RU2164691C1 - Device for measuring turbulent fluctuations of speed - Google Patents

Abstract

FIELD: study of hydrophysical fields; ecology researches; experimental hydrodynamics, oceanology and other fields of engineering where monitoring of turbulent medium parameters is required. SUBSTANCE: proposed device includes three identical speed converters for converting speed into electrical signal which are located in one straight line. Functional unit whose inputs (from first to third) are connected with outputs of converters converting the speed to electrical signal is designed for calculating the output signal depending on signals furnished from converters and distances between them. EFFECT: enhanced accuracy of measurements; reduction of effect of additive electrical interference. 2 cl, 2 dwg

Description

 The invention relates to the field of research of hydrophysical fields and can be used in environmental studies, in experimental hydrodynamics, oceanology and other fields of technology where it is necessary to control the parameters of a turbulent medium.

 There are various devices known for measuring the parameters of a turbulent medium, containing converters of speed into an electric signal (sensors) of the medium (see, for example, [1], [2]).

 The device [1] contains a speed transducer into an electric signal (speed sensor of an electrically conductive medium), made in the form of a permanent magnet, in the gap of which is mounted a holder with electrodes connected to an electronic amplifier. When measuring turbulent pulsations of speed, the speed transducer into an electric signal is installed in the flow being studied and the flow parameters are judged by the parameters of the electric signal at the output of the electronic amplifier.

 A disadvantage of the known device [1] is the lack of accuracy in determining the parameters of a turbulent medium due to the high sensitivity of the speed transducer to electric signal to spurious signals resulting from vibrations and uneven movement of the carrier mounted, for example, on a towed line.

 The device [2] contains a speed transducer into an electrical signal (speed sensor of an electrically conductive medium), made in the form of a permanent magnet, in the gap of which is mounted a holder with electrodes connected to an electronic amplifier. To compensate for spurious signals resulting from uneven motion of the transducer in the studied liquid medium, the device further comprises a series-connected accelerometer, the longitudinal axis of which is parallel to the longitudinal axis of the electromagnetic speed transducer into an electric signal, amplifier, integrator and adder, the second input of which is connected to the output of the amplifier, connected to an electromagnetic speed transducer into an electrical signal.

 The introduction of an accelerometer, an amplifier, an integrator, and an adder can somewhat reduce the influence on the measurement results of interference caused by uneven movement of the medium. However, the effectiveness of reducing the influence of interference in the device [2] is low.

 Also known is a device for measuring turbulent pulsations of the velocity of an electrically conductive liquid [3], which is the closest to the proposed device in technical essence. This device contains three electrodes, one of which is located between the other two, a permanent magnet made in the form of a body of revolution. Three electrodes and sections of a magnetic system including a permanent magnet form three transducers of speed into an electrical signal. The speed converters are connected to an electronic circuit including two differential amplifiers and an adder.

 The disadvantage of this device is a prototype device is the low accuracy of the measurement. This drawback is due to the fact that to compensate for the influence of vibrations and uneven movement of the carrier, the same electrodes are used as for generating a useful signal. As a result, along with the compensation of interference signals, useful signals are also compensated.

где U - сигнал на выходе упомянутого блока вычисления функции; К - масштабный коэффициент; R₂, R₃ - расстояния от первого преобразователя скорости в электрический сигнал до второго и третьего преобразователей скорости в электрический сигнал соответственно, м; U₁, U₂, U₃ - напряжения на первом, втором и третьем входах упомянутого блока вычисления функции соответственно, B,
при этом входы упомянутого блока вычисления функции с первого по третий соединены с выходами преобразователей скорости в электрический сигнал с первого по третий соответственно, а выход упомянутого блока вычисления функции является выходом устройства.This drawback is eliminated in the present invention, the essence of which lies in the fact that in the device for measuring turbulent pulsations of speed, containing the first transducer of speed to an electric signal located between the second and third converters of speed to an electric signal, the first, second and third converters of speed to electric the signal is identical, the second and third converters of speed into an electrical signal are located on one straight line with the first converter The distance to the electric signal is at distances (0.1-1.0) m from it, and a function calculation unit is introduced into the device

where U is the signal at the output of said function calculation unit; K is a scale factor; R ₂ , R ₃ - the distance from the first speed converter into an electric signal to the second and third speed converters into an electric signal, respectively, m; U ₁ , U ₂ , U ₃ - voltage at the first, second and third inputs of the said block computing function, respectively, B,
wherein the inputs of said first to third function calculation unit are connected to the outputs of the speed converters into an electrical signal from first to third, respectively, and the output of said function calculation unit is the output of the device.

 In the proposed device, the second and third converters of speed to an electrical signal can be located at equal distances from the first converter of speed to an electrical signal.

The invention is illustrated by drawings, which depict:
in FIG. 1 is a functional diagram of a device;
in FIG. 2 is a diagram for explaining the relative position of speed converters in an electric signal.

In FIG. 1 marked:
1 - the first Converter of speed into an electrical signal;
2 - the second Converter of speed into an electrical signal;
3 - the third Converter of speed into an electrical signal;
4 - block calculation function (1).

In FIG. 2 are indicated:
1 - the first Converter of speed into an electrical signal;
2 - the second Converter of speed into an electrical signal;
3 - the third Converter of speed into an electrical signal;
R ₂ , R ₃ are the distances from the first transducer to electric signal to the second and third transducers to electric signal, respectively.

 In accordance with FIG. 1, the device contains identical first, second and third converters 1, 2, 3 of the speed into an electrical signal, the outputs of which are connected, respectively, with the first, second and third inputs of the unit 4 for calculating function (1), the output of which is the output of the device.

 Converters 1-3 speed into an electrical signal can be electromagnetic, hot-wire or other known type.

 The unit 4 for calculating the function (1) can be performed, for example, on operational amplifiers that implement the functions of weighted summation and subtraction, or include a multi-channel analog-to-digital converter and a microprocessor calculator for function (1).

The speed converters 2 and 3 into an electric signal are located on one straight line at distances R ₂ = (0.1-1.0) m and R ₃ = (0.1-1.0) m from the transducer 1 (Fig. 2). In this case, the straight line on which the transducers 1-3 are located can have any position in space, provided that their transducers 1-3 remain operational. In particular, converters 1-3 should be correctly oriented with respect to the direction of the oncoming flow and should not "obscure" each other.

Предлагаемое устройство работает следующим образом.The simplest and most preferred option is the one in which the condition R ₂ = R ₃ is fulfilled, in this case expression (1) is simplified:

The proposed device operates as follows.

 A carrier, for example, a towed line of an environmental monitoring vehicle, moves rigidly coupled speed converters 1-3 to an electrical signal in the medium under study. From the output signal of the converter in block 4, the signals of the converters 2 and 3 are subtracted by the formula (1) or, in the particular case, by the formula (2). After processing in block 4, the undistorted signal, free of vibrational interference, is supplied for subsequent processing and determination of turbulence parameters.

 The present invention can be used both for measuring single-component velocity pulsations, and for multi-component. In the latter case, the output signals for each channel are processed using the function calculation blocks (1), the number of which corresponds to the number of measured velocity components.

 Thus, the use of the invention allows to increase the accuracy of measuring turbulent velocity pulsations under the influence of interference due to uneven movement of the carrier. In addition, the invention allows to significantly expand the working range of the spatial scales of the measured turbulent velocity pulsations.

 The presented description and drawings allow, using the existing element base, to manufacture the proposed device and use it in those areas of technology where it is necessary to determine the turbulence parameters, including monitoring the state of the marine environment from a mobile carrier, which characterizes the invention as industrially applicable.

List of references
1. Auth. St. USSR N 356564, IPC G 01 P 5/08, 1972

 2. Auth. St. USSR N 685984, IPC G 01 P 5/08, 1979

 3. Auth. St. USSR N 773496, IPC G 01 P 5/08, 1980 (prototype).

Claims (2)

1. A device for measuring turbulent fluctuations in speed, comprising a first speed transducer into an electric signal, a second and third speed transducers into an electric signal, between which a first speed transducer into an electric signal is located, characterized in that the first, second and third speed converters into an electric signal made identical, the second and third converters of speed into an electric signal are located on one straight line with the first converter of speed into electric ignal at distances of 0.1 - 1.0 m from it, and a function calculation unit is introduced into the device

where U is the signal at the output of said function calculation unit;
K is the scale factor;
R ₂ and R ₃ are the distances from the first speed converter into an electric signal to the second and third speed converters into an electric signal, respectively, m;
U ₁ , U _2, and U ₃ are the voltages at the first, second, and third inputs of said function calculation unit, respectively, V,
wherein the inputs of said first to third function calculation unit are connected to the outputs of the speed converters into an electrical signal from first to third, respectively, and the output of said function calculation unit is the output of the device.  2. The device according to claim 1, characterized in that the second and third converters of speed into an electric signal are located at equal distances from the first converter of speed into an electric signal.

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