Concrete single-side heat conduction test device and test method thereof
阅读说明：本技术 一种混凝土单面热传导试验装置及其试验方法 (Concrete single-side heat conduction test device and test method thereof ) 是由 徐港 罗强 杨亚会 周万清 于 2020-06-18 设计创作，主要内容包括：本发明提供了一种混凝土单面热传导试验装置,包括保温装置,所述保温装置设有试样孔,混凝土试件放置在试样孔内。本发明还提供一种混凝土表面换热系数的试验方法,包括如下步骤：步骤一、搭建混凝土单面热传导试验装置,保证混凝土单面与环境进行热交换；步骤二、将混凝土单面热传导试验装置放置在环境箱中,测量混凝土表层的温度数据,计算混凝土表面温度梯度；步骤三、计算混凝土表面换热系数<Image he="16" wi="10" file="DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>。该装置和方法能够实现混凝土的单面热传导,方便研究单面换热系数的影响因素。(The invention provides a concrete single-side heat conduction test device which comprises a heat preservation device, wherein the heat preservation device is provided with a sample hole, and a concrete sample is placed in the sample hole. The invention also provides a test method of the surface heat exchange coefficient of the concrete, which comprises the following steps: step one, building a concrete single-side heat conduction test device to ensure that the concrete single side exchanges heat with the environment; placing the concrete single-side heat conduction test device in an environment box, measuring the temperature data of the concrete surface layer, and calculating the temperature gradient of the concrete surface; step three, calculating the heat exchange coefficient of the concrete surface . The device and the method can realize the single-side heat conduction of the concrete, and are convenient for researching the influence factors of the single-side heat exchange coefficient.)
1. The utility model provides a concrete single face heat conduction test device which characterized in that, includes the heat preservation device, the heat preservation device is equipped with the sample hole, and the concrete sample is placed downtheholely at the sample.
2. The concrete single-sided heat conduction test device of claim 1, wherein the heat insulation device is made of polyurethane.
3. The concrete single-sided heat conduction test device according to claim 1, wherein an electric heating wire is arranged in the heat preservation device, the electric heating wire is arranged around the concrete sample, and the electric heating wire is electrically connected with the heating temperature control device.
4. The concrete single-side heat conduction test device according to claim 3, wherein a cooling liquid circulating pipe is arranged in the heat preservation device, and the cooling liquid circulating pipe is connected with a liquid cooling temperature control device.
5. The concrete single-side heat conduction test device according to claim 4, wherein a temperature probe is arranged in the heat preservation device, and the temperature probe is connected with a temperature real-time collector through a data line.
6. The concrete single-sided heat conduction test device according to claim 5, further comprising a controller, wherein the controller is electrically connected with the real-time temperature collector, the liquid cooling temperature control equipment and the heating temperature control equipment.
7. A test method for the surface heat exchange coefficient of concrete is characterized by comprising the following steps:
step one, building a concrete single-side heat conduction test device to ensure that the concrete single side exchanges heat with the environment;
placing the concrete single-side heat conduction test device in an environment box, measuring the temperature data of the concrete surface layer, and calculating the temperature gradient of the concrete surface;
and step three, calculating the heat exchange coefficient beta of the concrete surface.
8. The method for testing the heat exchange coefficient of the surface of the concrete according to claim 7, wherein in the second step, each group of temperature data is subjected to a quadratic polynomial y ═ a0+a1·x+a2·x2Fitting to obtain a0And a1Wherein a is0I.e. the surface temperature of the concrete, a1Namely the concrete surface temperature gradient.
9. The method for testing the surface heat exchange coefficient of concrete according to claim 7, wherein in the third step, the surface heat exchange coefficient β of concrete can be calculated according to the formula (1)
Wherein:
Twis the concrete surface temperature;
Tfis ambient temperature;
lambda is the heat conductivity coefficient of the concrete;
is the concrete surface temperature gradient.
10. The method for testing the heat exchange coefficient of the surface of the concrete according to claim 7, wherein in the third step, after the heat exchange coefficient of the surface of the concrete is calculated, the relationship between the heat exchange coefficient of the surface of the concrete and the temperature difference between the environment and the concrete sample is tested.
Technical Field
The invention belongs to the technical field of civil engineering test devices, and particularly relates to a concrete single-side heat conduction test device and a test method thereof.
Background
With the acceleration of the urbanization process in China, the energy consumption is higher and higher, and the building industry, as the national pillar industry, meets the social requirements, promotes the national economic development and consumes a large amount of resources at the same time, thus causing negative effects such as environmental pollution and climate warming. Globally, building energy consumption accounts for 29.74% of total energy consumption, and in building energy consumption, the heat dissipated through the outer wall accounts for about 40% of the total heat of the building. Therefore, the heat insulation performance of the building material is very important, the heat conductivity coefficient and the heat transfer coefficient related in the heat conduction process are important indexes for identifying the heat insulation performance of the material, and the concrete is also a main building material, so that the heat conduction test needs to be carried out on the concrete. Factors influencing the heat conductivity coefficient and the heat transfer coefficient are multiple, in order to research the influence of each factor on the heat conductivity coefficient and the heat transfer coefficient, a fine test needs to be carried out, the traditional test method cannot meet the requirement, or the influence of other factors cannot be eliminated, so that the concrete single-side heat conduction test device is designed to meet the requirements of related scientific researchers and testers. The device is easy and simple to handle, but automatically regulated has greatly improved test efficiency and precision.
Disclosure of Invention
The invention provides a concrete single-side heat conduction test device and a test method thereof, which are used for realizing the single-side heat conduction of concrete and facilitating the research of influencing factors of single-side heat exchange coefficients.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the utility model provides a concrete single face heat conduction test device, includes the heat preservation device, the heat preservation device is equipped with the sample hole, and the concrete sample is placed downtheholely at the sample.
In a preferred scheme, the heat preservation device is made of polyurethane.
In the preferred scheme, be equipped with electric heating wire in the heat preservation device, electric heating wire sets up around the concrete test piece, electric heating wire and heating temperature control equipment electric connection.
In the preferred scheme, a cooling liquid circulating pipe is arranged in the heat preservation device and is connected with the liquid cooling temperature control equipment.
In the preferred scheme, a temperature probe is arranged in the heat preservation device and is connected with the real-time temperature collector through a data line.
In the preferred scheme, the temperature control device further comprises a controller, and the controller is electrically connected with the temperature real-time collector, the liquid cooling temperature control equipment and the heating temperature control equipment.
The invention also provides a test method of the surface heat exchange coefficient of the concrete, which comprises the following steps:
step one, building a concrete single-side heat conduction test device to ensure that the concrete single side exchanges heat with the environment;
placing the concrete single-side heat conduction test device in an environment box, measuring the temperature data of the concrete surface layer, and calculating the temperature gradient of the concrete surface;
and step three, calculating the heat exchange coefficient beta of the concrete surface.
In a preferred embodiment, in the second step, each set of temperature data is subjected to a quadratic polynomial y ═ a0+a1·x+a2·x2Fitting to obtain a0And a1Wherein a is0I.e. the surface temperature of the concrete, a1Namely the concrete surface temperature gradient.
In the preferable scheme, in the third step, the heat exchange coefficient beta of the concrete surface can be calculated according to the formula (1)
Wherein:
Twis the concrete surface temperature;
Tfis ambient temperature;
lambda is the heat conductivity coefficient of the concrete;
is the concrete surface temperature gradient.
In the preferred scheme, in the third step, after the heat exchange coefficient of the surface of the concrete is calculated, the change relation between the heat exchange coefficient of the surface of the concrete and the temperature difference between the environment and the concrete sample is tested.
The concrete single-side heat conduction test device and the test method thereof provided by the invention have the following beneficial effects:
1. according to the invention, the side surface and the bottom surface of the concrete sample are both contacted with the heat preservation device, and only the top surface exchanges heat with the environment, so that the single-side heat conduction of the concrete is realized.
2. The heat preservation device is made of polyurethane, and sample holes in different shapes can be dug out, so that the heat preservation device can be suitable for concrete samples in different shapes, such as cylinders, cuboids, cubes and the like, so as to meet the requirements of different tests.
3. The invention can realize automatic temperature rise and temperature reduction in the polyurethane heat preservation device and ensure the heat preservation effect of the polyurethane heat preservation device.
4. Through the establishment of the concrete single-side heat conduction test device, the research on the influence factors of the concrete single-side heat exchange coefficient is realized.
Drawings
The invention is further illustrated by the following examples in conjunction with the accompanying drawings:
FIG. 1 is a schematic view of the overall structure of a single-sided thermal conductivity testing apparatus according to the present invention;
FIG. 2 is a top view of a single-sided thermal conductivity testing apparatus of the present invention;
FIG. 3 is a temperature fit curve of a concrete sample;
FIG. 4 is a graph showing the relationship between the heat transfer coefficient of the concrete surface and the temperature difference;
in the figure: the device comprises a heat preservation device 1, a
Detailed Description
As shown in fig. 1-2, the concrete single-side heat conduction test device comprises a heat preservation device, wherein the heat preservation device is provided with a sample hole, a concrete sample is placed in the sample hole, and the sample hole is in close contact with the concrete sample.
In this embodiment, the heat-insulating device is made of polyurethane. The heat preservation device prepares the sample hole according to the size and the shape of the concrete sample.
Be equipped with electric heating wire in the heat preservation device, electric heating wire sets up around the concrete sample, and electric heating wire buries underground electric heating wire and heating temperature control device nature in the heat preservation device and is connected, and heating temperature control device adopts intelligent digital display temperature control box ff 300.
The heating temperature control equipment is used for realizing the on-off of the electric heating wire, the heat preservation device is heated through the electric heating wire, the heat dissipated by the concrete sample through the heat preservation device is compensated, and the condition that the concrete sample and the environment can only carry out single-side heat exchange is ensured.
And a cooling liquid circulating pipe is arranged in the heat preservation device, and is embedded in the heat preservation device, and is connected with the liquid cooling temperature control equipment. The liquid cooling temperature control equipment is XMTD-818 CPK.
A temperature probe is arranged in the heat preservation device and is connected with a temperature real-time collector through a data line. The real-time temperature collector adopts a 16-path PT100 collecting module, can automatically collect temperature data measured by the temperature probe and display the temperature data on the real-time temperature collector, so that testers can observe and know the real-time temperature condition inside the heat preservation device conveniently.
The temperature real-time collector is electrically connected with the liquid cooling temperature control device and the heating temperature control device.
Setting a control temperature value in the controller, wherein when the temperature probe detects that the temperature data is higher than a set value, the liquid cooling temperature control equipment is automatically powered on and reduces the temperature of circulating liquid, and the cooled circulating liquid is continuously circulated through a cooling liquid circulating pipe, so that the temperature in the heat preservation device is reduced until the temperature reaches the set value; when the temperature probe detects that the temperature data is lower than the set value, the heating temperature control device controls the electric heating wire to be electrified to realize heating of the heat preservation device until the temperature reaches the set value.
A test method for the surface heat exchange coefficient of concrete comprises the following steps:
step one, building a concrete single-side heat conduction test device to ensure that the concrete single side and the environment exchange heat.
Step two, placing the concrete single-side heat conduction test device in an environment box, measuring the temperature data of the concrete surface layer, calculating the temperature gradient of the concrete surface, and performing quadratic polynomial y ═ a on each group of temperature data0+a1·x+a2·x2Fitting to obtain a0And a1Wherein a is0I.e. the surface temperature of the concrete, a1Namely the concrete surface temperature gradient.
Calculating the heat exchange coefficient beta of the concrete surface, and calculating the heat exchange coefficient beta of the concrete surface according to the formula (1)
Wherein:
Twis the concrete surface temperature;
Tfis ambient temperature;
lambda is the heat conductivity coefficient of the concrete;
And after calculating the heat exchange coefficient of the concrete surface, drawing a change relation graph of the heat exchange coefficient of the concrete surface and the temperature difference between the environment and the concrete sample.
The ambient temperature in this example was-20 ℃ and the initial concrete temperature was 20 ℃. The concrete thermal conductivity coefficient is 1.61W/(m.K) after the measurement is carried out by a thermal conductivity coefficient tester and the average value is taken after a plurality of times of measurement.
The temperature data of the surface layer of the concrete sample is measured by a high-precision temperature probe, and fitting is carried out by applying a quadratic polynomial, wherein a fitting curve of the quadratic polynomial is shown in figure 3.
0.999186826456288, the square of the correlation coefficient (R)2):0.998374314163788。
Calculating to obtain the concrete surface temperature gradient of 157 ℃/mm.
The heat exchange coefficient beta of the concrete surface can be calculated according to the formula (1)
The heat exchange coefficient is calculated to be 39.8 kJ/(h.m)2·℃)。
Thereby calculating the one-way heat exchange coefficient of the concrete under certain conditions.
Further study was made on the influence of the environmental temperature on the heat transfer coefficient, and in this example, the concrete temperature was set at 20 ℃ and the environmental temperatures were-10 ℃, 5 ℃, 0 ℃, 5 ℃, 10 ℃, 15 ℃, 25 ℃, 30 ℃, 35 ℃, 40 ℃, 45 ℃ and 50 ℃, respectively, and the heat transfer coefficient of the concrete surface was monitored during the test.
The relationship of the heat exchange coefficient of the concrete surface along with the change of the temperature difference is shown in figure 4, the heat exchange coefficient is increased along with the increase of the temperature difference, and when the ambient temperature is higher than the temperature of the concrete, the rate of the heat exchange coefficient which is increased along with the increase of the temperature difference is gradually reduced. When the ambient temperature is lower than the concrete temperature, the rate of the heat exchange coefficient increasing along with the increase of the temperature difference is gradually increased.
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