CN112985347B - Method for calculating roughness of icing surface of airplane - Google Patents

Method for calculating roughness of icing surface of airplane Download PDF

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CN112985347B
CN112985347B CN202110511952.XA CN202110511952A CN112985347B CN 112985347 B CN112985347 B CN 112985347B CN 202110511952 A CN202110511952 A CN 202110511952A CN 112985347 B CN112985347 B CN 112985347B
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liquid water
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water
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CN112985347A (en
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李维浩
易贤
刘宇
任靖豪
王强
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Low Speed Aerodynamics Institute of China Aerodynamics Research and Development Center
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
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Abstract

The invention is suitable for the technical field of airplane icing, and provides a method for calculating the roughness of an icing surface of an airplane, which comprises the following steps: taking water droplet size distribution, selecting according to the water droplet size distributionnParticle size of seed water dropd i And calculating the corresponding mass fraction
Figure 100004_DEST_PATH_IMAGE001
(ii) a Respectively calculate outnParticle size of seed water dropd i Corresponding local liquid water collection coefficient
Figure 808621DEST_PATH_IMAGE002
，sThe distance between the impact point of the water drop and the object plane of the front edge point of the airplane wing; calculating the local average volume diameter of liquid water dropMVD(s) And local liquid water contentLWC(s) (ii) a Using the calculated local liquid water contentLWC(s) And local liquid water droplet mean volume diameterMVD(s) Calculating the roughness of the wing wallk s (s). The invention adopts the average volume diameter of the liquid water drops changed after the water drops are redistributedMVDAnd liquid water contentLWCCalculating the roughness of the wall of the airfoilk s . The roughness calculated by the method is more suitable for the actual situation and more accurate, and the icing condition of the surface of the wing can be accurately judged in the follow-up process.

Description

Method for calculating roughness of icing surface of airplane
Technical Field
The invention relates to an aircraft icing calculation method, in particular to an aircraft icing surface roughness calculation method.
Background
When an aircraft is flying at a temperature below freezing, if a cloud layer containing supercooled water droplets is encountered, the water droplets in the cloud layer impact on the surface of the aircraft, and icing can be caused. Icing can change the flow around the aircraft, resulting in changes in component load distribution, thereby destroying aerodynamic performance, affecting maneuverability and stability of the aircraft, and compromising flight safety.
Numerical calculations can quickly predict the severity of aircraft icing. In the icing numerical value calculation, the convective heat transfer is one of important factors influencing the icing calculation result, and the convective heat transfer coefficient has great influence on the icing growth rate and the freezing coefficient. When the surface of the airplane is not frozen, the surface is considered to be smooth, the influence of roughness on heat convection is small, and when the roughness value is equal to or higher than the thickness of the boundary layer, the heat convection process is greatly enhanced. Meanwhile, the roughness of the ice surface also affects the water collection coefficient, the friction coefficient and the like, and these changes also affect the calculation result of ice, so it is very important to correctly calculate the roughness.
The equivalent grit roughness height model is a widely used roughness calculation model that considers the roughness of the ice surface and the liquid water contentLWCTemperature of incoming airTAnd velocity of airvIt is related. Through further analysis of experimental data, the average volume diameter of liquid water drops in the air is consideredMVDThe effect of (c), while the effect of the velocity of the streaming air is negligible.
Although the equivalent grit roughness height model is a classical roughness model, there are certain disadvantages: after determining the parameters of the frozen cloud and mist field, the content of the used liquid water is calculated in the whole freezing numerical valueLWCRefers to the liquid water content of the incoming streamLWC、Using average volume diameter of liquid water dropsMVDRefers to the average volume diameter of the liquid water drops flowing inMVD. And the liquid water content of the incoming flowLWCAnd mean volume diameter of incoming liquid water dropletsMVDThe cloud and fog field parameters are fixed values after being determined, and the values of the cloud and fog field parameters are kept unchanged in the whole icing calculation and cannot be changed along with the change of the surface position. In fact, after the liquid droplets impact the aircraft surface, they are redistributed and the liquid water contentLWC、Average volume diameter of liquid water dropMVDEtc. will change and no longer equal the incoming liquid water contentLWCAnd mean volume diameter of incoming liquid water dropletsMVD。Therefore, the incoming liquid water content is adoptedLWCAnd mean volume diameter of incoming liquid water dropletsMVDThe calculated roughness values deviate significantly from the actual values.
Disclosure of Invention
In order to fully consider the change of cloud and mist parameters after water drops impact the surface of an object, the invention provides an aircraft icing surface roughness calculation method considering water drop redistribution, which comprises the following steps:
step S10: selecting the water drop particle size distribution, and selecting according to the water drop particle size distributionnParticle size of seed water drop
Figure 191386DEST_PATH_IMAGE001
And calculating the particle diameter of each water drop
Figure 394834DEST_PATH_IMAGE002
Corresponding mass fraction
Figure 909123DEST_PATH_IMAGE003
；
Figure 946349DEST_PATH_IMAGE004
The number of the particle size of the water droplets,nthe number of types of the particle size of the water droplets,
Figure 490463DEST_PATH_IMAGE005
；
step S20: respectively calculate out
Figure 153394DEST_PATH_IMAGE006
Particle size of seed water drop
Figure 771457DEST_PATH_IMAGE007
Corresponding local liquid water collection coefficient
Figure 979585DEST_PATH_IMAGE008
，
Figure 417519DEST_PATH_IMAGE009
Object plane of water drop impact point from front edge point of airplane wingA distance;
step S30: calculating the local liquid water content
Figure 713503DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 186072DEST_PATH_IMAGE011
；
Step S40: using the calculated local liquid water content
Figure 876686DEST_PATH_IMAGE012
And local liquid water droplet mean volume diameter
Figure 801916DEST_PATH_IMAGE013
Calculating the roughness of the wing wall
Figure 557383DEST_PATH_IMAGE014
。
In the above scheme, the local liquid water content
Figure 150038DEST_PATH_IMAGE010
Means that: when the liquid water impacts the object, the liquid water content of the redistributed liquid water drops, namely the liquid water content of the micro elements on the surface of the object;
average volume diameter of local liquid water drop
Figure 513017DEST_PATH_IMAGE013
Is worth: when the water drop impacts the surface of the object element, the average volume diameter of the liquid water drop after the liquid water drop is redistributed.
Further, in step S30, the local liquid water content
Figure 191123DEST_PATH_IMAGE010
The calculation formula of (2) is as follows:
Figure 219122DEST_PATH_IMAGE015
in the formula:
Figure 666284DEST_PATH_IMAGE016
is the incoming liquid water content.
Further, in step S30, the local liquid water droplet has an average volume diameter
Figure 652695DEST_PATH_IMAGE013
The calculation formula of (2) is as follows:
Figure 129681DEST_PATH_IMAGE017
Figure 226950DEST_PATH_IMAGE018
in the formula (I), the compound is shown in the specification,ta coefficient of 0 to 1,ksatisfies the following conditions:
Figure 528619DEST_PATH_IMAGE019
and is and
Figure 436663DEST_PATH_IMAGE020
，
Figure 338629DEST_PATH_IMAGE021
is as followskThe diameter of the seed water drops is such that,
Figure 36326DEST_PATH_IMAGE022
is as followsk+1The diameter of the seed water droplet.
Further, in step S40, the roughness
Figure 707348DEST_PATH_IMAGE014
The calculation formula of (2) is as follows:
Figure 35561DEST_PATH_IMAGE023
in the formula: c is the characteristic length and T is the temperature;
Figure 972293DEST_PATH_IMAGE024
Figure 880206DEST_PATH_IMAGE025
Figure 172778DEST_PATH_IMAGE026
。
compared with the prior art, the invention has the beneficial effects that:
the invention considers that the water drops are redistributed after the liquid water is adopted to impact the surface of the wing, so the liquid water content of the wingLWCAnd liquid level mean volume diameterMVDThe liquid water content used in the traditional roughness calculation method changes correspondinglyLWCAnd liquid level mean volume diameterMVDRespectively the liquid water content of the incoming flow
Figure 406314DEST_PATH_IMAGE027
And incoming liquid water mean volume diameter
Figure 33604DEST_PATH_IMAGE028
. In order to fully consider the influence of the full distribution of the liquid water drops on the roughness calculation, the invention provides that the local liquid water content is adopted
Figure 322372DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 453139DEST_PATH_IMAGE013
Roughness calculations were performed for the parameters. And using the local liquid water content
Figure 123155DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 706583DEST_PATH_IMAGE013
The roughness calculation for the parameters is not easily conceivable to the person skilled in the art and is not a routine technical measure.
1) The roughness calculated by the method is more fit with the actual situation and more accurate, and the icing condition of the surface of the wing can be accurately judged in the follow-up process.
2) The invention also specifically provides the local liquid water content
Figure 300506DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 285780DEST_PATH_IMAGE013
The specific calculation method can provide a powerful basis for subsequent roughness calculation.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention or in the description of the prior art will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of a roughness calculation method as described in the present invention;
FIG. 2 is a graph of a fit of liquid water collection coefficients for different diameter water droplets according to an embodiment of the present invention;
FIG. 3 is the average volume diameter of the local liquid water droplets after redistribution of the water droplets according to one embodiment of the present inventionMVDA graph;
FIG. 4 is the local liquid water content after redistribution of water droplets according to one embodiment of the present inventionLWCA graph;
FIG. 5 is a graph of roughness calculated by one embodiment of the present invention.
Detailed Description
The following description provides many different embodiments, or examples, for implementing different features of the invention. The particular examples set forth below are illustrative only and are not intended to be limiting.
When an airplane flies in a cloud layer containing supercooled water drops, the water drops are frozen after impacting a windward surface, and the airplane freezes. Icing build-up results in uneven aircraft surfaces and increased roughness. The icing surface roughness influences the airflow flow on the surface of the airplane, so that the transition position of the airflow boundary layer moves forward, and the convective heat transfer between the surface of the airplane and the airflow is enhanced. In the icing calculation, the roughness and the convective heat transfer process have great influence on the generated ice amount and ice shape, so the accuracy of the icing prediction result can be improved by considering the reason and the measuring method of the roughness and embedding the improved roughness model into the existing icing calculation model.
The equivalent grit roughness height model is a widely used roughness calculation model that considers the roughness of the ice surface and the liquid water contentLWCTemperature of incoming airTAnd velocity of airv、Average volume diameter of liquid water dropMVDIt is related. Wherein the content of the first and second substances,
liquid Water Content (Liquid Water Content,LWC），means that the cloud contains the total mass of liquid water drops per unit volume, usually in grams/meter3。
The average volume diameter (medium volume multiplex diameter,MVD) The method comprises the following steps: the diameter of water drops in the air is not single, but has certain distribution, and in the research of ice accumulation,MVDdefined as the critical dimension dividing the total water volume into two halves, i.e. the diameter is considered to be greater thanMVDThe total volume and diameter of the large water drops are less than MVD The total volume of the water droplets of (a) is equal.
It is noted that the liquid water content in the model LWCIn fact, refers to the incoming liquid water content
Figure 126697DEST_PATH_IMAGE029
，Average volume diameter of liquid water dropMVDIn fact, means the average volume diameter of the incoming liquid water drops
Figure 197421DEST_PATH_IMAGE030
。
The model has certain disadvantages: liquid water content of incoming flow
Figure 781986DEST_PATH_IMAGE031
And mean volume diameter of incoming liquid water droplets
Figure 198930DEST_PATH_IMAGE032
The cloud and fog field parameters are fixed values after being determined, and the values of the cloud and fog field parameters are kept unchanged in the whole icing calculation and cannot be changed along with the change of the surface position. In fact, after the liquid droplets impact the aircraft surface, they are redistributed and the liquid water contentLWC、Average volume diameter of liquid water dropMVDEtc. will change and no longer equal the incoming liquid water content
Figure 210748DEST_PATH_IMAGE033
And mean volume diameter of incoming liquid water droplets
Figure 316238DEST_PATH_IMAGE034
。Therefore, the incoming liquid water content is adopted
Figure 235653DEST_PATH_IMAGE035
And mean volume diameter of incoming liquid water droplets
Figure 195519DEST_PATH_IMAGE036
The calculated roughness values deviate significantly from the actual values.
In order to make the roughness calculation more accurate and more practical in consideration of the deficiency, the invention provides a roughness calculation method which adopts the local liquid water content
Figure 112659DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 672822DEST_PATH_IMAGE013
Roughness calculations were performed for the parameters. And using the local liquid water content
Figure 395928DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 210300DEST_PATH_IMAGE013
The roughness calculation for the parameters is not easily conceivable to the person skilled in the art and is not a routine technical measure. And using the local liquid water content
Figure 563921DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 847266DEST_PATH_IMAGE013
And calculating the roughness for the parameters, wherein the calculated roughness is more suitable for the actual situation and more accurate.
Wherein the local liquid water content
Figure 577324DEST_PATH_IMAGE010
The liquid water content redistributed when the water drops impact the surface of the object element, namely the liquid water content of the surface of the object element;
average volume diameter of local liquid water drop
Figure 574099DEST_PATH_IMAGE013
This means the average volume diameter of the liquid water droplets after redistribution when the droplets strike the surface of the object.
Meanwhile, in one embodiment of the invention, an aircraft icing surface roughness calculation method considering water drop redistribution is provided, and a flow chart of the calculation method is shown in fig. 1.
The method specifically comprises the following steps:
step S10: selecting the particle size distribution of the water drops, and selecting according to the selected particle size distributionnParticle size of seed water drop
Figure 82310DEST_PATH_IMAGE007
And calculating the corresponding mass fraction
Figure 836639DEST_PATH_IMAGE037
（iGo through 1 to n); in this step, the larger the number of the selected water droplet diameters is, the more accurate the calculation result is. In the above-mentioned steps, the step of,
the particle size of the water drops is as follows: since the liquid droplets are only approximately spherical, the diameter of the sphere, which corresponds to its volume, is introduced to characterize the size of the supercooled droplets, typically in microns. Generally, most water droplets are less than 40 microns in diameter, mostly concentrated between 10-20 microns. In this embodiment use
Figure 370389DEST_PATH_IMAGE007
And (4) showing.
The mass fraction is as follows: the proportion of the water drops with different sizes in the total liquid water content is distributed. In this embodiment use
Figure 221670DEST_PATH_IMAGE037
And (4) showing.
In the icing calculation, the water droplet diameter distribution is often a Langmuir D distribution, a normal distribution, or the like.
Wherein the Langmuir D distribution comprises water droplets of 7 water droplet sizes, each size having a water droplet diameter
Figure 667826DEST_PATH_IMAGE007
And average water droplet diameterMVDAnd the mass ratio (i.e., mass fraction) of such water droplets in the air
Figure 175031DEST_PATH_IMAGE037
) Have a fixed value, as shown in table 1.
TABLE 1 Langmuir D distribution Water droplet diameter and mass fraction
Numbering 1 2 3 4 5 6 7
Mass fraction 0.05 0.10 0.20 0.30 0.20 0.10 0.05
Diameter of water drop 6.2 10.4 14.2 20 27.4 34.8 44.4
Step S20: respectively calculate out
Figure 715734DEST_PATH_IMAGE038
Particle size of seed water drop
Figure 733106DEST_PATH_IMAGE007
Corresponding local liquid water collection coefficient
Figure 599431DEST_PATH_IMAGE039
，
Figure 141402DEST_PATH_IMAGE009
The distance between the impact point of the water drop and the object plane of the front edge point of the airplane wing;
in the above-mentioned steps, the step of,
the local liquid water collection coefficient refers to: the ratio of the actual water collection at the surface of a infinitesimal to the maximum possible water collection at the surface of the infinitesimal is a parameter characterizing the water-collecting capacity of the surface of the infinitesimal. In this embodiment use
Figure 16954DEST_PATH_IMAGE040
And (4) showing.
There is special data analysis and calculation software available to calculate local liquid water collection factors such as FENSAP-ICE, LEWICE, NNWICE, etc.
In one embodiment of the invention, icing numerical simulation software NNWICE is used to calculate separately
Figure 514931DEST_PATH_IMAGE038
Particle size of seed water drop
Figure 286578DEST_PATH_IMAGE041
Corresponding local liquid water collection coefficient
Figure 768375DEST_PATH_IMAGE039
；
Step S30:calculating the local liquid water content
Figure 228044DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 111686DEST_PATH_IMAGE013
；
Liquid water content
Figure 319814DEST_PATH_IMAGE042
And liquid water droplet average volume diameter
Figure 757748DEST_PATH_IMAGE043
Is an important parameter for calculating the roughness subsequently. In the above step, it is considered that the liquid water droplets are redistributed when they strike the wing surface of the aircraft, resulting in a liquid water content thereof
Figure 725836DEST_PATH_IMAGE042
And liquid water droplet average volume diameter
Figure 260722DEST_PATH_IMAGE043
Will vary, and therefore, the local liquid water content according to the invention as set forth above is calculated in this step
Figure 639751DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 345408DEST_PATH_IMAGE013
To provide a basis for subsequent roughness calculations.
Step S40: using the calculated local liquid water content
Figure 428770DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 772158DEST_PATH_IMAGE013
Calculating the roughness of the wing wall
Figure 790929DEST_PATH_IMAGE014
。
In the above steps, the local liquid water content calculated in step S30 is used
Figure 734615DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 90510DEST_PATH_IMAGE013
Roughness for parameters
Figure 786939DEST_PATH_IMAGE014
Calculation which takes into account the liquid water droplet redistribution versus roughness when it hits the aircraft wing surface
Figure 773350DEST_PATH_IMAGE014
The resulting effect is calculated. Therefore, the calculation result is more fit for the actual situation and more accurate, and the icing situation on the surface of the wing can be accurately judged in the follow-up process.
In one embodiment of the invention, the local liquid water content is provided
Figure 407593DEST_PATH_IMAGE010
The specific calculation method of (3) has the following calculation formula:
Figure 301600DEST_PATH_IMAGE044
in the formula:
Figure 885159DEST_PATH_IMAGE045
is the incoming liquid water content.
In the above-described embodiments, it is known that water droplets having various particle diameters exist on the surface of the infinitesimal object when the water flows. Firstly, according to the definition of liquid water content, the particle size obtained by the steps is
Figure 776892DEST_PATH_IMAGE007
Mass fraction of liquid water droplets of
Figure 898432DEST_PATH_IMAGE037
Local liquid water collection coefficient
Figure 596129DEST_PATH_IMAGE039
Calculating a certain particle diameter of
Figure 532730DEST_PATH_IMAGE007
The liquid water content of the liquid water drop on the surface of the object infinitesimal element, the specific calculation formula is as follows:
Figure 595364DEST_PATH_IMAGE046
on the basis, the liquid water content of the liquid water drops with other particle sizes on the surface of the object micro-element is respectively calculated by the same method, and the liquid water content of all the particle sizes is calculated
Figure 735358DEST_PATH_IMAGE007
（i=1~n) The liquid water content of the liquid water drops on the surface of the object micro element is summed, and the local liquid water content can be obtained
Figure 721900DEST_PATH_IMAGE010
The specific calculation formula is as follows:
Figure 732581DEST_PATH_IMAGE047
in one embodiment of the invention, the average volume diameter of local liquid water drops is provided
Figure 497275DEST_PATH_IMAGE013
The specific calculation formula of the calculation method is as follows:
Figure 124565DEST_PATH_IMAGE048
Figure 436771DEST_PATH_IMAGE049
in the formula (I), the compound is shown in the specification,ta coefficient of 0 to 1,ksatisfies the following conditions:
Figure 567538DEST_PATH_IMAGE050
and is and
Figure 237553DEST_PATH_IMAGE051
，
Figure 899610DEST_PATH_IMAGE021
is as followskThe diameter of the seed water drops is such that,
Figure 211643DEST_PATH_IMAGE022
is as followsk+1The diameter of the seed water droplet.
In the research of the ice accretion,MVDdefined as the critical dimension dividing the total water volume into two halves, i.e. the diameter is considered to be greater thanMVDThe total volume and diameter of the large water drops are less thanMVDThe total volume of the water droplets of (a) is equal.
According toMVDBy definition of (1), for a given distribution of ice cloud (cluster of water droplets), we need only find a size such that the total mass of water droplets larger than this size is equal to the total mass of water droplets smaller than this size, which is the size of the given ice cloudMVD。
The particle diameter of the water drops is less than or equal to
Figure 711763DEST_PATH_IMAGE021
The ratio of the total mass of water droplets to the total mass of water droplets can be expressed as:
Figure 349418DEST_PATH_IMAGE052
the particle diameter of water drops is less than or equal toIn that
Figure 685721DEST_PATH_IMAGE022
The ratio of the total mass of water droplets to the total mass of water droplets can be expressed as:
Figure 21019DEST_PATH_IMAGE053
when the following conditions are satisfied:
Figure 188695DEST_PATH_IMAGE054
Figure 200513DEST_PATH_IMAGE054
the method comprises the following steps:
Figure 758534DEST_PATH_IMAGE055
to obtain a more accurate average volume diameter of the local liquid water droplets, further, the
Figure 864899DEST_PATH_IMAGE021
，
Figure 90344DEST_PATH_IMAGE022
Linear interpolation is carried out, even if the average volume diameter of the local liquid water drops can be obtained
Figure 335380DEST_PATH_IMAGE013
That is to say that,
Figure 397008DEST_PATH_IMAGE056
wherein the content of the first and second substances,ta coefficient of 0 to 1,tsatisfies the following conditions:
Figure 792217DEST_PATH_IMAGE057
further, in step S40, the roughness
Figure 872169DEST_PATH_IMAGE058
The calculation formula of (2) is as follows:
Figure 22528DEST_PATH_IMAGE059
in the formula: c is the characteristic length and T is the temperature;
Figure 335566DEST_PATH_IMAGE060
Figure 65625DEST_PATH_IMAGE061
Figure 813132DEST_PATH_IMAGE062
。
in the above step, the roughness is calculated
Figure 337654DEST_PATH_IMAGE014
When the local liquid water content obtained in the previous step
Figure 91984DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 94575DEST_PATH_IMAGE013
And substituting the parameters into a roughness calculation model to perform roughness calculation. Since the local liquid water content is calculated
Figure 149118DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 156126DEST_PATH_IMAGE013
The influence that water drops can be redistributed after the water drops impact the surface of the wing is considered, so the roughness calculated by the method is more fit to the actual situation and more accurate, and the icing situation on the surface of the wing can be accurately judged subsequently.
Examples of the experiments
In an experimental example of the present invention, typical icing calculation conditions were chosen:MVD=20
Figure 663331DEST_PATH_IMAGE063
、
Figure 938455DEST_PATH_IMAGE064
=1g/m3、T=265K、p=101325Pa、v=78.2m/s, NACA23012 two-dimensional airfoil with characteristic length c of 0.9144 m.
Step S10: respectively calculate out
Figure 113084DEST_PATH_IMAGE006
Particle size of seed water drop
Figure 526879DEST_PATH_IMAGE041
Corresponding local liquid water collection coefficient
Figure 786959DEST_PATH_IMAGE039
，
Figure 131353DEST_PATH_IMAGE065
The distance between the impact point of the water drop and the object plane of the front edge point of the airplane wing; in this step, the larger the number of the selected water droplet diameters is, the more accurate the calculation result is.
In this example, the size distribution law of the droplet size was selected from Langmuir D distribution, which includes 7 droplet sizes, and the droplet size distribution and mass fraction are shown in table 1. In order to make the calculation result more accurate, all 7 kinds of water droplet particle sizes are selected in this embodiment.
Step S20: calculating the local liquid water collection coefficient corresponding to the particle size of each water drop
Figure 629330DEST_PATH_IMAGE040
The distance between the impact point of water drop and the object plane of the front edge point of the airplane wing
Figure 181403DEST_PATH_IMAGE065
For the abscissa, the local liquid water collection coefficient
Figure 459938DEST_PATH_IMAGE040
Synthetic curve
Figure 608022DEST_PATH_IMAGE039
。
In the embodiment, icing numerical simulation software NNWICE is used for calculating the local liquid water collection coefficient corresponding to each particle size
Figure 960506DEST_PATH_IMAGE040
The results are shown in FIG. 2.
Step S30: calculating the local liquid water content
Figure 184945DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 950776DEST_PATH_IMAGE013
；
In the above steps, the average volume diameter of the local liquid water drops after the liquid water drops on the surface of the wing are redistributed is calculated by the method
Figure 902551DEST_PATH_IMAGE013
And local liquid water content
Figure 889968DEST_PATH_IMAGE010
. Wherein the average volume diameter of local liquid water drops
Figure 3417DEST_PATH_IMAGE013
The calculation results are shown in FIG. 3, the local liquid water content
Figure 459807DEST_PATH_IMAGE010
The calculation results of (2) are shown in fig. 4.
Step S40: using the calculated local liquid water content
Figure 12011DEST_PATH_IMAGE010
And local liquid water droplet mean volume diameter
Figure 355398DEST_PATH_IMAGE013
Calculating the roughness of the wing wall surface as a parameter
Figure 905328DEST_PATH_IMAGE014
。
In this example, the calculated average volume diameter of the local liquid water droplets was used
Figure 645751DEST_PATH_IMAGE013
And local liquid water content
Figure 673750DEST_PATH_IMAGE010
As parameters, roughness calculations were performed. The roughness calculation results are shown in fig. 5.
As can be seen from fig. 5, the roughness of the aircraft icing surface in consideration of the redistribution of water droplets shows a tendency of high impact limit near the stagnation point, and in the prior art, the roughness obtained by using the traditional calculation method is constant on the wall surface, so that the calculated roughness is more suitable for the actual situation and more accurate, and the icing condition of the wing surface can be accurately judged in the follow-up process.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (2)

1. The method for calculating the roughness of the icing surface of the airplane is characterized by comprising the following steps of:
step S10: selecting the particle size distribution of water drops according to the particle size distribution of the water dropsCloth selectionnParticle size of seed water drop
Figure DEST_PATH_IMAGE001
And calculating the particle diameter of each water drop
Figure 248750DEST_PATH_IMAGE001
Corresponding mass fraction
Figure 115075DEST_PATH_IMAGE002
Wherein, in the step (A),
Figure DEST_PATH_IMAGE003
the number of the particle size of the water droplets,nthe number of types of the particle size of the water droplets,
Figure 968630DEST_PATH_IMAGE004
；
step S20: respectively calculate out
Figure DEST_PATH_IMAGE005
Particle size of seed water drop
Figure 879735DEST_PATH_IMAGE001
Corresponding local liquid water collection coefficient
Figure 174450DEST_PATH_IMAGE006
，
Figure DEST_PATH_IMAGE007
The distance between the impact point of the water drop and the object plane of the front edge point of the airplane wing;
step S30: calculating the local liquid water content
Figure 805152DEST_PATH_IMAGE008
And local liquid water droplet mean volume diameter
Figure DEST_PATH_IMAGE009
；
Step S40: using the calculated local liquid water content
Figure 850730DEST_PATH_IMAGE008
And local liquid water droplet mean volume diameter
Figure 264394DEST_PATH_IMAGE009
Calculating the roughness of the icing surface of the aircraft as a parameter
Figure 288982DEST_PATH_IMAGE010
；
In step S30, the local liquid water content
Figure 762689DEST_PATH_IMAGE008
The calculation formula of (2) is as follows:
Figure DEST_PATH_IMAGE011
in the formula:
Figure 528519DEST_PATH_IMAGE012
is the incoming liquid water content;
in step S30, the local liquid water droplet average volume diameter
Figure 745874DEST_PATH_IMAGE009
The calculation formula of (2) is as follows:
Figure DEST_PATH_IMAGE013
Figure 841613DEST_PATH_IMAGE014
in the formula (I), the compound is shown in the specification,ta coefficient of 0 to 1,ksatisfies the following conditions:
Figure DEST_PATH_IMAGE015
and is and
Figure 79696DEST_PATH_IMAGE016
，
Figure DEST_PATH_IMAGE017
is as followskThe particle size of the seed water drops is,
Figure 834288DEST_PATH_IMAGE018
is as followsk+1The particle size of the seed water droplets.
2. An aircraft icing surface roughness calculation method as claimed in claim 1, characterised by: in step S40, roughness
Figure DEST_PATH_IMAGE019
The calculation formula of (2) is as follows:
Figure 511126DEST_PATH_IMAGE020
in the formula: c is the characteristic length of the light beam,Tis the temperature;
Figure DEST_PATH_IMAGE021
Figure 189932DEST_PATH_IMAGE022
Figure DEST_PATH_IMAGE023
。
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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
CN114676560B (en) * 2022-03-07 2023-04-11 中国空气动力研究与发展中心低速空气动力研究所 Cloud and mist parameter calculation and ice shape prediction method and medium based on optical fiber icing detection
CN114688950B (en) * 2022-05-31 2022-08-23 陕西建工第一建设集团有限公司 Aluminum alloy plate flattening detection device for building construction
CN115248022B (en) * 2022-09-22 2022-12-06 四川大学 Icing thickness detection method for power transmission line
CN116401834B (en) * 2023-03-17 2024-02-13 中国民航大学 Method and device for calculating impact characteristics of water drops of airplane, equipment and storage medium
CN117875224B (en) * 2024-03-12 2024-06-04 南京航空航天大学 Non-equal-division continuous multi-particle-size water drop coupling Euler method

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101281046A (en) * 2008-05-16 2008-10-08 重庆大学 Atmospheric structure ice covering parameter measurement method and multi-conductor ice accumulation device
CN102663238A (en) * 2012-03-21 2012-09-12 南京航空航天大学 Ice surface roughness measuring method based on liquid water distribution
CN102663239A (en) * 2012-03-21 2012-09-12 南京航空航天大学 Method for measuring roughness of ice-forming surface based on surface geometry
CN102682145A (en) * 2011-11-30 2012-09-19 天津空中代码工程应用软件开发有限公司 Numerical simulation method of flight icing
CN109657275A (en) * 2018-11-16 2019-04-19 中国航空工业集团公司沈阳空气动力研究所 A kind of analogy method and system considering frozen surface roughness

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4411944B2 (en) * 2003-11-12 2010-02-10 横浜ゴム株式会社 Method for predicting ice surface roughness or friction coefficient
US10899045B2 (en) * 2013-03-12 2021-01-26 U.S.A. As Represented By The Administrator Of The National Aeronautics And Space Administration High pressure soft lithography for micro-topographical patterning of molded polymers and composites
JP6246906B2 (en) * 2013-05-14 2017-12-13 ウーペーエム−キュンメネ コーポレイションＵＰＭ−Ｋｙｍｍｅｎｅ Ｃｏｒｐｏｒａｔｉｏｎ Composite material structure having surface roughness
CN106909707B (en) * 2017-01-05 2020-11-24 上海交通大学 Method for measuring surface roughness of wind field by utilizing fractal dimension
CN107153731A (en) * 2017-05-02 2017-09-12 上海理工大学 Magnetic field aids in low-speed WEDM machined surface roughness Forecasting Methodology
CN107036913B (en) * 2017-06-07 2023-03-24 中国空气动力研究与发展中心低速空气动力研究所 Method for measuring shear strength between ice layer and solid material in icing wind tunnel experiment section
CN110837698B (en) * 2019-10-30 2021-06-04 中国科学院遥感与数字地球研究所 Method and system for simulating growth process of ice cloud
CN111368485B (en) * 2020-03-03 2020-11-10 中国水利水电科学研究院 Method for calculating surface roughness based on Manning equation
CN111950206B (en) * 2020-07-21 2024-04-26 西安理工大学 Design method of parabolic groove on surface of miniature dynamic pressure gas thrust bearing

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101281046A (en) * 2008-05-16 2008-10-08 重庆大学 Atmospheric structure ice covering parameter measurement method and multi-conductor ice accumulation device
CN102682145A (en) * 2011-11-30 2012-09-19 天津空中代码工程应用软件开发有限公司 Numerical simulation method of flight icing
CN102663238A (en) * 2012-03-21 2012-09-12 南京航空航天大学 Ice surface roughness measuring method based on liquid water distribution
CN102663239A (en) * 2012-03-21 2012-09-12 南京航空航天大学 Method for measuring roughness of ice-forming surface based on surface geometry
CN109657275A (en) * 2018-11-16 2019-04-19 中国航空工业集团公司沈阳空气动力研究所 A kind of analogy method and system considering frozen surface roughness

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