CN107421713A - Turbulent liquid film wave frequency and the system of velocity of wave in a kind of measurement pipe - Google Patents
Turbulent liquid film wave frequency and the system of velocity of wave in a kind of measurement pipe Download PDFInfo
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- CN107421713A CN107421713A CN201710647411.3A CN201710647411A CN107421713A CN 107421713 A CN107421713 A CN 107421713A CN 201710647411 A CN201710647411 A CN 201710647411A CN 107421713 A CN107421713 A CN 107421713A
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- infrarede emitting
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M10/00—Hydrodynamic testing; Arrangements in or on ship-testing tanks or water tunnels
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- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The strength signal of light is changed into current signal by measuring system of the present invention using photoelectric sensor, so as to realize the measurement to turbulent liquid film wave frequency and velocity of wave.Principle of the present invention is：The light that infrarede emitting diode is sent occurs to dissipate color when passing through turbulent liquid film interface, and only some light is absorbed by infrared photodiode.A pair of infrarede emitting diodes and infrared photodiode at test section pipe outer wall form upstream and downstream sensor, the strength signal of light is changed into current signal by sensor, after amplifier amplifies, discrete data signal is transformed into by A/D converter, based on Fourier transformation (FFT) and cross-correlation analysis principle, data signal is handled using MATLAB software programming programs, draws the wave frequency and velocity of wave of turbulent liquid film.The beneficial effects of the invention are as follows can measurement fluctuation liquid film simultaneously wave frequency and velocity of wave, the statistics uncertainty of measurement data is less than 5%.
Description
Technical field
The invention belongs to the technical field of turbulent liquid film wave characteristic parameter measurement in falling film evaporator, and in particular to a kind of
The current signal that photoelectric sensor is received, obtained in pipe and fluctuated by Fast Fourier Transform (FFT) (FFT) and cross-correlation analysis
The system of liquid film wave frequency and velocity of wave.
Background technology
Steam condensation is widely used in oil, chemical industry, refrigeration, the energy, Aero-Space and seawater as efficient heat transfer technology
The fields such as desalination.The condensate film wave characteristic occurred in actual application makes heat and mass transfer process be strengthened.Condensation
Liquid film wave contains the dynamics of complexity over time and space, due to the limitation of tested person technology and method of testing,
Accurate measurement can not be carried out to the wave frequency and velocity of wave for characterizing condensate film fluctuation dynamics characteristic, therefore condensate film be fluctuated strong
Change the mechanism of heat and mass up for further research.
The main kinetic parameter for using induced fluorescence method measurement fluctuation liquid film at present, by manually distinguishing in diverse location
The image of the same ripple of shooting, measure the velocity of wave that the undulatory displacements in shooting time interval obtain turbulent liquid film.This surveys skill
Following subject matter be present in art：Identify that same ripple depends on the subjective judgement of gauger；It is easy that the fluorescence factor is added in a liquid
Change the physical characteristic of liquid film；Liquid film velocity of wave can only be measured and wave frequency can not be measured.Therefore exploitation one kind is needed accurately to survey
Turbulent liquid film wave frequency and the system of velocity of wave are measured, the mechanism process that heat and mass transfer enhancement is fluctuated to condensate film carries out exploratory development,
Innovative development for high efficient heat exchanging technology is provided fundamental basis and technological reserve.
The content of the invention
Problem to be solved by this invention is to provide turbulent liquid film wave frequency and the system of velocity of wave, the system in a kind of measurement pipe
Can accurate real-time measurement fluctuation liquid film wave frequency and velocity of wave.The device of measurement fluctuation liquid film wave frequency provided by the present invention and velocity of wave
It need to be used under unglazed or dim light.
What the technical solution of the present invention was realized in：
Turbulent liquid film wave frequency and the system of velocity of wave in a kind of measurement pipe, including：It is two infrarede emitting diodes, two infrared
Photodiode, amplifier, A/D converter, computer, power supply, wire, data wire；
Infrarede emitting diode of the present invention forms a pair of optical sensors with infrared photodiode, according to liquid
Flow direction, it is referred to as upstream sensor and downstream sensor；
Two infrarede emitting diodes of the present invention are arranged on the same side of test section pipe outer wall, separation L；
Two infrared photodiodes of the present invention are arranged on the pipe test section symmetrical with infrarede emitting diode
At outer wall, receive the light that infrarede emitting diode is sent and the strength signal of the light received is transformed into current signal；
Signal amplifier of the present invention is connected by wire with infrared photodiode, and infrared photodiode is produced
Raw weak current electric signal amplification；
A/D converter of the present invention is connected with signal amplifier by data wire, and the continuous signal of amplification is changed
For discrete data signal；
Computer of the present invention is connected with A/D converter by data wire, utilizes MATLAB software programming programs pair
Data signal is handled, and draws turbulent liquid film wave frequency and velocity of wave.
Another technical scheme of the present invention be two above-mentioned optical sensors mounting distance L be scope be 9~
11cm。
Another technical scheme of the present invention is wavelength of light that above-mentioned infrarede emitting diode is sent in 935~945nm
Between infrared ray.
Another technical scheme of the present invention is that the light intensity that above-mentioned infrarede emitting diode is sent can be according to ripple in pipe
Hydrodynamic film thickness is adjusted.
Another technical scheme of the present invention be the light that receives of above-mentioned infrared photodiode for wavelength 935~
Between 945nm with infrarede emitting diode identical infrared ray.
The light that described infrarede emitting diode is sent occurs to dissipate color when passing through turbulent liquid film interface, and a part of light is by ripple
Dynamic interfacial refraction is reflected away, and another part light is absorbed by infrared photodiode, and then the strength signal of light is changed
Into electric signal.
The application method of turbulent liquid film wave frequency and the system of velocity of wave is in a kind of measurement pipe of the present invention：
1), device is installed：Two infrarede emitting diodes are arranged on the same side of test section pipe outer wall and are apart
L, two infrared photodiodes are arranged at the pipe test section outer wall symmetrical with infrarede emitting diode, by signal amplifier
It is connected with infrared photodiode by wire, A/D converter is connected with signal amplifier by data wire, computer and A/D
Converter is connected by data wire；
2), device adjusts：The relative position of infrarede emitting diode and infrared photodiode is adjusted, keeps its center
It is point-blank and vertical with pipe axis direction；
3), device debugging：Be powered current signal caused by record infrared photodiode in pipe in the case of not water flowing,
If electric current value changes, Regulate signal amplifier is needed, fixes current value；
4), water flowing is tested：Water flowing can carry out the measurement of turbulent liquid film wave frequency and velocity of wave in pipe in pipe；
5), data acquisition and analysis：Discrete signal that computer acquisition A/D converter is converted to and storage, then profit
Discrete digital signal is handled with MATLAB software programming programs, draws turbulent liquid film wave frequency and velocity of wave.
It is as follows to digital signal processing using MATLAB software programming dedicated programs：
The signal of upstream sensor output is x (t), and the signal of downstream sensor output is y (t)；
Fast Fourier Transform (FFT) (FFT) is carried out to signal x (t) and y (t) by the program write respectively and obtains corresponding work(
Rate spectral density function figure；
Frequency corresponding with peak value is respectively f in corresponding power spectral density plot1、f2；
Then the wave frequency of turbulent liquid film is：
F=(f1+f2)/2
Signal x (t) is regard as output signal as input signal, y (t), signal is carried out using the program write mutual
Analysis is closed, obtains cross-correlation function figure；
τ values corresponding with peak value are time shifting τ in cross-correlation function figure0；
Then turbulent liquid film speed is：
V=L/ τ0
The advantages of invention is it will be apparent that being mainly manifested in：
1st, measurement accuracy of the present invention is high, and the statistics uncertainty of wave frequency and velocity of wave data is less than 5%；
2nd, the present invention can measure the velocity of wave and wave frequency of liquid film simultaneously；
3rd, the present invention can be handled signal in real time, obtain wave frequency and the Transient distribution of velocity of wave.
The present invention has simple in construction, installation and debugging are convenient, measurement accuracy is high, the real-time processing of signal can be achieved to obtain ripple
The advantages that Transient distribution of frequency and velocity of wave.
Brief description of the drawings
The present invention shares 6 width accompanying drawings, wherein：
Accompanying drawing 1 is present system schematic diagram；
Accompanying drawing 2 is the signal function image schematic diagram using upstream sensor of the present invention output；
Accompanying drawing 3 is the power spectral density plot to being drawn after signal x (t) progress Fast Fourier Transform (FFT)s；
Accompanying drawing 4 is the signal function image schematic diagram using downstream sensor of the present invention output；
Accompanying drawing 5 is the power spectral density plot to being drawn after signal y (t) progress Fast Fourier Transform (FFT)s；
Accompanying drawing 6 is that the cross-correlation function image schematic diagram that cross-correlation analysis is drawn is carried out to signal x (t) and y (t).
In figure：1st, infrarede emitting diode 2, pipe 3, infrared photodiode 4, signal amplifier 5, A/D turn
Parallel operation 6, computer 7, turbulent liquid film, X, liquid flow direction, L, mounting distance.
Embodiment
As shown in Figure 1, turbulent liquid film wave frequency and the system of velocity of wave include the specific embodiment of the present invention in measurement pipe：It is red
UV light-emitting diode 1, infrared photodiode 3, signal amplifier 4, A/D converter 5, computer 6, wire and data wire；
Infrarede emitting diode 1 and infrared photodiode 3 form a pair of optical sensors, according to liquid flow direction,
It is referred to as upstream sensor and downstream sensor；
Two infrarede emitting diodes 1 are arranged on the same side of test section pipe outer wall, separation L, L 10cm；
Two infrared photodiodes 3 are arranged at the pipe test section outer wall symmetrical with infrarede emitting diode 1, are received
The strength signal of the light received is simultaneously transformed into current signal by light that infrarede emitting diode 1 is sent；
Signal amplifier 4 is connected by wire with infrared photodiode 3, will be faint caused by infrared photodiode 3
Current electrical signal amplifies；
A/D converter 5 is connected with signal amplifier 4 by data wire, and the continuous signal of amplification is changed into discrete number
Word signal；
Computer 6 is connected with A/D converter 5 by data wire, and data signal is entered using MATLAB software programming programs
Row processing, draws turbulent liquid film wave frequency and velocity of wave.
Infrared ray of the wavelength of light that infrarede emitting diode 1 is sent between 935~945nm；The light intensity sent
It can be adjusted according to liquid in pipe flow regime.
Infrared photodiode 3 receive light for wavelength between 935~945nm with the phase of infrarede emitting diode 1
Same infrared ray
Fig. 2-6 is the image of this implementation gained：
Fig. 2 and Fig. 4 is signal x (t) images of upstream sensor output and the signal y (t) of downstream sensor output respectively
Image；
Fast Fourier Transform (FFT) (FFT) is carried out to signal x (t) and y (t) by the program write respectively and obtains corresponding work(
Rate spectral density function figure is Fig. 3 and Fig. 5；
Frequency corresponding with peak value in Fig. 3
f1=39.06Hz
Frequency corresponding with peak value in Fig. 5
f2=41.99Hz
Then turbulent liquid film wave frequency is：
F=(f1+f2)/2=40.53Hz
Cross-correlation analysis is carried out using the program write as output signal using signal x (t) as input signal, y (t),
It is Fig. 6 to obtain cross-correlation function figure；
τ values corresponding with peak value are time shifting τ in Fig. 60,
τ0=13.8ms
Then turbulent liquid film velocity of wave is：
V=L/ τ0=0.1/0.0138=7.2m/s.
Claims (5)
1. turbulent liquid film wave frequency and the system of velocity of wave in a kind of measurement pipe, it is characterised in that fluctuation liquid in a kind of described measurement pipe
Film wave frequency and the system of velocity of wave include：Infrarede emitting diode (1), infrared photodiode (3), signal amplifier (4), A/D
Converter (5), computer (6), wire and data wire；
Described infrarede emitting diode (1) forms a pair of optical sensors with infrared photodiode (3), is flowed according to liquid
Direction, it is referred to as upstream sensor and downstream sensor；
Two described infrarede emitting diodes (1) are arranged on the same side of test section pipe outer wall, separation L；
Two described infrared photodiodes (3) are arranged on the pipe test section outer wall symmetrical with infrarede emitting diode (1)
Place, receive the light that infrarede emitting diode (1) is sent and the strength signal of the light received is transformed into current signal；
Described signal amplifier (4) is connected by wire with infrared photodiode (3), and infrared photodiode (3) is produced
Raw weak current electric signal amplification；
Described A/D converter (5) is connected with signal amplifier (4) by data wire, by the continuous signal of amplification be changed into from
Scattered data signal；
Described computer (6) is connected with A/D converter (5) by data wire, using MATLAB software programming programs to numeral
Signal is handled, and draws turbulent liquid film wave frequency and velocity of wave.
2. turbulent liquid film wave frequency and the system of velocity of wave in a kind of measurement pipe according to claim 1, it is characterised in that described
The mounting distance L scopes of two optical sensors be 9~11cm.
3. turbulent liquid film wave frequency and the system of velocity of wave in a kind of measurement pipe according to claim 1, it is characterised in that described
Infrared ray of the wavelength of light that sends of infrarede emitting diode (1) between 935~945nm.
4. turbulent liquid film wave frequency and the system of velocity of wave in a kind of measurement pipe according to claim 1, it is characterised in that described
The light intensity that sends of infrarede emitting diode (1) can be adjusted according to turbulent liquid film thickness in pipe.
5. turbulent liquid film wave frequency and the system of velocity of wave in a kind of measurement pipe according to claim 1, it is characterised in that described
Infrared photodiode (3) receive light for wavelength it is identical with infrarede emitting diode (1) between 935~945nm
Infrared ray.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710647411.3A CN107421713B (en) | 2017-08-01 | 2017-08-01 | System for measuring wave frequency and wave speed of wave liquid film in pipe |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710647411.3A CN107421713B (en) | 2017-08-01 | 2017-08-01 | System for measuring wave frequency and wave speed of wave liquid film in pipe |
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| CN107421713A true CN107421713A (en) | 2017-12-01 |
| CN107421713B CN107421713B (en) | 2020-02-18 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH074943A (en) * | 1993-06-14 | 1995-01-10 | Ulvac Japan Ltd | Film-formation monitoring and control apparatus |
| US20020129904A1 (en) * | 2001-03-19 | 2002-09-19 | Hitachi, Ltd. | Plasma treatment apparatus and method of producing semiconductor device using the apparatus |
| CN105701842A (en) * | 2016-01-08 | 2016-06-22 | 天津大学 | Liquid film fluctuation speed measurement method based on chain code contour features |
| CN107314738A (en) * | 2017-06-13 | 2017-11-03 | 中国科学院力学研究所 | The thick measurement experiment system of hypersonic overflow liquid film cooling film and data processing method |
-
2017
- 2017-08-01 CN CN201710647411.3A patent/CN107421713B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH074943A (en) * | 1993-06-14 | 1995-01-10 | Ulvac Japan Ltd | Film-formation monitoring and control apparatus |
| US20020129904A1 (en) * | 2001-03-19 | 2002-09-19 | Hitachi, Ltd. | Plasma treatment apparatus and method of producing semiconductor device using the apparatus |
| CN105701842A (en) * | 2016-01-08 | 2016-06-22 | 天津大学 | Liquid film fluctuation speed measurement method based on chain code contour features |
| CN107314738A (en) * | 2017-06-13 | 2017-11-03 | 中国科学院力学研究所 | The thick measurement experiment system of hypersonic overflow liquid film cooling film and data processing method |
Non-Patent Citations (1)
| Title |
|---|
| E. T. HURLBURT 等: "Optical measurement of liquid film thickness and wave velocity in liquid film flows"", 《EXPERIMENTS IN FLUIDS》 * |
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