CN101318551B - Quick wing tip vortex weakening apparatus - Google Patents

Abstract

The invention relates to a wingtip vortex fast weakening device which designs the back edge of an alula at the wingtip of an airfoil into a sawtooth structure and leads the sawtooth structure to be parallel with the back edge of the alula at the wingtip. The structure of the invention is simple and is improved based on the original alula structure at the wingtip, which can not bring any additional quantity to an airplane. Simultaneously, the invention runs stably, does not need to be provided with power when running and is convenient for being maintained. The wingtip vortex fast weakening device of the alula at the wingtip in the sawtooth shape of the back edge designed by the invention has physical characteristic scales of the wingtip vortex, can speed up and induce the mixing between a high speed air flow and a low speed air flow generated by the wingtip vortex and can lead the wingtip vortex to fast break into a vortex with a small scale, thus achieving the effect of speeding up the dissipation of the wingtip vortex and fast weakening the wingtip vortex.

Description

A kind of quick wing tip vortex weakening apparatus

Technical field

The present invention relates to a kind of quick wing tip vortex weakening apparatus, particularly a kind of quick wing tip vortex weakening apparatus of trailing edge serrations shape wing tip winglet.

Background technology

Fixed wing aircraft can produce in flight course has the very high wing tip whirlpool of intensity, dissipate in the atmosphere of fly past and could disappear for a long time in this wing tip whirlpool, so very large flight safety hidden danger can be brought to flying through this regional aircraft and cluster formation flight once more in the wing tip whirlpool, the generation in this wing tip whirlpool simultaneously brings very big induced drag can for aircraft itself.For addressing this problem, American-European large aircraft manufacturing company (as Boeing and the Airbus etc.) technical schemes of wing tip winglet that adopt reduce the problem that bring in the wing tip whirlpool more, the wing tip winglet also is the good scheme of aircraft lift-rising drag reduction simultaneously, but the existence of wing tip winglet can not make the wing tip whirlpool dissipate fast.

Summary of the invention

Technology of the present invention is dealt with problems: overcome the deficiencies in the prior art, a kind of quick wing tip vortex weakening apparatus is provided, this apparatus structure is simple, and is easy to maintenance, can impel the wing tip whirlpool to be broken into microvortex, accelerates its dissipation.

Technical scheme of the present invention: a kind of quick wing tip vortex weakening apparatus is characterized in that: the trailing edge of aircraft wing wing tip winglet is designed to broached-tooth design, and this broached-tooth design is parallel with wing tip winglet trailing edge.

The length of described trailing edge serrations structure is 10～500mm, and width is 10～500mm, and thickness is 1～30mm.

The length of described trailing edge serrations structure is 100mm, and width is 100mm, and thickness is 10mm.

The present invention's advantage compared with prior art is as follows: of the present invention simple in structure, on the basis of the little wing structure of original wing tip, improve, and can not bring any additional mass to aircraft, the present invention simultaneously is stable, need not provide power during operation, and is easy to maintenance.The wing tip whirlpool weakening apparatus of design-calculated trailing edge serrations shape wing tip winglet of the present invention has the physical features yardstick in wing tip whirlpool, can accelerate to bring out the high velocity air of wing tip whirlpool generation and the blending between the low speed flow, broken fast in the wing tip whirlpool and become microvortex, its dissipation is accelerated in the wing tip whirlpool of can weakening fast.

Description of drawings

Fig. 1 is a scheme drawing of the present invention;

Fig. 2 is a constructional drawing of the present invention.

The specific embodiment

As shown in Figure 1, a kind of quick wing tip vortex weakening apparatus is the trailing edge serrations shape structure 2 of fixed wing aircraft wing wing tip winglet 1, the sawtooth of this structure has wing tip whirlpool characteristic dimension, rapid mixing behind wing tip winglet both sides high velocity air and the low speed flow process of the flowing through during aircraft flight zig-zag device, the wing tip whirlpool fragmentation that air-flow forms becomes microvortex 3, microvortex 3 can dissipate fast, to reach quick reduction wing tip whirlpool purpose.This device can be made by rigid material, elastomeric material or flexible material.

The present invention has carried out numerical simulation in the whirlpool after to the wing tip winglet, by compressible Navier-Stokes equation is found the solution, can carry out numerical value research to the wing tip whirlpool problem of wing tip winglet.

For model equation

$\frac{\∂U}{\∂t}+\frac{\∂F}{\∂x}=0---\left(1\right)$

It is second accurate explicit NND form (being the NND-2 form) that the numerical discretization form adopts direction in space.

F=AU in the formula, the discrete scheme of NND-2 is

$u_j^{n+1}=u_j^n-\frac{\mathrm{\Δt}}{\mathrm{\Δx}}({\tilde{h}}_{j+\frac{1}{2}}^n-{\tilde{h}}_{j-\frac{1}{2}}^n)---\left(2\right)$

In the formula:

${\tilde{h}}_{j+\frac{1}{2}}^n=f_j^{+n}+\frac{1}{2}(1-a_j^n\frac{\mathrm{\Δt}}{\mathrm{\Δx}})\min \mathrm{mod}({\mathrm{\Δf}}_{j-\frac{1}{2}}^{+n},{\mathrm{\Δf}}_{j+\frac{1}{2}}^{+n})$

$+f_{j+1}^{-n}-\frac{1}{2}(1+a_{j+1}^n\frac{\mathrm{\Δt}}{\mathrm{\Δx}})\min \mathrm{mod}({\mathrm{\Δf}}_{j+\frac{1}{2}}^{-n},{\mathrm{\Δf}}_{j+\frac{3}{2}}^{-n})$

${\mathrm{\Δf}}_{j+\frac{1}{2}}=f_{j+1}-f_j$

Using form (2) can be found the solution the Navjer-Stokes set of equations of three dimensional compressible preferably.

Three dimensional compressible Navier-Stokes equation is:

$\frac{\∂U}{\∂t}+\frac{\∂(E-E_V)}{\∂x}+\frac{\∂(F-F_V)}{\∂y}+\frac{\∂(G-G_V)}{\∂z}=0---\left(3\right)$

Wherein:

$U=\left[\begin{array}{c}\mathrm{\ρ}\\ \mathrm{\ρu}\\ \mathrm{\ρv}\\ \mathrm{\ρw}\\ e\end{array}\right],$ $E=\left[\begin{array}{c}\mathrm{\ρu}\\ \mathrm{\ρ}{u}^2+p\\ \mathrm{\ρuv}\\ \mathrm{\ρuw}\\ (e+p)u\end{array}\right],$ $F=\left[\begin{array}{c}\mathrm{\ρv}\\ \mathrm{\ρuv}\\ \mathrm{\ρ}{v}^2+p\\ \mathrm{\ρvw}\\ (e+p)v\end{array}\right],$ $G=\left[\begin{array}{c}\mathrm{\ρw}\\ \mathrm{\ρuw}\\ \mathrm{\ρvw}\\ \mathrm{\ρ}{w}^2+p\\ (e+p)w\end{array}\right]$

$E_v={\mathrm{Re}}^{-1}\left[\begin{array}{c}0\\ {\mathrm{\τ}}_{\mathrm{xx}}\\ {\mathrm{\τ}}_{\mathrm{xy}}\\ {\mathrm{\τ}}_{\mathrm{xz}}\\ {\mathrm{u\τ}}_{\mathrm{xx}}+{\mathrm{v\τ}}_{\mathrm{xy}}+{\mathrm{w\τ}}_{\mathrm{xz}}-q_x\end{array}\right],$ $F_v={\mathrm{Re}}^{-1}\left[\begin{array}{c}0\\ {\mathrm{\τ}}_{\mathrm{xy}}\\ {\mathrm{\τ}}_{\mathrm{yy}}\\ {\mathrm{\τ}}_{\mathrm{yz}}\\ {\mathrm{u\τ}}_{\mathrm{xy}}+{\mathrm{v\τ}}_{\mathrm{yy}}+{\mathrm{w\τ}}_{\mathrm{yz}}-q_y\end{array}\right]$

$G_v={\mathrm{Re}}^{-1}\left[\begin{array}{c}0\\ {\mathrm{\τ}}_{\mathrm{xz}}\\ {\mathrm{\τ}}_{\mathrm{yz}}\\ {\mathrm{\τ}}_{\mathrm{zz}}\\ {\mathrm{u\τ}}_{\mathrm{xz}}+{\mathrm{v\τ}}_{\mathrm{yz}}+{\mathrm{w\τ}}_{\mathrm{zz}}-q_z\end{array}\right]$

$e=\frac{p}{\mathrm{\&gamma;}-1}+\frac{1}{2}\mathrm{\&rho;}({\mathrm{<figure-callout\; id="2"\; label="u"\; filenames="H2008101134402E00011.png"\; state="\{\{state\}\}">u</figure-callout>}}^2+{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="H2008101134402E00011.png"\; state="\{\{state\}\}">v</figure-callout>}}^2+w^2)$

${\mathrm{\&tau;}}_{\mathrm{xx}}=\frac{2}{3}\mathrm{\&mu;}(2\frac{\&PartialD;u}{\&PartialD;x}-\frac{\&PartialD;v}{\&PartialD;y}-\frac{\&PartialD;w}{\&PartialD;z}),$ ${\mathrm{\&tau;}}_{\mathrm{xy}}=\mathrm{\&mu;}(\frac{\&PartialD;u}{\&PartialD;y}+\frac{\&PartialD;v}{\&PartialD;x}),$ ${\mathrm{\&tau;}}_{\mathrm{xz}}=\mathrm{\&mu;}(\frac{\&PartialD;u}{\&PartialD;z}+\frac{\&PartialD;w}{\&PartialD;x}),$

${\mathrm{\&tau;}}_{\mathrm{yy}}=\frac{2}{3}\mathrm{\&mu;}(2\frac{\&PartialD;v}{\&PartialD;y}-\frac{\&PartialD;u}{\&PartialD;x}-\frac{\&PartialD;w}{\&PartialD;z}),$ ${\mathrm{\&tau;}}_{\mathrm{yz}}=\mathrm{\&mu;}(\frac{\&PartialD;v}{\&PartialD;z}+\frac{\&PartialD;w}{\&PartialD;y}),$ ${\mathrm{\&tau;}}_{\mathrm{zz}}=\frac{2}{3}\mathrm{\&mu;}(2\frac{\&PartialD;w}{\&PartialD;z}-\frac{\&PartialD;u}{\&PartialD;x}-\frac{\&PartialD;v}{\&PartialD;y})$

$q_x=-\frac{\mathrm{\&mu;}}{(\mathrm{\&gamma;}-1)M_{\&infin;}^2\mathrm{Pr}}\frac{\&PartialD;T}{\&PartialD;x},$ $q_y=-\frac{\mathrm{\&mu;}}{(\mathrm{\&gamma;}-1)M_{\&infin;}^2\mathrm{Pr}}\frac{\&PartialD;T}{\&PartialD;y},$ $q_z=-\frac{\mathrm{\&mu;}}{(\mathrm{\&gamma;}-1)M_{\&infin;}^2\mathrm{Pr}}\frac{\&PartialD;T}{\&PartialD;z}$

$\mathrm{\&mu;}=T^{1.5}\frac{1+C}{T+C},$ $T=\mathrm{\&gamma;}{M}_{\&infin;}^2\frac{p}{\mathrm{\&rho;}},$ C＝110.4K/T _∞

Wherein:

U, E, F, G flux term

E _v, F _v, G _vViscosity term

The t time

X, y, z three-dimensional vector

ρ density

U, v, w speed

P pressure

Energy in the e

The q hot-fluid

τ shears should

The Re Reynolds number

M _∞Mach number

The T temperature

The Pr Prandtl number

The μ coefficient of viscosity

γ body constant

According to above theoretical method, under certain airplane operating conditions, can obtain the parameters such as physical dimension of wing tip whirlpool weakening apparatus.

The general flying condition of aircraft is height 0Km～15Km, flying speed 0m/s～300m/s.The problem that all has the wing tip whirlpool in whole flying condition scope is for example in takeoff phase, because the existence in wing tip whirlpool needs to strengthen the time gap that the airport is taken off and landed; When aircraft is formed into columns in high-altitude flight, be subjected to the influence in wing tip whirlpool, need widen the flight spacing of formation flight.Or the like situation all be because the existence in wing tip whirlpool and dissipate and cause more slowly needs the wing tip whirlpool of weakening fast for this reason, reduce the adverse effect that bring in the wing tip whirlpool.Can calculate wing wing tip vortex structure and intensity according to above airplane operating conditions, by sawtooth pattern structure in wing tip winglet trailing edge design difformity size, as shown in Figure 2, with the general flying condition of aircraft, height 0Km～15Km, flying speed 0m/s～300m/s flying condition, design-calculated sawtooth physical dimension (length, width, thickness) and corresponding installation site and setting angle be: length is L=10～500mm, and width is D=10～500mm, and thickness is H=1～30mm, the installation site is a wing wing tip winglet trailing edge, and broached-tooth design is parallel with wing tip winglet trailing edge.

Can calculate wing tip whirlpool size and intensity behind the wing tip winglet zigzag fashion according to the Navier-Stokes equation, therefrom select optimum design plan, promptly wing tip whirlpool size minimum strength is the most weak.For example, at flight Mach number M _∞=0.8, flying height is the aircraft of H=10Km, and flying speed is u=240.1m/s, edge thickness 10mm behind the wing tip winglet, and atmospheric density is ρ=0.41351Kg/m ³, the size that can calculate the wing tip whirlpool is in the 1m magnitude.The neutral wave wavelength is about 0.1m to use above numerical value emulation method can calculate least, corresponding to this device, trailing edge serrations shape structure is as follows: long is 100mm, width is 100mm, thickness is edge thickness 10mm behind the wing tip winglet, the installation site is a wing wing tip winglet trailing edge, and broached-tooth design is parallel with wing tip winglet trailing edge.

The present invention not detailed description is a technology as well known to those skilled in the art.

Claims (1)

1. quick wing tip vortex weakening apparatus, it is characterized in that: the trailing edge of aircraft wing wing tip winglet (1) is designed to broached-tooth design (2), and this broached-tooth design is parallel with wing tip winglet trailing edge, and the length of described trailing edge serrations structure (2) is 100mm, width is 100mm, and thickness is 10mm.

Images