CN-122016183-A - Bottom water leakage stopping water flow excitation vibration resonance judging method and device considering self-vibration frequency of gate

CN122016183ACN 122016183 ACN122016183 ACN 122016183ACN-122016183-A

Abstract

The invention discloses a bottom water leakage prevention water flow excitation vibration resonance judging method and device considering the self-vibration frequency of a gate. The method comprises the steps of obtaining flow field agent excitation signals and synchronously collected vibration response signals of a structure to be tested under a preset fluid boundary condition, extracting excitation main frequency and corresponding excitation initial phases based on the flow field agent excitation signals, extracting same-frequency response phases from the vibration response signals based on the excitation main frequency, calculating excitation response phase differences of the same-frequency response phases and the excitation initial phases, mapping the excitation response phase differences to a preset main value interval to obtain normalized phase differences, and finally comparing the normalized phase differences with preset theoretical resonance phase differences to judge whether resonance occurs or not. The invention avoids the interference of the contact sensor on the slit flow field and the damping sensitivity defect of the traditional amplitude judgment, and realizes the high-precision automatic positioning of the resonance critical point under the complex fluid-solid coupling working condition.

Inventors

WANG XIN
Bi Lirui
LU GUOQING
YANG MING
XU HUANMIN
CHENG YAO
Meng Wanshang
LI JUN
Xue shu
Zhu Xunsong
XU XINYU
HONG MIN
MOU KAILONG
YANG NING
QIAO XUEFENG

Assignees

水利部交通运输部国家能源局南京水利科学研究院
镇江市港航事业发展中心

Dates

Publication Date: 20260512
Application Date: 20260416

Claims (10)

1. A bottom water leakage stopping water flow excitation vibration resonance judging method considering the self-vibration frequency of a gate is characterized by comprising the following steps: Acquiring a flow field agent excitation signal of a structure to be tested under a preset fluid boundary condition and synchronously acquiring a vibration response signal; Extracting excitation main frequency based on the flow field agent excitation signal, and acquiring an excitation initial phase of the flow field agent excitation signal at the excitation main frequency; based on the excitation main frequency, extracting a corresponding same-frequency response phase from the vibration response signal; calculating an excitation response phase difference based on the same-frequency response phase and the excitation initial phase, and mapping the excitation response phase difference to a preset main value interval to obtain a normalized phase difference; And comparing the normalized phase difference with a preset theoretical resonance phase difference, and judging whether the structure to be tested resonates under the preset fluid boundary condition or not based on the comparison result.
2. The method of claim 1, wherein obtaining flow field proxy excitation signals and synchronously acquired vibration response signals for the structure under test at a predetermined fluid boundary condition comprises: Acquiring a continuous gray image sequence of a water leakage jet flow area of a structure to be tested under a preset fluid boundary condition; extracting jet boundary central line displacement at a predetermined characteristic monitoring point from a continuous gray image sequence, and generating a flow field agent excitation signal based on the jet boundary central line displacement; And acquiring the time sequence vibration speed of the structure to be tested, which is acquired synchronously with the continuous gray image sequence, and taking the time sequence vibration speed as a vibration response signal.
3. The method of claim 2, wherein the characteristic monitoring points are determined by: Acquiring a predetermined water leakage gap outlet position and a water leakage gap width; And taking a single position which is positioned at the downstream of the outlet position of the water leakage gap and is at a preset multiple of the width of the water leakage gap as a characteristic monitoring point.
4. The method of claim 2, wherein the characteristic monitoring points are determined by: Setting a plurality of candidate monitoring points along the flow direction in a water leakage jet flow area, and extracting candidate time sequence signals corresponding to the candidate monitoring points from a continuous gray level image sequence; Calculating the signal-to-noise ratio of each candidate time sequence signal in the frequency domain, and extracting a target candidate point corresponding to the maximum value of the signal-to-noise ratio from each candidate monitoring point; Extracting a first peak frequency of the target candidate point and a second peak frequency of the rest candidate monitoring points, wherein the signal-to-noise ratio of the second peak frequency meets a preset condition; And when the deviation of the first peak frequency and the second peak frequency meets a preset frequency consistency condition, taking the target candidate point as a characteristic monitoring point.
5. The method of claim 1, wherein the step of extracting the corresponding on-channel response phase from the vibration response signal based on the excitation dominant frequency comprises: constructing a dynamic band-pass filter by taking the excitation main frequency as the center frequency; Filtering the vibration response signal by using a dynamic band-pass filter to obtain a target frequency band response signal; the phase angle at the excitation dominant frequency is extracted from the target band response signal as the same frequency response phase.
6. The method of claim 5, wherein the steps of obtaining an excitation initial phase of the flow field agent excitation signal at the excitation dominant frequency and extracting a phase angle at the excitation dominant frequency from the target band response signal are each accomplished by: converting the corresponding signals to a frequency domain, and obtaining frequency domain complex values of the signals at the excitation main frequency; extracting the imaginary part and the real part of the frequency domain complex value; And (3) calling a four-quadrant arctangent function to calculate an imaginary part and a real part, and obtaining a phase angle of which a value range covers a complete single-cycle interval, wherein the phase angle is respectively used as an excitation initial phase and a same-frequency response phase.
7. The method of claim 1, further comprising, prior to the step of calculating the excitation response phase difference based on the on-channel response phase and the excitation initial phase: Acquiring synchronously acquired upstream and downstream differential pressure signals, and extracting differential pressure phases of the upstream and downstream differential pressure signals at an excitation main frequency; Calculating a phase transfer correction amount based on a difference value between the differential pressure phase and the excitation initial phase and combining a preset hydrodynamic coupling relation; and superposing the phase transfer correction quantity to the excitation initial phase to obtain a corrected excitation initial phase.
8. The method of claim 7, wherein calculating the phase transfer correction based on the difference between the differential pressure phase and the excitation initial phase in combination with the predetermined hydrodynamic coupling relationship comprises: Extracting the differential pressure pulsation amplitude and the average differential pressure of upstream and downstream differential pressure signals, and acquiring the gap width pulsation amplitude and the average gap width based on the geometric parameters of the water leakage gap of the structure to be detected; calculating a differential pressure gap coupling ratio based on the differential pressure pulsation amplitude, the average differential pressure, the gap width pulsation amplitude and the average gap width; a phase transfer correction amount is calculated based on the differential pressure slot coupling ratio and the differential pressure phase and the excitation initial phase difference.
9. The method according to claim 1, wherein mapping the excitation response phase difference to a preset main value interval yields a normalized phase difference, specifically: Translating and mapping the excitation response phase difference into a preset single-period main value interval through modulo operation to obtain a normalized phase difference; The preset single-period main value interval is an interval of more than minus one hundred eighty degrees and less than or equal to plus one hundred eighty degrees.
10. A bottom water leakage prevention water flow excitation vibration resonance determination device considering a gate self-vibration frequency, comprising: the high-pressure water circulation system comprises a water inlet pipeline, a water inlet pressure stabilizing unit, a test unit and a water outlet pipeline which are sequentially communicated; The test unit comprises a box body, wherein a gate sill and a gate structure boundary are fixedly connected in the box body respectively, a water stop seat plate is also arranged in the box body, and a bottom water stop test piece is fixedly connected to the bottom end of the water stop seat plate; The natural frequency excitation module is arranged in the box body and comprises an elastic element and a guide constraint mechanism, wherein the first end of the elastic element is fixed on the top wall of the box body, the second end of the elastic element is connected with the water stop seat plate and applies elastic acting force in the longitudinal direction, the guide constraint mechanism is symmetrically arranged on two sides of the water stop seat plate and is abutted against the side wall of the water stop seat plate, and the transverse displacement of the water stop seat plate is limited and the water stop seat plate is allowed to slide along the guide constraint mechanism in the longitudinal direction.

Description

Bottom water leakage stopping water flow excitation vibration resonance judging method and device considering self-vibration frequency of gate Technical Field The invention relates to the technical field of water conservancy and hydropower engineering tests, in particular to a bottom water leakage prevention water flow excitation vibration resonance judging method and device considering the self-vibration frequency of a gate. Background The gate bottom water stop is easy to be damaged and leaked under the working conditions of long-term bearing of high water pressure and frequent opening and closing, forms high-pressure jet flow and induces flow excitation vibration. The method accurately obtains the pulsation evolution characteristics of the water leakage jet flow, quantifies the dynamic coupling relation between the excitation force of the clear fluid and the inherent mechanical frequency of the gate structure or the parts thereof, and is a technical basis for predicting resonance instability and even self-excited vibration critical conditions, guiding the vibration suppression design of the hydraulic structure and guaranteeing the operation safety. In the current physical model test aiming at gate water-stop flow excitation vibration, the research method is basically concentrated on the research of the response mechanism of the whole structure, the numerical simulation research and the physical model test research. In a specific test scheme, a contact sensor such as a miniature dynamic water pressure gauge or a strain gauge is usually attached near a water stop gap or a wall surface to acquire a fluid pulsation signal, and an acceleration sensor is used for acquiring the vibration response of a structure. In the resonance judgment link, the main stream method mainly extracts the amplitude spectrum of the structural vibration response by scanning working conditions with different flow rates, and marks the working condition point that the amplitude amplification coefficient reaches the global peak value as a resonance critical point. However, the existing contact measurement and amplitude peak value judgment mechanism faces the technical problems of low extraction precision and large mechanism error under the complex fluid-solid coupling working condition. The method comprises the steps of firstly, invading and damaging an extremely sensitive original jet flow field in a narrow water leakage gap by the physical volume of a contact sensor, so that acquired fluid pulsation frequency characteristic distortion is caused, secondly, highly sensitive to friction damping and fluid viscous damping of a structural system by a resonance judging method based on amplitude peaks, enabling resonance peaks to be wide in range and fuzzy in boundary under strong hydrodynamic background noise, and difficult to accurately position resonance critical frequency points, and thirdly, generally neglecting inherent physical phase shift existing between an observable apparent agent signal (such as jet geometric boundary fluctuation) and actual physical exciting force at the present stage, and carrying out transmission correction on a hydrodynamic mechanism level on the extracted exciting phase, so that systematic static deviation exists in a finally deduced phase-frequency response rule. Disclosure of Invention The invention aims to provide a bottom water leakage stopping water flow excitation vibration resonance judging method and device considering the self-vibration frequency of a gate, so as to solve the problems in the prior art. According to the technical scheme, the bottom water leakage prevention water flow excitation vibration resonance judging method considering the self-vibration frequency of the gate comprises the following steps: Acquiring a flow field agent excitation signal of a structure to be tested under a preset fluid boundary condition and synchronously acquiring a vibration response signal; Extracting excitation main frequency based on the flow field agent excitation signal, and acquiring an excitation initial phase of the flow field agent excitation signal at the excitation main frequency; based on the excitation main frequency, extracting a corresponding same-frequency response phase from the vibration response signal; calculating an excitation response phase difference based on the same-frequency response phase and the excitation initial phase, and mapping the excitation response phase difference to a preset main value interval to obtain a normalized phase difference; And comparing the normalized phase difference with a preset theoretical resonance phase difference, and judging whether the structure to be tested resonates under the preset fluid boundary condition or not based on the comparison result. The method has the beneficial effects that aiming at the problem that the signal distortion is caused by the invasion of the contact sensor into the flow field, the scheme adopts a non-contact heterogeneous sign