Wind sensor housing and wind sensor comprising such a housing
阅读说明:本技术 风传感器壳体和包括这种壳体的风传感器 (Wind sensor housing and wind sensor comprising such a housing ) 是由 罗宾·斯特罗恩 于 2016-09-09 设计创作,主要内容包括:提供了一种用于风传感器2的壳体6。传感元件4安装在壳体6中用于测量通过的流体流的速度,并且壳体6包括至少一个表面40、42,该至少一个表面具有诸如从表面40、42的突起的突出部和/或凹入表面40、42中的凹入部的成形表面元件38,用于在跨过表面40、42流动的流体中引起湍流。由成形表面元件38所引起的湍流使得通过风传感器2测量的速度较少地受到层流和湍流气流之间的不受控制的转变的影响,并因此实现风传感器2的更精确的校准。(A housing 6 for a wind sensor 2 is provided. The sensing element 4 is mounted in a housing 6 for measuring the velocity of the passing fluid flow, and the housing 6 comprises at least one surface 40, 42 having shaped surface elements 38 such as protrusions from the surface 40, 42 and/or recesses into the surface 40, 42 for inducing turbulence in the fluid flowing across the surface 40, 42. The turbulence caused by the shaped surface elements 38 makes the velocity measured by the wind sensor 2 less affected by uncontrolled transitions between laminar and turbulent air flows and thus enables a more accurate calibration of the wind sensor 2.)
1. A housing for a wind sensor, the housing comprising:
a first housing body having a cylindrical cross-section;
a second housing body having a cylindrical cross-section;
a first reflector in the first housing body; and
a second reflector mounted in the second housing body and coaxially with the first reflector, thereby defining a resonant cavity between the first and second reflectors;
the housing has at least one surface comprising one or more shaped surface elements for inducing turbulence in a fluid flowing across the surface, wherein the one or more shaped surface elements are arranged on a surface extending around a periphery of the first housing body and/or the second housing body.
2. The housing of claim 1, wherein at least one shaped surface element comprises a protrusion from the surface.
3. The housing of claim 1, wherein at least one shaped surface element comprises a recess into the surface.
4. The housing of claim 1, wherein at least one shaped surface element is integral with the surface.
5. The housing according to any one of claims 1 to 4, comprising a plurality of shaped surface elements, wherein the shaped surface elements are evenly arranged on the surface.
6. The housing according to any one of claims 1 to 4, comprising a plurality of shaped surface elements, wherein the shaped surface elements are of uniform size.
7. The housing according to any one of claims 1 to 4, wherein the shaped surface elements induce turbulence in a fluid flowing across the surface at a velocity of more than 3 m/s.
8. The housing of any of claims 1-4, wherein the surface elements are disposed on at least one surface over which a fluid flows as it passes through the housing.
9. A housing according to any one of claims 1 to 4, wherein the housing is arranged to house a sensing element therein to measure fluid flow therethrough.
10. The housing according to any one of claims 1 to 4, wherein the surface elements are arranged on at least one surface of the housing adjoining the resonant cavity.
11. A wind sensor comprising a housing as claimed in any one of claims 1 to 4.
Technical Field
The present invention relates to a housing for a wind sensor, and a wind sensor incorporating the housing.
Background
Wind sensors can be used to measure the flow velocity of air or fluid in a free field. In many applications, it is desirable or necessary to accurately measure fluid velocity.
Wind speed measurements made by the wind sensor can be affected by changes in the orientation of the wind sensor relative to the airflow and the transition from laminar to turbulent flow in the vicinity of the wind sensor, resulting in errors in the measured wind speed.
The present invention seeks to provide a novel housing for a wind sensor.
Drawings
FIG. 1 is a schematic block diagram of the main elements of a wind sensor according to one embodiment of the present invention.
FIG. 2 is a side view of a portion of a wind sensor according to one embodiment.
FIG. 3 is a side view of a central portion of the housing of the wind sensor shown in FIG. 2.
Fig. 4 is a horizontal cross-sectional view through the AA section in fig. 2.
Fig. 5 is a diagram showing a plan view of a separated laminar flow around a cylindrical object.
Fig. 6 is a diagram illustrating a plan view of the separation turbulence around a cylindrical object.
Fig. 7 shows the relationship of reynolds number between resistance and surface property.
Fig. 8 illustrates fluid flow over a fluid flow sensor.
Detailed Description
According to an aspect of the invention, a housing for a wind sensor is provided. The housing includes a first housing body having a cylindrical cross-section, a second housing body having a cylindrical cross-section, a first reflector in the first housing body, and a second reflector in the second housing body and mounted coaxially with the first reflector to define a resonant cavity between the first and second reflectors. The housing has at least one surface comprising one or more shaped surface elements for inducing turbulence in a fluid flowing across the surface. One or more shaped surface elements are arranged on a surface extending around the periphery of the first housing body and/or the second housing body.
According to another aspect of the invention there is provided a housing for a wind sensor, the housing having at least one surface comprising one or more shaped surface elements for inducing turbulence in a fluid flowing across the surface.
According to another aspect of the present invention there is provided a wind sensor comprising a housing according to any of the preceding aspects of the present invention.
The housing according to embodiments of the invention mitigates errors associated with the orientation of the wind speed sensor with respect to the airflow and the transition between laminar and turbulent flow.
Specific embodiments will now be described, by way of example only, with reference to the accompanying drawings.
An embodiment of the wind sensor of the present invention will now be described with reference to fig. 1 to 6. In one embodiment, the fluid being measured is air. However, the velocity of other moving fluids may be measured using a wind sensor having the disclosed housing. The terms "wind sensor" and "airflow" should therefore be understood accordingly, and embodiments generally extend to fluid flow sensors.
Referring to the drawings, a
In the disclosed embodiment, the housing 6 is substantially cylindrical and comprises a first
In the disclosed embodiment, the sensing element 4 uses the principle of acoustic resonance in order to sense the velocity of the passing air flow. The first
In the disclosed embodiment, the first
The
In the disclosed embodiment, the
The acoustic signals received by the transducers 26, 28, 30 are converted to electrical signals and the electrical signals are passed to the
Thus, in the disclosed embodiment, the sensing element 4 includes a first reflector 16 and a second reflector 18 that define a
At least one shaped surface element 38 is arranged on or applied to a
The
The
In the disclosed embodiment, the
In the disclosed embodiment, the shaped surface element 38 is integral with the
In one embodiment, the shaped surface element 38 includes protrusions protruding from the
In one embodiment, the shaped surface element 38 includes a recess or indentation into the
In the disclosed embodiment, the plurality of shaped surface elements 38 are raised to a uniform height from the
In some embodiments, the adjacent shaped surface elements 38 applied to the
In some embodiments, the shaped surface element 38 may include protrusions protruding from the
In the disclosed embodiment, the shaped surface elements 38 are evenly spaced on the
The shaped surface elements 38 may be disposed at even angular intervals around the circumference or circumference of the housing 6. The even spacing of the shaped surface elements 38 around the circumference or circumference of the housing 6 results in a uniform performance of the
In the disclosed embodiment, the shaped surface elements 38 have a uniform size. The uniform size of the shaped surface elements 38 may result in a uniform performance of the
In the disclosed embodiment, the length of the shaped surface element 38, i.e. the length of the shaped surface element 38 in the longitudinal direction of the shell 6, is typically at least 2 mm (0.002 m) and typically in the range of 5 mm to 15 mm (0.005 m to 0.015 m). In some embodiments, the shaped surface elements 38 may extend along the entire height of the first
In the disclosed embodiment, the width of the shaped surface elements 38 (i.e., the size of the shaped surface elements 38 in the circumferential direction of the shell 6) is typically at least 2 millimeters (0.002 meters), and typically in the range of 3 millimeters to 15 millimeters (0.003 meters to 0.015 meters). In some embodiments, the shaped surface elements 38 may extend around the perimeter or circumference of the housing 6.
In the disclosed embodiment, the shaped surface element 38 is substantially rectangular in plan view and has a cross-sectional profile that is, for example, substantially rectangular, such as a cuboid. In other embodiments, shaped surface elements 38 having square, oval, triangular, and other shapes in cross-sectional profile when viewed in plan, work effectively and can be more easily manufactured by automated tooling. In one embodiment, all the shaped surface elements 38 are identical. In some embodiments, different planar or contoured shapes may be used for each of the plurality of shaped surface elements 38. The use of a plurality of non-identical shaped surface elements 38 may create a greater degree of turbulence.
The shaped surface elements 38 of the disclosed embodiments induce turbulence in the fluid flowing across the
The fluid flow around the object is laminar or turbulent, depending on factors such as the viscosity of the fluid, the velocity of the fluid flow, and the shape of the object or the direction of the object relative to the fluid flow, and can be analyzed using the reynolds number. Laminar flow of fluid occurs at low reynolds numbers and is characterized by smooth fluid motion. At high reynolds numbers, the fluid exhibits turbulence. In air, the boundary between the laminar flow of air and the turbulent flow following it is generally produced at about 105Reynolds number of (d).
The difference between laminar flow around a cylindrical object and turbulent flow around a cylindrical object can be more clearly understood with reference to fig. 5 to 7.
Figure 5 shows the fluid flowing around the cylinder at a given flow rate. It can be seen that the fluid flow is laminar at the sides of the cylinder, but separates from the cylinder, creating a large low pressure area on the lee side of the cylinder. In this case, the cylinder body may generate a considerable resistance.
Figure 6 shows different forms of fluid flowing around the cylinder at a higher flow rate than that experienced in the configuration shown in figure 5. A turbulent boundary layer is along the sides of the cylinder. Contrary to the flow regime seen in fig. 5, the fluid flow in fig. 6 flows further along the contour of the cylinder to the lee side of the cylinder. In such a flow structure, the low pressure area is smaller, and thus the resistance is reduced.
The graph in fig. 7 illustrates the dependence of the resistance on the reynolds number. The reynolds number is a well-known quantity that is proportional to the relative velocity of the fluid flow over the surface of the object. It can be seen that at low reynolds numbers/slow fluid flow rates, the resistance is high. At these flow rates there is a laminar flow regime as shown in figure 5. However, as the fluid flow velocity/reynolds number increases, turbulent fluid flow conditions are created, resulting in a sharp and abrupt decrease in resistance at a reynolds number that is specific to the object over which the fluid is flowing. It has been recognized that sudden changes between laminar and turbulent fluid flow conditions considerably affect the measurement accuracy of fluid velocity sensors, and it is therefore desirable to cause such changes at low wind speeds as occurs where the effect of drag is minimized.
In the example shown in fig. 7, the operating range begins at zero fluid flow velocity and extends to a maximum fluid flow velocity. At low fluid flow rates, the flow regime shown in fig. 5 is very common and therefore experiences high resistance. At the upper end of the operating range shown in fig. 7, the fluid flow conditions shown in fig. 6 are prevalent and experience a correspondingly small amount of resistance. As can be seen from fig. 7, the transition between these two states is an abrupt transition. Experiments have shown that for a smooth walled version of the fluid flow sensor of the type shown in fig. 2 and 3 (i.e. a fluid sensor that does not include shaped surface elements as comprised in the embodiments shown in these figures) and a constant fluid flow velocity, although the sensor appears symmetrical, switching or alternating switching between laminar and turbulent fluid flow conditions may occur and significantly affect the measurement accuracy. It was found, particularly surprisingly, that even small changes in the direction of entry of the fluid flow on the sensor lead to significant changes in the measured fluid flow velocity. Without wishing to be bound by theory, it is believed that this change in the incoming direction of the fluid flow exposes the plurality of
As also shown in fig. 7, the transition between high and low resistance fluid flow states occurs at different reynolds numbers for smooth walled objects and for objects with rough surfaces. It will be appreciated that the sensitivity of the sensor to these changing flow conditions is higher for high fluid flow velocities than for lower fluid flow velocities. It will thus be appreciated that the use of shaped surface elements is desirable to incorporate therein. Furthermore, it has also been found that the change in resistance magnitude at transitions between two flow states, as also shown in FIG. 7, transitions less at lower Reynolds numbers than at higher Reynolds numbers.
FIG. 8 illustrates fluid flow incident on a sensor housing of an embodiment. The fluid flow may be considered to include a
Embodiments of the present disclosure thus provide a housing 6 for a
In the disclosed embodiment, the shaped surface elements 38 are arranged on a surface on which air flows when passing through the
Other variations and modifications will be apparent to persons skilled in the art. Such variations and modifications may involve equivalent and other features which are already known and which may be used instead of or in addition to features already described herein. Features which are described in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, features which are described in the context of a single embodiment can also be provided separately or in any suitable subcombination.
It should be noted that the term "comprising" does not exclude other elements, the terms "a" or "an" do not exclude a plurality, a single feature may fulfil the functions of several features recited in the claims and reference signs in the claims shall not be construed as limiting the scope of the claims. It should also be noted that the drawings are not necessarily to scale; emphasis instead generally being placed upon illustrating the principles of the disclosure.
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