CN109632201A - A kind of SRM sealing structure sealing performance appraisal procedure - Google Patents
A kind of SRM sealing structure sealing performance appraisal procedure Download PDFInfo
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- CN109632201A CN109632201A CN201811613028.7A CN201811613028A CN109632201A CN 109632201 A CN109632201 A CN 109632201A CN 201811613028 A CN201811613028 A CN 201811613028A CN 109632201 A CN109632201 A CN 109632201A
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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
- G01M3/00—Investigating fluid-tightness of structures
- G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
- G01M3/04—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point
- G01M3/20—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material
- G01M3/202—Investigating fluid-tightness of structures by using fluid or vacuum by detecting the presence of fluid at the leakage point using special tracer materials, e.g. dye, fluorescent material, radioactive material using mass spectrometer detection systems
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Abstract
A kind of SRM sealing structure sealing performance appraisal procedure, belong to solid propellant rocket sealing propertytest field, it is characterized by comprising following steps: (1) leaking theory according to Roth molecular flow, establish the leak hole molecular flow leak model of SRM rubber o-ring sealing mechanism；(2) ageing of rubber prediction model is established according to time variable；(3) step (1), (2) is combined to establish SRM rubber ring slip model under long-term storage requirement, solution obtains the assessment result of SRM sealing structure sealing performance.It is leaked based on Roth molecular flow theoretical, by introducing ageing of rubber prediction model, establish SRM sealing structure slip model under long-term store, it realizes and the long-term sealing performance for storing lower SRM sealing structure is assessed, solve the problems, such as that the sealing performance of sealing structure because of caused by aging is not easy check and evaluation.
Description
Technical field
The invention belongs to solid propellant rocket sealing propertytest fields more particularly to a kind of solid propellant rocket to seal
Sealing structure performance estimating method.
Background technique
Solid propellant rocket (SRM) is wide the advantages that convenient for storage, transport and maintenance because structure is simple, reliable operation
It is general to be used for various missile armament as main power source.For the service life for extending SRM, high temperature, high compression ignition when avoiding its work
Gas leaks out of shell, and the SRM powder column during storage and transhipment is avoided to be invaded by moist, etchant gas, each connecting portion
Good sealing performance should all be kept.
In SRM sealing structure, rubber o-ring is a kind of sealing element being most widely used.However in solid missile
In storage process, rubber o-ring is to be easiest to one of element of problem of aging occur, its failure will result directly in whole knot
The working performance of the important components such as structure, powder column, electronic device declines.The superiority and inferiority of rubber seal sealing performance is to influence solid fire
One of the principal element of arrow engine quality.Guided missile is the weapon of long-term storage first use, will be in after delivering to unit of use
Heart library is stored for a long time, and some guided missiles may be stored 10 years or more.Because rubber o-ring belongs to nonmetallic materials, long-term
Natural aging can occur for nonmetallic materials in storage, so that the physical property of rubber ring and mechanical property is deteriorated, so as to cause sealing
Performance decline.
Solid propellant rocket airtight test is frequently with pressure decline method at present, however pressure decline method is only able to detect rubber ring and breaks
The case where slip caused by splitting etc. increases extremely, and sealing structure performance degradation problems caused by cannot checking because of aging.
Summary of the invention
Present invention seek to address that the above problem, provides a kind of SRM sealing structure sealing performance appraisal procedure.
SRM sealing structure sealing performance appraisal procedure of the present invention, includes the following steps:
(1) theory is leaked according to Roth molecular flow, establishes the leak hole molecular flow leak model of SRM rubber o-ring sealing mechanism；
(2) ageing of rubber prediction model is established according to time variable；
(3) step (1), step (2) is combined to establish SRM rubber ring slip model under long-term storage requirement, it is close that solution obtains SRM
The assessment result of seal structure sealing performance.
SRM sealing structure sealing performance appraisal procedure of the present invention, SRM generally require the longer storage rank of experience
Section, the aging of rubber are the key factors of slip variation.The essence of ageing of rubber is it in long-term extruded situation, portion
Point elastic strain is transformed into plastic strain, so that the ability of filling intermetallic composite coating surface irregularity groove reduces, i.e., it is close
Sealing property is deteriorated.To introduce ageing time factor, step (2) the ageing of rubber prediction model in slip model are as follows:
In formula: B and α is Ageing Model coefficient；KcFor aging speed constant.
SRM sealing structure sealing performance appraisal procedure of the present invention, the main table of flowing of the fluid in close clearance
It is now viscous flow and molecular flow.Consider that the geometric dimension of leakage path is very small, SRM working environment pressure is big, can be by SRM rubber
Glue O-ring sealing mechanism is summarized as the molecular flow leak model of leak hole, i.e., the leakage that gas passes through SRM sealing structure is " molecule
Stream " state.The fundamental equation for assuming the single rubber seal proposed leakage based on molecular flow according to Roth.A considers SRM sealing
There are two sealing surface, step (1) the molecular flow leak models in structure are as follows:
In formula: Q is slip；C is the total conductance that gas is flowed through from sealing surface；Δ p is sealing device inside and outside differential pressure；T is gas
Absolute temperature；M is gas medium molecular weight；H is the elemental height of single leakage path triangular-section, i.e. intermetallic composite coating face
Surface roughness；L is the section contact length of sealing surface, according to geometrical relationship, the section contact length L=π (D+ of sealing surface
D), D is rubber ring internal diameter, and d is rubber ring diameter of section；B is interface width；It contacts and answers on sealing surface when for extrusion packing
Power；RsFor gasket factor, the ability that soft sealing material fills leakage path under the effect of certain pressing force is reflected, reality can be passed through
It tests or Finite Element Method Numerical Simulation obtains.
The sealing of SRM sealing structure sealing performance appraisal procedure of the present invention, SRM rubber o-ring is situated between by work
The superimposed realization of precompressed stress under compression that the contact stress and pretightning force that matter pressure generates on sealing surface generate on sealing surface, connects
Touching stress can be expressed as:
In formula, k is carry-over factor of the pressure medium to contact stress, depends on Poisson's ratio γ；σ0It indicates are as follows:
In formula: coefficient of friction of the μ between sealing ring and flange；γ is Poisson's ratio；KεFor the contact width b and O-ring of O-ring
The ratio between diameter of section d.When (ε is true by the compressed height of sealing ring and the ratio of original height for decrement 0.10≤ε≤0.40
It is fixed) when, the contact width b of compressed O-ring seals and flange can be provided by following empirical equation
B=(4 ε0 2+0.34ε0+0.31)d
Then
SRM sealing structure sealing performance appraisal procedure of the present invention, it is characterised in that: SRM rubber under long-term storage requirement
Enclose slip model are as follows:
SRM sealing structure sealing performance appraisal procedure of the present invention, it is theoretical based on the leakage of Roth molecular flow, by introducing rubber
Glue ageing predetermination model establishes the lower SRM sealing structure slip model of long-term storage, realizes to SRM sealing knot under long-term store
The sealing performance of structure is assessed, and is solved the sealing performance of sealing structure because of caused by aging and is not easy asking for check and evaluation
Topic.
Detailed description of the invention
Fig. 1 is flat seal surface microscopic topographic figure；
Fig. 2 is rubber o-ring primary sealing area Roth model schematic；
Fig. 3 is rubber o-ring leakage rate detection apparatus；
Fig. 4 is the schematic cross-section of sealing flange combination；
Wherein 1- sealing surface A, 2- sealing surface B, 3- rubber o-ring, 4- flange, 5- primary sealing area, 6- leak hole, 7- helium tank, 8-
Air inlet, the gas outlet 9-, 10- sealing flange, 11- temperature sensor, 12- pressure sensor, 13- leak detection mouth, the inspection of 14- helium mass spectrum
Leak instrument, 15- end cap, 16- pedestal, 17- bolt hole, 18- leak detection tube, 19- air chamber, 20- seal groove and rubber ring.
Specific embodiment
The technical program is illustrated below with reference to embodiment:
The sealing of SRM rubber o-ring 3 can be classified as flat seal problem.Two sealing surface as shown in Figure 1 includes sealing surface A1 and sealing surface
B2.From the point of view of macroscopically, two sealing surfaces of flat seal are regarded as " plane ".From microcosmic, in machining process,
Due to the bounce of mandrel, finished surface is not ideal plane, but the plane being made of many microcosmic convex peaks and trench,
The presence of these convex peaks and trench is the channel for generating leakage.
The leak hole 6 of leakage is reduced to by several shapes be the miniature of isosceles triangle and constant cross-sectional area by Roth model
Leak hole 6 is formed in parallel.Single 3 seal process primary sealing area 5 of rubber o-ring is simplified, seals and simplifies signal such as Fig. 2 institute
Show.
Flowing of the fluid in close clearance is mainly shown as viscous flow and molecular flow.Consider the geometric dimension of leakage path
Very small, SRM working environment pressure is big, and SRM rubber o-ring sealing mechanism can be summarized as to the molecular flow tunnelling ray of leak hole 6
The leakage that type, i.e. gas pass through SRM sealing structure is " molecular flow " state.The list of proposition is assumed based on molecular flow according to Roth.A
The fundamental equation of rubber seal leakage considers that there are two the bases that sealing surface, single rubber o-ring 3 leak in SRM sealing structure
This equation may be expressed as:
In formula: Q is slip；C is the total conductance that gas is flowed through from sealing surface；Δ p is sealing device inside and outside differential pressure；T is gas
Absolute temperature；M is gas medium molecular weight；H is the elemental height of single leakage path triangular-section, i.e. intermetallic composite coating face
Surface roughness；L is the section contact length of sealing surface, according to geometrical relationship, the section contact length L=π (D+ of sealing surface
D), D is rubber ring internal diameter, and d is rubber ring diameter of section；B is interface width；It contacts and answers on sealing surface when for extrusion packing
Power；RsFor gasket factor, the ability that soft sealing material fills leakage path under the effect of certain pressing force is reflected, reality can be passed through
It tests or Finite Element Method Numerical Simulation obtains.
The contact stress and pretightning force that the sealing of SRM rubber o-ring 3 is generated on sealing surface by working medium pressure exist
The superimposed realization of precompressed stress under compression generated on sealing surface considers that the influence of precompressed stress under compression and the medium internal pressure of SRM, contact are answered
Power can be expressed as:
In formula, k is carry-over factor of the pressure medium to contact stress, depends on Poisson's ratio γ.σ0Generally with rubber material, section
Shape, decrement and internal pressure are related, for O shape rubber seal, generally have
In formula: for the coefficient of friction between sealing ring and flange 4；γ is Poisson's ratio；KεFor the contact width b and O-ring of O-ring
The ratio between diameter of section d.
As 0.10≤ε of decrement≤0.40, the contact width b of compressed O-ring seals and flange 4 can be by passing through below
Formula is tested to provide
B=(4 ε0 2+0.34ε0+0.31)d (4)
Then
SRM generally requires the longer storage period of experience, and the aging of rubber is the key factor of slip variation.Ageing of rubber
Essence is it in long-term extruded situation, and partial elastic transformation for strain becomes plastic strain, so that filling metal adds
The ability of work surface irregularity groove reduces, i.e., sealing performance is deteriorated.To introduce ageing time factor in slip model, adopt
With following empirical equation:
In formula: B and α is Ageing Model coefficient；KcFor aging speed constant.
It brings formula (6) into formula (1), obtains SRM rubber ring slip model under long-term storage requirement:
For the reasonability for verifying calculated result, devises slip development test and slip model is verified, it is specific to try
Proved recipe case is as follows:
Accelerated aging test is carried out to rubber o-ring 3 first, shortens the period of slip measurement test, and combines A Leiniwu
This derivation of equation calculates the equivalent period of storage of room temperature: acceleration of the G105 silicon rubber loop that initial compression amount is 25% at 130 DEG C
It is equivalent to natural storage 6 years, 12 years, 20 years within accelerated ageing 8 days, 16 days, 28 days in ageing oven.Silicon rubber loop is installed in setting
In the special fixture of compression ratio, according to equivalent period of storage, fixture is put into accelerated ageing case and carries out accelerated storage test.
On this basis, by 10 leakage rate detection apparatus of sealing flange, as shown in figure 3, including sequentially connected helium
Bottle 7, sealing flange 10 and helium mass spectrometer leak detector 14；Air inlet 8, gas outlet 9, temperature sensing are provided on the sealing flange 10
Device 11, pressure sensor 12；Leak detection mouth 13 is provided between the sealing flange 10 and helium matter leak detector；Helium tank 7 passes through valve
Door is connected with air inlet 8；The combined schematic cross-section of sealing flange 10 is as shown in figure 4, include end cap 15 and pedestal 16, end cap
15 and pedestal 16 on be provided with bolt hole 17；Its test philosophy is as follows: helium tank 7 enters helium by air inlet 8 close
It seals in flange 10, in air chamber 19 as shown in Figure 4, can be obtained by temperature sensor 11 and pressure sensor 12 in air chamber 19
Pressure and temperature is obtained, it is static close by shelving rubber ring progress to be measured in seal groove 20 between air chamber 19 and leak detection tube 18
Envelope.Helium mass spectrometer leak detector 14 obtains the leakage rate of rubber ring by detection 18 concentrations of helium of leak detection tube.To by accelerated ageing
Rubber ring afterwards carries out slip measurement, and selective analysis period of storage, initial compression rate, pressure medium are to SRM rubber o-ring 3
The influence of sealing performance, and the result calculated with numerical value compares verifying.
Such as rubber ring is placed in 130 DEG C of ageing oven and is taken out after 28 days, it is put into sealing flange 10 and carries out slip
Measurement test.Record the registration that rubber ring slip changes with pressure medium under four kinds of initial compression rates, and with slip model
Numerical result is compared, as shown in table 1 below.The test measurement result and numerical value of rubber ring slip under the same conditions
Calculated result is on the same order of magnitude, to demonstrate the correctness of SRM rubber ring slip model under long-term storage requirement.
The registration that slip changes with pressure medium under the different compression ratios of table 1
Claims (5)
1. a kind of SRM sealing structure sealing performance appraisal procedure, characterized by the following steps:
(1) theory is leaked according to Roth molecular flow, establishes the leak hole molecular flow leak model of SRM rubber o-ring sealing mechanism；
(2) ageing of rubber prediction model is established according to time variable；
(3) step (1), step (2) is combined to establish SRM rubber ring slip model under long-term storage requirement, it is close that solution obtains SRM
The assessment result of seal structure sealing performance.
2. SRM sealing structure sealing performance appraisal procedure according to claim 1, it is characterised in that: step (2) described rubber
Glue ageing predetermination model are as follows:
In formula: B and α is Ageing Model coefficient；KcFor aging speed constant.
3. SRM sealing structure sealing performance appraisal procedure according to claim 2, it is characterised in that: described point of step (1)
Subflow leak model are as follows:
In formula: Q is slip；C is the total conductance that gas is flowed through from sealing surface；Δ p is sealing device inside and outside differential pressure；T is gas
Absolute temperature；M is gas medium molecular weight；H is the elemental height of single leakage path triangular-section；L is sealing surface
Section contact length；B is interface width；Contact stress on sealing surface when for extrusion packing；RsFor gasket factor.
4. SRM sealing structure sealing performance appraisal procedure according to claim 3, it is characterised in that: SRM rubber o-ring
The contact stress that is generated on sealing surface by working medium pressure of sealing and the precommpression that is generated on sealing surface of pretightning force
The superimposed realization of stress, contact stress can be expressed as:
In formula, k is carry-over factor of the pressure medium to contact stress, depends on Poisson's ratio γ；σ0It indicates are as follows:
In formula: coefficient of friction of the μ between sealing ring and flange；γ is Poisson's ratio；KεFor the contact width b and O-ring of O-ring
The ratio between diameter of section d.
5. SRM sealing structure sealing performance appraisal procedure according to claim 4, it is characterised in that: long-term storage requirement
Lower SRM rubber ring slip model are as follows:
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112287576A (en) * | 2020-10-12 | 2021-01-29 | 浙江大学 | Method for predicting seal leakage between macro-micro combined sheet type multi-channel valve plates |
| CN112989652A (en) * | 2021-02-24 | 2021-06-18 | 河北工业大学 | Method for predicting leakage rate of flange connection |
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|---|---|---|---|---|
| CN102411669A (en) * | 2011-07-27 | 2012-04-11 | 南京林业大学 | Prediction method of leakage rate of contact mechanical seal |
| CN105302990A (en) * | 2015-11-16 | 2016-02-03 | 深圳大学 | Microcosmic wall slippage model establishment method used for injection molding |
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2018
- 2018-12-27 CN CN201811613028.7A patent/CN109632201A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102411669A (en) * | 2011-07-27 | 2012-04-11 | 南京林业大学 | Prediction method of leakage rate of contact mechanical seal |
| CN105302990A (en) * | 2015-11-16 | 2016-02-03 | 深圳大学 | Microcosmic wall slippage model establishment method used for injection molding |
Non-Patent Citations (1)
| Title |
|---|
| 陈家照 等: "固体火箭发动机长期贮存下橡胶O形圈泄漏分析", 《润滑与密封》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112287576A (en) * | 2020-10-12 | 2021-01-29 | 浙江大学 | Method for predicting seal leakage between macro-micro combined sheet type multi-channel valve plates |
| CN112287576B (en) * | 2020-10-12 | 2022-06-21 | 浙江大学 | Method for predicting seal leakage between macro-micro combined sheet type multi-channel valve plates |
| CN112989652A (en) * | 2021-02-24 | 2021-06-18 | 河北工业大学 | Method for predicting leakage rate of flange connection |
| CN112989652B (en) * | 2021-02-24 | 2022-04-15 | 河北工业大学 | Method for predicting leakage rate of flange connection |
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Application publication date: 20190416 |