Non-contact mud flowmeter signal processing system and method

Abstract

The invention discloses a non-contact mud flowmeter signal processing system, which comprises a sensor unit, a signal amplification unit, a signal processing unit, a control unit and a flow calculation and display unit, and is characterized in that the sensor unit is used for acquiring a pressure pulsation signal of fluid in a pipeline; the signal amplification unit is used for performing signal pre-amplification and filtering; the signal processing unit carries out signal conditioning and conversion. The control unit is used for storing the digital signal and simultaneously carrying out time sequence control; and the flow calculation and display unit calculates and displays the flow velocity and the flow of the pipeline. Through non-contact flow measurement, the problems of abrasion, water leakage and regular overturning of a detection sensor of a traditional dredger electromagnetic flow meter are effectively avoided, the service life is long, and meanwhile the precision is higher than that of an ultrasonic flow meter.

Description

Technical Field

[0001] The invention belongs to the field of measurement technology, and in particular relates to a non-contact mud flowmeter signal processing system and method. Background Art

[0002] Flow meter is an important instrument for dredging ships. Its main function is to detect the mud velocity and flow rate of the dredging pipeline system, providing an important basis for ship operators to carry out reasonable and efficient dredging operations. At the same time, it also forms a production meter together with the mud concentration meter to calculate the instantaneous production and cumulative production in real time for production statistics and assessment. It is an indispensable equipment for dredging ships. Its measurement accuracy and durability are directly related to the calculation of production efficiency, which is of great significance to dredging operations.

[0003] At present, the flow measurement of dredging ships generally adopts contact electromagnetic flowmeters, whose working principle is: when the conductive fluid flows in the pipeline and vertically cuts the magnetic field passing through the pipeline, an induced electromotive force will be generated on the electrodes on both sides of the pipeline. This electromotive force is proportional to the average flow velocity of the fluid. By measuring the electromotive force, the flow velocity of the fluid in the pipeline can be calculated; and this contact measurement method will bring the following shortcomings: 1. The sensor needs to be replaced regularly due to wear, leakage and other reasons; 2. When installing in a non-vertical pipe section, the installation angle needs to be rotated regularly to balance the wear on the bottom of the sensor; 3. The sensor needs to be installed at the lowest point or vertical section of the pipeline to ensure the measurement accuracy, and the installation requirements are high; 4. The measurement accuracy is easily affected by external electromagnetic interference.

[0004] In this regard, although the industry has also studied non-contact ultrasonic flow meters, which use the correspondence between the speed at which ultrasonic pulses propagate in the fluid and the fluid velocity to estimate the fluid velocity, they are unable to overcome the requirements for large-diameter, high-concentration mud flow monitoring due to the limitations of ultrasonic penetration capabilities. Summary of the invention

[0005] In order to overcome the various deficiencies of the contact flowmeter in the prior art and the weak penetration ability of the non-contact ultrasonic flowmeter, the present invention provides the following technical solutions:

[0006] A non-contact mud flowmeter signal processing system includes: a sensor unit, a signal amplification unit, a signal processing unit, a control unit, and a flow calculation and display unit, wherein:

[0007] The sensor unit is a flexible film array sensor, which is used to obtain the pressure pulsation signal of the fluid in the pipeline to form a first analog signal;

[0008] The signal amplification unit is used to pre-amplify and filter the first analog signal acquired by the flexible film array sensor, and output a second analog signal;

[0009] The signal processing unit performs signal conditioning and conversion on the second analog signal and outputs a digital signal;

[0010] The control unit stores the digital signal and performs timing control on the signal amplification unit and the signal processing unit;

[0011] The flow calculation and display unit receives the digital signal, and calculates and displays the pipeline flow velocity and flow rate through the digital signal.

[0012] Furthermore, the flexible film array sensor is wrapped around the wall of the pipe to be tested, and includes: a stainless steel fastening belt, a flexible piezoelectric film arranged on the stainless steel fastening belt, an insulating protective film arranged under the stainless steel fastening belt, fixed guide rails arranged on both sides of the stainless steel fastening belt, and bolt holes opened on the fixed guide rails.

[0013] Furthermore, the signal amplification unit pre-amplifies the first analog signal through an operational amplifier integrated circuit, and filters the first analog signal through a low-pass filter circuit.

[0014] Furthermore, the signal processing unit includes: a gain adaptive amplifier circuit, a common mode suppression circuit, an A / D sampling circuit, and a communication circuit;

[0015] The gain adaptive amplification circuit and the common mode suppression circuit perform gain adaptive amplification processing and common mode suppression processing on the second analog signal;

[0016] The A / D sampling circuit is used to convert the second analog signal after the gain adaptive amplification processing and the common mode suppression processing into a digital signal.

[0017] Furthermore, the control unit includes: a main processor DSP, a coprocessor FPGA, a buffer memory and a storage device;

[0018] The coprocessor FPGA is used to control the signal amplification unit and the signal processing unit to perform signal pre-amplification and filtering as well as signal conditioning and conversion, and temporarily store the processed digital signal in a buffer memory;

[0019] The main processor DSP schedules the coprocessor FPGA according to system requirements and storage strategies to store digital signals in storage devices, and is also responsible for verifying the integrity and accuracy of data storage to ensure that data is saved correctly.

[0020] Further, the flow rate calculation and display unit includes: a host computer, a visualization device, and processing software installed in the host computer;

[0021] The host computer communicates with the control unit, obtains digital signals from a storage device in the control unit, and analyzes and calculates the obtained digital signals to obtain the flow velocity and flow rate in the pipeline;

[0022] The processing software includes a turbulent flow velocity detection algorithm, which converts the pressure pulsation signal of the fluid in the pipeline into flow velocity and calculates the flow rate according to different pipe diameters;

[0023] The visualization device provides a graphical display of flow rate and flow information.

[0024] A non-contact mud flowmeter signal processing method comprises the following steps:

[0025] S1. The flexible film array sensor obtains the pressure signal generated by the turbulence in the pipeline fluid on the pipe wall to form a first analog signal;

[0026] S2. The signal amplification unit receives the first analog signal of the flexible film array sensor, amplifies it using an operational amplifier integrated circuit, and filters the signal through a low-pass filter circuit to form a second analog signal;

[0027] S3. The signal processing unit sequentially performs adaptive gain amplification processing, common mode suppression processing, and signal conversion processing on the second analog signal to form a digital signal;

[0028] S4. The control unit stores the digital signal and performs timing control on the signal amplification unit and the signal processing unit;

[0029] S5. The flow calculation and display unit receives the digital signal from the control unit, analyzes, calculates and extracts the data, and finally obtains the flow velocity and flow information.

[0030] The present invention wraps an external clamp-on flexible thin film array sensor around the pipe wall to obtain non-contact information, and obtains the mud flow in the pipeline through signal amplification, filtering, signal conversion and other circuits, and finally obtains the mud flow in the pipeline through signal analysis and calculation. This non-contact flow measurement effectively avoids the problems of wear, leakage and regular flipping of the traditional dredger electromagnetic flowmeter detection sensor. It has a long service life and higher accuracy than ultrasonic flowmeters. It is the only choice for mud flow monitoring of dredging ships in the future and can bring significant economic and social benefits to the dredging industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the non-contact mud flowmeter signal processing system of the present invention.

[0032] Figure 2 It is a schematic diagram of the structure of the flexible film array sensor in the signal processing system of the non-contact mud flowmeter of the present invention.

[0033] Figure 3 The diagram is a schematic diagram of fixing the flexible film array sensor to the wall of the pipe to be measured in the non-contact mud flowmeter signal processing system of the present invention.

[0034] Figure 4 It is a schematic diagram of the implementation effect of the non-contact mud flowmeter signal processing system and method of the present invention.

[0035] In the figure:

[0036] 1-Sensor unit, 2-Signal amplification unit, 3-Signal processing unit, 4-Control unit, 5-Flow calculation and display

[0037] unit;

[0038] 11-first analog signal, 12-second analog signal, 13-digital signal, 15-flexible piezoelectric film;

[0039] 16-stainless steel fastening belt, 17-insulating protective film, 18-fixing rail, 19-bolt hole, 20-wall of the pipe to be tested, 21-fixing bolt. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is described clearly and completely with specific embodiments in conjunction with the accompanying drawings. It should be understood that the described embodiments are only used to illustrate the present invention, but not to limit the scope of the present invention.

[0041] Embodiment 1: A non-contact mud flowmeter signal processing system and method:

[0042] according to Figure 1 As shown, a non-contact mud flowmeter signal processing system includes: a sensor unit 1, a signal amplification unit 2, a signal processing unit 3, a control unit 4 and a flow calculation and display unit 5, wherein:

[0043] The sensor unit 1 is a flexible thin film array sensor, which is used to obtain the pressure signal of the turbulent fluid in the pipeline to form a first analog signal 11;

[0044] The signal amplification unit 2 is used to pre-amplify and filter the first analog signal 11 obtained by the flexible film array sensor, and output a second analog signal 12 to facilitate subsequent signal processing;

[0045] The signal processing unit 3 performs signal conditioning and conversion on the second analog signal 12 output by the signal amplifying unit 2, and outputs a digital signal 13 for subsequent signal storage;

[0046] The control unit 4 stores the digital signal 13 output by the signal processing unit 3, and performs timing control on the signal amplification unit 2 and the signal processing unit 3;

[0047] The flow calculation and display unit 5 receives the digital signal 13 stored in the control unit 4, calculates the pipeline flow velocity and flow rate through the digital signal 13, and displays the flow velocity and flow rate information.

[0048] Further, such as Figure 2 As shown, the specific structure of the flexible film array sensor includes: a stainless steel fastening belt 16, a flexible piezoelectric film 15 arranged on the stainless steel fastening belt 16, an insulating protective film 17 arranged under the stainless steel fastening belt 16, fixed rails 18 arranged on both sides of the stainless steel fastening belt 16, and bolt holes 19 opened on the fixed rails 18; Figure 2 and Figure 3 By screwing the fixing bolts 21 into the bolt holes 19 on the fixing guide rails 18, the flexible film array sensor is wrapped outside the wall 20 of the pipe to be tested.

[0049] Further, back to Figure 1 , the signal amplifying unit 2 includes an operational amplifier integrated circuit and a low-pass filter circuit (not shown in the figure);

[0050] The operational amplifier integrated circuit is used to pre-amplify the first analog signal 11, and the low-pass filter circuit is used to filter the first analog signal 11, thereby amplifying and filtering the first analog signal 11 into a second analog signal 12; the operational amplifier integrated circuit and the low-pass filter circuit are both circuit designs that have been disclosed in the prior art and will not be described in detail.

[0051] Furthermore, the signal processing unit 3 includes: a gain adaptive amplifier circuit, a common mode suppression circuit, an A / D sampling circuit, and a communication circuit;

[0052] The gain adaptive amplifier circuit is used to perform gain adaptive amplification processing on the second analog signal 12;

[0053] The common mode suppression circuit is used to perform common mode suppression processing on the second analog signal 12;

[0054] The A / D sampling circuit is used to convert the second analog signal 12 after the gain adaptive amplification process and the common mode suppression process into a digital signal 13;

[0055] The gain adaptive amplifier circuit, common mode suppression circuit, A / D sampling circuit, and communication circuit are all circuit designs that have been disclosed in the prior art and will not be described in detail.

[0056] Furthermore, the control unit 4 includes: a main processor DSP, a coprocessor FPGA, a buffer memory and a storage device;

[0057] The coprocessor FPGA is used to perform timing control on the signal amplification unit 2 and the signal processing unit 3; control the signal amplification unit 2 and the signal processing unit 3 to perform pre-amplification and filtering, conditioning and conversion of the signal in a predetermined order and time interval, and temporarily store the processed digital signal 13 in the buffer memory;

[0058] The main processor DSP schedules the coprocessor FPGA according to system requirements and storage strategies to store the digital signal 13 in the storage device, and is also responsible for verifying the integrity and accuracy of the data storage to ensure that the data is saved correctly.

[0059] Furthermore, the flow rate calculation and display unit 5 includes: a host computer, a visualization device, and processing software installed in the host computer;

[0060] The host computer communicates with the control unit 4, obtains the digital signal 13 from the storage device in the control unit 4, and analyzes and calculates the obtained digital signal 13 to obtain the flow velocity and flow rate in the pipeline;

[0061] The processing software includes a turbulent flow velocity detection algorithm; the visualization device provides a graphical display of flow velocity and flow information, such as a curve of flow velocity changing over time, a histogram or a pie chart.

[0062] Furthermore, the turbulent flow velocity detection algorithm comprises the following steps:

[0063] S1-Get array signal

[0064] X=AS+N

[0065] Where X is the output of the flexible film array sensor, A is the direction vector, S is the incident signal, and N represents the noise of the array;

[0066] S2-Calculate the covariance matrix of the array signal

[0067] R x =E[XX H ]

[0068] S3-Get the eigenvector matrix and eigenvector matrix:

[0069] R x Eigenvalue decomposition, we get the following formula:

[0070] R x =[U]Σ[U] H

[0071] Among them, Σ is the eigenvector matrix, and the matrix [U] is the eigenvector matrix, including the signal eigenvector [U s ] and the noise eigenvector matrix [U N ];

[0072] S4-Eigenvalue sorting:

[0073] Sort the eigenvector matrix Σ from small to large according to the eigenvalue

[0074] S5-Calculate the number of signal sources:

[0075] Calculate the number of signal sources D through the Geiger circle;

[0076] S6-intercepted noise feature vector matrix:

[0077] The noise feature vector matrix corresponding to the intercepted (MD) smaller eigenvalues ​​[U N ];

[0078] Among them, M refers to the number of array signals and D refers to the number of signal sources.

[0079] S7-Get spatial spectrum extremes:

[0080] According to the spatial spectrum function Scan the frequency and wave number in two dimensions to obtain the extreme values ​​of the spatial spectrum and plot them on the two-dimensional spatial spectrum diagram.

[0081] S8-Fitting calculation:

[0082] After scanning, the slope of the line is calculated using a straight line fitting algorithm on the two-dimensional spatial spectrum. According to the principle, the slope represents the average flow rate of the fluid:

[0083]

[0084] Among them, V fluid That is, the average speed of turbulence, f is the frequency of the signal, λ is the wavelength of the signal, ω is the frequency of the signal, and 1 / k is the wave speed.

[0085] A non-contact mud flowmeter signal processing method comprises the following steps:

[0086] S1. The flexible film array sensor obtains the pressure pulsation signal caused by the turbulent flow of the pipeline fluid on the pipe wall to form a first analog signal;

[0087] S2. The signal amplification unit receives the first analog signal of the flexible film array sensor, amplifies it using an operational amplifier integrated circuit, and filters the signal through a low-pass filter circuit to form a second analog signal;

[0088] S3. The signal processing unit sequentially performs adaptive gain amplification processing, common mode suppression processing, and signal conversion processing on the second analog signal to form a digital signal;

[0089] S4. The control unit stores the digital signal and performs timing control on the signal amplification unit and the signal processing unit;

[0090] S5. The flow calculation and display unit receives the digital signal from the control unit, analyzes, calculates and extracts the data, and finally obtains the flow velocity and flow information.

[0091] Example 2: Application Example

[0092] Engineering examples based on the system and steps of the above embodiment 1:

[0093] 1. Implementation process

[0094] Firstly, a flexible thin film array sensor made of PVDF piezoelectric film is used to obtain the pressure signal of the pipe wall formed by the turbulence in the pipeline fluid; secondly, the TL084 amplifier with an operational amplifier integrated circuit is used to amplify the signal, and the signal is filtered by a fourth-order low-pass filter circuit composed of two second-order low-pass filter circuits connected in series; then, the signal is conditioned by a gain adaptive amplifier circuit and a common-mode suppression circuit, and then converted and output by an A / D sampling circuit; finally, the signal is analyzed, calculated and extracted by CFD software, and finally the flow velocity and flow information are obtained.

[0095] 2. Implementation effect:

[0096] The implementation effects of the present invention are as follows Figure 4 As shown, with the pipeline fluid flow rate as the vertical axis, 10 test points are counted, and the flow meter of the present invention is compared with the traditional electromagnetic flow meter. Data is recorded 10 times at each test point, and the average value is calculated. The relative deviation of the comparison has a maximum value of 1.7%, a minimum value of 0.32%, and an average value of 1.04%, which meets the use requirements.

[0097] 3. Implementation principle:

[0098] The present invention is based on the spatial spectrum function equation, two-dimensional Fourier transform, and the correlation principle between turbulent velocity and fluid velocity to form a two-dimensional Fourier transform formula as shown below:

[0099]

[0100] Among them, V fluidIt is the average speed of turbulence, f is the frequency of the signal, λ is the wavelength of the signal, ω is the frequency of the signal, and 1 / k is the wave speed. Turbulence distributes information in two dimensions in space. After two-dimensional Fourier transform, the time domain signal is converted to the frequency-wave number domain, and a three-dimensional spectrum of turbulence signal data can be obtained. A straight line will be formed where the energy is concentrated, and the slope represents the turbulent flow velocity. Through experimental tests, it is known that the average flow velocity of turbulence is about 92% of the mud flow velocity, so the mud flow velocity can be expressed as the turbulent flow velocity.

[0101] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A non-contact mud flowmeter signal processing system, characterized in that: include: Sensor unit, signal amplification unit, signal processing unit, control unit, flow calculation and display unit, wherein: The sensor unit is a flexible film array sensor, which is used to obtain the pressure signal of the fluid in the pipeline to form a first analog signal; The signal amplification unit is used to pre-amplify and filter the first analog signal acquired by the flexible film array sensor, and output a second analog signal; The signal processing unit performs signal conditioning and conversion on the second analog signal and outputs a digital signal; The control unit stores the digital signal and performs timing control on the signal amplification unit and the signal processing unit; The flow calculation and display unit receives the digital signal, and calculates and displays the pipeline flow velocity and flow rate through the digital signal.

2. The non-contact mud flowmeter signal processing system according to claim 1, characterized in that: The flexible film array sensor is wrapped around the wall of the pipe to be tested, and includes: a stainless steel fastening belt, a flexible piezoelectric film arranged on the stainless steel fastening belt, an insulating protective film arranged under the stainless steel fastening belt, fixed guide rails arranged on both sides of the stainless steel fastening belt, and bolt holes opened on the fixed guide rails.

3. The non-contact mud flowmeter signal processing system according to claim 1, characterized in that: The signal amplification unit pre-amplifies the first analog signal through an operational amplifier integrated circuit, and filters the first analog signal through a low-pass filter circuit.

4. The non-contact mud flowmeter signal processing system according to claim 1, characterized in that: The signal processing unit includes: a gain adaptive amplifier circuit, a common mode suppression circuit, an A / D sampling circuit, and a communication circuit; The gain adaptive amplification circuit and the common mode suppression circuit perform gain adaptive amplification processing and common mode suppression processing on the second analog signal; The A / D sampling circuit is used to convert the second analog signal after the gain adaptive amplification processing and the common mode suppression processing into a digital signal.

5. The non-contact mud flowmeter signal processing system according to claim 1, characterized in that: The control unit includes: a main processor DSP, a coprocessor FPGA, a buffer memory and a storage device; The coprocessor FPGA is used to control the signal amplification unit and the signal processing unit to perform signal pre-amplification and filtering as well as signal conditioning and conversion, and temporarily store the processed digital signal in a buffer memory; The main processor DSP schedules the coprocessor FPGA according to system requirements and storage strategies to store digital signals in storage devices, and is also responsible for verifying the integrity and accuracy of data storage to ensure that data is saved correctly.

6. The non-contact mud flowmeter signal processing system according to claim 5, characterized in that: The flow rate calculation and display unit comprises: a host computer, a visualization device and processing software installed in the host computer; The host computer communicates with the control unit, obtains digital signals from the storage device in the control unit, and analyzes and calculates the obtained digital signals to obtain the flow velocity and flow rate in the pipeline; The processing software includes a turbulent flow velocity detection algorithm, which converts the pressure pulsation signal of the fluid in the pipeline into flow velocity and calculates the flow rate according to different pipe diameters; The visualization device provides a graphical display of flow rate and flow information.

7. The non-contact mud flowmeter signal processing system according to claim 6, characterized in that: The turbulent flow velocity detection algorithm comprises the following steps: S1-acquire array signal; S2-calculate the covariance matrix of the array signal; S3-decompose the covariance matrix eigenvalues ​​to obtain eigenvector matrix and eigenvector matrix; S4-sort the eigenvector matrix Σ from small to large according to the eigenvalue; S5- Calculate the number of signal sources through the Geiger circle; S6-intercepted noise feature vector matrix; S7-obtaining spatial spectrum extremes; S8-Fit and calculate the average flow rate.

8. A non-contact mud flowmeter signal processing method, characterized in that: The steps include: S1. The flexible film array sensor obtains the pressure pulsation signal caused by the turbulence in the pipeline fluid on the pipe wall to form a first analog signal; S2. The signal amplification unit receives the first analog signal of the flexible film array sensor, amplifies it using an operational amplifier integrated circuit, and filters the signal through a low-pass filter circuit to form a second analog signal; S3. The signal processing unit sequentially performs adaptive gain amplification processing, common mode suppression processing, and signal conversion processing on the second analog signal to form a digital signal; S4. The control unit stores the digital signal and performs timing control on the signal amplification unit and the signal processing unit; S5. The flow calculation and display unit receives the digital signal from the control unit, analyzes, calculates and extracts the data, and finally obtains the flow velocity and flow information.

Images