RU189744U1 - Ultrasonic flow velocity meter - Google Patents

Abstract

Use: to measure horizontal speeds and wind direction, as well as the vertical component of wind speed. The essence of the utility model lies in the fact that the ultrasonic flow velocity meter contains four pairs of reversible electroacoustic transducers mounted on the central rack, forming measuring bases that are relative to each other at an angle of 90 degrees arc, relative to the central rack they are at an angle of 0 degrees arc relative to the horizontal plane, they are located at an angle in the range from 30 to 60 degrees of arc. Reversible electroacoustic transducers are connected through a switching device to the information input of the microcontroller, the control outputs of which are connected via the control bus to the control inputs of the switching device. Technical result: improved accuracy of measurement of horizontal and vertical velocities, as well as wind direction. 4 ill.

Description

The ultrasonic flow velocity meter relates to the field of instrumentation, in particular, to the technique of measuring wind parameters, in particular for measuring horizontal speeds and wind direction, as well as the vertical component of wind speed, and can be used at airports to ensure the safety of aircraft operations.

The known device for measuring the speed and direction of the wind by the ultrasonic method (ultrasonic anemometers), the principle of which is based on measuring the time of flight of ultrasonic pulses through the air between the acoustic emitters and receivers. So, for example, an ultrasonic meter of pulsating flow rates [RF author's certificate for invention No. 1081544, IPC: GO1P 5/00, GO1F 1/66, 1984] contains two reversible electroacoustic transducers forming the measuring base and connected via a switch to the transmitter and a pulse signal receiver; a time-digit converter; the output of which is connected to the first subtraction unit through a division unit, a synchronizer and a recorder. The disadvantages of this meter include its limited capabilities, since it is intended only to measure wind speed, and parameters such as wind direction and the vertical component of the wind cannot be measured.

Known devices for measuring horizontal speeds and wind direction, as well as vertical components of wind speed (Ultrasonic three-dimensional anemometer. Operating Instructions 021507/01/08: material from / ADOLF THIES GmbH & CO. KG. - p. 1. - [electronic resource ]. - https://icbcom.ru/wp-content/uploads/2016/01/TC-UA3D.pdf; IPV-U ultrasonic wind parameters meters: description of measuring instrument: annex to certificate No. 38022 on type approval of measuring instruments / DOMO METEO LLC. - 2015. - pp. 1-2.). In these devices, three pairs of reversible electroacoustic transducers and computing devices are used to measure wind parameters in 3 coordinates. Pairs of reversible electroacoustic transducers form three measuring bases. Reversible electro-acoustic transducers are mounted through brackets on the central rack. The disadvantage of these devices is the lack of measurement accuracy caused by wind shading of the measuring bases of the central rack.

The closest in technical essence to the proposed utility model is an ultrasonic flow velocity meter (RF patent for utility model No. 77975, MKI G01P 5/01). The ultrasonic flow velocity meter contains three channels for measuring wind speed, each of which includes two reversible electroacoustic transducers. Reversible electro-acoustic transducers through brackets mounted on the center rack. The outputs of reversible electroacoustic transducers are connected through a switch to the transmitter and receiver of pulse signals. The ultrasonic flow velocity meter also contains a time-digit-digitizer, the output of which is connected to the subtraction unit through a division unit. The outputs of the subtraction units are connected to the computing device. Electroacoustic transducers of each channel measuring wind speed form three measuring bases located at the same distance at an angle of 120 ° relative to each other and at an angle in the interval from 30 to 60 in the vertical plane.

The disadvantage of the prototype is the lack of measurement accuracy caused by wind shading of the measuring bases of the Central rack.

The task, which the utility model is aimed at, is to improve the measurement accuracy by eliminating wind shading of the measurement bases of the central rack.

The problem is solved by the fact that in an ultrasonic flow velocity meter containing three pairs of reversible electroacoustic transducers mounted on the central rack connected to information inputs / outputs of a switching device, whose information output is connected to the information input of the microcontroller, with the measuring bases located relative to the horizontal plane at an angle 30-60 degrees of arc, entered the fourth pair of reversible electro-acoustic transducers connected to inf the switching inputs and outputs of the switching device, and the control outputs of the microcontroller are connected to the control inputs of the switching device via the control bus, with the measuring bases relative to each other located at an angle of 90 degrees arc, relative to the central rack they are at an angle of 0 degrees of arc, and the measuring base of the fourth pair Reversible electroacoustic transducers with respect to the horizontal plane are also located at an angle in the range from 30 to 60 degrees of arc.

The proposed utility model is illustrated by the drawings of FIG. 1, fig. 2, FIG. 3, FIG. four.

FIG. 1 shows a functional diagram of an ultrasonic flow velocity meter.

FIG. 2 shows the mutual arrangement of electroacoustic transducers in a vertical plane — front view (electroacoustic transducers 3, 4 are conventionally not shown).

FIG. 3 shows the mutual arrangement of electroacoustic transducers in a vertical plane - side view (electroacoustic transducers 5, 6 are conventionally not shown).

FIG. 4 shows the mutual arrangement of electroacoustic transducers in the horizontal plane - a top view.

Ultrasonic flow velocity meter contains four identical pairs of reversible electroacoustic transducers 1-8, which form the measuring bases A, B, C, E; switching device 9, to informational inputs / outputs of which reversible electroacoustic transducers 1-8 are connected; the microcontroller 10, the information input of which is connected to the information output of the switching device 9; a control bus 11 connecting the control outputs of the microcontroller 10 to the control inputs of the switching device 9; four identical brackets 12, on which reversible electroacoustic transducers 2, 4, 6, 8 are mounted; four identical brackets 13, on which are installed reversible electroacoustic transducers 1,3, 5, 7; and the central rack 14, to which the brackets 12, 13 are attached. Reversible electro-acoustic transducers 1 and 2 form a measuring base A of length Lba. Reversible electroacoustic transducers 3 and 4 form a measuring base B of length Lbb. Reversible electroacoustic transducers 5 and 6 form a measuring base With a length of Lbc. Reversible electroacoustic transducers 7 and 8 form a measuring base E of length Lbe. Relative to each other, the measuring bases are located at an angle of 90 degrees arc. Relative to the central rack, the measuring bases are located at an angle of 0 degrees arc. With respect to the horizontal plane, the measuring bases A, B, C, and E are located at an angle α in the range of 30 to 60 degrees of arc.

Ultrasonic flow velocity meter works as follows.

The device is controlled by a microcontroller 10, which cyclically solves two tasks:

1. Determination of flow rates along all measuring bases A, B, C and E: Va, Vb, Vc and Ve;

2. Calculation from the obtained Va, Vb, Vc and Ve values of the horizontal flow rate V, the flow direction D and the vertical flow rate W with the subsequent issuance of the calculated values to the host device.

The first task is solved by measuring the time of movement of the ultrasonic wave between reversible electroacoustic transducers (OED) 1-2, 3-4, 5-6 and 7-8 of each measuring base as in the positive (from odd OEP to even - T _{a +} , T _{b +} , T _{c +} and T _{e +} ) and in the negative (from even OEP to odd - T _a- , T _b- , T _c- and T _e- ) direction. For this purpose, the microcontroller 10 uses the signals of the control bus 11, with which it installs (via switching device 9):

- number of measuring base: A, B, C or E;

- direction of the wave: positive / negative;

- the moment of the beginning (start) of the motion of the wave by means of a triggering pulse.

The microcontroller 10 carries out the measurement of the time of movement of the ultrasonic wave using the built-in counter, which is triggered by the trigger pulse, and stops by a signal from the switching device 9, which is fed to the information input of the microcontroller 10. The time is determined by multiplying the counter content by the counter clock frequency.

After measuring all the times, the microcontroller 10 proceeds to calculate the speeds of the measuring bases in the positive direction V _{a +} , V _{b +} , V _{c +} , V _{e +} and in the negative direction V _a- , V _b- , V _c- , V _e- by the formulas:

where Lba, Lbb, Lbc, Lbe are the lengths of the corresponding measuring bases (Fig. 2, Fig. 3).

The required speeds Va, Vb, Vc and Ve are according to the formulas:

The execution of the second task of the microcontroller 10 is reduced to solving the system of equations (4), (5), (6) and (7) with respect to the desired V, D and W. The system is composed using FIG. 2, FIG. 3 and FIG. 4, which shows all the variables and parameters of the system of equations (4), (5), (6) and (7). The right parts of the system are the projections of V and W to the corresponding measurement bases, which come with a positive sign, if the directions of V and W coincide with the positive direction of the corresponding bases and with a negative sign otherwise.

The horizontal flow rate V, the flow direction D and the vertical flow rate W are calculated using the formulas of claim 1 in accordance with the processing algorithm of the measured data Va, Vb, Vc, Ve item 2. 2 Formulas

1.1 Complete system of equations

where: V - the module of horizontal wind speed;

D is the direction of the horizontal wind speed;

W is the value of the vertical wind speed;

k1 = 1 / cos (α); k2 = 1 / sin (α),

where α is the angle of inclination of the measuring axes to the horizontal plane, which is in the range from 30 ° to 60 °.

In system (4), (5), (6) and (7) you can make replacements:

where: X, Y are the projections of the module of the horizontal wind speed on the corresponding coordinates (the X axis lies in the plane of the measurement bases AC, with the device heading north); Y - in the plane of the measuring bases B-E at their intersection with the horizontal plane).

Taking into account (8), (9), system (4), (5), (6) and (7) will take the following form:

Decision:

From (10), (11), (12) and (13) follows:

From (14) it follows:

where Z is the axis normal to the horizontal plane

From (10) it follows:

From (11) it follows:

From (12) it follows:

From (13) it follows:

From (16), (17) it follows:

Where:

- atan2 is a standard arctangent calculation function in various programming languages that correctly handles situations Yb = 0, Xa = 0 in various combinations;

- if Dab <0, then 360 must be added to its value.

From (16), (19) it follows:

From (17), (18) it follows:

From (19), (18) it follows:

The final value of the horizontal wind speed is determined by the formula:

The final value of the direction of the horizontal wind speed is determined by the formula (21):

D = Dab

1.2 System of equations without measuring base E

Decision:

From (10), (12) follows:

From (26) it follows:

To calculate V and D, formulas (16), (17), (18), (20), (21) and (23) are valid.

Then:

1.3 System of equations without measuring base C

Decision:

From (11), (13) it follows:

From (30) it follows:

To calculate V and D, formulas (16), (17), (19), (20), (21) and (22) are valid.

Then:

1.4 System of equations without measuring base B

Decision:

From (10), (12) follows:

From (34) it follows:

To calculate V and D, formulas (16), (18), (19), (21), (22) and (24) are valid.

Then:

1.5 System of equations without measuring base A

Decision:

From (11), (13) it follows:

From (38) it follows:

To calculate V and D, formulas (17), (18), (19), (21), (23), (24) are valid.

Then:

2 Algorithm for processing the measured data

2.1 Using formulas (15), (16), (17), (18) and (19), calculate the values W, Xa, Yb, Xc, Ye.

2.2 Check the condition: (Xa> = 0) and (Yb> = 0).

If this condition is not met, then go to section 2.3.

If Yb = 0, then calculate the values of V, D, W by the formulas of Section 1.3 and complete the processing, otherwise calculate L = Xa / Yb.

If L <Lmin (Lmin is determined experimentally, for a start, you can take Lmin = 0.09 - the velocity vector is adjacent to the measuring base B), then calculate the values of V, D, W by the formulas of § 1.2 and complete the processing.

Otherwise, check if L> Lmax (Lmax is determined experimentally, for a start, you can take Lmax = 1 - the velocity vector is adjacent to the measuring base A), then calculate the values of V, D, W using the formulas of 1.3 and complete the processing.

Otherwise, calculate the values of V, D, W by the formulas of § 1.1 and complete the processing.

2.3 Check condition: (Yb> = 0) and (Xc> = 0).

If this condition is not met, then go to section 2.4.

If Xc = 0, then calculate the values of V, D, W by the formulas of Section 1.2 and complete the processing, otherwise calculate L = Yb / Xc.

If L <Lmin (the velocity vector is adjacent to the measuring base C), then calculate the values of V, D, W using the formulas of p. 1.5 and complete the processing.

Otherwise, check if L> Lmax (the velocity vector is adjacent to the measuring base B), then calculate the values of V, D, W using the formulas in § 1.2 and complete the processing.

Otherwise, calculate the values of V, D, W by the formulas of § 1.1 and complete the processing.

2.4 Check condition: (Xc> = 0) and (Ye> = 0).

If this condition is not satisfied, then go to section 2.5.

If Ye = 0, then calculate the values of V, D, W using the formulas in Section 1.5 and complete the processing, otherwise calculate L = Xc / Ye.

If L <Lmin (the velocity vector is adjacent to the measuring base E), then calculate the values of V, D, W using the formulas of § 1.4 and complete the processing.

Otherwise, check if L> Lmax (the velocity vector is adjacent to the measuring base C), then calculate the values of V, D, W using the formulas in Section 1.5 and complete the processing.

Otherwise, calculate the values of V, D, W by the formulas of § 1.1 and complete the processing.

2.5 Check condition: (Ye> = 0) and (Xa> = 0).

If this condition is not satisfied, then go to section 2.6.

If Xa = 0, then calculate the values of V, D, W by the formulas of Section 1.4 and complete the processing, otherwise calculate L = Ye / Xa.

If L <Lmin (the velocity vector is adjacent to the A axis), then calculate the values of V, D, W using the formulas in Section 1.3 and complete the processing.

Otherwise, check if L> Lmax (the velocity vector is adjacent to the measuring base E), then calculate the values of V, D, W using the formulas in § 1.4 and complete the processing.

Otherwise, calculate the values of V, D, W by the formulas of § 1.1 and complete the processing.

2.6 Handle the error and complete processing.

The pattern in FIG. 4 shows that the sector of flow directions without shading the measurement bases is almost 360 ° except for narrow sectors adjacent to the planes of the measuring bases A - C and B - E. But the algorithm for processing the measured data in Section 2 allows you to identify these directions and exclude from the calculation of the V values , D, W shaded measurement base.

Thus, the introduction of the fourth pair of reversible electroacoustic transducers can improve the accuracy of measurements of the parameters of the wind V, D, W.

Claims (1)

Ultrasonic flow velocity meter containing three pairs of reversible electroacoustic transducers attached to the central rack, connected to informational inputs / outputs of the switching device, whose information output is connected to the microcontroller information input, and the measurement bases formed by pairs of reversible electroacoustic transducers are angled to the horizontal plane in the range from 30 to 60 degrees of arc, characterized in that One is the fourth pair of reversible electroacoustic transducers connected to the information inputs / outputs of the switching device, and the microcontroller's control outputs are connected via the control bus to the control inputs of the switching device, with the measuring bases relative to each other located at an angle of 90 degrees arc, relative to the central rack they are angled 0 degrees of arc, and the measuring base of the fourth pair of reversible electroacoustic transducers relative to the horizontal plane and is also at an angle in the range from 30 to 60 degrees of arc.

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