CN105224713B - A kind of derated design method of aero-engine intershaft bearing - Google Patents
A kind of derated design method of aero-engine intershaft bearing Download PDFInfo
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Abstract
A kind of derated design method of aero-engine intershaft bearing, propose the principle for making intershaft bearing from synchronous impact, N number of rotating speed point is chosen out of slow train rotating speed maximum (top) speed working range in aero-engine, determines the defect characteristic octave frequency of the defect characteristic octave frequency and outer shroud of intershaft bearing inner ring under each rotating speed.Mark the lobe numbers of fan.Check fan blade number and its integral multiple whether with the defect characteristic octave frequency and outer shroud the defect characteristic octave frequency of inner ring at a distance of within 2%.If the rotating speed section for meeting this condition is more than the 10% of engine operating speed range, then adjust lobe numbers or high low pressure rotor speed ratio, ensure in 90% or more engine operating speed range, fan blade number and its integral multiple are differed with intershaft bearing inner ring and outer rings the defect characteristic octave frequency 2% or more, and present invention effectively prevents intershaft bearings synchronous impact occurs.
Description
Technical field
The present invention relates to aero-engine Structural Dynamic Design field, specifically a kind of aero-engine intershaft bearing
Off-load method.
Background technology
Intershaft bearing is load and transmission parts crucial in birotor aero-engine.Its outer shroud is mounted on high-pressure turbine
On rotor, inner ring is mounted on Low Pressure Turbine Rotor；Or on the contrary, outer shroud is mounted on Low Pressure Turbine Rotor, inner ring is mounted on
On High Pressure Turbine Rotor.Therefore, intershaft bearing inner and outer ring rotates simultaneously.Intershaft bearing works in high temperature, alternating load, is not easy to moisten
In sliding environment, it is easy to happen failure, once the safe operation of engine will be seriously threatened by breaking down, and reduces intershaft bearing
Dynamic loading be reduce rate of breakdown effective way.
For micro-damage point P in the intershaft bearing inner ring in Fig. 1, it often contacts a roller, by one-shot, with Z
The frequency of impact of a roller is fP.Fig. 2 is impact force schematic diagram of the rolling element to inner ring.
It is mounted on low pressure rotor with inner ring, outer shroud is mounted on high pressure rotor, right for two rotor rotating Vortex schemes
In the intershaft bearing of Z rolling element, rolling element in inner ring point P, the frequency of point Q contacts is respectively on outer shroud：
In formula：
ΩH、ΩLThe angular velocity of rotation of high pressure rotor, low pressure rotor.
D rolling element diameters；
DmBearing pitch diameter；
α contact angles, the angle between abutment face center and the rolling element line of centres and bearing sagittal plane.
As can be seen from the above equation：For single spool system, due to outer shroud rotating speed ΩH=0, andGenerally it is not whole
Number, therefore bearing inner ring characteristic frequency fP, outer shroud characteristic frequency fQIt can not possibly be equal with the frequency of rotor multiple frequency periodical exciting force.
But it for the birotary engine with intershaft bearing, is required according to engine performance, high pressure rotating speed ΩHWith low pressure rotating speed ΩL
Variation in wide range, it is entirely possible to make intershaft bearing inner ring characteristic frequency or outer shroud characteristic frequency and rotor excitation force frequency
It is equal or close.
In the birotary engine course of work, the period of the periodical exciting force or low pressure rotor that act on high pressure rotor swashs
Power of shaking is the main source of the born dynamic loading of intershaft bearing.When a certain micro-damage point P connects with bearing roller on raceway
When touching, while also by the percussion of rotation exciting force, the dynamic loading of P points is rolling element impact force and rotation exciting force
Superposition.
Fig. 3 is the exciting force F acted on rotorinterThe dynamic loading formed on raceway.Roller IV, roller III and roller
II when rolling across point P in inner ring successively, and the load change that P points are subject to is as shown in the figure.Wherein, Fig. 3 (a) is excitation force frequency and inner ring
Dynamic loading under the conditions of characteristic frequency is unequal, Fig. 3 (b) be excitation force frequency and inner ring characteristic frequency it is equal under the conditions of dynamic load
Lotus.τ in figureFIt is the period for rotating exciting force, τPIt is period of the roller to inner ring impact force.
As can be seen that the load that raceway is born consists of two parts：Rolling element impact force and rotation exciting force.Rotate exciting
When power frequency and unequal inner ring characteristic frequency, the impact force that P points are subject to will not be always rolling element impact force and rotation exciting force
The sum of power width；But when rotate exciting force and rolling element impact force with frequency with phase when, the impact force that point P is subject to is rolling element impact force
With rotation the sum of exciting force width, and P points are continuingly acted on.This phenomenon is referred to as synchronous impact.Under synchronous percussion,
The dynamic loading that intershaft bearing is subject to increases, and easily causes the local damage of raceway, reduces the service life of intershaft bearing.
It is above-mentioned by taking inner ring as an example, illustrate synchronous impact phenomenon.When rotation excitation force frequency and outer shroud characteristic frequency are equal
When, it can also obtain similar as a result, point Q will be impacted by synchronous on outer shroud.
For birotary engine, fan blade will generate periodic gas exciting force, and frequency is fan leaf the piece number
Mesh integral multiple and low pressure rotating speed ΩLProduct.Engine high low pressure rotor speed ratio changes according to engine performance control rate,
Intershaft bearing inner ring or outer ring the defect characteristic octave frequency can be made to be equal or close to fan blade number in a certain range, fan blade is just
It will produce the frequency rotation exciting force equal with intershaft bearing inner ring or outer ring characteristic frequency, the impact force of the power and rolling element is folded
Add, will result in the synchronous impact of agency bearing.
For the ease of derated design, the characteristic frequency of the characteristic frequency of intershaft bearing inner ring and outer shroud is rewritten into low pressure and is turned
The form of fast multiple, i.e. inner and outer rings the defect characteristic octave frequency number.Formula (1) and formula (2) become：
In formula (3) and (4), including high low pressure rotor speed ratioWhen high-low pressure rotating ratio changes, inner ring feature times
Frequency XPWith outer shroud the defect characteristic octave frequency number XQChange therewith.
In previous design, the influence of the born dynamic loading of rotor exciting force agency bearing is not considered generally.But for double
Rotary engine, if fan blade number is equal or close to intershaft bearing inner ring or outer ring the defect characteristic octave frequency, fan blade is just
It will produce the frequency rotation exciting force equal with intershaft bearing inner ring or outer ring characteristic frequency.At this point, rushing of bearing of raceway
Hit the sum of the power width that power is rolling element impact force and rotation exciting force.The impact force acted on micro-damage point increases, and continues
It is acted on by impact force so that thus damage aggravation reduces the service life of intershaft bearing.For this problem, the present invention proposes
A kind of method of aero-engine intershaft bearing derated design.
《Aviation power journal》ISSN:1000-8055, what the 12nd periodical of volume 28 in 2013 was stepped on《In aero-engine
The fault signature and diagnostic method of Jie's bearing》One text, the method for establishing diagnosis aero-engine intershaft bearing failure.It establishes
The method for diagnosing aero-engine intershaft bearing failure.Using the slip of engine high and low pressure as trigger signal, shake to engine
Dynamic signal carries out equal slips period acquisition, and carries out frequency spectrum and envelope spectrum analysis to vibration signal in slip domain.Utilize stub
Failure response is held in " permanent spacing " feature and " constant frequency " feature in slip domain, recognizes intershaft bearing local fault.But it is not related to
How the design method of intershaft bearing dynamic loading is reduced.
Chinese invention patent CN200910109202.9, a kind of method for testing service life of rolling bearings have invented a kind of rolling
The method of bearing degradation implements the strenuous test and quickly of rolling bearing life and reliability under equivalent stress level
Evaluation.But the feature and derated design method of test bearing component stress are not provided.
Chinese invention patent CN201410146849.X, a kind of design method of aeroengine rotor Structural Dynamics,
By the parameter for optimizing rotor and bearing so that the hot-die state of rotor-support-foundation system avoids the mode of rotor when bearing absolute rigidity, makes
Rotor-support-foundation system meets the requirement of vibration standard under hot-die state.Its core is to ensure rotor in the entire operating rotational speed range of engine
It is interior, it can smooth working.But optimization design object is rotor-support-foundation system, is not related to intershaft bearing.
Russ P RU2110781 (C1) " METHOD OF FORECASTING OF MECHANICAL CONDITION
OF INTERSHAFT ANTIFRICTION BEARING IN TWIN-SHAFT TURBOMACHINE " describe one kind double
Sensor is installed on rotary engine intershaft bearing, and judges the method for intershaft bearing state according to vibration signal.But it is not
Relate to how the design method of reduction intershaft bearing dynamic loading.
United States Patent (USP) 20120070278 " GAS TURBINE ENGINE BEARING ARRANGEMENT ", describes one
Kind is using the reverse rotation rotor structure of intershaft bearing, and a rotor-support-foundation system is with rotor and stator structure, another rotor system
System only has rotating part.The retainer rotating speed for trying hard to control intershaft bearing by structure design, reduces the load of intershaft bearing, increases
Add the service life of bearing.It can only be directed to the case where two rotors reversely rotate rotor structure, are not applied for rotating Vortex.
Invention content
To overcome the problems, such as that aero-engine intershaft bearing has synchronous impact in operation process in the prior art, with drop
Low intershaft bearing failure rate, the present invention propose a kind of derated design method of aero-engine intershaft bearing.
The present invention detailed process be：
Step 1: determining the rotating ratio of birotary engine mesohigh rotor and low pressure rotor.
Step 2: determining intershaft bearing inner ring characteristic frequency and outer shroud characteristic frequency.
Step 3: determining the defect characteristic octave frequency of intershaft bearing.
Step 4: drawing synchronous impact checks figure.
The synchronous impact check figure is inner ring the defect characteristic octave frequency and the outer shroud feature by fan blade number and intershaft bearing
Relationship between frequency multiplication is showed by way of figure, provides foundation to check synchronous impact, which is known as synchronous impact school
Core figure.
In figure is checked in the synchronous impact, when intermediary's bearing roller is to the impact force frequency and fan leaf of inner race
When piece excitation force frequency is close, the two superposition is in inner race；When intermediary's bearing roller is to the impact force of outer-race ball track
When frequency is close with fan blade excitation force frequency, the two superposition is in outer-race ball track.
Drawing the detailed process of the synchronous impact check figure is：
I by inner ring the defect characteristic octave frequency with the rule X of rotation speed changeinner,iIt is plotted on synchronous impact check figure, is synchronized
The inner ring the defect characteristic octave frequency X in figure is checked in impactinner,iCurve.
II draws inner ring the defect characteristic octave frequency number Xinner+ 2%XinnerAnd Xinner- 2%XinnerBoundary line, respectively obtain
The X in figure is checked in synchronous impactinner+ 2%XinnerBoundary line and Xinner- 2%XinnerBoundary line.
III by outer shroud the defect characteristic octave frequency with the rule X of rotation speed changeouterIt is plotted on synchronous impact check figure, obtains synchronous flushing
Hit the outer shroud the defect characteristic octave frequency X in check figureouterCurve.
IV draws outer shroud the defect characteristic octave frequency number Xouter+ 2%XouterAnd Xouter- 2%XouterBoundary line, respectively obtain
The X in figure is checked in synchronous impactouter+ 2%XouterBoundary line and Xouter- 2%XouterBoundary line.
V by 2 multiple F of fan blade numbers at different levels and the fan leaf the piece numbers at different levelsbk,jSynchronous impact is marked on successively to check
On figure, the straight line of one group of performance fan blade numbers at different levels is obtained.
Step 5: checking world live load situation suffered by intershaft bearing, avoid that synchronous impact occurs.
Figure is checked according to synchronous impact, if any straight line in showing the straight lines of fan blade numbers at different levels is in
Xinner+ 2%XinnerBoundary line and Xinner- 2%XinnerBetween boundary line；Or performance fan blade numbers at different levels is straight
Any straight line in line is in Xouter+ 2%XouterBoundary line and Xouter- 2%XouterBetween boundary line, then show
Intershaft bearing inner ring characteristic frequency or outer shroud characteristic frequency are close with fan blade excitation force frequency, and intershaft bearing may at this time
Synchronous impact phenomenon occurs.
When synchronous impact occurs, the load that load or outer-race ball track that intershaft bearing inner race is subject to are subject to is rolling
The sum of kinetoplast impact force and fan blade exciting force width.Intershaft bearing is under severe loaded-up condition at this time, is forbidden herein
Long-term work under state.
If there is the straight line of the performance fan blade numbers at different levels is in by Xinner+ 2%XinnerBoundary line and
Xinner- 2%XinnerIn the danger zone that boundary line is constituted, and more than engine operating speed range shown in abscissa
When 10%；Or any straight line in the straight line of the performance fan blade numbers at different levels is in by Xouter+ 2%
XouterBoundary line and Xouter- 2%XouterIn the danger zone that boundary line is constituted, and more than engine operating speed range
When 10%, then necessary adjusted design parameter, reduces the dynamic loading that intershaft bearing is born.
Step 6: reducing the dynamic loading that intershaft bearing is born.The born dynamic loading of the reduction intershaft bearing is to pass through
It is turned up or turns down high low pressure rotor speed ratio, to reduce the dynamic loading that intershaft bearing inner race and outer shroud are born.
When reducing the dynamic loading that intershaft bearing inner race is born：
In figure is checked in the synchronous impact of drafting, by Xinner+ 2%XinnerBoundary line and XinnerCurve constitutes region
D1, by Xinner- 2%XinnerBoundary line 4 and XinnerIt is D that curve, which constitutes region,2。
When the straight line of the performance fan blade numbers at different levels is in D1Length in inherent X-coordinate, which is more than, is in D2Inherent X
When length on coordinate, high low pressure rotor speed ratio need to be turned down.Specifically, by former high low pressure rotor speed than with 0.1%
Step-length is gradually turned down, until the straight line of the performance fan blade numbers at different levels is located at except the danger zone, and makes non-danger
Danger zone domain is more than 90% of engine operating speed range shown in abscissa.
When the straight line of the performance fan blade numbers at different levels is in D1Length in inherent X-coordinate, which is less than, is in D2Inherent X
When length on coordinate, high low pressure rotor speed ratio need to be turned up.Specifically, by former high low pressure rotor speed than with 0.1%
Step-length is gradually turned up, until the straight line of the performance fan blade numbers at different levels is located at except the danger zone, and makes non-danger
Danger zone domain is more than 90% of engine operating speed range shown in abscissa.
When reducing the dynamic loading that intershaft bearing outer-race ball track is born：
In figure is checked in the synchronous impact of drafting, by Xouter+ 2%XouterBoundary line and XouterCurve constitutes region
D3, by Xouter- 2%XouterBoundary line and XouterIt is D that curve, which constitutes region,4。
When the straight line of the performance fan blade numbers at different levels is in D3Length in inherent X-coordinate, which is more than, is in D4Inherent X
When length on coordinate, high low pressure rotor speed ratio need to be turned down.Specifically, by former high low pressure rotor speed than with 0.1%
Step-length is gradually turned down, until the straight line of the performance fan blade numbers at different levels is located at except the danger zone, and makes non-danger
Danger zone domain is more than 90% of engine operating speed range shown in abscissa.
When the straight line of the performance fan blade numbers at different levels is in D3Length in inherent X-coordinate, which is less than, is in D4Inherent X
When length on coordinate, high low pressure rotor speed ratio need to be turned up.Specifically, by former high low pressure rotor speed than with 0.1%
Step-length is gradually turned up, until the straight line of the performance fan blade numbers at different levels is located at except the danger zone, and makes non-danger
Danger zone domain is more than 90% of engine operating speed range shown in abscissa.
So far, complete to engine high low pressure rotor speed than adjustment, avoid intershaft bearing and synchronous flushing occur
It hits.
The present invention proposes the principle for making intershaft bearing from synchronous impact, i.e.,：Intershaft bearing inner ring the defect characteristic octave frequency, outer shroud
The defect characteristic octave frequency with fan blade number and its integral multiple close to in the range of 2% the case where be danger zone, forbid engine
In this region long-term work.
The present invention proposes the design method for avoiding intershaft bearing by synchronous impact.Fig. 4 is design proposed by the present invention
The flow chart of method.Choose N number of rotating speed point out of slow train rotating speed-maximum (top) speed working range in aero-engine first, really
The defect characteristic octave frequency of intershaft bearing inner ring and the defect characteristic octave frequency of outer shroud under fixed each rotating speed；Then the lobe numbers of fan are marked；School
Core fan blade number and its integral multiple whether with the defect characteristic octave frequency and outer shroud the defect characteristic octave frequency of inner ring at a distance of within 2%.If full
The rotating speed section of this condition of foot is more than the 10% of engine operating speed range, then adjusts lobe numbers or high low pressure rotor
Rotating ratio ensures in 90% or more engine operating speed range, fan blade number and its integral multiple and intershaft bearing
Inner ring and outer rings the defect characteristic octave frequency is differed 2% or more.
The invention also provides a kind of check fan blade number and its integral multiple and intershaft bearing inner ring the defect characteristic octave frequency and
The whether close graphic technique of outer shroud the defect characteristic octave frequency, the figure are known as synchronous impact and check figure.Abscissa is engine speed in figure
Operating mode, coordinate range are included at least from slow train to maximum rating, and unit is absolute rotating speed (r/min) or percentage specific speed (%).
Ordinate unit is frequency multiplication (X).Fan blade number is marked on the diagram, then draws bearing inner ring and outer shroud the defect characteristic octave frequency with rotating speed
Change curve.High low pressure rotor speed ratio is adjusted, is ensured in 90% or more engine operating speed range, above-mentioned leaf
Piece number is differed with intershaft bearing inner ring the defect characteristic octave frequency and outer shroud the defect characteristic octave frequency 2% or more.
By above-mentioned design procedure, intershaft bearing can be made to be impacted from synchronous, can effectively reduce the dynamic loading on raceway,
Improve the fatigue life of intershaft bearing.
The beneficial effects of the present invention are：
For the fixed bearing of outer shroud, it is impossible to excitation force frequency and the equal situation of bearing features frequency occur.But it is right
In the intershaft bearing of birotary engine, if design is improper, synchronous impact phenomenon may occur, raceway is made to bear
Dynamic loading increased dramatically, and bring challenges for bearing reliability.The present invention proposes that the synchronous principle impacted is avoided for intershaft bearing to subtract
It carries design and specifies direction.
Intershaft bearing can be made to be impacted from synchronous by derated design step, avoid rolling element impact force and rotation exciting force same
The superimposed same point acted on raceway, the dynamic loading that can be effectively reduced on inner race and outer-race ball track then carry
The fatigue life of high intershaft bearing.The theoretical analysis result of comparison diagram 3 (a) and Fig. 3 (b), can be clearly seen that dynamic loading
It reduces.
Synchronous impact check figure proposed by the present invention is effective derated design tool, for the design engineer of this field
For, drafting is easy, statement physical significance is apparent, helps to improve the efficiency of intershaft bearing derated design.
Description of the drawings
Fig. 1 is intershaft bearing kinetic model schematic diagram.
Fig. 2 is impact force schematic diagram of the intershaft bearing rolling element to raceway.
Fig. 3 is the overlaying relation figure for rotating exciting force and rolling element impact force, wherein 3a is that excitation force frequency and inner ring are special
Levy frequency it is unequal under the conditions of dynamic loading, 3b be excitation force frequency and inner ring characteristic frequency it is equal under the conditions of dynamic loading.
Fig. 4 is the flow chart of the present invention.
Fig. 5 is intershaft bearing derated design process schematic.
Fig. 6 is synchronous impact check figure.
Fig. 7 is the synchronous impact check figure of prior art design.
Fig. 8 is the synchronous impact check figure of derated design of the present invention.
In figure：1. the straight line of performance fan blade numbers at different levels；2.Xinner+ 2%XinnerBoundary line；3. inner ring feature
Frequency multiplication XinnerCurve；4.Xinner- 2%XinnerBoundary line；5. danger zone；6.Xouter+ 2%XouterBoundary line；Outside 7.
Ring the defect characteristic octave frequency XouterCurve；8.Xouter- 2%XouterBoundary line.
Specific implementation mode
The present embodiment is a kind of method of aero-engine intershaft bearing derated design, and detailed process is：
Step 1: determining the rotating ratio of birotary engine mesohigh rotor and low pressure rotor.
According to rotating speed principle at equal intervals, selected in operating rotational speed range of the aero-engine from slow train rotating speed to maximum (top) speed
Take N number of speed conditions point.According to engine high pressure rotor design rotating speed and low pressure rotor design speed, each speed conditions are calculated
Under high low pressure rotor speed ratio γi=ΩH,i/ΩL,i=n2,i/n1,i, i=(1,2 ... N).Wherein, ΩHIt is high pressure rotor
Angular velocity of rotation, ΩLIt is the angular velocity of rotation of low pressure rotor.n2It is high pressure rotor design speed, dimension is rev/min；n1It is low pressure
Rotor design rotating speed, dimension are rev/min.
If by common outer shroud be mounted on High Pressure Turbine Rotor on, inner ring be mounted on Low Pressure Turbine Rotor structure for,
Obtained high low pressure rotor speed ratio γiThe as outer shroud of intershaft bearing/inner ring rotating ratio.The high low pressure rotor being calculated
Rotating ratio γiIt is one of design parameter important in intershaft bearing derated design.
Step 2: determining intershaft bearing inner ring characteristic frequency and outer shroud characteristic frequency.
Determine intershaft bearing inner ring characteristic frequency：
It is determined under each speed conditions by formula (5), intershaft bearing inner ring characteristic frequency finner,i, i=(1,2 ...
N)
Determine intershaft bearing outer shroud characteristic frequency：
It is determined under each speed conditions by formula (6), intershaft bearing outer shroud characteristic frequency fouter,i, i=(1,2 ...
N)
In formula (5) and (6), d is the diameter of rolling element in intershaft bearing, DmIt is bearing pitch diameter, α is contact angle, and z is rolling
Kinetoplast number.Each parameter is obtained by bearing design requirements.
When high pressure rotor and low pressure rotor rotating Vortex, minus sign "-" is taken, when reverse rotation, take plus sige "+".
Step 3: determining the defect characteristic octave frequency of intershaft bearing.
The defect characteristic octave frequency of the determining intershaft bearing includes the defect characteristic octave frequency and the stub of the determining intershaft bearing inner ring
Hold the defect characteristic octave frequency of outer shroud.
By formula (7), by inner ring characteristic frequency finner,iIt is converted into the frequency multiplication of rotational speed of lower pressure turbine rotor：
Obtain the defect characteristic octave frequency X of intershaft bearing inner ringinner,i。
By formula (8), by outer shroud characteristic frequency fouter,iIt is converted into the frequency multiplication of rotational speed of lower pressure turbine rotor：
Obtain the defect characteristic octave frequency X of intershaft bearing outer shroudouter,i。
Step 4: drawing synchronous impact checks figure.
The synchronous impact check figure is inner ring the defect characteristic octave frequency and the outer shroud feature by fan blade number and intershaft bearing
Relationship between frequency multiplication is showed by way of figure, provides foundation to check synchronous impact, which is known as synchronous impact school
Core figure.
In figure is checked in the synchronous impact, when intermediary's bearing roller is to the impact force frequency and fan leaf of inner race
When piece excitation force frequency is close, for the two superposition in inner race, power width is the sum of two force width；When intermediary's bearing roller
When close with fan blade excitation force frequency to the impact force frequency of outer-race ball track, the two superposition is in outer-race ball track, power width
For the sum of two force width.
Drawing the detailed process of synchronous impact check figure Fig. 6 is：
I by inner ring the defect characteristic octave frequency with the rule X of rotation speed changeinner,iIt is plotted on synchronous impact check figure, Z is synchronized
The inner ring the defect characteristic octave frequency X in figure is checked in impactinner,iCurve 3.
II draws inner ring the defect characteristic octave frequency number Xinner+ 2%XinnerAnd Xinner- 2%XinnerBoundary line, respectively obtain
The X in figure is checked in synchronous impactinner+ 2%XinnerBoundary line 2 and Xinner- 2%XinnerBoundary line 4.
III by outer shroud the defect characteristic octave frequency with the rule X of rotation speed changeouterIt is plotted on synchronous impact check figure, obtains synchronous flushing
Hit the outer shroud the defect characteristic octave frequency X in check figureouterCurve 7.
IV draws outer shroud the defect characteristic octave frequency number Xouter+ 2%XouterAnd Xouter- 2%XouterBoundary line, respectively obtain
The X in figure is checked in synchronous impactouter+ 2%XouterBoundary line 6 and Xouter- 2%XouterBoundary line 8.
V by 2 multiple F of fan blade numbers at different levels and the fan leaf the piece numbers at different levelsbk,jSynchronous impact is marked on successively to check
On figure, the straight line of one group of performance fan blade numbers at different levels is obtained.
In the present embodiment, the fan blade at different levels include 1~3 grade.Wherein, light breeze fan leaf has 37, the 2nd grade
Fan blade has 45, and 3rd level fan blade has 43.It is then checked on figure in synchronous impact, marks light breeze fan successively
F1,1=37 ×, F1,2=74 ×；The F of gentle breeze fan2,1=45 ×, F2,2=90 ×；The F of 3rd level fan3,1=43 ×, F3,2=
86×。
Step 5: checking world live load situation suffered by intershaft bearing, avoid that synchronous impact occurs.
Figure is checked in synchronous impact, if at any straight line in showing the straight lines 1 of fan blade numbers at different levels
In Xinner+ 2%XinnerBoundary line 2 and Xinner- 2%XinnerBetween boundary line 4；Or performance fan blade numbers at different levels
Straight line 1 in any straight line be in Xouter+ 2%XouterBoundary line 6 and Xouter- 2%XouterBetween boundary line 8,
Then show that intershaft bearing inner ring characteristic frequency or outer shroud characteristic frequency are close with fan blade excitation force frequency, at this time stub
Synchronous impact phenomenon may be occurred by holding.
When synchronous impact occurs, the load that load or outer-race ball track that intershaft bearing inner race is subject to are subject to is rolling
The sum of kinetoplast impact force and fan blade exciting force width, at this time intershaft bearing be under severe loaded-up condition, forbid herein
Long-term work under state.
If there is the straight line 1 of the performance fan blade numbers at different levels is in by Xinner+ 2%Xinner2 He of boundary line
Xinner- 2%XinnerIn the danger zone 5 that boundary line 4 is constituted, and more than engine operating speed range shown in abscissa
When 10%；Or any straight line in the straight line 1 of the performance fan blade numbers at different levels is in by Xouter+ 2%
XouterBoundary line 6 and Xouter- 2%XouterIn the danger zone 5 that boundary line 8 is constituted, and it is more than engine operating speed range
10% when, then must adjusted design parameter, reduce the dynamic loading that intershaft bearing is born.
Step 6: reducing the optimization design of the born dynamic loading of intershaft bearing.
Based on existing design method, intershaft bearing there is a possibility that synchronous impact occurs.For example, Fig. 6 existing designs
Synchronous impact check in figure, the straight line 1 of performance gentle breeze fan leaf number is in Xinner+ 2%Xinner2 He of curve
Xinner- 2%XinnerRotating speed section between curve 4 has been over the 10% of engine operating speed range.
At this point, by adjusting high low pressure rotor speed ratio, change fan blade excitation force frequency and rolling element impact force frequency
The correlation of rate avoids synchronous impact, reduces the dynamic loading that intershaft bearing raceway is born.
The adjustment high low pressure rotor speed ratio is turned up or is turned down and is high/low by adjusting control of engine speed rate
Rotor speed ratio is pressed, to reduce the dynamic loading that intershaft bearing inner race and outer shroud are born.The control of engine speed rate
It is identified in engine design.
When reducing the dynamic loading that intershaft bearing inner race is born：
In figure is checked in the synchronous impact of drafting, by Xinner+ 2%XinnerBoundary line 2 and XinnerCurve 3 constitutes region
For D1, by Xinner- 2%XinnerBoundary line 4 and XinnerIt is D that curve 3, which constitutes region,2。
When the straight line 1 of the performance fan blade numbers at different levels is in D1Length in inherent X-coordinate, which is more than, is in D2It is inherent
When length in X-coordinate, high low pressure rotor speed ratio need to be turned down.Specifically, by former high low pressure rotor speed than with 0.1%
Step-length is gradually turned down, until the straight line 1 of the performance fan blade numbers at different levels is located at except the danger zone 5, and is made non-
Danger zone is more than 90% of engine operating speed range shown in abscissa.
When the straight line 1 of the performance fan blade numbers at different levels is in D1Length in inherent X-coordinate, which is less than, is in D2It is inherent
When length in X-coordinate, high low pressure rotor speed ratio need to be turned up.Specifically, by former high low pressure rotor speed than with 0.1%
Step-length is gradually turned up, until the straight line 1 of the performance fan blade numbers at different levels is located at except the danger zone 5, and makes non-
Danger zone is more than 90% of engine operating speed range shown in abscissa.
When reducing the dynamic loading that intershaft bearing outer-race ball track is born：
In figure is checked in the synchronous impact of drafting, by Xouter+ 2%XouterBoundary line 6 and XouterCurve 7 constitutes region
For D3, by Xouter- 2%XouterBoundary line 8 and XouterIt is D that curve 7, which constitutes region,4。
When the straight line 1 of the performance fan blade numbers at different levels is in D3Length in inherent X-coordinate, which is more than, is in D4It is inherent
When length in X-coordinate, high low pressure rotor speed ratio need to be turned down.Specifically, by former high low pressure rotor speed than with 0.1%
Step-length is gradually turned down, until the straight line 1 of the performance fan blade numbers at different levels is located at except the danger zone 5, and is made non-
Danger zone is more than 90% of engine operating speed range shown in abscissa.
When the straight line 1 of the performance fan blade numbers at different levels is in D3Length in inherent X-coordinate, which is less than, is in D4It is inherent
When length in X-coordinate, high low pressure rotor speed ratio need to be turned up.Specifically, by former high low pressure rotor speed than with 0.1%
Step-length is gradually turned up, until the straight line 1 of the performance fan blade numbers at different levels is located at except the danger zone 5, and makes non-
Danger zone is more than 90% of engine operating speed range shown in abscissa.
So far, complete to engine high low pressure rotor speed than adjustment, avoid intershaft bearing and synchronous flushing occur
It hits.
By above-mentioned design procedure, intershaft bearing can be made to be impacted from synchronous, can effectively reduce the dynamic loading on raceway,
Improve the fatigue life of intershaft bearing.
Claims (4)
1. a kind of derated design method of aero-engine intershaft bearing, which is characterized in that detailed process is：
Step 1: determining the rotating ratio of birotary engine mesohigh rotor and low pressure rotor；
Step 2: determining intershaft bearing inner ring characteristic frequency and outer shroud characteristic frequency；
Step 3: determining the defect characteristic octave frequency of intershaft bearing；
Step 4: drawing synchronous impact checks figure；
The synchronous impact check figure is inner ring the defect characteristic octave frequency and the outer shroud the defect characteristic octave frequency by fan blade number and intershaft bearing
Between relationship showed by way of figure, provide foundation to check synchronous impact, which is known as synchronous impact and checks figure；
In figure is checked in the synchronous impact, when intermediary's bearing roller swashs the impact force frequency of inner race with fan blade
When power of shaking frequency is close, the two superposition is in inner race；When intermediary's bearing roller is to the impact force frequency of outer-race ball track
When close with fan blade excitation force frequency, the two superposition is in outer-race ball track；
Figure is checked in the synchronous impact, and abscissa is engine speed conditions in figure, and coordinate range is included at least from slow train to most
Big state, unit are absolute rotating speed or percentage specific speed；Ordinate unit is multiple --- the frequency multiplication X of rotor rotation frequency；Figure
Include reflect fan blade number cluster horizontal line and bearing inner ring and outer shroud the defect characteristic octave frequency with rotating speed change curve；
Since the fan blade number on rotor is not with rotation speed change, it is necessarily parallel to the horizontal line of abscissa；In intershaft bearing
The defect characteristic octave frequency X of ringinner,iWith high pressure rotating speed n2,iWith low pressure rotating speed n1,iChange curve obtained by formula (7)
The defect characteristic octave frequency X of intershaft bearing outer shroudouter,iWith high pressure rotating speed n2,iWith low pressure rotating speed n1,iChange curve then by formula
(8) it is calculated：
In formula (7) and (8)：fouter,iFor intershaft bearing outer shroud characteristic frequency；D is the diameter of rolling element in intershaft bearing；DmIt is
Bearing pitch diameter；α is contact angle；Z is rolling element number；γiIt is the high low pressure rotor speed ratio under each speed conditions；finner,i
For intershaft bearing inner ring characteristic frequency；
Step 5: checking world live load situation suffered by intershaft bearing, avoid that synchronous impact occurs；
Figure is checked according to synchronous impact, if any straight line in showing the straight lines of fan blade numbers at different levels is in Xinner
+ 2%XinnerBoundary line and Xinner- 2%XinnerBetween boundary line；Or in the straight line of performance fan blade numbers at different levels
Any straight line be in Xouter+ 2%XouterBoundary line and Xouter- 2%XouterBetween boundary line, then show intermediary
Bearing inner ring characteristic frequency or outer shroud characteristic frequency are close with fan blade excitation force frequency, and intershaft bearing may occur at this time
Synchronous impact phenomenon；
When synchronous impact occurs, the load that load or outer-race ball track that intershaft bearing inner race is subject to are subject to is rolling element
The sum of impact force and fan blade exciting force width, at this time intershaft bearing be under severe loaded-up condition, forbid in this state
Lower long-term work；
If there is the straight line of the performance fan blade numbers at different levels is in by Xinner+ 2%XinnerBoundary line and Xinner-
2%XinnerIn the danger zone that boundary line is constituted, and more than engine operating speed range shown in abscissa 10% when；Or
Any straight line in the straight line of performance fan blade numbers at different levels described in person is in by Xouter+ 2%XouterBoundary line with
Xouter- 2%XouterBoundary line constitute danger zone in, and more than engine operating speed range 10% when, then it is necessary
Adjusted design parameter reduces the dynamic loading that intershaft bearing is born；
Step 6: reducing the dynamic loading that intershaft bearing is born；The born dynamic loading of the reduction intershaft bearing is to pass through height-regulating
Or high low pressure rotor speed ratio is turned down, to reduce the dynamic loading that intershaft bearing inner race and outer shroud are born；
So far, complete to engine high low pressure rotor speed than adjustment, avoid intershaft bearing and synchronous impact occur.
2. the derated design method of aero-engine intershaft bearing as described in claim 1, which is characterized in that draw the synchronization
Impacting the detailed process of check figure is：
I by inner ring the defect characteristic octave frequency XinnerIt is plotted on synchronous impact check figure with the rule of rotation speed change, obtains synchronous impact school
Inner ring the defect characteristic octave frequency X in core figureinnerCurve；
II draws inner ring the defect characteristic octave frequency number Xinner+ 2%XinnerAnd Xinner- 2%XinnerBoundary line, respectively obtain synchronization
The X in figure is checked in impactinner+ 2%XinnerBoundary line and Xinner- 2%XinnerBoundary line；
III by outer shroud the defect characteristic octave frequency XouterIt is plotted on synchronous impact check figure with the rule of rotation speed change, obtains synchronous impact school
Outer shroud the defect characteristic octave frequency X in core figureouterCurve；
IV draws outer shroud the defect characteristic octave frequency number Xouter+ 2%XouterAnd Xouter- 2%XouterBoundary line, respectively obtain synchronization
The X in figure is checked in impactouter+ 2%XouterBoundary line and Xouter- 2%XouterBoundary line；
V by the multiple F of fan blade numbers at different levels and the fan leaf the piece numbers at different levelsbk,jIt is marked on successively on synchronous impact check figure,
Obtain the straight line of one group of performance fan blade numbers at different levels.
3. the derated design method of aero-engine intershaft bearing as described in claim 1, which is characterized in that reducing stub
When holding the dynamic loading that inner race is born：
In figure is checked in the synchronous impact of drafting, by Xinner+ 2%XinnerBoundary line and XinnerIt is D that curve, which constitutes region,1, by
Xinner- 2%XinnerBoundary line and XinnerIt is D that curve, which constitutes region,2；
When the straight line of the performance fan blade numbers at different levels is in D1Length in inherent X-coordinate, which is more than, is in D2Inherent X-coordinate
On length when, high low pressure rotor speed ratio need to be turned down；Specifically, by former high low pressure rotor speed than with 0.1% step-length
It gradually turns down, until the straight line of the performance fan blade numbers at different levels is located at except the danger zone, and makes non-hazardous area
Domain is more than 90% of engine operating speed range shown in abscissa；
When the straight line of the performance fan blade numbers at different levels is in D1Length in inherent X-coordinate, which is less than, is in D2Inherent X-coordinate
On length when, high low pressure rotor speed ratio need to be turned up；Specifically, by former high low pressure rotor speed than with 0.1% step-length
It is gradually turned up, until the straight line of the performance fan blade numbers at different levels is located at except the danger zone, and makes non-hazardous area
Domain is more than 90% of engine operating speed range shown in abscissa.
4. the derated design method of aero-engine intershaft bearing as described in claim 1, which is characterized in that reducing stub
When holding the dynamic loading that outer-race ball track is born：
In figure is checked in the synchronous impact of drafting, by Xouter+ 2%XouterBoundary line and XouterIt is D that curve, which constitutes region,3, by
Xouter- 2%XouterBoundary line and XouterIt is D that curve, which constitutes region,4；
When the straight line of the performance fan blade numbers at different levels is in D3Length in inherent X-coordinate, which is more than, is in D4Inherent X-coordinate
On length when, high low pressure rotor speed ratio need to be turned down；Specifically, by former high low pressure rotor speed than with 0.1% step-length
It gradually turns down, until the straight line of the performance fan blade numbers at different levels is located at except the danger zone, and makes non-hazardous area
Domain is more than 90% of engine operating speed range shown in abscissa；
When the straight line of the performance fan blade numbers at different levels is in D3Length in inherent X-coordinate, which is less than, is in D4Inherent X-coordinate
On length when, high low pressure rotor speed ratio need to be turned up；Specifically, by former high low pressure rotor speed than with 0.1% step-length
It is gradually turned up, until the straight line of the performance fan blade numbers at different levels is located at except the danger zone, and makes non-hazardous area
Domain is more than 90% of engine operating speed range shown in abscissa.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1167788A1 (en) * | 2000-06-30 | 2002-01-02 | Techspace Aero S.A. | Sealing device of a squeeze film damper incorporated in a rolling element bearing |
| CN101988862A (en) * | 2009-07-30 | 2011-03-23 | 比亚迪股份有限公司 | Method for testing service life of rolling bearings |
| CN103912315A (en) * | 2014-04-14 | 2014-07-09 | 西北工业大学 | Structural dynamics design method of rotor of aerial engine |
-
2015
- 2015-07-30 CN CN201510458891.XA patent/CN105224713B/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1167788A1 (en) * | 2000-06-30 | 2002-01-02 | Techspace Aero S.A. | Sealing device of a squeeze film damper incorporated in a rolling element bearing |
| CN101988862A (en) * | 2009-07-30 | 2011-03-23 | 比亚迪股份有限公司 | Method for testing service life of rolling bearings |
| CN103912315A (en) * | 2014-04-14 | 2014-07-09 | 西北工业大学 | Structural dynamics design method of rotor of aerial engine |
Non-Patent Citations (5)
| Title |
|---|
| Joseph Poplawski 等.Effect of Internal Clearance on Load Distribution and Life of Radially Loaded Ball and Roller Bearings.《Tribology Transactions》.2012,第55卷(第2期),第245-265页. * |
| Michael Flouros 等.Active Outer Ring Cooling of High Loaded and High Speed Ball Bearings.《Asme Turbo Expo: Turbine Technical Conference & Exposition》.2013,第135卷(第8期),第1-8页. * |
| 中介轴承动态特性分析;郭向东 等;《轴承》;20130531;第2013年卷(第3期);第28-32,64页 * |
| 航空发动机中介轴承的故障特征与诊断方法;廖明夫 等;《航空动力学报》;20131231;第28卷(第12期);第2752-2758页 * |
| 航空发动机滚子轴承载荷分布分析及寿命计算;洪杰 等;《轴承》;20080602;第2008年卷(第4期);第1-4页 * |
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