A high-sensitivity measuring device for fluctuating pressure in a turbulent flow in a hole

Abstract

The utility model relates to a kind of high-sensitivity hole cavity turbulent fluctuation pressure measuring device, it relates to the field of acoustics measurement.It solves the traditional problem involved.This invention straight pipe is arranged in the right side of spherical tank, the V-shaped groove embedded in the inner wall of straight pipe, coil is annular on straight pipe, sensor is distributed in the threaded hole of spherical tank shell respectively, exhaust valve is arranged in the upper of spherical tank, spherical tank and pressure cylinder are communicated by pressure tube, pressure gauge is arranged on pressure tube.The utility model eliminates the frictional resistance influence of fluid in straight pipe using V-shaped groove in straight pipe and heating technology, pressure cylinder and pressure tube pressurize in spherical tank, eliminate the sound absorption effect generated by straight pipe and spherical tank as helmholtz resonator, improve the measurement precision of fluctuation pressure in hole cavity shear oscillation.

Description

Technical Field

[0001] This invention relates to the field of acoustic measurement. Specifically, it relates to a highly sensitive measuring device for turbulent pulsating pressure in a cavity. Background Technology

[0002] Currently, instruments used to measure pulsating pressure in underwater cavities caused by shear oscillations due to fluid interface interruption are generally pulsating pressure sensors and hydrophones. The advantage of pulsating pressure sensors is that their mounting plane can be flush with the incoming flow plane; however, their disadvantage is also significant: a spatial averaging effect exists. High wavenumber components are averaged on the sensor surface, causing a decrease in the magnitude of the measurement result, thus leading to discrepancies between numerical calculations and experimental results. In hydrophone measurements of turbulent pulsating pressure, especially inside cavities, the cylindrical structure of the hydrophone affects the flow field within the cavity, which is another reason for the discrepancy between numerical calculations and experimental results. The fundamental requirement for verifying numerical calculation results with experimental measurements is high reliability, meaning the smaller the combined measurement uncertainty, the better. For example, a measurement uncertainty of less than 3 dB (k=2) is typically required. However, due to the inherent randomness of flow field experiments and the requirement that statistical averaging results ensure the turbulent process is temporally stable and spatially uniform, achieving a combined uncertainty of less than 3 dB after multiple statistical averagings places extremely high demands on the flow field and testing instruments used in the cavity test. Only when the experimental measurements meet these high requirements can the difference between the experimental and numerical calculation results for the peak values ​​(first, second, and third orders) of the shear oscillations in the cavity shear oscillation process be within 3 dB, with a frequency of 10 Hz to 2 kHz. Therefore, to improve the accuracy of cavity turbulent pulsating pressure experimental measurements, it is necessary to develop new pulsating pressure measurement experimental devices to provide technical support for accurately verifying the control of low-frequency line spectrum noise generated by cavity shear oscillations. Summary of the Invention

[0003] This invention addresses the spatial averaging effect in existing pulsating pressure sensors. The high wavenumber components are averaged on the sensor surface, causing a decrease in the magnitude of the measurement result, leading to discrepancies between numerical calculations and experimental results. Furthermore, in hydrophone measurements of turbulent pulsating pressure, especially within orifice chambers, the cylindrical structure of the hydrophone affects the flow field within the orifice, also contributing to discrepancies between numerical calculations and experimental results. This invention provides a highly sensitive orifice turbulent pulsating pressure measurement device. The specific technical solution to this problem is as follows:

[0004] This invention discloses a highly sensitive orifice turbulent pulsating pressure measuring device, comprising a straight tube, a coil, a power supply, a spherical tank, a sensor group, an exhaust valve, a pressure gauge, a pressure-resistant tube, a pressure cylinder, a piston, a nut, and a bolt. The straight tube is located on the right side of the spherical tank, with a V-shaped groove embedded in its inner wall. A coil is wound around the straight tube and connected to the power supply. The shell of the spherical tank has multiple threaded through holes. Each sensor of the sensor group is fixed in one of the threaded through holes distributed in the shell of the spherical tank. The exhaust valve is located above the spherical tank. The spherical tank and the pressure cylinder are connected by a pressure-resistant tube. The pressure gauge is located on the pressure-resistant tube. A piston is located on the left side of the pressure cylinder. The left end of the bolt is connected to the piston, and the nut engages with the bolt.

[0005] The sensor group consists of a first sensor, a second sensor, a third sensor, a fourth sensor, and a fifth sensor, which are distributed on the shell of the spherical tank.

[0006] The advantages of the high-sensitivity orifice turbulent pulsating pressure measurement device of the present invention compared with the prior art are as follows: 1. It avoids the problems of high wavenumber components being averaged or flow field being destroyed due to flush installation of pulsating pressure sensors or insertion of hydrophones, resulting in less damage to the orifice turbulent flow field and improving the reliability of experimental measurement results; 2. The V-groove in the straight pipe can reduce the drag of the flow in the straight pipe, reducing the energy loss of the fluid in the pressure transmission process during orifice shear oscillation; 3. The rapid heating device composed of coil and power supply can heat the fluid in the straight pipe, reducing the loss of pressure transmission in the straight pipe and further improving the accuracy of orifice shear oscillation frequency testing; 4. The sensor group on the spherical tank. By combining multiple sensors and summing and averaging the data measured by these sensors, the signal-to-noise ratio of the cavity shear oscillation process is improved, achieving high sensitivity. This is because multiple sensors significantly increase the pressure sensing area compared to a single sensor. Fifth, a pressure cylinder, pressure-resistant pipe, and vent valve constitute the pressure regulation and de-bubbling device within the spherical tank, maintaining the pressure balance between the spherical tank and the fluid in the circulating water tank or gravity-fed water tunnel. Because water has a very low compressibility (approximately 0.4%), pressure changes on the outer surface of the straight pipe can be reliably transmitted to the spherical tank. According to Pascal's principle, the sensor group in the spherical tank can reliably sense the turbulent pulsating pressure at the cavity to be measured. When measuring the cavity shear oscillation process, the small diameter of the straight pipe, the use of V-grooves and heating techniques to reduce the friction of the fluid oscillation in the straight pipe, and the pressurization within the spherical tank minimize the device's potential to become a Helmholtz silencer, thus negligible impact on the acoustic feedback process during cavity shear oscillation. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of a highly sensitive orifice turbulent pulsating pressure measuring device. Detailed Implementation

[0008] Specific implementation method one: Combining Figure 1 This embodiment is described. It consists of a straight pipe 1, a coil 2, a power supply 3, a spherical tank 4, a sensor group 5, an exhaust valve 6, a pressure gauge 7, a pressure-resistant pipe 8, a pressure cylinder 9, a piston 10, a nut 11, and a bolt 12. The straight pipe 1 is located on the right side of the spherical tank 4, with a V-shaped groove embedded in its inner wall. The coil 2 is wound around the straight pipe 1 and connected to the power supply 3. Multiple threaded through holes are opened on the shell of the spherical tank 4. Each sensor of the sensor group 5 is fixed in one of these threaded through holes distributed in the shell of the spherical tank 4. The exhaust valve 6 is located above the spherical tank 4. The spherical tank 4 and the pressure cylinder 9 are connected by the pressure-resistant pipe 8. The pressure gauge 7 is located on the pressure-resistant pipe 8. A piston 10 is located on the left side of the pressure cylinder 9. The left end of the bolt 12 is connected to the piston 10, and the nut 11 cooperates with the bolt 12.

[0009] The sensor group 5 consists of a first sensor 5-1, a second sensor 5-2, a third sensor 5-3, a fourth sensor 5-4, and a fifth sensor 5-5, which are distributed on the shell of the spherical tank 4.

[0010] Specific Implementation Method Two: Combining Figure 1 This embodiment is described. The sensor group 5 in this embodiment consists of a first sensor 5-1, a second sensor 5-2, a third sensor 5-3, a fourth sensor 5-4, and a fifth sensor 5-5. The first sensor 5-1, the second sensor 5-2, the third sensor 5-3, the fourth sensor 5-4, and the fifth sensor 5-5 are distributed on the shell of the spherical tank 4.

[0011] Specific implementation method three: Combining Figure 1 This embodiment is described. The inner wall of the straight pipe 1 described in this embodiment is embedded with a V-shaped groove.

[0012] Specific implementation method four: Combination Figure 1 This embodiment is described. The spherical tank 4 described in this embodiment is made of titanium alloy.

[0013] Specific Implementation Method Five: Combining Figure 1 This embodiment describes a coil 2 made of 0Cr27Al7Mo2 alloy steel resistance wire with a diameter of 2.5 mm.

[0014] Specific Implementation Method Six: Combination Figure 1This embodiment describes the following: The first sensor 5-1, the second sensor 5-2, the third sensor 5-3, the fourth sensor 5-4, and the fifth sensor 5-5 described in this embodiment are pulsating pressure sensors or hydrophones. The pulsating pressure sensor is model CY-YD-211, with a pressure sensitivity of 50000 pC / MPa, a pressure measurement range of 50 Pa to 10 MPa, and a natural frequency greater than 50 kHz, used for measuring pulsating pressure. The hydrophone is model 8103 manufactured by B&K GmbH in Denmark, with a sensitivity of -211 dB (re1 V / μPa) and a cable length of 6 m, used for measuring pulsating pressure.

[0015] Specific implementation method seven: Combining Figure 1 This embodiment describes the power supply 3.

[0016] An AC power supply with a frequency of 50Hz and a voltage of 220V is used to power coil 2, thereby heating the fluid inside straight pipe 1.

[0017] Specific implementation method eight: Combination Figure 1 This embodiment describes the vent valve 6, which is a TAOQI brand, model M, used to release air from the spherical tank 4.

[0018] Specific Implementation Method Nine: Combining Figure 1 This embodiment describes the pressure gauge 7, which is a Sycif brand, model Y-100, installed on the side of the pressure-resistant tube 8, and used to monitor the pressure inside the spherical tank 4.

[0019] Specific Implementation Method Ten: Combining Figure 1 This embodiment describes a pressure-resistant pipe 8, which is a high-pressure pipe with external threads at both ends, and is sealed to the spherical tank 4 and pressure cylinder 9 using raw material.

[0020] Detailed Implementation Method Eleven: Combining Figure 1 This embodiment describes a pressure cylinder 9, which is a cylindrical rod-type water storage tank with a pressure section in the middle and a safety bumper for support. Inside the pressure cylinder, a piston 10 acts as a pressure regulating valve. By rotating a bolt 12 in the pressure cylinder 9, one end of the pressure cylinder 9 is connected to a pressure-resistant pipe 8, and the other end of the pressure cylinder 9 has a nut 11 and a bolt 12. The piston 10 is connected to the bolt 12. By adjusting the length of the bolt 12, the pressure of the pressure cylinder 9 can be adjusted, thereby adjusting the pressure of the spherical tank 4.

[0021] The above embodiments are merely exemplary and do not limit the present invention. It should be noted that the technical aspects of this invention are not limited.

[0022] For those skilled in the art, any other equivalent changes, modifications, substitutions, and variations made under the guidance of the technical solutions provided by this invention should be considered within the scope of protection of this invention.

Claims

1. A highly sensitive measuring device for turbulent pulsating pressure in a cavity, comprising a straight tube, coil, power supply, spherical container, sensor group, exhaust valve, pressure gauge, pressure-resistant tube, pressure cylinder, piston, nut, and bolt, characterized in that: A straight tube is located on the right side of the spherical tank. The inner wall of the straight tube has a V-shaped groove, and a coil is wound around the straight tube. The coil is connected to the power supply. The shell of the spherical tank has multiple threaded through holes. Each sensor of the sensor group is fixed in the threaded through hole of the shell of the spherical tank. The exhaust valve is located above the spherical tank. The spherical tank and the pressure cylinder are connected by a pressure-resistant pipe. The pressure gauge is located on the pressure-resistant pipe. A piston is located on the left side of the pressure cylinder. The left end of the bolt is connected to the piston, and the nut is engaged with the bolt.

2. The highly sensitive measuring device for turbulent pulsating pressure in a cavity according to claim 1, characterized in that: The sensor group consists of a first sensor, a second sensor, a third sensor, a fourth sensor, and a fifth sensor, which are distributed on the shell of the spherical tank.

3. The highly sensitive measuring device for turbulent pulsating pressure in a cavity according to claim 1, characterized in that: The spherical tank is made of titanium alloy.

4. The highly sensitive measuring device for turbulent pulsating pressure in a cavity according to claim 1, characterized in that: The coil is a resistance wire made of 0Cr27Al7Mo2 alloy steel with a diameter of 2.5 mm.

5. The highly sensitive measuring device for turbulent pulsating pressure in a cavity according to claim 2, characterized in that: The first, second, third, fourth, and fifth sensors are either pulsating pressure sensors or hydrophones. The pulsating pressure sensor is model CY-YD-211, with a pressure sensitivity of 50000 pC / MPa, a pressure measurement range of 50 Pa to 10 MPa, and a natural frequency greater than 50 kHz, used to measure pulsating pressure. The hydrophone is model 8103 manufactured by B&K in Denmark, with a sensitivity of -211 dB (re1 V / μPa) and a cable length of 6 m, used to measure pulsating pressure.

6. The highly sensitive measuring device for turbulent pulsating pressure in a cavity according to claim 1, characterized in that: The exhaust valve is a TAOQI brand, model M.

7. The highly sensitive measuring device for turbulent pulsating pressure in a cavity according to claim 1, characterized in that: The pressure gauge is a Sycif brand, model Y-100, and is installed on the side of the pressure-resistant pipe.

8. The highly sensitive measuring device for turbulent pulsating pressure in a cavity according to claim 1, characterized in that: The pressure-resistant pipe is a high-pressure pipe with external threads at both ends, and is sealed to the spherical tank and pressure cylinder using raw material.

9. The highly sensitive measuring device for turbulent pulsating pressure in a cavity according to claim 1, characterized in that: The pressure cylinder is a cylindrical rod-type water storage tank with a pressure section in the middle and a safety bar for support around it. Inside the pressure cylinder, a piston acts as a pressure regulating valve, and the pressure of the pressure cylinder can be adjusted by adjusting the length of the bolt.

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