SU783595A1

SU783595A1 - Method of absolute graduating of hydrophones in chambers controlled by flexible-mass impedance

Info

Publication number: SU783595A1
Application number: SU792725090A
Authority: SU
Inventors: Юрий Герасимович Рачков
Original assignee: Предприятие П/Я Р-6805
Priority date: 1979-02-14
Filing date: 1979-02-14
Publication date: 1980-11-30

Description

Изобретение относится к измерительной технике и может быть использовано при испытании гидрофонов.The invention relates to measuring technique and can be used in testing hydrophones.

Известен способ абсолютной градуировки гидрофонов в камерах, управляемых упруго-массовым импедансом, заключающийся в том, что ^sустанавливают гидрофон в измерительной камере, заполненной жидкостью, создают переменное избыточное давление на входе испытуемого гидрофона путем колебаний измерительной камеры и определяют чувствительность как отноше- ¹⁰ние напряжения с выхода гидрофона к давлению на входе (1].A method is known absolute calibration of hydrophones in the chambers controlled elastically weight impedance, consisting in that the hydrophone set ^s in a measuring chamber filled with liquid, creates alternating overpressure at the inlet of the test hydrophone by oscillations of the measuring chamber and determine the sensitivity as the ratio of the voltage ¹⁰ from the hydrophone output to the inlet pressure (1].

Недостатком такого способа является невысокая точность градуировки вследствие необходимости контроля координат сечения с нулевым избыточным давлением.The disadvantage of this method is the low accuracy of the calibration due to the need to control the coordinates of the cross section with zero gauge pressure.

Цель изобретения - повышение точности градуировки.The purpose of the invention is improving the accuracy of calibration.

Это достигается тем, что устанавливают гидрофон в двух различных поперечных сечениях измерительной' камеры, измеряют расстояние от гидрофона до уровня жидкости, после Создания переменного избыточного давления опрег ляют. амплитуды напряжения с выхода гидрофона при закреплении его в двух этих сечениях, находят разницу амплитуд измеренных напряжений и определяют чувствительность с учетом вышеуказанных параметров. Кроме того, параметры движения камеры при измерении напряжений с выхода гидрофона поддерживают постоянным.This is achieved by installing a hydrophone in two different cross sections of the measuring chamber, measuring the distance from the hydrophone to the liquid level, and after creating an alternating overpressure, they are measured. the voltage amplitudes from the hydrophone output when fixing it in these two sections, find the difference in the amplitudes of the measured voltages and determine the sensitivity taking into account the above parameters. In addition, the parameters of the movement of the chamber when measuring voltages from the hydrophone output are kept constant.

Способ осуществляется следующим образом. Выражение для распределения амплитуд избыточного давления можно записать в виде где р — плотность жидкости;The method is as follows. The expression for the distribution of the amplitudes of the excess pressure can be written in the form where p is the density of the liquid;

а — амплитуда угла колебания камеры;a is the amplitude of the angle of oscillation of the camera;

g/ — ускорение силы тяжести;g / - acceleration of gravity;

1.) — круговая частота колебаний камеры; Н — расстояние текущего поперечного сечения от верхней крышки камеры;1.) - the circular frequency of the oscillations of the camera; H is the distance of the current cross section from the top cover of the camera;

Ηθ - расстояние от верхней крышки до поперечного сечения, где амплитуда избыточного давления равна нулю.Ηθ is the distance from the top cover to the cross section, where the amplitude of the overpressure is zero.

Если гидрофон закрепить в сечении на расстоянии Hj от верхней крышки, то сигнал V/ с выхода гидрофона можно записать в виде уЛтгчрсно)], (2)If the hydrophone is fixed in cross section at a distance Hj from the top cover, then the V / s output signal of the hydrophone can be written in the form ()), (2)

При закреплении гидрофона в другом сече- 5 нии на расстоянии от верхней крышки Н₂> Hj, сигнал V₂ с выхода гидрофона имеет вид:When fixing the hydrophone in another section 5 at a distance from the top cover Н ₂ > Hj, the signal V ₂ from the output of the hydrophone has the form:

\ =i (р(н₂) - Р(н_о)] , (3) j где Д - чувствительность испытуемого гидрофона, которая не зависит от его пере- щ становки в камере.\ = i (p (n ₂ ) - P (n _o )], (3) j where D is the sensitivity of the tested hydrophone, which does not depend on its rearrangement in the chamber.

Используя выражение (1) и вычитая из вы ражения (2) выражение (3), можем чувствительность д испытуемого гидрофона записать в виде 15Using expression (1) and subtracting expression (3) from expression (2), we can write the sensitivity q of the tested hydrophone in the form 15

Анализ (4) показывает, что чувствительность можно определять, не измеряя координаты сечения с нулевым избыточным давлением.Analysis (4) shows that sensitivity can be determined without measuring the coordinates of the cross section with zero overpressure.

Аналогична чувствительность испытуемого гидрофона при калибровке описанным способом, когда замкнутая измерительная камера возбуждается инерционным методом, можно записать в виде «У ⁽⁵⁾где а — ускорение камеры.The sensitivity of the tested hydrophone during calibration in the described way is similar, when the closed measuring chamber is excited by the inertial method, it can be written in the form “U ⁽⁵⁾ where a is the acceleration of the chamber.

Анализ двух последних выражений показывает, что для определения чувствительности описанным способом отпадают операции определения и контроля сечения с нулевым избыточным давлением.An analysis of the last two expressions shows that to determine the sensitivity in the described way, the operations of determining and monitoring the cross section with zero gauge pressure are no longer needed.

Основным преимуществом способа является повышение точности калибровки гидрофонов.The main advantage of the method is to increase the accuracy of calibration of hydrophones.

Claims

The invention relates to a measurement technique and can be used when testing hydrophones. A known method of absolute calibration of hydrophones in chambers controlled by elastic mass impedance, which consists in installing a hydrophone in a measuring chamber filled with liquid, creates a variable overpressure at the inlet of the test hydrophone by oscillation of the measuring chamber and determines the sensitivity as the ratio pressure from the hydrophone output to the inlet pressure 1. The disadvantage of this method is the low calibration accuracy due to the need to control the coordinates of sections with zero ytochnym pressure. The purpose of the invention is the precision of graduation. This is achieved by placing the hydrophone in two different cross sections of the measuring chamber, measuring the distance from the hydrophone to the level of the liquid, after creating a variable overpressure is determined. the amplitudes of the voltage from the output of the headphone when it is fixed in these two sections, find the difference in the amplitudes of the measured voltages and determine the sensitivity taking into account the above parameters. In addition, the camera movement parameters when measuring voltages from the hydrophone output are kept constant. The method is carried out as follows. The expression for the distribution of the amplitudes of the overpressure can be written in the form PCH) - p (H) -TCHo J goc4 H-H.), Where p is the density of the liquid; about; - amplitude of the camera oscillation angle; - acceleration of the strength of the body; Io - circular frequency of the camera; H is the distance of the current cross section from the top of the chamber; HQ is the distance from the top cover to the cross section where the excess pressure amplitude is zero. 37 If the hydrophone is fixed in cross section at the HI distance from the top cover, then the signal from the hydrophone output can be recorded as V, (H,) - (P (Ho). (2) When the hydrophone is fixed in another section, the distance from the top H2 H2 caps, the signal Vj from the hydrophone output is: V (H2) - P (But), (3), where D is the sensitivity of the test hydro: background, which does not depend on its permutation in the chamber. Using expression (1) and subtracting expression (2) from expression (2), we can write the sensitivity l of the test hydrophone as CN /, - Vg 5., Vnw, i J3g4 (b Analysis (4) shows that & t can be determined by not measuring cross section coordinates with zero overpressure.A similar sensitivity of the test hydrophone when calibrated in the described manner when the measurement chamber is closed is excited by the inertial method, it can be written as. NI, -N / g pa (I-H ,) () where a is the acceleration of the chamber. Analysis of the last two expressions shows that, for determining the sensitivity in the manner described, the determination and control of the cross section with zero excess pressure is eliminated. The main advantage of the method is to increase the accuracy of the calibration of hydrophones. Claim 1. An absolute calibration method for hydrophones in chambers controlled by an elastic mass impedance, which consists in installing a hydrophone in a measuring chamber filled with liquid, creating a variable excess pressure at the input of the tested hydrophone by oscillation of the measuring chamber and determining the sensitivity as the ratio of the voltage from the output of the hydrophone to the pressure at the inlet is different from the fact that, in order to increase the accuracy of the calibration, the hydrophone is installed in two different cross sections and x measuring chamber, measuring the distance from the hydroxy to the liquid level, after creating a variable overpressure, determine the amplitudes of the stresses from the output of the hydrophone while fixing it in two sections, find the difference of the amplitudes of the measured stresses and determine the sensitivity taking into account the above parameters.

2. The method according to claim 1, wherein the movement parameters of the camera when measuring the voltage from the output of the hydrophone are kept constant. Sources of information taken into account in the examination 1. USSR author's certificate in accordance with the application W 2562805 / 18-28, cl. G 01 And 3/10, 1978 (prototype).