot water tunnel concrete material, comprising the steps of:
s1: installing a test device;
The test device comprises a probe type temperature sensor (1), ceramic fiber cloth (2), a high-temperature-resistant heat-insulation foam board (3), a waterproof board (4), heat-conducting water (6), a waterproof board placing frame (7), a concrete test piece placing frame (8), a concrete test mold (9), a water bath box (10), a limiting piece (12), a heat flow sensor (13), a patch type temperature sensor (14) and a water temperature sensor (15); reserved openings for installing a concrete test mold (9) are formed in the waterproof board placing frame (7), the waterproof board (4), the ceramic fiber cloth (2) and the high-temperature-resistant heat-insulation foam board (3); a plurality of test mould preformed holes (11) are arranged at the bottom of the concrete test mould (9);
s2: manufacturing a concrete test piece (5), arranging a plurality of thin-wall metal pipes (16) in the concrete test piece (5), fixing the probe type temperature sensor (1) at the bottom of the thin-wall metal pipes (16), arranging patch type temperature sensors (14) on the upper surface and the lower surface of the concrete test piece (5) respectively, and arranging heat flow sensors (13) on the upper surface and the lower surface of the concrete test piece (5) respectively;
A patch type temperature sensor (14) and a heat flow sensor (13) are fixed at the bottom of a concrete test mould (9) in advance, concrete mixture is filled into the concrete test mould (9) with a test mould preformed hole at the bottom, and then the concrete test mould (9) filled with the concrete mixture is placed on a vibrating table for vibrating and shaping; after vibration molding, the concrete test piece (5) with the mold is taken down from the vibration table, and the arrangement of the thin-wall metal tube (16) and the probe type temperature sensor (1) in the concrete test piece (5) and the arrangement of the rest patch type temperature sensor (14) and the rest heat flow sensor (13) are carried out;
S3: the probe type temperature sensor (1), the patch type temperature sensor (14) and the heat flow sensor (13) of each measuring point are connected with a data acquisition instrument, and the acquisition frequency is set; placing a concrete test piece with a mould at a reserved position of a water bath box, after setting a temperature value of heat conducting water (6), starting a heating device in the water bath box (10) to heat the water to the set temperature value T w of the heat conducting water, recording the temperature T a of ambient air, and then carrying out uninterrupted data acquisition until the change of data of each measuring point tends to be stable; collecting and obtaining the contact interface temperature T s1 of the bottom of the concrete sample and hot water, the contact interface temperature T s2 of the surface of the concrete sample and air, the thermoelectric potential E 1 of the surface of the concrete sample and the thermoelectric potential E 2 of the bottom surface of the concrete sample;
S4: according to the data collected in the step S3, calculating various parameters of heat transmissibility of the high-temperature tunnel concrete material in the high-temperature hot water;
Calculating the heat flux density q of the concrete material:
q＝Kr·|E1-E2|
Wherein q is the heat flux density of the concrete material, the unit is W/m 2;Kr, the resolution of a heat flux sensor is W/(m 2 mV);
calculating a convection heat exchange coefficient h 1 of the contact interface surface of the bottom of the concrete test piece and hot water:
In the formula, h 1 is the convective heat transfer coefficient of the surface of the contact interface between the bottom of the concrete test piece and hot water, and the unit is W/(m 2. K);
calculating a convective heat transfer coefficient h 2 of the surface of the concrete test piece and the surface of the air contact interface:
In the formula, h 2 is the convective heat transfer coefficient of the surface of the concrete test piece and the surface of the air contact interface, and the unit is W/(m 2. K);
Calculating the heat conductivity coefficient lambda of the concrete material:
Wherein, lambda is the thermal conductivity coefficient of the concrete material, and the unit is W/(m.K); delta-thickness of concrete material, unit m;
Meanwhile, according to temperature data obtained by probe type temperature sensors embedded in different depths of the interior of the concrete test piece, the temperature gradient distribution of the interior of the concrete test piece is obtained.
2. The method for testing heat transfer properties of a hot water tunnel concrete material according to claim 1, wherein the step S1 further comprises the steps of:
S11: during installation, firstly placing the concrete test piece placing frame (8) in the water bath box (10), then adjusting the liquid level of the heat conduction water (6) to the position of 2-3cm above the concrete test piece placing frame (8), and then placing the waterproof board placing frame (7) on the concrete test piece placing frame (8);
s12: sequentially paving a waterproof board (4) with reserved openings, ceramic fiber cloth (2) and a high-temperature-resistant heat-insulating foam board (3) on the upper part of a waterproof board placing frame (7); the waterproof board (4) is provided with a reserved opening for placing the concrete test piece (5), and the reserved opening is attached to the outside of the concrete test piece (5).
3. The method for testing the heat transfer property of the high-temperature hot-water tunnel concrete material according to claim 2, wherein the heating device in the water bath box (10) is an electric heating rod or a heating pipe, and the water bath box (10) is further provided with a water inlet and a water outlet.
4. The method for testing the heat transfer performance of the high-temperature hot-water tunnel concrete material according to claim 1, wherein a plurality of thin-wall metal pipes (16) with different lengths are arranged in the concrete test piece (5), the bottoms of the thin-wall metal pipes (16) are pre-buried at different depths of each measuring point of the concrete test piece (5), and the probe type temperature sensor (1) stretches into the bottoms of the thin-wall metal pipes (16) to be in contact with concrete through holes in the thin-wall metal pipes (16).
5. The method for testing the heat transfer performance of the high-temperature hot-water tunnel concrete material according to claim 1, wherein a heat flow sensor (13) at the bottom of the concrete test piece (5) is bonded through a high-temperature-resistant insulating adhesive, and the heat flow sensor at the upper surface of the concrete test piece (5) is bonded through vaseline.
6. The method for testing the heat transfer property of the concrete material of the high-temperature hot water tunnel according to claim 1, wherein the concrete test piece placing rack (8) is a hollowed-out plate or a net rack; the concrete test mould (9) is a thermoplastic test mould, and a plurality of test mould preformed holes (11) are formed in the bottom of the thermoplastic test mould.
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