CN109883338A - A kind of oil film thickness measurement method and its device based on TDLAS technology - Google Patents
A kind of oil film thickness measurement method and its device based on TDLAS technology Download PDFInfo
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- CN109883338A CN109883338A CN201910194770.7A CN201910194770A CN109883338A CN 109883338 A CN109883338 A CN 109883338A CN 201910194770 A CN201910194770 A CN 201910194770A CN 109883338 A CN109883338 A CN 109883338A
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Abstract
The invention belongs to laser testing fields, and in particular to a kind of oil film thickness measurement method and its device based on TDLAS technology, comprising the following steps: selection wave number is v1And v2Two beam laser, their Infrared spectra adsorption section σ is measured by Fourier Transform Infrared Spectrometer1And σ2；It enables two beam laser be each passed through same oil film, obtains respective transmissivity β1And β2；Utilize β1And β2Ratio eliminate other light intensity and decline influence caused by u；The thickness d of oil film is obtained, the present invention is provided with different optical paths, can obtain initial beam intensity signal while measuring oil film transmitted light intensity signal, is not necessarily to fit procedure, guarantees to improve measurement accuracy while real-time；Laser does not change the distribution of oil film when passing through lubricating oil film, to detect without wound, reduce measurement error.
Description
Technical field
The invention belongs to laser testing fields, and in particular to a kind of oil film thickness measurement side based on TDLAS technology
Method and its device.
Background technique
In modern industry, all there is friction between any two contact surface, friction will cause abrasion and reduce device
Operating accuracy even will cause machine breakdown when serious, in order to reduce abrasion and fever, extend the service life of machine, it is necessary to
Lubricant is added between two contact surfaces, reduces abrasion.Fluid lubrication is the most common lubricating system, micro- by one layer 1.5~2
Meter or more lubricating oil film two friction surfaces are completely separable, friction be produced from lubrication oil molecule between interior friction, effectively drop
Low abrasion improves working performance.Fluid lubrication is widely used in various fields, gear, bearing, and the mechanical parts such as piston are normal
The lubricating oil of micron order thickness is added, separated contact surfaces make component smooth motion.Lubrication failure is that machine run breaks down
One of the main reasons, therefore the greasy property for detecting mechanical equipment has important meaning, the thickness of lubricating oil film is that judgement is mechanical
The important parameter of equipment lubrication performance.With industrial progress and Technological research, equipment is constantly to high power development, to lubricating system
Requirement it is also higher and higher, if piston does linear reciprocating motion in cylinder in boat diesel engine, generated between casing wall violent
Friction, lubricating difficulties.Internal cylinder temperature pressure is very high in real work engineering, and operating condition is severe, and load impacting is strong, holds
It is thinning to easily lead to lubricating oil film, oil film is excessively thin to be will lead to piston and directly contact with casing wall, is worn and is generated heat after a period of work
Degree sharply increases, and diesel engine is caused to damage；And when oil film is blocked up, and the bearing capacity of equipment can be reduced, prevent it from steady
Fixed work, will cause oil leak and violent energy loss when serious.To sum up, the oil film thickness between two rubbing surfaces is measured to monitoring
State of runtime machine, improving machine performance has important meaning, and many scholars conduct in-depth research oil film thickness measurement,
Measurement method common at present has resistance method of temperature measurement, capacitance measurement and optical measuring method.
Resistance method of temperature measurement and capacitance measurement belong to measurement method of electricity, need an electrical isolation plane or a complete electricity
The osculating element of isolation installs sensor, increases the complexity of structure, and measurement result is vulnerable to such environmental effects, therefore
It is difficult to be widely used in industrial circle.Optical measuring method has measurement accuracy high, and measuring device is easily built, and dynamic response is good
Well, it the advantages that non-cpntact measurement, in aviation, is widely applied in the national defences such as space flight and ship.For optical measurement
Method, domestic and foreign scholars conduct extensive research.
Nineteen sixty, Sibley et al. successfully measure film thickness using X-ray transmission property, have obtained fairly accurate
Measurement result, but this method is very high to the position accuracy demand of experimental facilities and larger to human injury.1980,
Ting is developed a kind of technology and come to piston ring lubrication process whereby using being equipped with the single-cylinder engine of a transparent cylinder
Visual research is carried out with engine oil loss mechanism.1998, Arcoumanis, Duszynski and Benoist et al. were used
Laser Induced Fluorescence Technology measures oil film thickness between piston ring and cylinder sleeve.
TDLAS mensuration is a kind of emerging optical measuring method, it is a kind of tunable laser absorption spectroscopy, closely
The great attention of scholars is obtained year a bit.Monza in 2000 measures the water down to the doping methylenum careuleum of 1mm using this technology
Film thickness.H Yang in 2010 et al. develops a kind of novel TDLAS film thickness measurement system, can be thick to liquid film in evaporation process
Degree measures, the liquid film which measures within the scope of 5~1000um thickness error less than 5%.2014 Nian Yanghui nanmus, Guo Xiao
Dragon et al. is measured using the dynamic that TDLAS technology realizes thickness of liquid film in evaporation process in flow channel, and by detector
Existing TDLAS film thickness measurement system is optimized in preceding placement integrating sphere.TDLAS technology has high sensitivity, and dynamic is rung
It answers characteristic good, is the development trend in optical measuring method future the advantages that non-cpntact measurement.
Summary of the invention
The purpose of the present invention is the measurement to oil film thickness is realized using TDLAS technology.
A kind of oil film thickness measurement method based on TDLAS technology, comprising the following steps:
(1) choosing wave number is v1And v2Two beam laser, their infrared light is measured by Fourier Transform Infrared Spectrometer
Compose absorption cross-section σ1And σ2；
(2) it enables two beam laser be each passed through same oil film, obtains respective transmissivity β1And β2；
(3) β is utilized1And β2Ratio eliminate other light intensity and decline influence caused by u；
(4) thickness d of oil film is obtained.
The selection wave number is v1And v2Two beam laser, the infrared of them is measured by Fourier Transform Infrared Spectrometer
Spectral absorption section σ1And σ2, comprising:
After the laser that a branch of wave number is v passes through oil film, the intensity of laser can decay, the transmission of attenuation degree laser
Rate β is indicated are as follows:
Wherein, I0For the initial beam intensity of laser, ItLight intensity after passing through oil film for laser, n is the molar concentration of lubricating oil, d
By survey oil film thickness, u be other factors caused by light intensity attenuation, σ be laser spectrum infrared absorption section.
It is described to utilize β1And β2Ratio eliminate other light intensity and decline influence caused by u, comprising:
Two-beam transmissivity β1And β2Ratio are as follows:
Wherein, n is the molar concentration of lubricating oil, d by survey oil film thickness, σ1It is v for wave number1Laser spectrum it is red
Outer absorption cross-section, σ2It is v for wave number2Laser spectrum infrared absorption section.
The thickness d of the oil film are as follows:
Wherein, σ1It is v for wave number1Laser spectrum infrared absorption section, σ2It is v for wave number2Laser spectrum it is infrared
Absorption cross-section, β1It is v for wave number1Laser transmissivity, β2It is v for wave number2Laser transmissivity.
A kind of oil film thickness measuring device based on TDLAS technology, by laser controller, laser, spectroscope, entirely
Reflecting mirror, rubbing surface, lubricating oil film, optical window, first laser detector, second laser detector, computer system composition,
Lubricating oil film is clipped between two pieces of rubbing surfaces, and there is an optical window at rubbing surface center, computer system respectively with laser controller,
One laser detector, second laser detector link together, and laser controller is connect with laser, and spectroscope is in laser
In optical path, a part of laser injects first laser detector through total reflection mirror, and another part laser injects second through optical window
Laser detector.
The beneficial effects of the present invention are:
(1) it is provided with different optical paths, initial beam intensity signal, nothing can be obtained while measuring oil film transmitted light intensity signal
Fit procedure is needed, guarantees to improve measurement accuracy while real-time；
(2) do not change the distribution of oil film when laser passes through lubricating oil film, to detect without wound, reduce measurement error.
Detailed description of the invention
Fig. 1 is the oil film thickness instrumentation plan based on TDLAS technology；
Fig. 2 is program flow diagram of the invention；
Specific embodiment
The present invention is described further with reference to the accompanying drawing.
1- laser controller, 2- laser, 3- spectroscope, 4- total reflection mirror, 5- rubbing surface, 6- lubricating oil film, 7- optics
Window, 8- first laser detector, 9- second laser detector, 10- computer system；
In modern industry, all there is friction between any two contact surface, friction will cause abrasion and reduce device
Operating accuracy even will cause machine breakdown when serious, in order to reduce abrasion and fever, extend the service life of machine, it is necessary to
Lubricant is added between two contact surfaces, reduces abrasion.Fluid lubrication is the most common lubricating system, micro- by one layer 1.5~2
Meter or more lubricating oil film two friction surfaces are completely separable, friction be produced from lubrication oil molecule between interior friction, effectively drop
Low abrasion improves working performance.Fluid lubrication is widely used in various fields, gear, bearing, and the mechanical parts such as piston are normal
The lubricating oil of micron order thickness is added, separated contact surfaces make component smooth motion.Lubrication failure is that machine run breaks down
One of the main reasons, therefore the greasy property for detecting mechanical equipment has important meaning, the thickness of lubricating oil film is that judgement is mechanical
The important parameter of equipment lubrication performance.With industrial progress and Technological research, equipment is constantly to high power development, to lubricating system
Requirement it is also higher and higher, if piston does linear reciprocating motion in cylinder in boat diesel engine, generated between casing wall violent
Friction, lubricating difficulties.Internal cylinder temperature pressure is very high in real work engineering, and operating condition is severe, and load impacting is strong, holds
It is thinning to easily lead to lubricating oil film, oil film is excessively thin to be will lead to piston and directly contact with casing wall, is worn and is generated heat after a period of work
Degree sharply increases, and diesel engine is caused to damage；And when oil film is blocked up, and the bearing capacity of equipment can be reduced, prevent it from steady
Fixed work, will cause oil leak and violent energy loss when serious.To sum up, the oil film thickness between two rubbing surfaces is measured to monitoring
State of runtime machine, improving machine performance has important meaning, and many scholars conduct in-depth research oil film thickness measurement,
Measurement method common at present has resistance method of temperature measurement, capacitance measurement and optical measuring method.
Resistance method of temperature measurement and capacitance measurement belong to measurement method of electricity, need an electrical isolation plane or a complete electricity
The osculating element of isolation installs sensor, increases the complexity of structure, and measurement result is vulnerable to such environmental effects, therefore
It is difficult to be widely used in industrial circle.Optical measuring method has measurement accuracy high, and measuring device is easily built, and dynamic response is good
Well, it the advantages that non-cpntact measurement, in aviation, is widely applied in the national defences such as space flight and ship.For optical measurement
Method, domestic and foreign scholars conduct extensive research.
Nineteen sixty, Sibley et al. successfully measure film thickness using X-ray transmission property, have obtained fairly accurate
Measurement result, but this method is very high to the position accuracy demand of experimental facilities and larger to human injury.1980,
Ting is developed a kind of technology and come to piston ring lubrication process whereby using being equipped with the single-cylinder engine of a transparent cylinder
Visual research is carried out with engine oil loss mechanism.1998, Arcoumanis, Duszynski and Benoist et al. were used
Laser Induced Fluorescence Technology measures oil film thickness between piston ring and cylinder sleeve.
TDLAS mensuration is a kind of emerging optical measuring method, it is a kind of tunable laser absorption spectroscopy, closely
The great attention of scholars is obtained year a bit.Monza in 2000 measures the water down to the doping methylenum careuleum of 1mm using this technology
Film thickness.H Yang in 2010 et al. develops a kind of novel TDLAS film thickness measurement system, can be thick to liquid film in evaporation process
Degree measures, the liquid film which measures within the scope of 5~1000um thickness error less than 5%.2014 Nian Yanghui nanmus, Guo Xiao
Dragon et al. is measured using the dynamic that TDLAS technology realizes thickness of liquid film in evaporation process in flow channel, and by detector
Existing TDLAS film thickness measurement system is optimized in preceding placement integrating sphere.TDLAS technology has high sensitivity, and dynamic is rung
It answers characteristic good, is the development trend in optical measuring method future the advantages that non-cpntact measurement.
The purpose of the present invention is the measurement to oil film thickness is realized using TDLAS technology.
The object of the present invention is achieved like this: according to Beer Lambert law, the laser that a branch of wave number is v passes through oil
After film, the intensity of laser can decay, and attenuation degree can be indicated by the transmissivity β of laser:
In formula: I0For the initial beam intensity of laser, ItLight intensity after passing through oil film for laser, n is the molar concentration of lubricating oil, d
By survey oil film thickness, u be other factors caused by light intensity attenuation, σ be laser spectrum infrared absorption section.
Selection wave number is v1And v2Two beam laser, their infrared spectroscopy is measured by Fourier Transform Infrared Spectrometer
Absorption cross-section σ1And σ2.It enables two beam laser be each passed through same oil film, obtains respective transmissivity β1And β2, utilize β1And β2Ratio
Value can eliminate other light intensity and decline influence caused by u, transmissivity ratio are as follows:
By transformation, the expression formula of oil film thickness d is obtained:
The molar concentration of lubricating oil is substituted into expression formula, the measurement to oil film thickness can be completed.
The invention also includes features some in this way: laser used is tunable laser, changes the electricity for being added in its both ends
The wave number of the i.e. changeable output laser of pressure.Measurement method is non-contact measurement, is not had any impact to lubricating oil film, is guaranteed
The accuracy of thickness measurement.Initial beam intensity I0It is directly detected and is obtained by laser detector, without to transmitted light intensity ItIt carries out
Fitting avoids the error caused by being fitted.If rubbing surface is opaque first to carry out visualization transformation at tested place, optics is installed
Window allows tested place to pass through laser.
As shown in Figure 1, laser controller control laser issues laser, spectroscope is different for being arranged from total reflection mirror
Optical path.2 intermediate distribution of rubbing surface 1 and rubbing surface certain thickness lubricating oil film, formed " rubbing surface-oil film-rubbing surface " knot
Structure.Optical window is used for propagated laser, and laser detector 1 and laser detector 2 are used to detect the light intensity of laser.Computer system
For adjusting laser controller, the output of signal processing and measurement result.
In the use of the present invention, adjusting laser controller by computer system, laser is made first to issue wave number v1Swash
Light, one half reflection when laser passes through spectroscope, a half transmitting, respectively along different paths, the part of reflection is by being all-trans
After penetrating mirror reflection, for direct irradiation on laser detector 1, the part of transmission passes through lubricating oil film by optical window, is radiated at
On laser detector 2, the signal that laser detector 1 detects is initial beam intensity I01, the signal that laser detector 2 detects is
Penetrate light intensity It1.Computer system receives I01Signal and It1After signal, laser controller is adjusted immediately, and laser is made to issue wave
Number is v2Laser, and obtain initial beam intensity signal I02With transmitted light intensity signal It2.Computer system is to I01, It1, I02, It2Into
Row processing, obtaining wave number is v1, v2The respective transmissivity β of laser1, β2, after formula (3) calculate, final output oil film thickness
Measurement result.
A kind of oil film thickness measurement method based on TDLAS technology, including laser controller 1, laser 2, light splitting
Mirror 3, total reflection mirror 4, rubbing surface 5, lubricating oil film 6, optical window 7, laser detector 18, laser detector 29, computer
The structures such as system 10 realize the measurement to oil film thickness using TDLAS technology.
The wave number of laser output laser is controlled by the voltage for being added in laser both ends.
Laser does not change the distribution of oil film when passing through lubricating oil film, to detect without wound, reduce measurement error.
Provided with different optical paths, initial beam intensity signal can be obtained while measuring oil film transmitted light intensity signal, is not necessarily to
Fit procedure guarantees to improve measurement accuracy while real-time.
Guarantee that laser can pass through at tested place, if material is opaque to be transformed, arranges optical window.
Claims (5)
1. a kind of oil film thickness measurement method based on TDLAS technology, which comprises the following steps:
(1) choosing wave number is v1And v2Two beam laser, by Fourier Transform Infrared Spectrometer measure they infrared spectroscopy inhale
Receive section σ1And σ2；
(2) it enables two beam laser be each passed through same oil film, obtains respective transmissivity β1And β2；
(3) β is utilized1And β2Ratio eliminate other light intensity and decline influence caused by u；
(4) thickness d of oil film is obtained.
2. a kind of oil film thickness measurement method based on TDLAS technology according to claim 1, which is characterized in that
The selection wave number is v1And v2Two beam laser, their Infrared spectra adsorption is measured by Fourier Transform Infrared Spectrometer
Section σ1And σ2, comprising:
After the laser that a branch of wave number is v passes through oil film, the intensity of laser can decay, the transmissivity β of attenuation degree laser
It indicates are as follows:
Wherein, I0For the initial beam intensity of laser, ItLight intensity after passing through oil film for laser, n is the molar concentration of lubricating oil, and d is institute
The thickness of oil film is surveyed, u is light intensity attenuation caused by other factors, and σ is the spectrum infrared absorption section of laser.
3. a kind of oil film thickness measurement method based on TDLAS technology according to claim 1, which is characterized in that
It is described to utilize β1And β2Ratio eliminate other light intensity and decline influence caused by u, comprising:
Two-beam transmissivity β1And β2Ratio are as follows:
Wherein, n is the molar concentration of lubricating oil, d by survey oil film thickness, σ1It is v for wave number1Laser the infrared suction of spectrum
Receive section, σ2It is v for wave number2Laser spectrum infrared absorption section.
4. a kind of oil film thickness measurement method based on TDLAS technology according to claim 1, which is characterized in that
The thickness d of the oil film are as follows:
Wherein, σ1It is v for wave number1Laser spectrum infrared absorption section, σ2It is v for wave number2Laser spectrum infrared absorption
Section, β1It is v for wave number1Laser transmissivity, β2It is v for wave number2Laser transmissivity.
5. a kind of oil film thickness measuring device based on TDLAS technology, by laser controller (1), laser (2), light splitting
Mirror (3), total reflection mirror (4), rubbing surface (5), lubricating oil film (6), optical window (7), first laser detector (8), second swashs
Optical detector (9), computer system (10) composition, which is characterized in that lubricating oil film (6) is clipped between two pieces of rubbing surfaces (5), is rubbed
Wiping face (5) center has optical window (7), computer system (10) respectively with laser controller (1), first laser detector (8),
Second laser detector (9) links together, and laser controller (1) is connect with laser (2), and spectroscope (3) is in laser (2)
Optical path on, a part of laser through total reflection mirror (4) inject first laser detector (8), another part laser is through optical window
(7) second laser detector (9) are injected.
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Cited By (3)
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| CN110260803A (en) * | 2019-07-04 | 2019-09-20 | 哈尔滨工程大学 | TDLAS technology measures cylinder of internal-combustion engine oil film thickness simulator |
| CN112747682A (en) * | 2020-12-22 | 2021-05-04 | 天津大学 | Liquid film thickness measurement system based on light carries microwave interference |
| CN114935313A (en) * | 2022-04-26 | 2022-08-23 | 香港中文大学（深圳） | Film thickness measuring method, device, equipment and computer program product |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110260803A (en) * | 2019-07-04 | 2019-09-20 | 哈尔滨工程大学 | TDLAS technology measures cylinder of internal-combustion engine oil film thickness simulator |
| CN112747682A (en) * | 2020-12-22 | 2021-05-04 | 天津大学 | Liquid film thickness measurement system based on light carries microwave interference |
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| CN114935313A (en) * | 2022-04-26 | 2022-08-23 | 香港中文大学（深圳） | Film thickness measuring method, device, equipment and computer program product |
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Application publication date: 20190614 |