JPH07905Y2 - Heat flow measurement sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a heat flow measuring sensor for measuring a heat flow density.

[Prior Art] A heat flow measuring sensor is one in which a heat resistance plate is arranged on the surface or inside of an object where the heat flow exists so as to be orthogonal to the heat flow direction, and the heat flow density or the heat flow is measured from the temperature difference between both surfaces of the heat resistance plate. Is. This principle will be described with reference to FIG.

In FIG. 4, reference numeral 1 denotes an object in which a heat flow exists, and a thin layer heat resistance plate 2 is arranged inside or on the surface thereof so as to be orthogonal to the direction of the heat flow Q indicated by an arrow. The thermal resistance plate 2 has a thermal constant, that is, a thermal conductivity λ [W / (m ° C.)] and a thickness d.
(M) and the temperature difference between both surfaces is ΔT, the heat flow density q (W / m ² ) at that position is given by the following equation.

q = λ / d · ΔT Therefore, if the thermal constants, that is, λ and d are known, the heat flow density q can be measured by detecting the temperatures on both surfaces of the thermal resistance plate 2.

Conventionally, a differentially wired thermocouple has been used for temperature detection on both sides of the thermal resistance plate 2. This heat flow measuring sensor will be described with reference to FIG. The thermocouple 3 is formed by alternately connecting the copper wire 4 and the constantan wire 5, and each of the contacts 6 and 7 is spirally wound so as to be located on both sides of the thermal resistance plate 2,
Both ends thereof are connected to an indicator 9 via a lead wire 8, and the indicator 9 can detect a temperature difference between both surfaces of the thermal resistance plate 2.

[Problems to be Solved by the Invention] However, since the temperature difference detection by the thermocouple described above is a spot type measurement, for example, for measuring the heat flow density of a long object such as a power cable, the sensor part (thin layer) of the heat flow meter is used. A large amount of heat resistance plates and thermocouples are required, resulting in enormous cost. Moreover, since a thermocouple is used for temperature measurement, there is a problem that it is not suitable for measurement in a place where there is an electric field or magnetic field.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a heat flow measuring sensor which can obtain a continuous heat flow density distribution without being affected by an electric field or a magnetic field.

[Means for Solving the Problem] In a heat flow measurement sensor, a heat resistance plate whose thermal constant is known is arranged orthogonally to the heat flow direction, and the heat flow density is obtained from the temperature difference between both surfaces of the heat resistance plate. The temperature measuring optical fibers are symmetrically arranged with the thermal resistance plate sandwiched therebetween.

[Operation] According to the above configuration, by arranging the temperature measurement optical fibers symmetrically with the thermal resistance plate sandwiched therebetween, the temperature difference between the front and back of the thermal resistance plate is obtained at an arbitrary position of the optical fiber, and the heat flow density thereof is obtained. The distribution can be calculated.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 10 is a thin-layer heat resistance plate whose thermal constants such as thermal conductivity λ [W / (m ° C)] and thickness d (m) are known in advance. Optical fiber for temperature measurement
The heat flow measuring sensor of the present invention is constructed by adhesively fixing 11a and 11b with the adhesive 12.

These temperature measuring optical fibers 11a and 11b detect the temperature at each position by injecting laser light from one end and measuring backscattered light that changes with temperature.
The heat flow density at that position can be obtained from the temperature difference based on the backscattered light at the corresponding positions of 11a and 11b.

Next, an example of obtaining the heat flow density distribution of the object to be measured using the sensor shown in FIG. 1 will be described with reference to FIG.

In FIG. 2, the heat flow measuring sensor of the present invention is arranged so as to be orthogonal to the heat flow direction of the DUT 13 although not shown. The optical fibers 14a and 14b integrally connected to the optical fibers 11a and 11b of this sensor are connected to the optical switch 15, and the switch 15 is connected to the optical fiber temperature measuring device 16 via the optical fiber 14 and the optical fiber A calculator 18 is connected to the temperature measuring device 16 via a connection cable 17. The optical switch 15 switches the laser light incident from the optical fiber temperature measuring device 16 through the optical fiber 14 to one of the optical fibers 14a and 14b, and one optical fiber 11a of the heat flow measuring sensor in the DUT 13 is measured. , 11b, and the backscattered light is returned to the optical fiber temperature measuring device 16 via the same path. The calculator 18 calculates the temperature at each position of the heat flow measurement sensor from the laser light emitted by the optical fiber temperature measuring device 16 and the backscattered light detected, and also obtains the temperature difference at the same point of the sensor to obtain the light of the sensor. The heat flow density distribution along the fibers 11a and 11b is obtained.

That is, assuming that the temperatures at the same point on the front and back of the thermal resistance plate 10 of the sensor are T ₁ and T ₂ , the temperature difference is ΔT = T ₁ −T ₂ , and therefore the distance in the longitudinal direction of the optical fibers 11a and 11b is x. Then, the heat flow density q (x) in the longitudinal direction can be obtained as q (x) = λ / d · ΔT (x).

FIG. 3 shows another embodiment of the present invention, FIG. 3 (a) shows an example in which optical fibers 11a and 11b are embedded in the front and back of the thermal resistance plate 10, and FIG. 3 (b) further shows the surface thereof. An example in which a metal tape 19 is installed on the optical fiber is shown in FIG. 3 (c).
An example in which a plurality of are embedded in the heat resistance plate 10 is shown.

In the above-described embodiment, the example in which the two optical fibers 11a and 11b are arranged with the thermal resistance plate 10 sandwiched therebetween has been described, but one optical fiber is provided and the optical fiber is folded back with the thermal resistance plate 10 sandwiched. The same function can be achieved even if they are arranged symmetrically. Although the optical fibers 11a and 11b are linearly arranged, the planar heat flow distribution can be measured by the same principle if the optical fibers 11a and 11b are bent and installed so as to cover the surface of the thermal resistance plate 10.

[Effects of the Invention] As is apparent from the above description, the present invention has the following effects.

(1) The heat flow density along the longitudinal direction of the heat resistance plate can be easily measured at low cost.

(2) Accurate measurement is possible even in a strong electric field or strong magnetic field.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a block diagram of an apparatus for measuring a heat flow density distribution using a sensor of the present invention, and FIG. 3 is another embodiment of the present invention. 4 and 5 are diagrams for explaining the principle of heat flow measurement, and FIG. 5 is a perspective view showing a conventional heat flow measurement sensor. In the figure, 10 is a heat flow resistance plate, and 11a and 11b are optical fibers for temperature measurement.

Claims (1)

[Scope of utility model registration request] 1. A heat flow measuring sensor in which a heat resistance plate whose thermal constant is known is arranged orthogonally to the heat flow direction and the heat flow density is obtained from the temperature difference between both surfaces of the heat resistance plate. A heat flow measuring sensor characterized in that optical fibers for temperature measurement are symmetrically arranged with a pinch in between.