CN208984180U - Low pressure critical flow venturi nozzle calibrating installation - Google Patents
Low pressure critical flow venturi nozzle calibrating installation Download PDFInfo
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- CN208984180U CN208984180U CN201821856417.8U CN201821856417U CN208984180U CN 208984180 U CN208984180 U CN 208984180U CN 201821856417 U CN201821856417 U CN 201821856417U CN 208984180 U CN208984180 U CN 208984180U
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Abstract
The utility model discloses a kind of low pressure critical flow venturi nozzle calibrating installation comprising: entrance pipeline section, entrance pipeline section one end are directly connected to atmosphere, and the other end of the entrance pipeline section extends for connection to the entrance of header；Include multiple channels between the outlet of the header and the entrance of reversed header, be provided with operated pneumatic valve and standard sonic nozzle in each channel, the standard sonic nozzle in the multiple channel has different larynx diameters；The multiple channel is connected to sonic nozzle to be measured, and the outlet end of the sonic nozzle to be measured is vacuum environment；Control section measures the temperature and pressure of standard sonic nozzle and sonic nozzle to be measured, and the operated pneumatic valve in the multiple channel is connected to the control section.The utility model establishes a set of directly calibrated suitable for ultralow pressure, under the conditions of big flow to sonic nozzle and the low pressure sonic nozzle calibrating installation of magnitude tracing is, it can be achieved that be tested the stagnation pressure of sonic nozzle down to the test condition of 10kPa.
Description
Technical field
The utility model relates to a kind of calibrating installations, more particularly to a kind of low pressure critical flow venturi nozzle calibration cartridge
It sets.
Background technique
Critical flow venturi nozzle (abbreviation sonic nozzle) be throat is tapered to by entrance, and flaring to outlet differential pressure type
Flowmeter, including contraction section, throat and diffuser.Sonic nozzle because its structure is simple, without movable member, accuracy is high, repeats
Property it is good the features such as, both at home and abroad generally using sonic nozzle as Transfer Standards to other types of gas flowmeter carry out magnitude biography
It passs.Meanwhile sonic nozzle can directly magnitude tracing to the simple standard set-up of national gas flow.Therefore, sonic nozzle is in gas
Critical positions are occupied in flowrate measurement value traceability system, are the key that guarantee that the measurement of gas flow is accurate and reliable and the unified ring of magnitude
Section.
Aero-engine is the heart of aviation aircraft, is the important symbol for showing national science and technology, industry and military capability of the country.
Aero-engine requires to survey its thrust performance by test bay in the room of ground in development, production and maintenance process
Examination.The test of motor power performance needs accurate gas flow measurement, and gas flow measurement accurately depends on gas stream
Measure the measurement capability of standard set-up.Aero-engine is usually operated in the ultralow pressure environment in high-altitude, and ultralow pressure, big flow are boats
The typical feature of empty engine gas flow rate metering, range of flow under the conditions of ultralow pressure is about 40~480kg/s, needs benefit
It is realized under the conditions of ultralow pressure with the sonic nozzle of larger size and the directly calibration of the big flow of aero-engine is passed with magnitude
It passs.Traditionally, sonic nozzle calibrates it by the simple standard set-up of gas flow.
The simple standard set-up of gas flow is broadly divided into mass method and volumetric method.Wherein, mass method mainly has mt method；Volume
Method includes pVTt method, bell-jar and piston type etc..Wherein, the operating pressure of the simple standard set-up of mt method is high, and flow is big, at present state
The maximum working pressure (MWP) of the interior simple standard set-up of mt method is 8MPa, and the expanded uncertainty of maximum stream flow 8kg/s, device are
0.1% (k=2)；The accuracy of the simple standard set-up of pVTt method is high, and device gas source can be that (i.e. operating pressure is for high pressure or negative pressure
One atmospheric pressure), the maximum stream flow of the simple standard set-up of state's negative pressure pVTt method is 1300m at present3The extension of/h, device are uncertain
Degree is 0.05% (k=2)；The operating pressure of the simple standard set-up of bell-jar is low and is affected by humidity, and flow is small；Piston type
Simple standard set-up by its volume pipe machining it is horizontal be affected, domestic HPPP (high pressure piston) method is former at present
The maximum working pressure (MWP) of grade standard device is 10MPa, maximum stream flow 480m3/ h, the expanded uncertainty of device are 0.07%
(k=2).
However, these conventional methods are all limited by device itself and space, operating pressure most down to 1 atmospheric pressure,
Measurable flow amount range under high pressure or negative-pressure gas medium is limited, is unable to satisfy sonic nozzle under the conditions of ultralow pressure, big flow
Direct calibration.
To sum up, transmission of quantity value is carried out to the gas flowmeter of aero-engine under the conditions of ultralow pressure, big flow to realize
With trace to the source, need sonic nozzle stable using performance, that accuracy is high as Transfer Standards, and establish and may be implemented in ultralow pressure, big
The calibrating installation of magnitude tracing is carried out under flow condition to sonic nozzle.
Utility model content
The purpose of this utility model be solve sonic nozzle can not directly be calibrated under the conditions of ultralow pressure, big flow and
The problems such as magnitude tracing.
The utility model provides a kind of low pressure critical flow venturi nozzle calibrating installation comprising:
Entrance pipeline section, entrance pipeline section one end are directly connected to atmosphere, and the other end of the entrance pipeline section extends connection
To the entrance of header；
Include multiple channels between the outlet of the header and the entrance of reversed header, is provided in each channel pneumatic
Valve and standard sonic nozzle, the standard sonic nozzle in the multiple channel have different larynx diameters；
The multiple channel is connected to sonic nozzle to be measured, and the outlet end of the sonic nozzle to be measured is vacuum environment；
Control section measures the temperature and pressure of standard sonic nozzle and sonic nozzle to be measured, the multiple channel
In operated pneumatic valve be connected to the control section.
Wherein, be provided on the pipeline development length of the entrance pipeline section standard sonic nozzle stagnation temperature temperature taking mouth and
Standard sonic nozzle stagnation pressure pressure tappings.
Wherein, the first temperature measuring instrument obtains corresponding position by the standard sonic nozzle stagnation temperature temperature taking mouth
Temperature data；First pressure measuring instrumentss obtain the number pressure of corresponding position by standard sonic nozzle stagnation pressure pressure tappings
According to.
Wherein, tested sound is provided on the pipeline between the outlet of the reversed header and the entrance of tested sonic nozzle
Fast nozzle stagnation temperature temperature taking mouth and tested sonic nozzle stagnation pressure pressure tappings.
Wherein, second temperature measuring instrumentss obtain corresponding position by the tested sonic nozzle stagnation temperature temperature taking mouth
Temperature data；Second pressure measuring instrumentss obtain the pressure of corresponding position by the tested sonic nozzle stagnation pressure pressure tappings
Data.
The utility model provides a kind of calibration method using above-mentioned calibrating installation, the steps include:
Start vacuum pump, forms vacuum environment in the outlet end of the sonic nozzle to be measured；
The operated pneumatic valve in corresponding channel is controlled, the standard sonic nozzle and tested sonic nozzle string of predetermined larynx diameter are selected
Connection；
The temperature data of the temperature taking mouth of corresponding standard sonic nozzle and sonic nozzle to be measured is acquired, corresponding standard velocity of sound is acquired
The pressure data of the pressure tappings of nozzle and sonic nozzle to be measured,
Realization calibrates tested sonic nozzle under multiple flow points, obtains tested sonic nozzle in each throat's thunder
Efflux coefficient under promise number.
The utility model establish it is a set of be suitable for ultralow pressure, sonic nozzle is directly calibrated under the conditions of big flow and
The low pressure sonic nozzle calibrating installation of magnitude tracing is, it can be achieved that be tested the stagnation pressure of sonic nozzle down to the test-strips of 10kPa
Part.The device 5 pieces of standard sonic nozzles in parallel are connected with tested sonic nozzle realize to tested sonic nozzle it is multiple compared with
Traffic alignment under low pressure point, so that sonic nozzle can not directly be calibrated under the conditions of ultralow pressure, big flow by realizing
And magnitude tracing.The utility model establishes one kind and may be implemented under the conditions of ultralow pressure, big flow to sonic nozzle progress magnitude
The calibrating installation traced to the source.
Detailed description of the invention
The test philosophy schematic diagram of Fig. 1 low pressure critical flow venturi nozzle calibrating installation；
The structural schematic diagram of Fig. 2 low pressure critical flow venturi nozzle calibrating installation；
Fig. 3 is detected the relation schematic diagram between the efflux coefficient of sonic nozzle and the inverse square root of throat's Reynolds number.
Specific embodiment
The embodiments of the present invention are illustrated with reference to the accompanying drawing for the ease of understanding the utility model, ability
Field technique personnel should be appreciated that following explanations only to facilitate explaining to utility model, and not as to its range
Specific restriction.
Efflux coefficient CdOne of important parameter as sonic nozzle outflow characteristic is that the practical matter of sonic nozzle is flowed through in association
The important parameter of flow and desirable quality flow is measured, and guarantees the crucial ginseng that the measurement of gas flow is accurate and reliable and magnitude is unified
Number.The test philosophy schematic diagram of the standard set-up flows through the mass flow of standard sonic nozzle as shown in Figure 1, based on the conservation of mass
It is equal with by the tested mass flow of sonic nozzle, by the stagnation temperature T of standard sonic nozzle0,m, stagnation pressure P0,mAnd stream
Coefficient C outd,mWait important parameters can be in the hope of by the mass flow q of standard sonic nozzlem,u, i.e., by being detected sonic nozzle
Actual mass flow, and the desirable quality flow q of tested sonic nozzlemi,uIt can be calculated by its corresponding physical parameter,
Therefore, the efflux coefficient calculation formula for being detected sonic nozzle is as follows:
Based on the above principles, the calibrating installation of the utility model is constructed, Fig. 2 is the low pressure critical flow text of the utility model
The structural schematic diagram of nozzle calibration device in mound.The low pressure critical flow venturi nozzle calibrating installation of the utility model includes being used for
The a series of components such as pipeline section, standard sonic nozzle, operated pneumatic valve and the sonic nozzle to be measured of connection, structure as shown in Figure 2
Only to facilitate help understands the design of the utility model, it is not intended as limiting the uniqueness of utility model content, this
Field personnel can be in replacement appropriate and change and mutual connection relationship to its construction package and directly connect
Situations such as touching is also possible to through intermediate member mediate contact, displacement or substitution within the scope of the rational expectation of those skilled in the art
Or it omits and should all fall within the scope of the utility model.
As shown in Fig. 2, entrance pipeline section 1, described 1 one end of entrance pipeline section is directly connected to atmosphere, the entrance pipeline section 1 it is another
One end extends for connection to header 4, and standard sonic nozzle stagnation is disposed on the pipeline development length of the entrance pipeline section 1
Temperature temperature taking mouth 2 and standard sonic nozzle stagnation pressure pressure tappings 3, the first temperature measuring instrument passes through the standard sonic nozzle
The temperature data of the acquisition corresponding position of stagnation temperature temperature taking mouth 2；First pressure measuring instrumentss pass through standard sonic nozzle stagnation pressure
The pressure data of the acquisition corresponding position of power pressure tappings 3.
The header 4 is single entry multiple exit mode, and the preferably described header includes 1 entrance and 5 outlets, such as Fig. 1 institute
The header 4 shown includes first entrance and first outlet, second outlet, third outlet, the 4th outlet and the 5th outlet.It is described
First outlet, second outlet, third outlet, the 4th outlet and the 5th outlet are connected to operated pneumatic valve 5, Mei Geqi by pipeline
Movable valve 5 corresponds to one outlet, and each operated pneumatic valve 5 is correspondingly connected with the arrival end to a standard sonic nozzle 6.
There is the case where 5 outlets, the first outlet, second outlet, third outlet, the 4th outlet corresponding to header 4
The standard sonic nozzle 6, the outlet of the standard sonic nozzle 6 have been correspondingly connected with each outlet in the 5th outlet
End is connected to the entrance of reversed header, and the outlet of multiple reversed headers is reversely pooled to one outlet by pipeline progress,
The outlet of the reversed header is connected to the arrival end of tested sonic nozzle 9.
It is disposed on pipeline between the outlet of the reversed header and the arrival end of tested sonic nozzle tested
Sonic nozzle stagnation temperature temperature taking mouth 7 and tested sonic nozzle stagnation pressure pressure tappings 8, second temperature measuring instrumentss pass through described
Tested sonic nozzle stagnation temperature temperature taking mouth 7 obtains the temperature data of corresponding position；Second pressure measuring instrumentss pass through the quilt
Examine the pressure data that sonic nozzle stagnation pressure pressure tappings 8 obtain corresponding position.The outlet end of the tested sonic nozzle 9 connects
To vacuum pump 10, by the effect of vacuum pump 10 so that the outlet of tested sonic nozzle 9 is in vacuum state.
The standard sonic nozzle stagnation temperature temperature taking mouth 2 and tested 7 position of sonic nozzle stagnation temperature temperature taking mouth
Locate corresponding first temperature measuring instrument and second temperature measuring instrumentss are all connected to temperature data acquisition device 11, the standard pronunciation
First pressure measuring instrumentss and second at fast nozzle stagnation pressure pressure tappings 3 and tested sonic nozzle stagnation pressure pressure tappings 8
Pressure measuring instruments is all connected to digital display pressure acquisition devices 13.The calibrating installation further comprises control section 12, the control
Part 12 processed measures the temperature and pressure of standard sonic nozzle and sonic nozzle to be measured, the measurement by temperature taking mouth and
Pressure tappings realize that the temperature data acquisition device 11 and the digital display pressure acquisition devices 13 are all connected to control section 12, institute
It states control section 12 also to control the opening and closing of the starting valve 5, the vacuum pump 10 and the control section
12 are connected.
Based on the structure of above-mentioned calibrating installation, preferably set gradually in first outlet into the 5th corresponding pipeline in outlet by
The standard sonic nozzle of 5 pieces of different larynx diameters in parallel begins through 12 pneumatic vacuum pump 10 of control section, in the velocity of sound to be measured
The outlet end of nozzle forms vacuum environment；By controlling the operated pneumatic valve 5 in corresponding access, the standard velocity of sound of predetermined larynx diameter is selected
Nozzle is connected with tested sonic nozzle, acquires corresponding standard velocity of sound by the first temperature measuring instrument and second temperature measuring instrumentss
The temperature data of the temperature taking mouth of nozzle and sonic nozzle to be measured, is adopted by first pressure measuring instrumentss and second pressure measuring instrumentss
Collect the pressure data of the pressure tappings of corresponding standard sonic nozzle and sonic nozzle to be measured, realizes in multiple points, 5 or more
Tested sonic nozzle is calibrated under point, obtains tested efflux coefficient of the sonic nozzle under each throat's Reynolds number.5 pieces of marks
The larynx diameter of quasi- sonic nozzle is smaller than the larynx diameter of tested sonic nozzle, and standard sonic nozzle is also made while as standard scale
For throttling element, it can be achieved that the stagnation pressure of tested sonic nozzle is realized down to the test condition of 10kPa to low pressure, big flow
Condition simulation, while can be calibrated again, measurement accuracy and convenience significantly improve.
As a further preference, it is repeated no more with condition as before, whole is cited in this, as further
Variant embodiment, the tube outlet quantity of header 4 can choose for 2,3,4,5,6,7,8, even
More, wherein the export volume of header 4 is corresponding with the entry number of reversed header, in the one outlet of header 4 and reversed
An access is constituted between one side's of being correspondingly connected with entrance of header, it is that first outlet as above is corresponding to the 5th outlet
One access to fifth passage and corresponding first access of first outlet, second outlet corresponds to alternate path, and third exports corresponding third
Access, the 4th exports corresponding fourth passage, and the 5th exports corresponding fifth passage, and the standard of different larynx diameters is arranged in each access
More than one standard sonic nozzle can also be arranged in sonic nozzle in an access as a further alternative, and such as two
Standard sonic nozzle is connected in an access.
Through experimental test, when throat's Reynolds number is lower than 1 × 106When, the boundary layer of sonic nozzle is in laminar condition, at this
It is linear relationship between the efflux coefficient of sonic nozzle and the inverse square root of throat's Reynolds number under state.It, should according to this characteristic
Method at least 5 groups of experimental datas will carry out linear fit, and obtained linear fit degree is higher, and the reliability of Trendline is got over
It is high.Based on the higher linear fit of fitting degree as a result, demonstrating the feasibility and accuracy of the calibration method.To guarantee magnitude
Unification and the again feasibility and accuracy of verification method, use the pVTt method gas flow benchmark of China National Measuring Science Research Inst.
Device under atmospheric conditions calibrates tested sonic nozzle, as shown in figure 3, by this group of experimental result and it is above-mentioned at least
5 groups of data combine, thus guaranteed discharge primary system one and accurate and reliable.
The utility model, which establishes, directly to be calibrated sonic nozzle under the conditions of achievable ultralow pressure, big flow and magnitude
The calibrating installation traced to the source.Using the standard sonic nozzle compared with small larynx diameter as standard scale and throttling element, the sound to larger larynx diameter is realized
Fast nozzle is in stagnation pressure down to directly being calibrated under 10kPa pressure.The device of the utility model can realize at least five stream
The lower calibration of amount point, and by fitting-method of inversion guaranteed discharge primary system one and accurately and reliably and sonic nozzle can be obtained in target
Efflux coefficient under pressure spot and corresponding throat's Reynolds number.According to sonic nozzle under laminar condition its efflux coefficient and throat's thunder
It is linear relationship this characteristic between the inverse square root of promise number as determining calibration method accurately and reliably and guaranteed discharge primary system one
Important evidence combines the simple standard set-up of pVTt method with the experimental data of low pressure sonic nozzle method standard set-up, guarantees
Magnitude is unified.
The utility model can calibrate larger larynx diameter sonic nozzle by the standard sonic nozzle compared with small larynx diameter, realize
Under the conditions of ultralow pressure, big flow to the transmission of quantity value of sonic nozzle with trace to the source.Magnitude is transmitted by standard sonic nozzle
Method can avoid the limitation in simple standard set-up itself and space, can continuously measure, the response time is fast, does not need sufficiently long
Time wait gas stablize, calibration it is more efficient.Tested sonic nozzle can be relatively easily obtained in laminar flow by the covering device
Relationship under state between efflux coefficient and throat's Reynolds number square root.
Although above-described embodiment is not it is understood that the utility model has been disclosed in the preferred embodiments as above
To limit the utility model.For any person skilled in the art, the utility model technical side is not being departed from
Under case ambit, many possible variations all are made to technical solutions of the utility model using the technology contents of the disclosure above
And modification or equivalent example modified to equivalent change.Therefore, all contents without departing from technical solutions of the utility model,
According to the technical essence of the utility model any simple modifications, equivalents, and modifications made to the above embodiment, still belong to
In the range of technical solutions of the utility model protection.
Claims (5)
1. a kind of low pressure critical flow venturi nozzle calibrating installation comprising:
Entrance pipeline section, entrance pipeline section one end are directly connected to atmosphere, and the other end of the entrance pipeline section extends for connection to remittance
The entrance of pipe；It is characterized by:
Include multiple channels between the outlet of the header and the entrance of reversed header, is provided with operated pneumatic valve in each channel
With standard sonic nozzle, the standard sonic nozzle in the multiple channel has different larynx diameters；
The multiple channel is connected to sonic nozzle to be measured, and the outlet end of the sonic nozzle to be measured is vacuum environment；
Control section measures the temperature and pressure of standard sonic nozzle and sonic nozzle to be measured, in the multiple channel
Operated pneumatic valve is connected to the control section.
2. low pressure critical flow venturi nozzle calibrating installation as described in claim 1, it is characterised in that: in the entrance pipeline section
Pipeline development length on be provided with standard sonic nozzle stagnation temperature temperature taking mouth and standard sonic nozzle stagnation pressure pressure tappings.
3. low pressure critical flow venturi nozzle calibrating installation as claimed in claim 2, it is characterised in that: the first temperature measuring set
Table obtains the temperature data of corresponding position by the standard sonic nozzle stagnation temperature temperature taking mouth；First pressure measuring instrumentss are logical
Cross the pressure data that standard sonic nozzle stagnation pressure pressure tappings obtain corresponding position.
4. low pressure critical flow venturi nozzle calibrating installation as described in claim 1, it is characterised in that: in the reversed header
Outlet and tested sonic nozzle entrance between pipeline on be provided with tested sonic nozzle stagnation temperature temperature taking mouth and tested
Sonic nozzle stagnation pressure pressure tappings.
5. low pressure critical flow venturi nozzle calibrating installation as claimed in claim 4, it is characterised in that: second temperature measuring instrument
Table obtains the temperature data of corresponding position by the tested sonic nozzle stagnation temperature temperature taking mouth；Second pressure measuring instrumentss are logical
Cross the pressure data that the tested sonic nozzle stagnation pressure pressure tappings obtain corresponding position.
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| CN201821856417.8U CN208984180U (en) | 2018-11-12 | 2018-11-12 | Low pressure critical flow venturi nozzle calibrating installation |
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| CN201821856417.8U CN208984180U (en) | 2018-11-12 | 2018-11-12 | Low pressure critical flow venturi nozzle calibrating installation |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109211372A (en) * | 2018-11-12 | 2019-01-15 | 中国计量科学研究院 | Low pressure critical flow venturi nozzle calibrating installation |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109211372A (en) * | 2018-11-12 | 2019-01-15 | 中国计量科学研究院 | Low pressure critical flow venturi nozzle calibrating installation |
| CN109211372B (en) * | 2018-11-12 | 2024-05-14 | 中国计量科学研究院 | Low-pressure critical flow venturi nozzle calibrating device |
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