JPH11264769A - Heat flow measuring device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily measure the flow of the heat radiated from a heat source to the peripheral space throughout the space with high accuracy and high response even when the flow velocity is high. SOLUTION: A heat flow velocity measuring device is provided with a heating member 1 which has the shape insertable into the space having the change of temperature and the flow, and ignoring the heat flow, a device for energizing the heating member 1 for rising the temperature thereof and a device for cooling the heating member 1, and measures the change of the temperature of the heating member by an infrared ray camera. On this occasion the heating member 1 comprises a spider web-shaped structure where the linear materials are concentrically and radially combined, or the wire mesh structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat flow measuring device and method for measuring the temperature of a space in an air conditioner or a production process of a housing of an electronic device, an OA device, a computer or the like. Things.

[0002]

2. Description of the Related Art In recent years, a rise in temperature due to heat generated from electronic components has become a problem as electronic devices have become smaller and more dense. In order to efficiently discharge the heat inside the device to the outside,
It is necessary to take heat measures in consideration of the heat transfer and the flow path, such as the arrangement of parts and the position of the fan. In taking the heat countermeasures, an apparatus and method for efficiently and accurately measuring the temperature and the direction of the heat flow radiated from the heat source to the surrounding space in advance are desired. In addition, indoor air conditioners measure the heat flow in the room, such as the direction of the outlet and its control, to perform efficient cooling and heating, preventing local temperature rise and temperature decrease,
Even when providing comfortable air conditioning, it is important to measure the temperature and direction of the heat flow generated in the surrounding space. Also, in the production process, there are many steps of manufacturing a device using heat, such as a heat treatment and a drying step, which are often important steps that affect quality. Even in this case, temperature control is important, and heat flow control is very important from the viewpoint of quality improvement.

[0003] The heat radiated from the heat source or the air conditioner to the surrounding space warms the air (cooling is the opposite). To measure the temperature and distribution of air in the surrounding space over a wide range, a number of temperature sensors are installed. Since it is necessary and complicated, it is actually difficult to measure only a limited number of points and to measure a wide range of space.

As a method for measuring the temperature at which heat is radiated from the heat source to the surrounding space by natural convection, a wire net method is known in which a thin nylon wire is placed in the space and the temperature of the transferred heat is measured by an infrared camera. The measurement method known as the wire net method can measure the temperature change in a space accompanied by a small flow velocity with an infrared camera, but it can be used for forced air cooling using a fan, suction of ducts, and fast flow such as a blower. In this case, a heat transfer delay occurs in a transient phenomenon in which a nylon wire, which is a wire for detecting a temperature change with an infrared camera, is heated by a heat flow, and the temperature change cannot follow the temperature change. For example,
If the flow velocity of the flow from the fan or blower exceeds about 2 m / s, sufficient response and accuracy cannot be obtained because the flow velocity is high, and the temperature change of the nylon wire may be small due to air cooling. Accurate temperature measurement is not possible.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and is an invention according to Japanese Patent Application No. 9-238648 filed earlier by the present applicant. The thin wire that captures the heat flow is heated by energization, and the temperature is raised in advance, and by capturing the phenomenon of cooling when the heating thin wire is exposed to wind, it is possible to measure the flow direction in space and at the same time measure the temperature of the temperature field Method of measuring heat and flow using an infrared camera in a temperature field with a flow that can also be performed.Specifically, temperature measurement using an infrared camera in a temperature field with a fast flow In order to enable the measurement, a phenomenon when a heated thin wire is air-cooled is improved so as to be measured by an infrared camera, whereby a flow direction can be measured, and a highly accurate measuring device and method are provided. It is intended.

More specifically, the thin wire is heated to a certain temperature by heating it in advance, and the flow of the thin wire is used to make a cooling response. By detecting the change, the direction of the flow in the space is measured. Also,
The shape and structure of the heating material are improved so that the entire flow can be grasped, and the direction of the flow is measured by detecting a temperature change with an infrared camera. An object of the present invention is to provide a measuring apparatus and method capable of performing a measurement with a fast response even when the flow velocity is large, enabling measurement of the entire space, and improving the accuracy.

[0007]

According to the first aspect of the present invention, there is provided a heating material having a shape which can be inserted into a space having a temperature change and a flow and has a shape in which a heat flow can be ignored, an apparatus for heating the heating material,
Equipped with a device for cooling the heating material, in a heat flow measuring device that measures the temperature change of the heating material with an infrared camera, the heating material has a structure in which concentric and radial wires are combined in a spider web shape. It is a device for measuring a certain heat flow.

According to a second aspect of the present invention, there is provided a heating material having a shape which can be inserted into a space having a temperature change and a flow and has a negligible heat flow, a device for heating the heating material, and a device for cooling the heating material. In the heat flow measuring device for measuring a temperature change of the heating material with an infrared camera, the heating material is a heat flow measuring device having a wire mesh structure made of a wire.

According to a third aspect of the present invention, there is provided the heat flow measuring device according to the first or second aspect, wherein an insulating member is provided at a position where the heating materials contact each other.

According to a fourth aspect of the present invention, in the heat flow measuring device according to the first or second aspect, the heat flow measuring device includes an electrically insulating layer on a surface where the heating materials contact each other. Device.

According to a fifth aspect of the present invention, in the heat flow measuring device according to the second aspect, one of the crossing adjacent heating materials is energized and the other adjacent one is de-energized to heat the heating material. It is a measuring device for the flow of heat.

According to a sixth aspect of the present invention, in the heat flow measuring device according to any one of the first to fifth aspects, the heating material is made of a material having an emissivity of 0.9 or more. It is a device for measuring the flow of heat.

According to a seventh aspect of the present invention, in the heat flow measuring device according to any one of the first to fifth aspects, there is provided an apparatus capable of variably setting a heating temperature of the heating material according to a measured flow velocity. It is a device for measuring the flow of heat.

According to an eighth aspect of the present invention, in the heat flow measuring device according to any one of the first to fifth aspects, there is provided an apparatus capable of variably setting a heating temperature of the heating material according to an ambient temperature. It is a device for measuring the flow of heat.

According to a ninth aspect of the present invention, there is provided a heat flow measuring device according to any one of the first to fifth aspects, wherein the heating temperature of the heating material can be variably set in accordance with a measured flow velocity and an ambient temperature. It is a device for measuring the flow of heat provided.

According to a tenth aspect of the present invention, a heating material having a shape with negligible heat flow is disposed in a space having a temperature change and a flow, the heating material is heated, the heating material is cooled, and the heating material is cooled. In a method for measuring a flow of heat by measuring a temperature change of a heating material with an infrared camera, the heating temperature of the heating material is measured by a flow rate and / or
Alternatively, it is a method of measuring the flow of heat variably set in accordance with the ambient temperature.

[0017]

FIG. 1 is a diagram schematically showing a heat flow measuring device according to the present invention. In the figure, 1 is a heating material, 2 is a holder for supporting the heating material, 3 is a constant current power supply for energizing the heating material, 4 is an infrared camera, 5 is a personal computer for analyzing and displaying data of the infrared camera. It is. The heating material 1 is a thin metal wire of φ1 mm, and the holder 2
Alumina ceramics for electrical insulation
As the constant current power supply 3, a DC power supply of 24V and 2A output, an infrared camera 4 (for example, an infrared camera manufactured by NIKON, Thermovision LAIRD3A), and a personal computer 5 were used.
The fan 6 is placed in the space to create a heat flow as shown in the figure.

FIG. 2 shows an embodiment of the heating material according to the first aspect of the present invention. Make the heating wire a spider web, and set the concentric circle to 6
The structure in which the heating material 1 is constituted by the formed wire net is shown. The number of spider web-shaped heating fine wires and the degree of density between the fine wires can be changed according to the measurement space, and the specific configuration of the heating material is not limited to this example. In the present embodiment, a thin wire formed in a spider web shape from the center of the circle to the outside is referred to as a first wire to a sixth wire W1 to W6, and has a radius of 20 mm.
mm are arranged as the first wire at intervals of 5 mm. Further, the four wires LW1 to LW4 are linearly stretched radially and arranged so as not to contact each other. At both ends of the wire, a current input terminal is provided on the insulator so that the wire can be heated by current.

FIG. 1 shows a wire net constructed as described above.
As shown in the figure, the heater was placed in a heat flow, and in that state, the heating material 1 was energized and heated to a temperature of about 80 ° C. When the air flow is generated by operating the fan 6, a part of the uniformly heated concentric tungsten wire of the heating material is air-cooled by the air of the heat flow, so that the temperature of the wire is reduced in the flow direction. To decline. By observing and monitoring the temperature change with an infrared camera, flow measurement in a flow field can be performed. Moreover, by making the shape concentric and radial, the entire heat flow can be captured, so that a wide range of measurement can be performed in a short time.

FIG. 3 shows an embodiment of the heating material according to the second aspect of the present invention. As shown in the drawing, the heating material 1 is configured as a wire net in which a heating thin wire is formed in a wire mesh shape. The number of fine wires constituting the wire net can be changed according to the measurement space and the degree of density, and is not limited to those shown here. In this example, a rectangular wire net of 60 mm × 40 mm was produced at 10 mm intervals. Tungsten wire was used as the thin wire, and the heating material 1 was formed in a wire mesh shape using the 12 wires, and the odd-numbered wires (1, 3,
5,...) The input terminals for current supply are provided on both ends of the insulator so that the insulator can be heated. Apply insulation paint to the joint of the wire mesh,
Measures are taken to prevent current from flowing through the even-numbered wires.

The wire net constructed as described above is arranged in a flow of heat as shown in FIG. 1, and a heating material is energized to heat the temperature to about 80 ° C., and a fan is operated to flow air into the space. Occurs, a part of the tungsten wire of the heated wire mesh heating material is cooled by air, the temperature of the wire decreases in the direction of flow, and the change is observed with an infrared camera, so that a wide range can be observed. The measurement of the heat flow in the flow field can be performed. Moreover, since the heating material 1 is wire-meshed and forms a net densely so that adjacent wires do not impede the flow of air, it is troublesome to scan on a secondary plane as in a conventional hot-wire anemometer. The stagnant flow and the fine turbulence can be measured in a short time without taking much time.

In the invention according to claim 1, in FIG.
The concentric wire and the radial wire are arranged at a certain interval so as not to come into contact with each other. Further, in the invention according to claim 2, the electric current is prevented from flowing by applying an insulating paint to the joint portion of the wire mesh in FIG. 3, but the invention according to claim 3 uses an alumina coating when the wires are in contact with each other. The electrical insulation of the contact portion is ensured by using an insulator tube, a glass tube, an alumina adhesive, a Teflon tube, or the like. For example, the insulating tube shown above can be coated on the wire of the contact portion. As described above, in the case where the heating wires overlap each other, whether the wire nets are concentric circles, radial wires, or wire nets, the entire wire net is heated to a uniform temperature by performing electrical insulation at the contact points. Measurement can be performed in an area where the flow is fine, and the measurement accuracy can be improved. In addition, since a short circuit can be prevented in the current supply circuit of the heating device, the reliability of measurement can be improved.

According to a fourth aspect of the present invention, an electrical insulating layer is secured by using a Kanthal wire for a wire of a heating material. By heating the Kanthal wire in air in advance, the metal component is oxidized on the wire surface and a dense insulating film can be naturally formed. Then, as shown in FIG. 2, the wire is made concentric and radial. Or Figure 3
By processing into a wire mesh shape as shown in (1), an electrical insulating layer can be secured even at the contact point. In the present invention, φ1
The Kanthal wire was heated by heating in air at about 600 ° C. for 12 hours to oxidize the surface. Next, the wire was processed into a wire net to form a wire net. According to the third aspect of the present invention, since all the points in contact with each other are subjected to insulation treatment, it is necessary to spend time in the work of making a wire net. In this respect, in the present invention, Kanthal wires and similar surface oxidation are required. By using the material to be heated as the heating material, the fabrication can be facilitated, local inhomogeneity at each contact point can be prevented, and the thermal image of the infrared camera can be easily analyzed.

According to a fifth aspect of the present invention, when the shape of the wire heating material is a wire mesh structure, only one of the adjacent wires is energized, and the other is heated alternately without electrical connection. It was made. This makes it possible to significantly reduce the time required for producing the heating material as compared with the invention according to the third or fourth aspect in which the wire is provided with electrical insulation.
On the other hand, the measurement and analysis of small areas is slightly reduced,
This is extremely useful because measurement can be performed with only a small amount of work required to remove the connection of the terminal.

When the temperature of an object is to be measured by an infrared camera, the thermal radiation from the object shows a true value as the emissivity on the surface thereof approaches 1. Therefore, it is desirable that the wire heating material also has a high emissivity, but there is no perfect black body, and it is desirable to improve the temperature accuracy by using a material or a covering material having a high emissivity as much as possible. Therefore, a nichrome wire with a metallic luster (emissivity: 0.1) or a surface coating color was selected as the heating material, and a nichrome wire with a different emissivity (emissivity:
The emissivity and actual temperature were compared using 0.7, 0.8, 0.85, 0.90) and a tungsten wire (emissivity: 0.95) blackened by surface oxidation. The actual temperature was measured on a tungsten wire using an alumel-chromel thermocouple (JI
S: K) was attached and the actual temperature was measured. On the other hand, while measuring the temperature with an infrared camera, the emissivity was corrected and the measurement accuracy of the temperature was compared. Table 1 shows the relationship between the emissivity and the temperature at a heating temperature of 100 ° C. From this result, it can be seen that the accuracy of the measured temperature almost coincides with the actually measured temperature of the thermocouple when the emissivity is 0.9 or more, and is preferable as a heating material for the wire. Thus, it has been found that a wire having an emissivity of 0.9 or more is effective as a measuring device for improving accuracy. Therefore, the invention according to claim 6 is a heat flow measuring device in which the heating material is made of a material having an emissivity of 0.9 or more.

[0026]

[Table 1]

When measuring the temperature of the wire heating material with an infrared camera, if the flow velocity of the air is high, the amount of heat taken by the flow from the wire increases, and the temperature difference in the wire decreases, which hinders the flow measurement accuracy. Cause. Therefore, claim 7
The invention according to (1) is such that the temperature difference can be measured clearly by changing the heating temperature according to the flow speed. When the flow rate is 2 m / sec or less, the heating temperature is set to 80 ° C., and when the flow rate is about 10 m / sec, the temperature is set to 200 ° C.
The heating current was controlled so as to be set to ° C., and the temperature could be continuously changed with a potentiometer. The case where the heating temperature is constant is shown as a comparative example.

Table 2 shows the relationship between the measured flow velocity of air, the heating temperature, and the temperature difference during measurement (which can also be interpreted as the contrast of an infrared camera). From this table, the flow velocity is 2
In the case of m / sec, the heating temperature was set to 80 ° C. and the temperature difference was 40 ° C. However, when the flow rate was 10 m / sec, the temperature difference was set to 200 ° C. to reduce the temperature difference to 140 ° C.
° C, and it is clear that sufficient contrast can be obtained. Thus, by changing the heating temperature according to the flow velocity, a sufficient temperature difference (contrast) can be obtained, and the measurement accuracy of the heat flow can be improved. On the other hand, according to the result of the comparative example in which the heating temperature was not changed even when the flow rate was changed, it was found that the temperature difference at the flow rate of 2 m / sec could not be obtained when the flow rate was 10 m / sec because the air cooling effect was large. Further, when the temperature is set to a high temperature from the beginning, the contrast changes between a case where the flow velocity is small and a case where the flow velocity is large, causing a problem that accuracy differs in the entire flow velocity range.

[0029]

[Table 2]

Even when the environmental temperature to be measured changes, the measurement accuracy of the flow is disturbed as in the case where the measured flow velocity of air is large. For example, an ambient temperature of 7
In the case where the flow direction is measured in a place where the temperature is 0 ° C., if the wire temperature is 80 ° C., the temperature difference cannot be obtained and the measurement cannot be performed. Therefore, in the invention according to claim 8, the wire temperature is made variable in accordance with the ambient temperature, and the temperature is sensed by a temperature measuring sensor such as a thermocouple or a thermistor, so that the wire temperature can be controlled. In the example, the measurement was performed while changing the heating temperature to 80 ° C. and 200 ° C. when the ambient temperature was 22 ° C. and 70 ° C., respectively. Comparative examples in which the heating temperature was not changed were also examined.

Table 3 shows the relationship between the ambient temperature, the heating temperature, and the temperature difference at the time of measurement. According to this table, the heating temperature was set to 8 for each of the ambient temperatures of 22 ° C. and 70 ° C.
As a result of changing the temperature to 0 ° C. and 200 ° C., the temperature difference was sufficiently obtained even at 70 ° C., and a great effect was obtained as compared with the comparative example. As described above, by changing the heating temperature according to the ambient temperature, a sufficient temperature difference (contrast) can be obtained, and the measurement accuracy of the heat flow can be improved. If the heating temperature is not changed according to the change in the ambient temperature, contrast cannot be obtained, and sufficient measurement accuracy cannot be obtained.

[0032]

[Table 3]

According to a ninth aspect of the present invention, the heating temperature of the wire can be controlled when both the temperature and the measured flow velocity of the air change. For the temperature change, the measured value of the temperature sensor was measured, and for the flow, the approximate flow velocity was measured with a germanium sensor, and the flow rate was controlled with a potentiometer. The control method may be manual or computer control having a feedback circuit. However, accurate control is not required, and a temperature difference may be given to the heating material. In the embodiment, when the ambient temperature is 50 ° C. and 70 ° C., the flow rate is 2 m / sec.
The effect of changing the heating temperature when the temperature was changed to 10 m / sec was examined. At the same time, comparative examples were also examined.

Table 4 shows the relationship between the set heating temperature and the temperature difference (contrast) when both the flow rate and the temperature change. Further, a comparative example in which the flow velocity and the temperature are not changed is also shown. Ambient temperature is 50 ° C
And 70 ° C, the flow rates are 2 m / sec and 10 m / sec
Even in the case of a complex change with c, the temperature difference (contrast) could be made sufficiently large by appropriately changing the heating temperature as shown in Table 4. In addition, a comparative example was also examined, but it was found that a large temperature difference (contrast) could not be obtained when the heating temperature was constant. As described above, by controlling the flow velocity and the temperature in combination, a highly accurate measurement system can be provided.

[0035]

[Table 4]

According to a tenth aspect of the present invention, there is provided a method for performing measurement by the heat flow measuring device described above,
Arrange a heating material having a shape with negligible heat flow in a space with temperature change and flow, heat the heating material to a constant temperature,
Next, in a method of measuring a heat flow in which a heating material is cooled by an air flow and a temperature change of the heating material is measured by an infrared camera, a heating temperature of the heating material is changed according to a measurement flow rate and / or an ambient temperature. By applying the present invention to the measuring device, the heat flow in the space can be measured simply, efficiently and with high accuracy.

[0037]

According to the first aspect of the present invention, a flow measurement in a flow field can be performed by observing and monitoring a change in the temperature of the wire in the direction of the flow with an infrared camera, and the shape of the heating material can be changed. By forming the concentric circles and the radial shape, the entire flow can be captured, so that a wide range of measurement can be performed in a short time.

According to the second aspect of the present invention, since the heating material is in the form of a wire mesh, a net can be formed densely so that adjacent wires do not hinder the flow, and the conventional hot-wire anemometer can be scanned on a secondary plane. The stagnant flow and fine turbulence can be measured in a short time without taking much time.

[0039] According to the third aspect of the present invention, whether the heating material is concentric and radial wire net or wire mesh wire net, when the heating wires overlap each other, the electrical insulation is performed at the contact point, so that the entire wire net is formed. Since heating is performed to a uniform temperature, measurement can be performed in a region where heat flow is fine, and accuracy can be improved. In addition, since a short circuit can be prevented in the current supply circuit of the heating device, the reliability of measurement can be improved.

Advantageous effect according to the fourth aspect: Since a heating material is made of a Kanthal wire or a similar material that oxidizes the surface, the heating material can be easily manufactured, and local unevenness at each contact point can be reduced. The thermal image of the infrared camera can be easily analyzed.

Effect corresponding to the fifth aspect: The time required for forming the heating material can be greatly reduced. In addition, the measurement can be performed with only a small amount of trouble to disconnect the connection of the terminal, which is very useful.

Effect corresponding to claim 6: Since the wire has an emissivity of 0.9 or more, it is effective in improving the accuracy of the measuring device.

Effect corresponding to claim 7: By changing the heating temperature in accordance with the flow velocity, a sufficient temperature difference (contrast) can be obtained, and the accuracy of measuring the flow of heat can be improved.

According to the eighth aspect, by changing the heating temperature in accordance with the ambient temperature, a sufficient temperature difference (contrast) can be obtained, and the measurement accuracy of the heat flow can be improved.

Effect corresponding to the ninth aspect: By controlling the flow velocity and the temperature in combination, a highly accurate measurement can be performed.

According to a tenth aspect of the present invention, in the heat flow measuring method, the heat flow in the space is reduced by setting the heating temperature of the heating material variably according to a measured flow rate and / or an ambient temperature. Measurement can be performed simply and efficiently with high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a heat flow measuring device of the present invention.

FIG. 2 is a diagram showing a first embodiment of a heating material.

FIG. 3 is a view showing a second embodiment of the heating material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heating material, 2 ... Holder, 3 ... Constant current power supply, 4 ... Infrared camera, 5 ... Personal computer, 6 ... Fan.

Claims (10)

[Claims] 1. A heating material having a shape which can be inserted into a space having a temperature change and a flow and has a shape in which a heat flow is negligible, a device for heating the heating material, and a device for cooling the heating material, wherein the heating material is provided. In a heat flow measuring device for measuring a temperature change by an infrared camera, the heating material has a structure in which concentric and radial wires are combined in a spider web shape. 2. A heating material having a shape which can be inserted into a space having a temperature change and a flow and has a shape in which a heat flow can be ignored, a device for heating the heating material, and a device for cooling the heating material, In a heat flow measuring device for measuring a temperature change of an object with an infrared camera, the heating material has a wire mesh structure made of a wire material. 3. The heat flow measuring device according to claim 1, wherein an insulating member is provided at a position where the heating materials come into contact with each other. 4. The heat flow measuring device according to claim 1, further comprising an electrically insulating layer on a surface where the heating materials come into contact with each other. apparatus. 5. The heat flow measuring device according to claim 2, wherein one of the intersecting adjacent heating materials is energized and the other adjacent one is de-energized to heat the heating material. Measuring device for heat flow. 6. The heat flow measuring device according to claim 1, wherein the heating material is made of a material having an emissivity of 0.9 or more. A device for measuring heat flow. 7. The heat flow measuring device according to claim 1, further comprising a device capable of variably setting a heating temperature of the heating material in accordance with a measured flow velocity. A device for measuring heat flow. 8. The heat flow measuring device according to claim 1, further comprising a device capable of variably setting a heating temperature of the heating material according to an ambient temperature. A device for measuring heat flow. 9. The heat flow measuring device according to claim 1, further comprising a device capable of variably setting a heating temperature of the heating material in accordance with a measured flow velocity and an ambient temperature. Measurement device for heat flow. 10. A heating material having a shape with negligible heat flow is arranged in a space having a temperature change and a flow, the heating material is heated, the heating material is cooled, and the temperature change of the heating material is detected by infrared rays. A method for measuring a heat flow, wherein the heating temperature of the heating material is variably set according to a measured flow rate and / or an ambient temperature.