CN102735587A - Jet flow density measurement device and method - Google Patents
Jet flow density measurement device and method Download PDFInfo
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- CN102735587A CN102735587A CN2012102343651A CN201210234365A CN102735587A CN 102735587 A CN102735587 A CN 102735587A CN 2012102343651 A CN2012102343651 A CN 2012102343651A CN 201210234365 A CN201210234365 A CN 201210234365A CN 102735587 A CN102735587 A CN 102735587A
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Abstract
The invention discloses a jet flow density measurement device and method. The jet flow density measurement device comprises a flow inlet, an inlet joint, a cover board, a jet flow oscillation element, a dynamic differential pressure high-pressure taking pipe, a jet flow nozzle, a jet flow attachment wall, a jet flow feedback loop, a dynamic differential pressure low-pressure taking pipe, an outlet joint and a flow outlet, wherein the plane where the jet flow oscillation element is positioned is perpendicular to the flow inlet and the flow outlet; a dynamic differential pressure sensor is used for measuring dynamic differential pressure between the two pressure taking pipes; and the dynamic differential pressure is input into a secondary instrument for density metering. According to the jet flow density measurement device and the jet flow density measurement method, when fluid enters the jet flow oscillation element through the inlet, a cavity is induced to oscillate due to a coanda effect and a feedback loop of the fluid; the differential pressure measured by the dynamic differential pressure sensor is pulse differential pressure of oscillation; the oscillation frequency of the differential pressure is in direct proportion to the working condition flow speed of the jet flow nozzle, and an average value of the differential pressure is in direct proportion to a dynamic pressure head of the fluid at the jet flow nozzle, so that a ratio of the dynamic pressure head to the square of the flow speed is in direct proportion to the density of a medium. The device and the method have the advantages that the density of the flow medium with low Reynolds number can be measured.
Description
Technical field
The present invention relates to a kind of densitometer, particularly relate to the close measurement mechanism of jet and the method for a kind of gas that can be applicable to flow or liquid density measurement, belong to the fluid measurement technical field.
Background technology
Densitometer is widely used in oil, rock gas measurement and industries such as chemical industry and printing; Present existing density is in respect of coriolis flow densitometer, gradiomanometer tool, radiodensity meter, oscillating tube densitometer etc.; The densitometric precision of coriolis flow is higher but cost an arm and a leg, and the medium cleanliness are had relatively high expectations; What gradiomanometer tool was more is applied in the oil density measurement, can be used for liquid measure and but can't carry out manoscopy; Radiodensity is measured because have radioactive source, has certain potential safety hazard; The oscillating tube densitometer needs the self-excitation Karman vortex street vibration of cylinder, and the Karman vortex street vibration has the Reynolds number lower limit, promptly works as flow velocity to be lower than after certain Reynolds number, can not produce Karman vortex street, and then density also can't be measured.
Summary of the invention
Technical matters to be solved by this invention is to overcome the deficiency of existing density measuring method, and a kind of low reynolds number pipe stream jet density measuring method and measurement mechanism are provided.
A kind of jet density measuring equipment is characterized in that: comprise cover plate and fluidic oscillation element; Above-mentioned fluidic oscillation element comprises entrance channel, jet nozzle, intermediate flow channel, outlet flow from front to back successively, wherein also has two-way jet backfeed loop between jet exit and the jet nozzle; Above-mentioned intermediate flow channel is the flaring form from front to back; Above-mentioned cover plate is installed on fluidic oscillation element top, is equipped with on the cover plate and above-mentioned entrance channel inlet communicating joint and the outlet connection that communicates with above-mentioned outlet flow; Inlet attack and outlet connection are used to be connected the medium pipeline of required measurement; Above-mentioned cover plate also is equipped with dynamic pressure drop sensor high pressure pressure pipe that stretches in the jet nozzle and the dynamic pressure drop sensor low pressure pressure pipe that stretches in the jet exit.
Utilize the jet density measuring method of the said jet density measuring equipment of right, it is characterized in that may further comprise the steps:
Steps A, the medium pipeline of required measurement is connected between inlet attack and the outlet connection; Make jet pass through the fluidic oscillation element, produce oscillating jet;
Step B, utilize dynamic pressure drop sensor high pressure pressure pipe and dynamic pressure drop sensor low pressure pressure pipe, measure the jet nozzle of fluidic oscillation element and the pressure reduction of jet exit;
Step C, according to the density of computes jet:
ρ?=K*(DP/f
2) ，
In the formula, ρ representes the density of jet; DP representes the jet nozzle of fluidic oscillation element, the pressure reduction mean value of jet exit; F representes the oscillation frequency of jet; K is a scale-up factor, and for specific fluidic oscillation element, it is a definite value, demarcates in advance according to experiment to obtain; The oscillation frequency f of said jet obtains through following method: differential pressure pick-up numerical value over time under the dynamically recording, and use Fast Fourier Transform (FFT) and change into frequency-region signal to time-domain signal, obtain oscillation frequency.
The oscillation frequency of said jet obtains through following method: differential pressure pick-up numerical value over time under the dynamically recording; Use Fast Fourier Transform (FFT) and change into frequency-region signal to time-domain signal; (it is inferior outstanding to shake with reference to what, theory of digital signal processing and application, Beijing: People's Telecon Publishing House to obtain oscillation frequency; Beijing, 1983).The jet nozzle that utilization has measured and the pressure reduction of jet exit through calculating the oscillation frequency of jet, need not be provided with independent oscillation frequency measurement component, simplify the structure, and have reduced cost.
The jet densitometer that the present invention relates to can reduce the lower limit of measuring Reynolds number greatly, and is simple in structure, with low cost.Flow through the fluidic oscillation element (with reference to Cai Wuchang by fluid media (medium); Should open the knock gently work, novel flow instrumentation, Beijing: Chemical Industry Press; Beijing; 2006), between jet inlet and outlet, form the differential pressure signal of vibration, through gathering the density measure that one road dynamic pressure drop signal promptly can carry out flow media.Compare prior art, the present invention can realize that the fluid density of liquids and gases measures, and the measurement scale COEFFICIENT K of liquids and gases is consistent, and of the present invention to survey the Reynolds number lower limit lower, and measurement mechanism is simple in structure, and cost is lower.
Description of drawings
Fig. 1 is a structural representation of the present invention; Fig. 2 is the vertical view of fluidic oscillation element 4.
The implication of each label is following: 1 mobile inlet, 2 inlet attacks, 3 cover plates, 4 fluidic oscillation elements, 5 dynamic pressure drop high pressure pressure pipes, 6 jet nozzles, 7 jets attach wall, 8 jet backfeed loops, 9 dynamic pressure drop low pressure pressure pipes, 10 outlet connections, 11 mobile outlets, 12 entrance channels, 13 intermediate flow channel, 14 outlet flow, 15 jet exits.
Embodiment
Below in conjunction with accompanying drawing technical scheme of the present invention is elaborated:
An embodiment of jet density measuring equipment of the present invention is as shown in Figure 1; It comprises: the inlet 1 that flows, inlet attack 2, cover plate 3, fluidic oscillation element 4, dynamic pressure drop high pressure pressure pipe 5, jet nozzle 6, jet attach wall 7, jet backfeed loop 8, dynamic pressure drop low pressure pressure pipe 9, outlet connection 10, outlet 11, entrance channel 12, intermediate flow channel 13, outlet flow 14 flow; Jet exit 15; Wherein fluidic oscillation element 4 comprises that jet nozzle 6, jet attach wall 7, jet backfeed loop 8, dynamic pressure drop low pressure pressure pipe 9, outlet connection 10, flow outlet 11, entrance channel 12, intermediate flow channel 13, outlet flow 14, jet exit 15.The port of inlet attack 2 is the inlet 1 that flows; The fluid line that can connect required measurement through flexible pipe; The lower end of inlet attack 2 and cover plate 3 are connected through screw threads for fastening; The lower end of outlet connection 10 also is connected with cover plate 3 screw threads for fastening, and the upper end of outlet connection 10 is the outlet of flowing, can be through the be linked back medium pipeline of required measurement of flexible pipe; Cover plate 3 covers on fluidic oscillation element 4 and through bolt and is connected with it; Jet nozzle 6 places of fluidic oscillation element 4 are provided with dynamic pressure drop high pressure pressure pipe 5, and jet exit 15 places of fluidic oscillation element 4 are provided with dynamic pressure drop low pressure pressure pipe 9.
When carrying out density measure; Above-mentioned measurement mechanism is connected with the flow line of treating fluid measured through inlet attack 2 usefulness flexible pipes; Fluid gets into fluidic oscillation element 4 from the inlet 1 that flows; Because the main body jet deflected jet that Coanda effect is come out jet nozzle 6 attaches one side of wall 7, power stream flows out through the jet exit 15 of fluidic oscillation element 4, and the sub-fraction jet is back to jet nozzle 6 places through the jet backfeed loop 8 of homonymy; Promote power stream and be partial to the wall that attaches of an other side, the sub-fraction jet is again through jet backfeed loop to jet nozzle 6 places of an other side; So constantly circulation forms cavity oscillation.Adopt the dynamic differential pressure sensor that the differential pressure between high pressure pressure pipe 5, the low pressure pressure pipe 9 is measured in real time, and measurement data is exported the density of jet according to computes and demonstration:
ρ?=K*(DP/f
2) ，
In the formula, ρ representes the density of jet; DP representes the mean value of the pressure reduction of differential pressure pickup output; F representes the oscillation frequency of jet; Obtain through following method: differential pressure pick-up numerical value over time under the dynamically recording, use Fast Fourier Transform (FFT) and change into frequency-region signal to time-domain signal, obtain oscillation frequency (with reference to what inferior work that shakes; Theory of digital signal processing and application; Beijing: People's Telecon Publishing House, Beijing, 1983); K is a scale-up factor, and for specific fluidic oscillation element, it is a definite value, demarcates in advance according to experiment to obtain.
For making the public be convenient to understand technical scheme of the present invention, be elaborated in the face of measuring principle of the present invention down:
The warp theory is studied and experiment showed, that the frequency f of the cavity oscillation of being lured into by the Coanda effect and the backfeed loop of jet is directly proportional with the flow velocity v at jet nozzle place, and formula is following:
v?=?k
1*?f (1)
Wherein, k
1Be scale-up factor; Oscillation frequency f can adopt existing through near feedback channel or gateway, being provided with detecting elements such as temperature-sensitive, power are quick, optical fiber, detect the method that obtains the fluidic oscillation frequency to obtain, and the present invention is for simplified structure; The method that utilization is done Fast Fourier Transform (FFT) to the dynamic pressure drop signal obtains; Be specially under the dynamically recording differential pressure pick-up numerical value over time, use Fast Fourier Transform (FFT) and change into frequency-region signal to time-domain signal, obtain oscillation frequency (with reference to what inferior work that shakes; Theory of digital signal processing and application; Beijing: People's Telecon Publishing House, Beijing, 1983).
And the dynamic head ρ v at the mean value DP of dynamic pressure drop signal and jet nozzle place
2Be directly proportional, formula is following:
ρv
2=k
2*DP (2)
Wherein, k
2Be scale-up factor; ρ is a fluid density;
Can obtain formula (3) as follows by formula (1) and formula (2):
ρ=(k
2/k
1 2)*(DP/f
2) (3)
The density of fluid is ρ, makes k
2/ k
1Value be K, formula (4) is then arranged:
ρ=K*(DP/f
2) (4)
For specific fluidic oscillation element, scale-up factor K is a definite value, can demarcate in advance according to experiment to obtain.
Claims (2)
1. jet density measuring equipment is characterized in that:
Comprise cover plate (3) and fluidic oscillation element (4);
Above-mentioned fluidic oscillation element (4) comprises entrance channel (12), jet nozzle (6), intermediate flow channel (13), outlet flow (14) from front to back successively, wherein also has two-way jet backfeed loop (8) between jet exit (15) and the jet nozzle (6); Above-mentioned intermediate flow channel (13) is the flaring form from front to back;
Above-mentioned cover plate (3) is installed on fluidic oscillation element (4) top, is equipped with on the cover plate (3) and above-mentioned entrance channel (12) inlet communicating joint (2) and the outlet connection (10) that communicates with above-mentioned outlet flow (14); Inlet attack (2) and outlet connection (10) are used to be connected the medium pipeline of required measurement;
Above-mentioned cover plate (3) also is equipped with and stretches into the dynamic pressure drop sensor high pressure pressure pipe (5) in the jet nozzle (6) and stretch into the dynamic pressure drop sensor low pressure pressure pipe (9) in the jet exit (15).
2. utilize the jet density measuring method of the said jet density measuring equipment of claim 1, it is characterized in that may further comprise the steps:
Steps A, the medium pipeline of required measurement is connected between inlet attack (2) and the outlet connection (10); Make jet pass through fluidic oscillation element (4), produce oscillating jet;
Step B, utilize dynamic pressure drop sensor high pressure pressure end (5) and dynamic pressure drop sensor low pressure pressure pipe (9), measure the jet nozzle (6) of fluidic oscillation element (4) and the pressure reduction of jet exit (15);
Step C, according to the density of computes jet:
ρ?=K*(DP/f
2) ，
In the formula, ρ representes the density of jet; DP representes the jet nozzle of fluidic oscillation element, the pressure reduction mean value of jet exit; F representes the oscillation frequency of jet; K is a scale-up factor, and for specific fluidic oscillation element, it is a definite value, demarcates in advance according to experiment to obtain;
The oscillation frequency f of said jet obtains through following method: differential pressure pick-up numerical value over time under the dynamically recording, and use Fast Fourier Transform (FFT) and change into frequency-region signal to time-domain signal, obtain oscillation frequency.
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|---|---|---|---|
| CN2012102343651A CN102735587A (en) | 2012-07-09 | 2012-07-09 | Jet flow density measurement device and method |
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|---|---|---|---|
| CN2012102343651A CN102735587A (en) | 2012-07-09 | 2012-07-09 | Jet flow density measurement device and method |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105403730A (en) * | 2015-11-13 | 2016-03-16 | 武汉大学 | Fluid instantaneous flow velocity measure apparatus and method based on Helmholtz instability |
| CN110268257A (en) * | 2016-12-20 | 2019-09-20 | 恩德斯+豪斯流量技术股份有限公司 | Gas analyzer and gas analyzing apparatus |
| CN110440410A (en) * | 2019-08-08 | 2019-11-12 | 珠海格力电器股份有限公司 | The guard method of Water cooled air conditioners unit and Water cooled air conditioners unit |
| CN113933211A (en) * | 2021-10-14 | 2022-01-14 | 国网安徽省电力有限公司电力科学研究院 | Ternary mixed gas mixing ratio measuring method and device based on gas substitution method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1673689A (en) * | 2005-04-22 | 2005-09-28 | 浙江大学 | Pipe wall differential pressure type vortex frequency detecting method and apparatus for vortex street flowmeter |
| CN201740553U (en) * | 2010-08-06 | 2011-02-09 | 北京博思达新世纪测控技术有限公司 | Double-parameter mass flow meter |
| CN102364308A (en) * | 2011-10-17 | 2012-02-29 | 南京航空航天大学 | Method and device for measuring mass flow of jet flow |
-
2012
- 2012-07-09 CN CN2012102343651A patent/CN102735587A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1673689A (en) * | 2005-04-22 | 2005-09-28 | 浙江大学 | Pipe wall differential pressure type vortex frequency detecting method and apparatus for vortex street flowmeter |
| CN201740553U (en) * | 2010-08-06 | 2011-02-09 | 北京博思达新世纪测控技术有限公司 | Double-parameter mass flow meter |
| CN102364308A (en) * | 2011-10-17 | 2012-02-29 | 南京航空航天大学 | Method and device for measuring mass flow of jet flow |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105403730A (en) * | 2015-11-13 | 2016-03-16 | 武汉大学 | Fluid instantaneous flow velocity measure apparatus and method based on Helmholtz instability |
| CN105403730B (en) * | 2015-11-13 | 2018-03-27 | 武汉大学 | Fluid instantaneous velocity measurement apparatus and method based on helmholtz instability |
| CN110268257A (en) * | 2016-12-20 | 2019-09-20 | 恩德斯+豪斯流量技术股份有限公司 | Gas analyzer and gas analyzing apparatus |
| US11112340B2 (en) | 2016-12-20 | 2021-09-07 | Endress+Hauser Flowtec Ag | Gas analyzer and gas analyzing device |
| CN110440410A (en) * | 2019-08-08 | 2019-11-12 | 珠海格力电器股份有限公司 | The guard method of Water cooled air conditioners unit and Water cooled air conditioners unit |
| CN113933211A (en) * | 2021-10-14 | 2022-01-14 | 国网安徽省电力有限公司电力科学研究院 | Ternary mixed gas mixing ratio measuring method and device based on gas substitution method |
| CN113933211B (en) * | 2021-10-14 | 2024-03-15 | 国网安徽省电力有限公司电力科学研究院 | Ternary mixed gas mixing ratio measuring method and device based on gas substitution method |
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Application publication date: 20121017 |