JP3702658B2 - Wind direction and wind speed measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wind direction and wind speed measuring apparatus for measuring wind direction and wind speed, and more particularly to a wind direction and wind speed measuring apparatus that is highly sensitive, compact, and suitable for measurement in a low wind speed range.
[0002]
[Prior art]
In order to evaluate heat resistance quality and exhaust quality required for automobile parts, measurement of wind direction and wind speed in an engine room or the like is performed. For example, even if a component is mounted near the engine that is a heat generation source, the amount of air received during traveling differs depending on the mounting position, resulting in a difference in required heat resistance.
[0003]
A thermal anemometer is known as this type of sensor, but it measures the wind speed by detecting the temperature change of the heater itself due to the wind speed, and cannot measure the wind direction. In addition, since the heat ray as a detection element is exposed to the outside, it is easily damaged and requires care in handling.
[0004]
As a device that can measure both the wind direction and the wind speed, a measurement device that captures the generation cycle of Karman vortices generated behind the cylinder as pressure fluctuations and obtains the wind speed from the pressure average pattern in the circumferential direction is obtained. (For example, refer to JP-A-9-196959).
[0005]
[Problems to be solved by the invention]
In the conventional wind direction and wind speed measuring apparatus described above, both the wind speed and the wind direction are obtained based on the pressure fluctuation value. However, since the pressure is proportional to the square of the wind speed, the pressure change in the low wind speed region is extremely small. For example, at a wind speed of about 1.8 m / s, only a pressure change of about 0.2 mmH ₂ O occurs. Therefore, there is a problem that the detection sensitivity in the low wind speed region is low.
[0006]
A pressure sensor that can detect such a small pressure change with high sensitivity is required to have a diameter of at least 10 mm and a thickness of 1.3 mm. Therefore, such a large and thick pressure sensor can be smoothly placed on a cylinder. When trying to do so, the cylinder becomes large with a diameter of 50 mm or more. Therefore, this measuring apparatus cannot measure the wind direction and the wind speed in a narrow space such as an engine room.
[0007]
If the wind speed of 50 m / s or more is measured, the cylindrical diameter can be reduced to several tens of millimeters, but this size is too large to be used in a narrow space such as an engine room, and the measurement is in a low wind speed range. There was a problem that could not.
[0008]
The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a wind direction and wind speed measuring device that is highly sensitive, compact, and capable of measuring a low wind speed region.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a wind direction wind speed measuring device according to claim 1 is a wind direction wind speed measuring device in which a cross-sectional shape with respect to at least a direction to be measured is substantially circular, a heater provided substantially at the center; A first thermal conductor provided around the heater and a second heat having a thermal conductivity smaller than that of the first thermal conductor provided around the first thermal conductor It is characterized by comprising a conductor and a plurality of temperature detection means provided on the surface of the second thermal conductor with a predetermined positional relationship with respect to the measurement direction.
[0010]
In this case, although not particularly limited, as in the wind direction and wind speed measuring device according to claim 2, the wind direction to be measured is obtained based on a distribution state with respect to the measurement direction of the temperature detected by the plurality of temperature detecting means, and the plurality It is preferable to obtain the wind speed to be measured based on the average value of the temperatures detected by the temperature detecting means.
[0011]
Moreover, although not particularly limited, it is preferable that the direction of the highest temperature among the temperatures detected by the plurality of temperature detecting means be the wind direction as in the wind direction and wind speed measuring device according to claim 3.
[0012]
Considering a model in which the heat from the heater (heat source) is conducted (transferred) to the surrounding gas through the solid, as shown in FIG. Furthermore, heat transfer from the solid surface to the gas is controlled by the heat transfer coefficient. However, while the thermal conductivity in the solid is uniquely determined as a value inherent to the solid, the heat transfer coefficient from the solid surface to the gas varies depending on the physical properties of the gas, the temperature of the gas, and the flow state.
[0013]
The wind direction and wind speed measuring device of the present invention pays attention to the fluctuation of the heat transfer coefficient depending on the flow state, and utilizes the fact that the surface temperature of the solid is distributed depending on the flow state of the boundary layer between the solid and the gas. The wind direction and wind speed are obtained by measuring and calculating.
[0014]
For example, as shown in FIG. 6, when the wind is flowing from the direction shown in the wind direction and wind speed measuring device of the present invention having a circular cross section, the boundary of the region facing the wind (indicated by “0” in the figure). The layer becomes a stagnation pool of gas, and the surface temperature of the solid is increased because the flow rate is low and the heat transfer is small. In addition, the boundary layer of the rear region (indicated by “4” in the figure) with respect to the wind direction becomes a turbulent flow region, and similarly the flow velocity is low and heat transfer is small, so the surface temperature of the solid is high.
[0015]
On the other hand, the boundary layer in the region along the wind direction (indicated by “2” in the figure) is a laminar flow region, and the flow velocity is high and heat transfer is large, so the surface temperature of the solid is low. In addition, the region 1 between the region 0 and the region 2 and the region 3 between the region 4 and the region 2 are in an intermediate flow state between these regions 0 and 4 and the region 2, and are solid. The surface temperature is also an intermediate temperature between them. FIG. 7 is a graph in which the solid surface temperature is plotted with respect to the region (orientation), and the direction of the highest temperature is the wind direction to be obtained.
[0016]
Incidentally, the relationship between the temperature T and the circumferential angle θ (0 ° to 360 °) has a maximum value in each of the two regions facing the wind direction as described above, and each of the two regions along the wind direction has a maximum value. Since a minimum value appears, it can be theoretically approximated by the following quintic function with the angle in the circumferential direction as a variable.
[0017]
[Expression 1]
T = aθ ⁵ + bθ ⁴ + cθ ³ + dθ ² + eθ + f (a to f are constants) (1)
FIG. 3 is a graph plotting the reciprocal of the average value of the solid surface temperature with respect to the wind speed. As is clear from this, the average value of the solid surface temperature and the wind speed are strongly correlated. A wind speed can be calculated | required based on the average value of the temperature measured by the means.
[0018]
In particular, in the wind direction and wind speed measuring device according to the present invention, the thermal conductivity of the second thermal conductor provided with the temperature detecting means is smaller than the thermal conductivity of the first thermal conductor, that is, a larger thermal conductivity on the heater side. The surface temperature distribution due to the airflow can be expanded, which can increase the detection sensitivity of the wind direction. .
[0019]
Further, in the wind direction and wind speed measuring device of the present invention, the wind direction and the wind speed are obtained based on the measured value of the surface temperature. Therefore, the temperature change in the low wind speed region is larger than the measuring device that obtains the wind direction and the wind speed based on the pressure of the air flow. Thus, the detection sensitivity of the wind direction and the wind speed is increased.
[0020]
Furthermore, since the detection sensitivity in the low wind speed region is good, the temperature detection means can be configured, for example, in the form of a film, and as a result, the measuring device itself can be configured compactly.
[0021]
In the present invention, the shape of the measuring device itself is not particularly limited. However, if the wind direction in a three-dimensional direction orthogonal to each other is measured, the second heat conductor as in the wind direction / wind speed measuring device according to claim 4. The surface of the second heat conductor is formed into a cylindrical side surface shape as in the wind direction and wind speed measuring device according to claim 5, if the surface is made spherical and the wind direction in a two-dimensional direction orthogonal to each other is measured. It is preferable.
[0022]
【The invention's effect】
According to invention of Claims 1-3, since the heat conductivity of the 2nd heat conductor in which a temperature detection means is provided is smaller than the heat conductivity of a 1st heat conductor, distribution of the surface temperature by airflow , So that the detection sensitivity of the wind direction is increased.
[0023]
In addition, because the wind direction and wind speed are obtained based on the measured surface temperature, the temperature change in the low wind speed region is larger than in the measurement device that obtains the wind direction and wind speed based on the airflow pressure, and the detection sensitivity of the wind direction and wind speed is improved. Get higher.
[0024]
Furthermore, since the detection sensitivity in the low wind speed region is good, the temperature detection means can be configured, for example, in the form of a film, and as a result, the measuring device itself can be configured compactly. In addition, since there are no parts that are easily damaged, it is easy to handle.
[0025]
According to the invention of claim 4, the wind direction in the three-dimensional direction can be measured, and according to the invention of claim 5, the wind direction in the two-dimensional direction can be measured.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the wind direction and wind speed measuring device of the present embodiment is a device that measures the wind direction and the wind speed in the XY plane, and has a cylindrical heater 1 serving as a heat source at the center and surrounds the heater 1. Thus, the 1st heat conductor 2 is provided concentrically. Further, on the surface of the first thermal conductor 2, a second thermal conductor 3 having a thermal conductivity smaller than the thermal conductivity of the first thermal conductor 2 is provided in a film shape, for example. .
[0027]
Further, eight thermocouples 4 as temperature detecting means are affixed to the surface of the second heat conductor 3 at a pitch of 45 ° along the circumferential direction of the cylinder. The temperature signal detected by each thermocouple is sent to a controller (not shown).
[0028]
In the case of measuring the wind direction and the wind speed using the wind direction and wind speed measuring apparatus of the present embodiment configured as described above, the heater 1 is first turned on to sufficiently heat the first and second heat conductors 2 and 3. Is conducted in the air stream, and the surface temperature of the second heat conductor 3 obtained by each thermocouple 4 is taken into the controller.
[0029]
And the reciprocal number of the average value of the surface temperature obtained by the eight thermocouples 4 is calculated | required, and the wind speed of the airflow is calculated | required from the relationship (refer FIG. 3) of the wind speed measured previously and the reciprocal number of average temperature.
[0030]
Further, the temperatures detected by the eight thermocouples 4 are approximated by substituting them into, for example, a quintic function (see the above relational expression (1)) having a circumferential angle in the XY plane as a variable. The wind direction of the airflow is assumed.
[0031]
In particular, in the wind direction and wind speed measuring device of the present embodiment, the thermal conductivity of the second thermal conductor 3 is smaller than the thermal conductivity of the first thermal conductor 2, so that the distribution of the surface temperature due to the air current is expanded. Thus, the detection sensitivity of the wind direction can be increased.
[0032]
Further, as described above, since the wind direction and the wind speed are obtained based on the measurement value of the surface temperature, for example, as shown in FIG. The temperature change in the low wind speed region of about s becomes large, and the detection sensitivity of the wind direction and the wind speed becomes high.
[0033]
Furthermore, since the detection sensitivity in the low wind speed region is good, the thermocouple 4 can be configured in a film shape, for example, and as a result, the measuring device itself can be configured compactly.
[0034]
The wind direction and wind speed measuring device of the present invention is not limited to the above-described embodiment, and can be variously modified. FIG. 2 is a perspective view showing another embodiment of the wind direction and wind speed measuring device of the present invention, which is a measuring device capable of obtaining a three-dimensional wind direction.
[0035]
The basic configuration is the same as that of the cylindrical embodiment described above, but in this embodiment, in order to obtain the three-dimensional orientation of the wind direction, the heater 1 provided at the center and the first thermal conductor surrounding the periphery thereof 2 and a main body made of a second heat conductor 3 provided in a film shape, for example, on the surface of the first heat conductor 2 is formed in a spherical shape. Thermocouples 4 as temperature detecting means attached to the surface of the second thermal conductor 3 are provided at a 45 ° pitch on the XY plane (equator) shown in the figure, and also on meridians (meridians). It is provided at a pitch of 45 °. That is, 16 thermocouples 4 (14 when two are shared) are provided on the surface of the second thermal conductor 3.
[0036]
When the wind direction and wind speed are measured using the spherical wind direction wind speed measuring device configured as described above, first, the heater 1 is turned on to sufficiently conduct heat to the first and second heat conductors 2 and 3. Then, the surface temperature of the second heat conductor 3 obtained by each thermocouple 4 is taken into the controller.
[0037]
And the reciprocal number of the average value of the surface temperature obtained by the 16 thermocouples 4 is calculated | required, and the wind speed of the airflow is calculated | required from the relationship (refer FIG. 3) of the wind speed measured in advance and the reciprocal number of average temperature.
[0038]
Further, the temperature detected by the 16 thermocouples 4 is approximated by substituting it into, for example, a quintic function (see the above relational expression (1)) having a circumferential angle in the XY plane as a variable. Is the wind direction in the XY plane of the airflow. Similarly, the wind direction in the YZ plane is obtained, and the wind direction in the three-dimensional space is obtained from the wind directions in the XY plane and the YZ plane.
[0039]
As described above, according to the wind direction and wind speed measuring apparatus of the present embodiment, the wind direction in the three-dimensional space can be obtained in addition to the effects described above.
[0040]
The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
[Brief description of the drawings]
FIG. 1 is a perspective view and a cross-sectional view showing an embodiment of a wind direction and wind speed measuring device of the present invention.
FIG. 2 is a perspective view showing another embodiment of the wind direction and wind speed measuring device of the present invention.
FIG. 3 is a graph showing the relationship between the wind speed and the reciprocal of the average temperature by the wind direction wind speed measuring apparatus of the present invention.
FIG. 4 is a graph showing the relationship between wind speed and surface temperature by the wind direction and wind speed measuring device of the present invention.
FIG. 5 is a conceptual diagram for explaining the measurement principle of the present invention.
FIG. 6 is a conceptual diagram for explaining the measurement principle of the present invention.
FIG. 7 is a graph for explaining the measurement principle of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Heater 2 ... 1st heat conductor 3 ... 2nd heat conductor 4 ... Thermocouple (temperature detection means)

Claims (5)

In the wind direction and wind speed measuring device in which the cross-sectional shape for at least the direction to be measured is substantially circular,
A heater provided substantially at the center;
A first thermal conductor provided around the heater;
A second thermal conductor provided around the first thermal conductor and having a thermal conductivity smaller than that of the first thermal conductor;
A wind direction and wind speed measuring device comprising: a plurality of temperature detecting means provided on the surface of the second heat conductor with a predetermined positional relationship with respect to the measurement direction. The wind direction to be measured is obtained based on the distribution state of the temperature detected by the plurality of temperature detection means with respect to the measurement direction, and the wind speed to be measured is obtained based on the average value of the temperatures detected by the plurality of temperature detection means. The wind direction and wind speed measuring device according to claim 1. The wind direction / wind speed measuring apparatus according to claim 2, wherein the highest direction among the temperatures detected by the plurality of temperature detecting means is defined as a wind direction. The wind direction and wind speed measuring device according to any one of claims 1 to 3, wherein the surface of the second heat conductor is spherical and measures wind directions in three-dimensional directions orthogonal to each other. The wind direction and wind speed measuring device according to any one of claims 1 to 3, wherein the surface of the second heat conductor has a cylindrical side surface shape and measures wind directions in a two-dimensional direction orthogonal to each other.

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