CN103324849B - A kind of single rod member Shape Coefficient of transmission tower based on CFD skew wind determines method - Google Patents

Abstract

The present invention relates to a kind of single rod member Shape Coefficient of transmission tower based on CFD skew wind and determine method, comprise the steps: that (1) sets up single rod member physical model, and under transmission tower coordinate system, be placed into the locus matched with actual point position；(2) the actual aerodynamic configuration of space bar member is determined；(3) set up rod member border and flow field regions, and stream field region carries out stress and strain model；(4) rod member beam wind is obtained to Shape Coefficient and down wind Shape Coefficient；(5) determine rod member horizontal line to wind load and fair line to wind load.The invention enables the numerous project planners can be in the case of not by wind-tunnel, it is possible to accurately to calculate the wind load suffered by space bar member, and the local strength of connecting elements is checked.

Description

A kind of single rod member Shape Coefficient of transmission tower based on CFD skew wind determines method

Technical field

The present invention relates to transmission tower Wind load calculating field, be specifically related to a kind of single rod member of transmission tower based on CFD skew wind Shape Coefficient determines method.

Background technology

Transmission tower is space truss system, and numerous space bar members is different space angles from flowing wind, this with rod member in The wind of certain space angle is referred to as skew wind.Under oblique wind action, even the rod member that specification is identical, still have different Shape Coefficient and wind load.But the wind load workload individually calculating every rod member is the hugest, therefore total when carrying out pole and tower design It is to carry out Wind load calculating and loading with truss internode for unit.But when needing the partial analysis carrying out some connecting elements, extremely Should accurately be informed in shaft tower windward side less, the wind load of effect on the every rod member being connected with connecting elements.Therefore, the most just have Necessary research single rod member Shape Coefficient under skew wind effect.

By dynamometer check, the Shape Coefficient under the meaning in office angle skew wind effect of single rod member can be obtained the most easily in wind-tunnel, But must be by wind-tunnel and cost intensive.Such as the single rod member Shape Coefficient value in direct code requirement, there is again rod member and exist Sectional form under different skew winds is inconsistent, it is impossible to the problems such as the change of the Shape Coefficient that the change of consideration aerodynamic configuration brings.

Summary of the invention

For the deficiencies in the prior art, it is an object of the invention to provide a kind of single rod member build of transmission tower based on CFD skew wind Coefficient determines method, and this method can directly count the change of the rod member section pneumatic profile shadow to Shape Coefficient under different angles skew wind Ring.

It is an object of the invention to use following technical proposals to realize:

The present invention provides a kind of single rod member Shape Coefficient of transmission tower based on CFD skew wind to determine method, and its improvements exist In, described method comprises the steps:

(1) set up single rod member physical model, and under transmission tower coordinate system, be placed into the sky matched with actual point position Between position；

(2) the actual aerodynamic configuration of space bar member is determined；

(3) set up rod member border and flow field regions, and stream field region carries out stress and strain model；

(4) rod member beam wind is obtained to Shape Coefficient and down wind Shape Coefficient；

(5) determine rod member horizontal line to wind load and fair line to wind load.

Wherein, in described step (1), the rectangular coordinate system with transmission tower structural system as object of reference, make rod member axial line two The space coordinates of end node i, j is respectively { x_i、y_i、z_iAnd { x_j、y_j、z_j, then the table of the direction cosines of rod member axial line Reach formula as follows:

$\left\{\begin{array}{c}\cos \mathrm{\α}=(x_j-x_i)/\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}\\ \cos \mathrm{\β}=(y_j-y_i)/\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}\\ \cos \mathrm{\γ}=(z_j-z_i)/\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}\end{array}---\left(a\right);\right.$

Rod member length | ij | expressions below represents:

$\left|\mathrm{ij}\right|=\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}---\left(b\right);$

During single rod member solid modelling, at y-o-z plane built-in vertical rod part section, and along x-axis tensile elongation | ij |；By entity Rod member is with i point as center of rotation, then rotates θ degree in the plane parallel with x-o-y plane；Subsequently coordinate system is rotated θ degree, In new x-o-z plane, rod member is rotated with i point for center of rotationDegree, i.e. obtains and real space position phase The rod member physical model joined；Wherein θ obtains according to following formula (c):

$\mathrm{\θ}=\arcsin \frac{\cos \mathrm{\β}}{\sin \mathrm{\γ}}---\left(c\right);$

Wherein: α, β, γ represent rod member axial line and x, y, the angle of z-axis respectively.

Wherein, in described step (2), carry out cutting by flowing wind levels in the face of space bar member physical model, obtain it at water Put down the actual aerodynamic configuration flowing under wind effect, and determine the angle of wind deflection relative position relation of itself and different angles.

Wherein, in described step (3), the actual aerodynamic configuration of rod member generated according to cutting, set up rod member border；Set up length Flow field regions with the width rod member width not less than 11 times；Described flow field regions all uses quadrilateral structure grid；Rod member limit 4 layers of body fitted anisotropic mesh, near wall minimum edge interlayer (nearest that from boundary region that near wall minimum edge interlayer refers to is used around boundary One layer of grid) grid height is 0.002m.

Wherein, in described step (4), rod member section Shape Coefficient under different angle of wind deflection is carried out fluid mechanical emulation calculating, Obtain rod member beam wind to Shape Coefficient and down wind Shape Coefficient；Described beam wind to Shape Coefficient with down wind Shape Coefficient with following Expression formula represents:

$\left.\begin{array}{c}{\mathrm{\μ}}_{\mathrm{sx}}={2F}_x/{\mathrm{\ρBU}}^2\\ {\mathrm{\μ}}_{\mathrm{sy}}={2F}_y/{\mathrm{\ρBU}}^2\end{array}\right\}---\left(d\right);$

Wherein: μ_sxRepresent that rod member beam wind is to Shape Coefficient；μ_syRepresent rod member down wind Shape Coefficient；F_xRepresent that horizontal line is to resistance； F_yRepresent that fair line is to resistance；B represents rod member characteristic width；U represents wind speed；ρ represents atmospheric density；

Revolving rod border, constantly change its with flow wind direction angle (0 °～90 ° all can, institute can be selected the most voluntarily The drift angle number of degrees that need to calculate), and repeat step (2)-(4), i.e. obtain different angle of wind deflection (0 °～90 ° all can, can be according to needing Ask and select the required drift angle number of degrees calculated voluntarily) under the beam wind of rod member to Shape Coefficient and down wind Shape Coefficient.

Wherein, in described step (5), rod member horizontal line represents to wind load expressions below to wind load and fair line:

$\left.\begin{array}{c}{W}_x=W_o\·{\mathrm{\μ}}_z\·{\mathrm{\μ}}_{\mathrm{sx}}\·{\mathrm{\β}}_z\·B\·l\\ W_y=W_o\·{\mathrm{\μ}}_z\·{\mathrm{\μ}}_{\mathrm{sy}}\·{\mathrm{\β}}_z\·B\·l\end{array}\right\}---\left(e\right);$

Wherein: W_oRepresent local fundamental wind pressure standard value；W_xRepresent that rod member horizontal line is to wind load；W_yRepresent rod member fair line to Wind load；μ_zRepresent height variation coefficient of wind pressure；μ_sxRepresent that beam wind is to rod member Shape Coefficient；μ_syRepresent down wind rod member build Coefficient；β_zRepresent shaft tower Wind Load Adjustment Coefficients；B represents rod member characteristic width；L represents rod member physical length.

Compared with the prior art, the present invention reaches to provide the benefit that:

At present in the local calculation for shaft tower component and connector, it is considered to wind load is the most rough.Specification provide only available The Shape Coefficient used when shaft tower global design, does not provide single rod member Shape Coefficient under different angle of wind deflection.By wind Hole test can realize the rod member Shape Coefficient under any angle of wind deflection and measure, but relatively costly, and cannot be convenient according to design needs Realization.Fluid calculation mechanics is to calculate flexible and changeable space bar member Shape Coefficient to provide an approach.The present invention is based on three Dimension modeling function, first obtains the space bar member actual aerodynamic configuration under level flows wind effect, then at hydrodynamics method The Shape Coefficient of space bar member section under different angle of wind deflection is measured by software FLUENT so that vast engineering design people Member can be in the case of not by wind-tunnel, it is possible to accurately calculates the wind load suffered by space bar member, and to connecting elements Local strength checks.

Accompanying drawing explanation

Fig. 1 is the mathematical model of single space bar member locus under transmission tower global coordinate system；

Fig. 2 is-yl shaft tower example rod node numbering and structural map, and in figure, 601-700 rod member is the rod member that sample calculation is chosen；

Fig. 3 is the sectional drawing that this rod member is perpendicular in the plane of rod member axle center；

Fig. 4 is this rod member real space attitude figure under transmission tower coordinate system；

Fig. 5 is that this rod member is being obtained actual aerodynamic configuration sectional drawing by level after flowing wind plane cutting；

1. figure flows wind plane for level；2. it is space bar member physical model；3. it is the actual aerodynamic configuration of rod member section

Fig. 6 be this rod member section under transmission tower global coordinate system from the relative position relation figure of different angle of wind deflection；

Fig. 7 is that example rod member calculates basin figure；

Fig. 8 is the division figure of basin grid around rod member section；

Fig. 9 is the flow chart that the single rod member Shape Coefficient of transmission tower based on CFD skew wind determines method.

Detailed description of the invention

Below in conjunction with the accompanying drawings the detailed description of the invention of the present invention is described in further detail.

It is first depending on two node coordinates of rod member, calculates rod member axial line deflection under transmission tower global coordinate system；Make Use d solid modeling function, set up rod member physical model, and make it consistent with real space position；By Feature matching work Tool, acquisition level flows the actual aerodynamic configuration of the rod member under wind effect；Set up and networking calculating fluid at GAMBIT(subsequently Mechanical model and other applied science and the software kit that designs) in set up Flow Field Calculation territory, divide rod member section under different angle of wind deflection Surrounding edge interlayer grid and territory, flow field grid；In commercial CFD code bag FLUENT, import grid file, calculating ginseng is set Number, carries out fluid calculation and extracts the horizontal stroke of rod member section, fair line to resistance；Finally, the resistance of rod member section is scaled difference Under angle of wind deflection, the horizontal stroke of rod member, fair line are to Shape Coefficient.

The present invention provide the single rod member Shape Coefficient of transmission tower based on CFD skew wind determine method flow chart as it is shown in figure 9, Comprise the steps:

(1) set up single rod member physical model, and under transmission tower coordinate system, be placed into the sky matched with actual point position Between position；

Set up the rectangular coordinate system with transmission tower structural system as object of reference as shown in Figure 1, it is assumed that known rod member axial line Two ends node i, the space coordinates of j are respectively { x_i、y_i、z_iAnd { x_j、y_j、z_j, then the direction cosines of this space line are such as Shown in formula (a).Shown in the computing formula such as formula (b) of its rod member length | ij |.

$\left\{\begin{array}{c}\cos \mathrm{\α}=(x_j-x_i)/\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}\\ \cos \mathrm{\β}=(y_j-y_i)/\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}\\ \cos \mathrm{\γ}=(z_j-z_i)/\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}\end{array}---\left(a\right);\right.$

$\left|\mathrm{ij}\right|=\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}---\left(b\right);$

After obtaining rod member axial line length and direction cosines, set up the physical model of rod member.During solid modelling, put down at y-o-z The built-in vertical rod in face part section, and along x-axis tensile elongation | ij |.Then by entity rod member with i point as center of rotation, first with x-o-y θ degree is rotated in the plane that plane is parallel.Subsequently coordinate system is rotated θ degree, in new x-o-z plane, with i point for rotating Rod member is rotated by centerDegree, the i.e. available rod member physical model being consistent with real space position.Wherein θ can be according to formula C () is calculated:

$\mathrm{\θ}=\arcsin \frac{\cos \mathrm{\β}}{\sin \mathrm{\γ}}---\left(c\right);$

Wherein: α, β, γ represent rod member axial line and x, y, the angle of z-axis respectively.

(2) the actual aerodynamic configuration of space bar member is determined:

Carry out cutting by flowing wind levels in the face of space bar member physical model, obtain it in level to the actual gas flowing under wind effect Dynamic profile, and determine the angle of wind deflection relative position relation of itself and different angles.

(3) set up rod member border and flow field regions, and stream field region carry out stress and strain model:

The actual aerodynamic configuration of rod member generated according to cutting in GAMBIT, sets up rod member border.Set up length and width the least Flow field regions in the rod member width of 11 times.For improving computational efficiency and degree of accuracy, whole flow field regions all uses quadrilateral structure Change grid.And distance rod member border is the nearest, grid division is the most intensive；Distance rod member border is the most remote, and grid division is the most sparse.Bar Have employed 4 layers of body fitted anisotropic mesh around part border, near wall minimum body fitted anisotropic mesh height is 0.002m, thus ensures gas as far as possible The accuracy of Cable Power Computation.

(4) rod member beam wind is obtained to Shape Coefficient and down wind Shape Coefficient；

Grid file is directed in FLUENT, carries out grid checking and the adjustment of corresponding dimensional units.Definition is used Analysis and solution model, defines turbulent parameters, definition initial calculation pressure parameter and pressure reference point position.Definition flow field inlet, Flow field exits, flow field up-and-down boundary and the boundary condition on rod member border, given initial inflow velocity.Definition solver and residual error prison The parameters of visual organ, and start iterative computation.Observation residual error monitor, treats that residual error curve therein becomes with the increase of iteration step After stable, extract the horizontal line suffered by rod member border to resistance F_xWith fair line to resistance F_y.And calculate rod member limit by formula (d) Boundary horizontal line to fair line Shape Coefficient in both direction.

$\left.\begin{array}{c}{\mathrm{\μ}}_{\mathrm{sx}}={2F}_x/{\mathrm{\ρBU}}^2\\ {\mathrm{\μ}}_{\mathrm{sy}}={2F}_y/{\mathrm{\ρBU}}^2\end{array}\right\}---\left(d\right);$

Revolving rod border, constantly changes it and flows the angle of wind direction, and repeating step (2)-(4), i.e. available difference The Shape Coefficient of rod member under angle of wind deflection.

Wherein: μ_sxRepresent that rod member beam wind is to Shape Coefficient；μ_syRepresent rod member down wind Shape Coefficient；F_xRepresent that horizontal line is to resistance； F_yRepresent that fair line is to resistance；B represents rod member characteristic width (such as width or the diameter of round steel pipe of angle with equal legs)；U represents Wind speed；ρ represents atmospheric density.

(5) determine rod member horizontal line to wind load and fair line to wind load:

Through the Shape Coefficient that above-mentioned steps obtains, it is for being attached the service of the local calculation of component.The present invention is based in specification The shaft tower Wind load calculating formula be given, has carried out suitable correction to it, so that build under its skew wind obtained with the inventive method Coefficient matches.Shown in rod member Wind load calculating formula such as formula (e) after being corrected.

$\left.\begin{array}{c}{W}_x=W_o\·{\mathrm{\μ}}_z\·{\mathrm{\μ}}_{\mathrm{sx}}\·{\mathrm{\β}}_z\·B\·l\\ W_y=W_o\·{\mathrm{\μ}}_z\·{\mathrm{\μ}}_{\mathrm{sy}}\·{\mathrm{\β}}_z\·B\·l\end{array}\right\}---\left(e\right);$

In formula: W_oLocal fundamental wind pressure standard value；W_xRod member horizontal line is to wind load；W_yRod member fair line is to wind load；μ_z Height variation coefficient of wind pressure；μ_sxBeam wind is to rod member Shape Coefficient；μ_syDown wind rod member Shape Coefficient；β_zShaft tower wind Load inversion coefficient；B rod member characteristic width；L rod member physical length.

Embodiment

Now application instantiation introduction uses said method to calculate a certain space bar member of angle steel tower Shape Coefficient under 0 ° of angle of wind deflection Calculating process.

Choose certain base angle head tower top as shown in Figure 2, as a example by two ends node serial number is respectively the space bar member of 601 and 700, The i of this space bar member sits up straight and is designated as (-0.208,0.208,2), and j sits up straight and is designated as (0.309,0.309,2.8).Based on formula (b) Be calculated a length of 0.958m of its rod member, based on formula (a) be calculated its deflection for (57.33 °, 83.94 °, 33.28 °), obtaining θ angle according to formula (c) is 11.09 °.

This rod member is the oblique material that one side connects, and sets up component section as shown in Figure 3 in y-o-z plane.And it is long along x-axis stretching Degree 0.958m.Then by entity rod member with i point as center of rotation, first rotate in the plane parallel with x-o-y plane 11.09°；Again coordinate system is rotated 11.09 °, in new x-o-z plane, for center of rotation, rod member is rotated with i point 56.72 °, the i.e. available rod member physical model being consistent with real space situation is as shown in Figure 4.Plane of flow pair is carried out with level After rod member carries out cutting, obtain the actual aerodynamic configuration of this space bar member as shown in Figure 5.The relative position of rod member section and angle of wind deflection Relation is as shown in Figure 6.

According to length and height, the principle of equal angle steel width not less than 11 times, sets up flow field regions as shown in Figure 7.By whole stream After field areas saves as * .sat file, GAMBIT imports the territory, flow field built up, and carries out stress and strain model.Wherein angle steel Around border, stress and strain model is as shown in Figure 8.

According to the operation item in step (4), the parameter in definition FLUENT, carries out fluid calculation subsequently, treats residual successively After residual error in difference monitor is stablized, extract angle steel section fair line to resistance F_yWith horizontal line to resistance F_x, and calculate by formula (d) Angle steel section Shape Coefficient under current angle of wind deflection.Take B=0.04m, then this rod member is becoming under 0 ° of angle of wind deflection horizontal line to build system Number μ_sx=0.006, fair line is to Shape Coefficient μ_sy=0.297.

Obtain the Shape Coefficient under other angle of wind deflection, only need to rotate angle steel section in GAMBIT to corresponding angle of wind deflection (such as figure Shown in 6), repartition angle steel periphery grid and import FLUENT and carry out fluid calculation.

After completing above-mentioned calculating, the wind load suffered by rod member under corresponding angle of wind deflection to be formed, only need to be by μ_sxAnd μ_syIt is brought into public affairs In formula (e).The wind load W that will obtain_xAnd W_yIt is loaded onto at the rod member connection node with connecting elements as equivalent load, Just the local checking computations work of connecting elements can be carried out further.

Finally should be noted that: above example is only in order to illustrate that technical scheme is not intended to limit, although reference The present invention has been described in detail by above-described embodiment, those of ordinary skill in the field it is understood that still can to this Invention detailed description of the invention modify or equivalent, and without departing from spirit and scope of the invention any amendment or etc. With replacing, it all should be contained in the middle of scope of the presently claimed invention.

Claims (5)

1. the single rod member Shape Coefficient of transmission tower based on CFD skew wind determines method, it is characterised in that Described method comprises the steps:

(1) set up single rod member physical model, and be placed into and actual point under transmission tower coordinate system The locus that position matches；

(2) the actual aerodynamic configuration of space bar member is determined；

(3) set up rod member border and flow field regions, and stream field region carries out stress and strain model；

(4) rod member beam wind is obtained to Shape Coefficient and down wind Shape Coefficient；

(5) determine rod member horizontal line to wind load and fair line to wind load；

In described step (1), the rectangular coordinate system with transmission tower structural system as object of reference, make rod member axle Heart line two ends node i, the space coordinates of j are respectively { x_i、y_i、z_iAnd { x_j、y_j、z_j, then rod member axle The expression formula of the direction cosines of heart line is as follows:

$\left\{\begin{array}{c}cos\mathrm{\α}=(x_j-x_i)/\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}\\ \cos \mathrm{\β}=(y_j-y_i)/\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}\\ \cos \mathrm{\γ}=(z_j-z_i)/\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}\end{array}\right.---\left(a\right);$

Rod member length | ij | expressions below represents:

$\left|ij\right|=\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2+{(z_i-z_j)}^2}---\left(b\right);$

During single rod member solid modelling, at y-o-z plane built-in vertical rod part section, and along x-axis tensile elongation |ij|；By entity rod member with i point as center of rotation, then in the plane parallel with x-o-y plane, rotate θ degree； Subsequently coordinate system is rotated θ degree, in new x-o-z plane, for center of rotation, rod member is rotated with i pointDegree, i.e. obtains the rod member physical model matched with real space position；Wherein θ is according to following expression Formula (c) obtains:

$\mathrm{\θ}=arcsin\frac{cos\mathrm{\β}}{\sin \mathrm{\γ}}---\left(c\right);$

Wherein: α, β, γ represent rod member axial line and x, y, the angle of z-axis respectively.

2. transmission tower single rod member Shape Coefficient as claimed in claim 1 determines method, it is characterised in that In described step (2), carry out cutting by flowing wind levels in the face of space bar member physical model, obtain its Level flows the actual aerodynamic configuration under wind effect, and determines the angle of wind deflection relative position relation of itself and different angles.

3. transmission tower single rod member Shape Coefficient as claimed in claim 1 determines method, it is characterised in that In described step (3), the actual aerodynamic configuration of rod member generated according to cutting, set up rod member border；Set up long Degree and the flow field regions of the width rod member width not less than 11 times；Described flow field regions all uses quadrilateral structure Change grid；Using 4 layers of body fitted anisotropic mesh around rod member border, near wall minimum body fitted anisotropic mesh height is 0.002m。

4. transmission tower single rod member Shape Coefficient as claimed in claim 1 determines method, it is characterised in that In described step (4), rod member section Shape Coefficient under different angle of wind deflection is carried out fluid mechanical emulation meter Calculate, obtain rod member beam wind to Shape Coefficient and down wind Shape Coefficient；Described beam wind is to Shape Coefficient and down wind Shape Coefficient expressions below represents:

$\left.\begin{array}{c}{\mathrm{\μ}}_{sx}=2F_x/{\mathrm{\ρBU}}^2\\ {\mathrm{\μ}}_{sy}=2F_y/{\mathrm{\ρBU}}^2\end{array}\right\}---\left(d\right);$

Wherein: μ_sxRepresent that rod member beam wind is to Shape Coefficient；μ_syRepresent rod member down wind Shape Coefficient；F_xRepresent Horizontal line is to resistance；F_yRepresent that fair line is to resistance；B represents rod member characteristic width；U represents wind speed；ρ represents Atmospheric density；

Revolving rod border, constantly changes it and flows the angle of wind direction, and repeating step (2)-(4), i.e. Obtain under different angle of wind deflection the beam wind of rod member to Shape Coefficient and down wind Shape Coefficient.

5. transmission tower single rod member Shape Coefficient as claimed in claim 1 determines method, it is characterised in that In described step (5), rod member horizontal line represents to wind load expressions below to wind load and fair line:

$\left.\begin{array}{c}{W}_x=W_o\·{\mathrm{\μ}}_z\·{\mathrm{\μ}}_{sx}\·{\mathrm{\β}}_z\·B\·l\\ W_y=W_o\·{\mathrm{\μ}}_z\·{\mathrm{\μ}}_{sy}\·{\mathrm{\β}}_z\·B\·l\end{array}\right\}---\left(e\right);$

Wherein: W_oRepresent local fundamental wind pressure standard value；W_xRepresent that rod member horizontal line is to wind load；W_yRepresent Rod member fair line is to wind load；μ_zRepresent height variation coefficient of wind pressure；μ_sxRepresent that beam wind is to rod member Shape Coefficient； μ_syRepresent down wind rod member Shape Coefficient；β_zRepresent shaft tower Wind Load Adjustment Coefficients；B represents rod member feature width Degree；L represents rod member physical length.