CN206876374U - A kind of super-cooling waterdrop ice detection - Google Patents
A kind of super-cooling waterdrop ice detection Download PDFInfo
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- CN206876374U CN206876374U CN201720652805.3U CN201720652805U CN206876374U CN 206876374 U CN206876374 U CN 206876374U CN 201720652805 U CN201720652805 U CN 201720652805U CN 206876374 U CN206876374 U CN 206876374U
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Abstract
The utility model discloses a kind of super-cooling waterdrop ice detection, cylindrical-array including being arranged on test surfaces, the cylindrical-array includes the cylinder for setting gradually three diameters along same axis and being not mutually equal, the arrangement of the cylinder diameter that passes through is stepped up, two neighboring periphery does not contact, it is cavity structure in the cylinder, vibrating member is provided with the cavity structure, the periphery is provided with acceleration transducer, and signal acquiring system is connected with vibrating member and acceleration transducer；The utility model combines traditional mechanics icing detection method, overcome the defects of it cannot be distinguished from large and small yardstick super-cooling waterdrop, the advantages of having given full play to traditional mechanicses icing detection, large scale super-cooling waterdrop and small yardstick super-cooling waterdrop icing detection the two contradictions preferably are coordinated to take into account, preferably solves the problems, such as the icing detection of aircraft surfaces, this is for solving the design of the anti-deicing system of aircraft and ensureing that flight safety has the meaning of reality.
Description
Technical field
The present invention relates to aerodynamic scope, and it is (right under the conditions of the icing meteorology of high-altitude to be used for more particularly to one kind
The method and apparatus that the various objects easily to freeze carry out icing detection.
Background technology
Icing is a kind of physical phenomenon for being widely present in flight practice, be cause flight safety accident main hidden danger it
One.When aircraft is below the freezing point in environment temperature or in flight under the conditions of the icing meteorology near freezing point, the subcooled water in air
Drop strikes aircraft surfaces, and icing phenomenon is just easy in wing, empennage, rotor, air intake duct, windshield, antenna house, instrument
The parts surfaces such as sensor occur.Aircraft, which freezes, not only increases the weight of aircraft, and destroys the pneumatic outer of aircraft surfaces
Shape, Flow Field is changed, destroy aeroperformance, cause aircraft maximum lift to decline, flight resistance rises, under operating characteristics
Drop, stability reduce, and very big threat are caused to flight safety, the aircraft accident triggered by icing is of common occurrence, sternly
The icing of weight even can cause fatal crass.
1994, airplane crash occurred for U.S.'s ATR-72 commuter planes, and accident investigation group passes through prolonged research and analysis, sent out
It is the main reason for causing the aircraft accident, so that researcher increasingly payes attention to big chi that existing large scale super-cooling waterdrop, which freezes,
Spend research and detection that super-cooling waterdrop freezes.Large scale super-cooling waterdrop freezes (SLD, supercooled large droplet)
It is the super-cooling waterdrop that average water droplet diameter is more than 50 microns in the appendix Cs of FAR 25.The super-cooling waterdrop of this yardstick due to volume is big,
Quality weight, inertia are big, and air-flow followability is poor, and the dynamic phenomena such as easily deform, crush, its movement locus and small yardstick
Super-cooling waterdrop has larger difference, meanwhile, heat rate of release is slow during freezing so that its aircraft surface without
Method is freezed at once, and a part of aqueous water overflows to the downstream on anti-icing surface, so as to form what can not be prevented and kill off outside anti-ice formation
Pressure ridge phenomenon, this pressure ridge freeze bigger, more unpredictable and controlled to the hazard ratio leading edge of flight safety, are anti-icing systems
Design must issues that need special attention.And under the conditions of the complicated icing meteorology that large and small yardstick super-cooling waterdrop is mutually mixed, design
To develop a kind of icing detection method that can distinguish large and small yardstick super-cooling waterdrop and related device, be for aircraft it is anti-icing
System provides the key of reasonable trigger signal.
Current ice detection is mainly designed by principles such as optics, mechanics, electricity.Initial optics, which freezes, to be visited
It is the eyes by pilot to survey device, gradually adopts camera or video camera with the high sensitive components of CCD later.Due to flying
The environment of row device flight is more severe, often in the state of cloud flying, therefore, under the larger environment of this cloud and mist, this
The ice detection limitation of kind principle is larger, it is easy to situation about judging by accident.Now, optical fiber ice detection can be with
Overcome the influence to cloud and mist environment around, start the study hotspot as non-contact icing detection.This icing detection is to pass through
The method that the principles such as light reflection, scattering and transmission carry out icing detection.But this detection method also has shortcoming, the hair of optical fiber
It is not a spot light to penetrate end, but has larger-diameter area source, and the light of its transmitting has a big chunk, by
There occurs phenomena such as loss and deviation when in special porous media material this through ice, measurement accuracy and accuracy are caused
Larger is influenceed very greatly dependent on fibre optical transmission end shape, size and area etc., and by the inner structural features to freeze, and this is
Current this ice detection often reports false-alarm or the larger key reason of measurement error.The ice detection of electrical method
It is to utilize a kind of conductive filament ice detection that its resistance is designed by the rule changed under icing condition, but it is excessively
Sensitivity, even if raindrop or dust on its conductive filament surface, can also produce the change of signal, so as to influence the accurate of icing detection
Property.
The ice detection of mechanics method is still the ice detection of current main flow, in the aircraft of various models
It is a large amount of to use and apply, there is the characteristics of reliability is high.The ice detection of mechanics method produces vibration by various
Component or device, the icing detection rod for being installed on aircraft surface is vibrated, by measuring its eigentone, come
The method for estimating its surface icing quality.But it is exactly that cannot be distinguished by that this method, which also has the defects of many problems, main,
The ice-formation condition of large and small yardstick super-cooling waterdrop, so the shortcomings that icing detection accuracy is inadequate be present.And large and small yardstick supercooling
The icing protection of water droplet, design and energy requirements to anti-icing system differ greatly, and are the major reasons for influenceing flight safety.Mesh
Before, the foundation of SLD icing detector Exterior Surface Designs, shortage configuration design that researcher proposes, is more by warp
Test and intuitively guess is designed.The SLD icing detectors of the easy invention such as virtuous of Chinese aerodynamic investigation and centre of development,
Very similar and close in design method with the SLD icing detectors of the invention such as Central China University of Science and Technology Ge Jun peaks, final is outer
Shape is also almost identical, is the diamond structure of an expansion one contracting.And this icing detector flies in zero flying drilling angle or very little
Under the flying condition of the angle of attack, there may be certain effect in the condition for distinguishing large and small yardstick super-cooling waterdrop, but in larger flight
Under the conditions of the angle of attack, there is that measurement error is larger, or even the situation of large and small super-cooling waterdrop can not be differentiated.
The content of the invention
The purpose of the present invention is the defects of being directed to above-mentioned traditional mechanicses ice detection, carries out supplement and improved one kind
The novel ice detection method and device of large and small yardstick super-cooling waterdrop can be distinguished.
To achieve the above object, the present invention adopts the following technical scheme that：
A kind of super-cooling waterdrop ice detection, including the cylindrical-array of test surfaces is arranged on, the cylindrical-array bag
The cylinder for setting gradually three diameters along same axis and being not mutually equal is included, the arrangement of cylinder passes through diameter progressively
Increase, two neighboring periphery do not contact；
It is cavity structure in the cylinder, vibrating member is provided with the cavity structure, the periphery, which is provided with, is added
Velocity sensor, signal acquiring system is connected with vibrating member and acceleration transducer.
In the above-mentioned technical solutions, direction of flow of the cylindrical-array along air is divided into the first cylinder, the second cylinder
With the 3rd cylinder, the upper shock limiting streamline of air stream and lower shock limiting streamline are to bypass the first cylinder leading edge upper surface with
Limiting streamline and lower shock limit stream are hit in the critical air streamline on surface, being arranged on for second cylinder and the 3rd cylinder
Between line.
In the above-mentioned technical solutions, the diameter of second cylinder is equal to the upper percussion flow of the second body diameter region
The distance between line and lower shock streamline.
In the above-mentioned technical solutions, the diameter of the 3rd cylinder be equal to the 3rd body diameter region upper shock streamline and
The distance between lower shock streamline.
In the above-mentioned technical solutions, the signal acquiring system includes dynamic analysis module, the dynamic analysis module
Signal input part is connected respectively to the acceleration transducer on cylinder.
In the above-mentioned technical solutions, the signal acquiring system includes power amplifier, and the power amplifier passes through each
From switch be connected on the vibrating member in each cylinder.
A kind of polycylindser array icing detection method, when air stream flows to polycylindser array from far field, cylindrical-array has
Three follow air stream to hit in same axis and axis direction three cylinders consistent with air flow field direction, super-cooling waterdrop
Hit the surface to the first cylinder, super-cooling waterdrop and the first periphery hit after generation splash phenomena, the subcooled water sputtered
Drop follows that air-flow continues to strike the second cylinder or the surface of the 3rd cylinder is frozen；
Vibrated by each cylinder of external drive, and periphery is obtained by periphery data acquisition
Vibration frequency, amplitude and phase parameter are vibrated, with the periphery parameter gathered after icing and the periphery parameter of icing money
Carry out calculating the volume for obtaining super-cooling waterdrop.
In the above-mentioned technical solutions, the cylindrical-array is not mutually equal including setting gradually three diameters along same axis
Cylinder, the arrangement of the cylinder diameter that passes through is stepped up, and two neighboring periphery does not contact.
A kind of polycylindser array icing detection method, it is characterised in that the upper shock limiting streamline of air stream and lower shock pole
Current limit line is to bypass the critical air streamline of the first cylinder leading edge upper and lower surface, second cylinder and the 3rd cylinder
It is arranged on and hits between limiting streamline and lower shock limiting streamline.
In the above-mentioned technical solutions, the diameter of second cylinder is equal to the upper percussion flow of the second body diameter region
The distance between line and lower shock streamline.
In the above-mentioned technical solutions, the diameter of the 3rd cylinder be equal to the 3rd body diameter region upper shock streamline and
The distance between lower shock streamline.
In the above-mentioned technical solutions, air stream includes the super-cooling waterdrop of two kinds of sizes, and a kind of being averaged for super-cooling waterdrop is straight
Footpath is no more than 50 microns, and the average diameter of another super-cooling waterdrop is more than 50 microns.
In the above-mentioned technical solutions, super-cooling waterdrop of the average diameter no more than 50 microns is in knockout process, its mistake
The motion streamline of cold water drop is identical with air flow line, and super-cooling waterdrop and the first cylinder bump against, and are frozen in the first periphery,
And second cylinder and the 3rd periphery icing phenomenon does not occur.
In the above-mentioned technical solutions, second cylinder and the 3rd cylinder are in the upper and lower shock limit stream of the first cylinder
In line, that is, in the droplet shadowed zone in the first cylinder.
In the above-mentioned technical solutions, in knockout process, it is subcooled super-cooling waterdrop of the average diameter more than 50 microns
Motion streamline and the air flow line of water droplet have differences, and the skew of the upper and lower shock limiting streamline of super-cooling waterdrop is small, super-cooling waterdrop with
After first cylinder hits, cylinder front edge area both sides that the water droplet that sputters follows air-flow to strike the second cylinder or the 3rd cylinder
Frozen.
In the above-mentioned technical solutions, super-cooling waterdrop of the average diameter more than 50 microns strikes the first periphery
When, water droplet will not freeze at once, and the aqueous water that part is not freezed is toward the overflow of cylinder downstream, if the surface perimeter of the first cylinder is not
Enough freezing, the aqueous water not freezed will be blown to the second cylinder front edge area surface by air-flow, and in the leading edge of the second cylinder,
Tied the front edge area for blowing down the 3rd cylinder to the overflow of cylinder downstream and then by air-flow of the aqueous water that part is not freezed equally
Ice.
In summary, by adopting the above-described technical solution, the beneficial effects of the invention are as follows：
The present invention is from another vision, use cylindrical shape the simplest, using this profile of cylinder to surrounding stream
Field influences the characteristics of small, by the permutation and combination of multiple cylinders, realizes the purpose of large and small yardstick super-cooling waterdrop detection, has non-
Chang Rongyi implements, is simple and practical, being adapted to the characteristics of various angles-of-attack conditions.
Present invention incorporates traditional mechanics icing detection method, on this basis, overcomes it and cannot be distinguished from large and small chi
The defects of spending super-cooling waterdrop, the advantages of having given full play to traditional mechanicses icing detection, preferably coordinate to take into account large scale supercooling
Water droplet and small yardstick super-cooling waterdrop icing detection the two contradictions, preferably solve the problems, such as the icing detection of aircraft surfaces, this is right
In the design for solving the anti-deicing system of aircraft and ensure that flight safety has the meaning of reality.
The present invention be directed to icing meteorology condition (including the icing meteorology bar under experimental simulation environment and Real Atmosphere environment
Part), using the method for polycylindser array icing detection, it is directly used in and aircraft, wind energy conversion system and transmission line of electricity etc. is easily frozen
Position carries out the process and purpose of icing detection.
Brief description of the drawings
Examples of the present invention will be described by way of reference to the accompanying drawings, wherein：
Fig. 1 is polycylindser array icing detection method schematic diagram under the conditions of small yardstick super-cooling waterdrop；
Fig. 2 is polycylindser array icing detection method schematic diagram under the conditions of large scale super-cooling waterdrop；
Fig. 3 is super-cooling waterdrop ice detection schematic diagram.
Embodiment
All features disclosed in this specification, or disclosed all methods or during the step of, except mutually exclusive
Feature and/or step beyond, can combine in any way.
The super-cooling waterdrop in far field is divided into two kinds, when large scale super-cooling waterdrop (average diameter is more than 50 microns), second, small
Yardstick super-cooling waterdrop (average diameter is no more than 50 microns).Air stream 1 flows to polycylindser array from far field in Fig. 1, Fig. 2, supercooling
The impact of air currents that water droplet 2 follows arrives or around polycylindser surface, (average diameter is less than 50 microns of water to small yardstick super-cooling waterdrop
Drip) because quality is relatively low, inertia is smaller, then air stream followability is good, and the motion streamline of its water droplet is almost identical with air flow line,
The upper shock limiting streamline 3 of air stream and lower shock limiting streamline 4 are to bypass facing for the upper and lower surface of leading edge of the first cylinder 6 respectively
Boundary's air flow line, accordingly, the upper and lower shock limiting streamline of small yardstick super-cooling waterdrop are consistent with 3,4.By numerical computations, if
The diameter for counting the second cylinder 7 is just equal to the distance between upper and lower shock streamline, and so, small yardstick super-cooling waterdrop 2 generally only exists
Icing 5 occurs for cylinder front edge area.And it is corresponding, analyzed from theoretical and numerical computations, the second cylinder 7, the surface of the 3rd cylinder 8
Icing phenomenon does not occur, because two cylinders are in the upper and lower shock limiting streamline of the first cylinder below, that is, in
In the droplet shadowed zone of one cylinder, so, usually not super-cooling waterdrop strikes the second cylinder and the 3rd periphery.And if
From far field follow air stream flow into be large scale super-cooling waterdrop 2, because its quality is higher, inertia is larger, the followability of air-flow
Poor, therefore, motion streamline and the air flow line of large scale super-cooling waterdrop differ greatly, more difficult generation deviation.So phase
The upper and lower shock limiting streamline skew answered is smaller, is so easier to the front edge area two in the second cylinder 7 and the 3rd cylinder 8
Icing phenomenon 9,10 occurs for side surface.Moreover, large scale super-cooling waterdrop is easily following air stream because its volume and size are big
Occur to crush in dynamic process, phenomena such as also easily splashing when striking cylinder wall surface admittedly, sputter solid wall surface
Part water droplet easily follow air-flow to strike cylinder front edge area both sides below.Meanwhile large scale super-cooling waterdrop strikes
Cylindrical surface portion, because its volume is larger, it is not easy to freeze at once, the aqueous water that part is not freezed is also easily toward cylinder
Downstream overflow, if the surface perimeter of the first cylinder is not enough freezed, the aqueous water not freezed will be blown to the second circle by air-flow
Post front edge area surface.Therefore, icing phenomenon will easily occur for the second cylinder front edge area both side surface.According to point above
Analysis, similar, also similar icing phenomenon will occur for the 3rd cylinder front edge area both side surface.
Using mass conservation law, for small yardstick super-cooling waterdrop, situation is relatively simple, the icing amount of the first periphery
W1 is equal to the super-cooling waterdrop quality in the upper and lower shock limiting streamline of small yardstick super-cooling waterdrop, and is directed to large scale subcooled water
Most icing phenomenon, the first cylinder icing amount (W1), the second cylinder icing amount occur for drop, the first cylinder leading edge surface
(W2), the gross mass (W) of the 3rd cylinder icing amount (W3), equal to the super-cooling waterdrop quality summation in upper and lower shock limiting streamline.
Numerical computations and theory analysis are aided in again, can be counter to release large and small yardstick subcooled water by the icing amount of each periphery
The Liquid water content of drop and average drop diameter.Spacing and diameter between each cylinder, can also pass through Fluid Mechanics Computation
Method be determined.
Ice detection composition is as shown in Figure 3.
In figure：
6 be the first cylinder：This is first cylinder of polycylindser array of the present invention, is minimum diameter in polycylindser array
Cylinder, it is mainly used in collecting the large scale super-cooling waterdrop of small yardstick super-cooling waterdrop and the overwhelming majority.
7 be the second cylinder：This is second cylinder of polycylindser array of the present invention, and diameter is more bigger than the first cylinder, and its is straight
Footpath D1 and the distance between the upper and lower shock limiting streamline of air stream are equal or close, are mainly used in collecting a small amount of not by the
Because volume is big, quality weight the dynamics such as broken, splashing occur for the super-cooling waterdrop that one cylinder is collected into, this part super-cooling waterdrop
The possibility of phenomenon is bigger, and the second cylinder, the front edge area surface of the 3rd cylinder are easily struck in the presence of air-flow, so as to
Both sides form the icing profile of horn shape above and below the second cylinder, the 3rd cylinder front edge area.
8 be the 3rd cylinder：This is the 3rd cylinder of polycylindser array of the present invention, and diameter is more bigger than the second cylinder, function
The supplement as the second cylinder, for supplement collect a small amount of large scale super-cooling waterdrop not being collected into by the first two cylinder and
The overflow water not freezed, so as to form a small amount of icing in the 3rd cylinder front edge area both sides.
13 be vibration component：This is a kind of piezoelectric ceramics axially or radially vibrated or the high frequency vibrating of other automatically controlled modes
Dynamic component, or the dither eccentric wheel of mechanical system, can produce higher vibration frequency, vibration frequency is from several hertz
Several KHzs can be arrived.Because the eigentone of object under the conditions of different quality is different, therefore, according to intrinsic vibration frequency
The relation of rate and cylinder mass property, the additional mass of the periphery can be obtained, so as to obtain the knot of periphery
Ice quality, according to the parameter such as the frozen surface product of covering periphery and the density of ice sheet, it is thick that average icing can be obtained
Degree, and the icing quality in the unit interval, namely icing intensity.
14 be power line：This is the conductor cable being connected between power supply, power amplifier and vibration component, is risen
Effect and function to transmission electric energy.
15 be switch：This is for controlling power supply and vibrating the electronic component of switching Electricity Functional between component.
16 be power amplifier：This is the instrument being connected with arbitrary-function generator, by caused by function generator not
Same type signal is biased, filters and gain, the signal of vibration is reached the requirement for destroying or peeling off ice sheet.
17 be power supply：This is the part that electric energy is provided for various instruments, sensor, can be by the 220V industry of routine
Voltage carries out rectification, transformation etc., so as to produce various instruments, the power supply unit needed for sensor.
18 be acceleration transducer：Showed acceleration characteristic is vibrated for measuring anti-ice components surface and producing, with this
To calculate and analyze the parameters such as vibration frequency, amplitude and phase.
19 be collection signal wire：This is the cable for transmitting various measurement signals, for connecting various instruments, sensor and number
It is input to according to acquisition module, and by the electric signal of collection in data acquisition module.
20 be dynamic analysis module：This be for gathering, analyzing the vibration signal measured by acceleration transducer, can be with
Obtain the intrinsic frequency caused by forward and backward anti-ice components surface vibration that freezes.By measuring the intrinsic of piezoelectric fabric vibration of thin membrane
Frequency, also can determine whether anti-icing surface freezes.If anti-icing surface freezes, the intrinsic frequency of piezoelectric fabric film will
Vary widely, if surface does not freeze, the intrinsic frequency of piezoelectric fabric film will keep constant.The intrinsic frequency
Thickness that rate freezes with vibration surface, icing type etc. are relevant, can be demarcated by largely testing, by vibration surface
Intrinsic frequency get up with icing thickness, icing type association, establish quantitative relationship, for vibration ice detachment adjustment vibration frequency
The parameters such as rate, amplitude and phase, which provide, to be differentiated and refers to.
21 be icing detection surface：This is the object that the present invention applies, and can be head, fuselage, wing and the tail of aircraft
Wing surface, can be blade surface, the transmission pressure surface of wind energy conversion system, or the related dress of other national economy such as bullet train
The standby parts surface for needing icing detection.
The present invention is icing detection method and device based on polycylindser array, and utilization is the most universal and the simplest round
Post profile, according to the air-flow followability feature of large and small yardstick super-cooling waterdrop, the power such as the broken of large scale super-cooling waterdrop, splashing
Learn characteristic, and collections characteristic of the cylinder to different scale super-cooling waterdrop and one kind for designing can distinguish large and small yardstick and be subcooled
The icing detection method and device of water droplet, this novel ice detection device and method, it is on mechanics icing detection method basis
On a kind of distillation, be to carry out periodicity to icing detection cylinder using the mechanically or electrically method for oscillating of control or electric pulse mode to shake
It is dynamic, its vibration frequency and Oscillation Amplitude parameter are obtained using accelerometer or strain gauge etc., then, according to cylinder intrinsic vibration frequency
Relation between rate and mass property, obtain additional icing quality and average thickness of icing detection periphery etc. and flight is pacified
Complete vital parameter, for as the signal and foundation for starting aircraft de-icing systems.
First of all, it is necessary to carry out the calculating and measurement of eigentone to each clean cylinder, obtain it and do not freeze
Under the conditions of the parameter such as vibration frequency, as periphery icing thickness and the reference value of icing Mass Calculation；
Periodically start the mechanical system vibration cam set in cylinder or the piezoelectric ceramics of automatically controlled mode or other means
Vibration component, periodic vibration strategy can largely reduce the energy expenditure needed for this icing detection, make its discontinuity
The vibration for producing certain frequency, amplitude and phase；
The sensors such as the accelerometer or strain gauge that are set using periphery are measured to the vibration frequency of cylinder, are obtained
The signal obtained is inputted into dynamic analysis module, carries out the calculating and analysis of intrinsic frequency；
If cylinder does not have icing phenomenon, its intrinsic frequency does not change, and function generator and power amplifier are kept
Original vibration parameters and its gain, biasing etc., keep step a periodic vibration strategy；
If having met with icing in cylinder vibration processes, the parameter such as vibration frequency of the icing cylinder will change,
Vibration signal after being frozen using the measurement of the sensors such as accelerometer or strain gauge, and be input in dynamic analysis module and divided
Analysis calculates, and obtains the eigentone of icing cylinder；
According to the relation icing quality and icing thickness and cylinder intrinsic frequency demarcated in advance between, by consolidating after icing
There is vibration frequency to be calculated by data acquisition module, and feed back in aircraft de-icing systems, as the triggering for starting deicing
Signal.
Distance and method for determining diameter between cylinder：
1) utilize Fluid Mechanics Computation method, using low speed it is incompressible when equal Navier-Stokes equations, to polycylindser
Flow field carries out corresponding numerical simulation around array, obtains the air flow field around polycylindser array.
2) on the basis of Flow Field Numerical Calculation around polycylindser array, using Lagrangian method, according to newton second
Law, the super-cooling waterdrop of stream field entrance follow the movement locus of air flow to carry out numerical simulation, obtain fixed subcooled water
Limiting streamline (3) and lower shock limiting streamline (4) are hit in drop, as the tangent line of the body diameter of determination second and the 3rd, emphasis
Obtain the upper and lower shock limiting streamline of critical 50 microns of average water droplet diameter.Accordingly, the second body diameter (D2) and the 3rd circle
Column diameter (D3) is equal to the distance between upper and lower shock limiting streamline.Meanwhile the first spacing between cylinder and the second cylinder
Spacing H2 between H1, the second cylinder and the 3rd cylinder, it is impossible to it is excessive, can not be too small, it then follows in equidistant principle, true
After the diameter of second, third fixed cylinder, due to the super-cooling waterdrop for different scale, upper and lower shock limiting streamline is true
Fixed, therefore, spacing H1 and H2 can also be determined.Or spacing H1 and H2 are first determined, then pass through fixed upper and lower shock limit stream
Line, determine the diameter (D2, D3) of second, third cylinder.
H1≈(D2-D1)/2 (1)
H2≈(D3-D2)/2 (2)
3) because the present invention relates to large scale super-cooling waterdrop, it easily becomes during air flow is followed
The dynamic phenomena such as shape, broken, resistance can also change with changing with respect to Reynolds number, therefore, small yardstick super-cooling waterdrop
The classical ball resistance formula of resistance selection, and the resistance of large scale super-cooling waterdrop increases then on the basis of ball resistance formula
Add the influence of the dynamics such as deformation, broken, make the seizure of its movement locus more accurate.
4) when super-cooling waterdrop is close to body surface, due to super-cooling waterdrop inertia ratio air particle it is big, therefore be subcooled
Water drop motion track will not so change acutely as the movement locus of air particle, will keep as far as possible original movement locus and
Direction.For large scale super-cooling waterdrop, because its quality and inertia are bigger, therefore it is easier to deviate air flow line, so as to be formed
The more slow movement locus line of change, therefore, these large scale super-cooling waterdrops are also easier to strike second and the 3rd cylinder
Leading edge both sides, so as to form overflow ice.
5) in all super-cooling waterdrop movement locus clusters, two motion rails with the upper and lower plane tangent of cylinder leading edge
Mark is upper and lower shock limiting streamline.All super-cooling waterdrops within this two movement locus, will all impinge upon cylinder table
Face.Super-cooling waterdrop outside two tangent movement locus, cylinder will be all bypassed without striking periphery.This two
Within the tangent movement locus of bar, it is exactly that super-cooling waterdrop is hit to periphery to impinge upon the super-cooling waterdrop quantity on periphery
The amount of hitting.
The determination method of small yardstick super-cooling waterdrop average diameter：
For simplicity, it is assumed that the diameter of super-cooling waterdrop is uniformity.
(1) by calculating and testing, the eigentone F of clean cylinder is obtained.
(2) different additional mass Wi is pasted in clean periphery, with reference to calculating and testing, is obtained under different additional mass
The new eigentone Fn of cylinder, and establish the frequency of correlation and the demarcation relational expression of additional mass, carried for icing detection
Referred to for nominal data.
(3) polycylindser array icing detection system is placed into icing wind tunnel, under the conditions of carrying out different icing meteorologies
Freeze experiment, and the eigentone of measurement surface icing cylinder, and compared with demarcating relational expression, further amendment is intrinsic
Demarcation relation between frequency Fn and icing additional mass Wi.
Wi=f (Fn) (3)
(4) assume that the super-cooling waterdrop in incoming be small yardstick super-cooling waterdrop, average diameter Dw, density ρ, so, singly
Individual super-cooling waterdrop quality dW1 meets following relation：
The π of dW=ρ 4/3 (Dw/2)3 (4)
(5) ice field reason is visited according to vibration, with reference to demarcation relational expression above, the ice that the first periphery is tied can be obtained
Quality is W1, and ice sheet averag density is ρ 1, can obtain the icing volume V1 and its average thickness h1 of periphery：
V1=W1/ ρ 1 (5)
H1=W1/ (ρ 1A1) (6)
Wherein, A1 is the icing area of the first periphery.
(6) the super-cooling waterdrop quantity NW1 that periphery freezes can also be obtained by following formula：
NW1=W1/dW (7)
In addition, the average icing thickness h 1 of periphery can also calculate according to following relational expression：
H1=NW14/3 π (Dw/2)3/A1 (8)
(7) assume incoming in super-cooling waterdrop Liquid water content be LWC, be clipped in it is upper and lower shock limiting streamline between
Inflow open area is A, speed of incoming flow V, and (for example small yardstick super-cooling waterdrop is completed in moment for θ for the freezing fraction of super-cooling waterdrop
Freeze, then θ=1, large scale super-cooling waterdrop can not be completed to freeze in moment, then θ ＜ 1), in unit interval t, in upper and lower
The super-cooling waterdrop hit in limiting streamline meets following relational expression：
W1=LWCVAt θ (9)
And hence it is also possible to obtain the super-cooling waterdrop Liquid water content LWC in incoming：
LWC=W1/ (VAt θ) (10)
Or Liquid water content LWC can also be calculated as follows：
In formula：Eb--- the collection efficiency of periphery, obtained by Fluid Mechanics Computation computational methods；
V --- far field flow speed, m/s；
T --- freezing time, s.
(8) according to the Liquid water content LWC above obtained, the supercooling in unit area or unit volume can be obtained
Water droplet quality.Fixed upper and lower shock limiting streamline is above obtained by numerical computations, is clipped between two limiting streamlines
Super-cooling waterdrop can just strike periphery, and other super-cooling waterdrops can then follow air stream away from cylinder.
The method that the determination method of large scale super-cooling waterdrop average diameter is similar to small water droplet, is satisfied by step (1)-(4)
And its corresponding formula, difference are icing phenomenon can occur in the second cylinder.
(9) ice field reason is visited according to vibration, with reference to demarcation relational expression above, the ice that the first periphery is tied can be obtained
Quality is W1, and ice sheet averag density is ρ 1, can obtain the icing volume V1 and its average thickness h1 of periphery：
V1=W1/ ρ 1 (12)
H1=W1/ (ρ 1A1) (13)
Wherein, A1 is the icing area of the first periphery.
The ice quality that second periphery is tied is W2, and ice sheet averag density is ρ 2, can obtain the icing of periphery
Volume V2 and its average thickness h2：
V2=W2/ ρ 2 (14)
H2=W2/ (ρ 2A2) (15)
The super-cooling waterdrop quantity NW1 that (10) first peripheries freeze can also be obtained by following formula：
NW1=W1/dW (16)
The super-cooling waterdrop quantity NW2 that second periphery freezes can also be obtained by following formula：
NW2=W2/dW (17)
NW3=W3/dW (18)
NW=NW1+NW2+NW3 (19)
(11) the super-cooling waterdrop Liquid water content LWC in incoming：
LWC=(W1+W2+W3)/(VAt θ) (20)
Or Liquid water content LWC can also be calculated as follows：
The invention is not limited in foregoing embodiment.The present invention, which expands to, any in this manual to be disclosed
New feature or any new combination, and disclose any new method or process the step of or any new combination.
Claims (6)
1. a kind of super-cooling waterdrop ice detection, it is characterised in that the cylindrical-array including being arranged on test surfaces, the circle
Post array includes the cylinder for setting gradually three diameters along same axis and being not mutually equal, and the arrangement of cylinder passes through
Diameter is stepped up, and two neighboring periphery does not contact；
It is cavity structure in the cylinder, vibrating member is provided with the cavity structure, the periphery is provided with acceleration
Sensor, signal acquiring system is connected with vibrating member and acceleration transducer.
A kind of 2. super-cooling waterdrop ice detection according to claim 1, it is characterised in that the cylindrical-array along
The direction of flow of air is divided into the first cylinder, the second cylinder and the 3rd cylinder, the upper shock limiting streamline of air stream and lower shock
Limiting streamline is to bypass the critical air streamline of the first cylinder leading edge upper and lower surface, second cylinder and the 3rd cylinder
Be arranged on hit limiting streamline and it is lower shock limiting streamline between.
A kind of 3. super-cooling waterdrop ice detection according to claim 2, it is characterised in that second cylinder it is straight
Footpath is equal to the distance between the upper shock streamline of the second body diameter region and lower shock streamline.
A kind of 4. super-cooling waterdrop ice detection according to claim 3, it is characterised in that diameter of the 3rd cylinder etc.
In the distance between the upper shock streamline of the 3rd body diameter region and lower shock streamline.
A kind of 5. super-cooling waterdrop ice detection according to claim 1, it is characterised in that the signal acquiring system
Including dynamic analysis module, the signal input part of the dynamic analysis module is connected respectively to the acceleration transducer on cylinder.
A kind of 6. super-cooling waterdrop ice detection according to claim 5, it is characterised in that the signal acquiring system
Including power amplifier, the power amplifier is switched on the vibrating member being connected in each cylinder by respective.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107132278A (en) * | 2017-06-07 | 2017-09-05 | 中国空气动力研究与发展中心低速空气动力研究所 | A kind of polycylindser array icing detection method |
| CN109767518A (en) * | 2018-12-14 | 2019-05-17 | 南京航空航天大学 | The Backstipping design of meteorologic parameter MVD is determined based on wing icing thickness |
| CN114048552A (en) * | 2022-01-12 | 2022-02-15 | 中国空气动力研究与发展中心计算空气动力研究所 | Rotor wing surface large water drop mass flow calculation method considering secondary impact and terminal |
| CN114754971A (en) * | 2022-06-15 | 2022-07-15 | 中国空气动力研究与发展中心低速空气动力研究所 | Method and device for testing height of waterless shielding area |
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2017
- 2017-06-07 CN CN201720652805.3U patent/CN206876374U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107132278A (en) * | 2017-06-07 | 2017-09-05 | 中国空气动力研究与发展中心低速空气动力研究所 | A kind of polycylindser array icing detection method |
| CN109767518A (en) * | 2018-12-14 | 2019-05-17 | 南京航空航天大学 | The Backstipping design of meteorologic parameter MVD is determined based on wing icing thickness |
| CN114048552A (en) * | 2022-01-12 | 2022-02-15 | 中国空气动力研究与发展中心计算空气动力研究所 | Rotor wing surface large water drop mass flow calculation method considering secondary impact and terminal |
| CN114048552B (en) * | 2022-01-12 | 2022-03-29 | 中国空气动力研究与发展中心计算空气动力研究所 | Rotor wing surface large water drop mass flow calculation method considering secondary impact and terminal |
| CN114754971A (en) * | 2022-06-15 | 2022-07-15 | 中国空气动力研究与发展中心低速空气动力研究所 | Method and device for testing height of waterless shielding area |
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