SU1185132A2 - Piezoelectric transducer of pressure fluctuations - Google Patents

Abstract

PIEZOELECTRIC CONVERTER OF PULSATIONS OF PRESSURE in auth. No. 1052896, characterized in that, in order to improve the measurement accuracy in moving turbulized media, in it each piezoelectric element having the shape of a spherical segment is made in a solid angle 0 determined from condition 8338 8. CX) ate with

Description

The invention relates to a measuring technique, in particular to devices for measuring pressure fluctuations in moving media caused by surface or internal 5 waves, as well as by changing the immersion depth of the transducer in the medium.

The aim of the invention is to improve the accuracy of measurements in moving turbulent environments. 1C

In FIG. 1 schematically shows a piezoelectric transducer of pressure pulsations, a section; in FIG. 2 is a diagram explaining a selection of a solid angle of execution of a spherical 1J piezoelectric segment.

The piezoelectric transducer of pressure pulsations consists of two piezoelectric spherical · jg segments 1 with electrodes 2 placed on their both surfaces. Segments 1 are fixed on the base 3 concentrically with respect to each other * through the annular conductive 25 gasket 4. On the outer surface of the first segment. 1, a thermal protective coating is made 5. The spherical segments are each made in solid. Angle Θ, determined from the condition ° 38 '<125 ° 34' „

The device operates as follows.

The pressure pulsation of the medium, acting through the coating 5 on the first 35 piezoelectric element 1, generates an electric charge on its electrodes 2 proportional to the magnitude of this action, which is recorded by a measuring circuit (not shown).

The total value of pressure pulsations ^P complete ^{for a} turbulent medium moving relative to the transducer can be represented as the sum P; _oln = _{Рс Г} + Рд, where Р ^ is the measured value of static pressure caused by surface or ¹ internal waves or a change in the immersion depth of the transducer in the medium, Рд is the velocity head pulsation caused by the action of a turbulent medium on the transducer, due to turbulence of the medium (or a change in its density.

When performing piezoelectric segments 1 at solid angles Θ, 483 ° ¹ '', the magnitude of the measurement error g _{st is} proportional to ^{1 is the} product of the average medium velocity V by the longitudinal component of the velocity pulsations V 'and reaches its maximum value at θ ₀ = 83 ° 38 *.

When performing piezoelectric segments 1 in solid angles in the range 83 ° 38 '<θ £ 1 25 ° 34', the value of the determination error P ^ decreases due to partial compensation of the electric charge arising on the electrodes 2 of the piezoelectric segment ί when the sign of the effect of the value of Рд changes (Fig. . 2). At an angle θ2 = 125 ° 35 ', full compensation of the pulsations of the velocity head Rd is provided. Moreover, the accuracy of the measurement P ^. increases by at least an order of magnitude.

VNIIIPI

Circulation 896

Order 6446/35

Subscription

Branch of PPP Patent,

Uzhhorod, Project 4,

Claims (1)

PIEZOELECTRIC CONVERTER OF PULSATION OF PRESSURE by ed. No. 1052896, characterized in that, in order to improve the accuracy of measurements in moving turbulized media, in it each piezoelectric element having the shape of a spherical segment is made in a solid angle θ determined from the condition 83 ° 38 <θ ί 125 ° 34. FIG. 1 00 cl 00 ye 1 1 1