CN111338386B - Heliostat light condensation efficiency evaluation method under wind load effect - Google Patents

Heliostat light condensation efficiency evaluation method under wind load effect Download PDF

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CN111338386B
CN111338386B CN201911324731.0A CN201911324731A CN111338386B CN 111338386 B CN111338386 B CN 111338386B CN 201911324731 A CN201911324731 A CN 201911324731A CN 111338386 B CN111338386 B CN 111338386B
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heliostat
calculating
points
area
preset
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CN111338386A (en
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吉柏锋
胥蓓蕾
沙正海
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Wuhan University of Technology WUT
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D3/00—Control of position or direction
    • G05D3/10—Control of position or direction without using feedback
    • G05D3/105—Solar tracker
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S20/00—Supporting structures for PV modules
    • H02S20/30—Supporting structures being movable or adjustable, e.g. for angle adjustment
    • H02S20/32—Supporting structures being movable or adjustable, e.g. for angle adjustment specially adapted for solar tracking
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S40/00—Components or accessories in combination with PV modules, not provided for in groups H02S10/00 - H02S30/00
    • H02S40/20—Optical components
    • H02S40/22—Light-reflecting or light-concentrating means
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/52—PV systems with concentrators

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Abstract

The invention provides a heliostat condensing efficiency evaluation method under the action of wind load, and belongs to the technical field of heliostat condensing efficiency evaluation. The heliostat condensing efficiency evaluation method under the wind load effect can solve the problem that structural deformation caused by wind load in the existing evaluation method needs to evaluate condensing efficiency, is not limited to verification evaluation after a heliostat field is built, can carry out calculation based on local meteorological data for priori evaluation, carries out evaluation before the heliostat field is built, can obtain the surface deformation information of the heliostat under the wind load effect by arranging a displacement sensor on the surface of the heliostat after the heliostat field is built, can still adopt the method to carry out long-term monitoring on condensing efficiency, and can provide calculation basis for the light and heat power station for evaluating the condensing efficiency of the heliostat in advance and monitoring afterwards.

Description

Heliostat light condensation efficiency evaluation method under wind load effect
Technical Field
The invention belongs to the technical field of heliostat condensing efficiency evaluation, and relates to a heliostat condensing efficiency evaluation method under the action of wind load.
Background
The heliostat structure is a light gathering device composed of a reflector, a supporting mirror frame, a bottom base, a tracking system, a control system and the like, wherein the reflector surface is supported by a back rigid support, the tracking system tracks the running track of the sun and feeds the track back to the control system, and finally the reflector surface is adjusted to be a proper pitch angle and an azimuth angle so as to ensure that the sunlight is accurately reflected to a heat absorption device on a heat collection tower. In order to accurately reflect the solar rays to the top of the heat collecting tower, the pitch angle and the azimuth angle of the heliostat structure are changed at any moment in work.
The current part researches the condensation efficiency of the heliostat under the action of wind load, and the result shows that the condensation loss of the heliostat caused by the wind load is the largest at 14 summer solstices and is as high as 10.73%. The deformation of the heliostat under wind load adopts the method of establishing the relation between discrete nodes and a deformed mirror surface curved surface and adopting a B-spline global curved surface interpolation method to carry out curved surface reconstruction on the discrete nodes. In practice, due to the material properties of the mirror glass, the mirror deformation of the heliostat is not characterized by curved surface bending deformation, but is mainly shear deformation as a whole; secondly, considering that the heliostat panel is provided with a plurality of small independent deformed block glasses, the deformation characteristic of the heliostat is not proper by adopting the reconstruction of the integral node curved surface.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a heliostat light condensation efficiency evaluation method under the action of wind load, and the technical problems to be solved by the invention are as follows: how to provide a heliostat condensing efficiency evaluation method under the action of wind load.
The purpose of the invention can be realized by the following technical scheme:
a heliostat condensing efficiency evaluation method under the action of wind load comprises the following steps:
s1: acquiring a pitch angle and a second azimuth angle of the heliostat at preset time through a first azimuth angle and a height angle of the sun relative to the earth at preset time;
s2: acquiring surface wind pressure of the heliostat at preset time, converting the surface wind pressure into an actual load applied to the finite element structure, and applying the actual load to the finite element structure to perform structural deformation calculation to acquire mirror surface deformation information of the heliostat;
s3: and extracting the coordinates of the deformation points in the subareas according to the mirror surface deformation information, establishing a heliostat field space coordinate system according to the coordinates of the deformation points, calculating the relation between a reflection line corresponding to the deformation points and a heat absorption area on the heat collection tower by utilizing a vector relation through a pitch angle and an azimuth angle under the heliostat field space coordinate system, and acquiring the light condensation efficiency caused by wind load when the heliostat is in preset time.
Preferably, step S1 includes:
s11: introducing an equatorial coordinate system and a horizon coordinate system;
s12: by the formula
Figure 100002_DEST_PATH_IMAGE001
Calculating declination angle
Figure DEST_PATH_IMAGE002
Wherein n represents a preset date in the year;
s13: by the formula
Figure 100002_DEST_PATH_IMAGE003
Calculating when the sun is presetFirst azimuth angle with respect to the earth at time
Figure DEST_PATH_IMAGE004
And by formula
Figure 100002_DEST_PATH_IMAGE005
Calculating the altitude angle of the sun relative to the earth at a preset time
Figure DEST_PATH_IMAGE006
Wherein
Figure 100002_DEST_PATH_IMAGE007
Representing the geographical latitude at a preset location,
Figure DEST_PATH_IMAGE008
representing the angle of time
Figure DEST_PATH_IMAGE010
，
Figure 100002_DEST_PATH_IMAGE011
Indicating the time of day.
Preferably, step S1 further includes:
s14: establishing a space coordinate system which takes the bottom of a heat absorption tower as an origin of coordinate axes, the height direction of the heat absorption tower as a Z axis and the ground plane of the heliostat as an X-Y plane;
s15: determining the central position of the heat absorption tower as the point A (0, 0, Z) in the space coordinate systemA) Determining a P point (X) of a predetermined heliostat in a heliostat field whose center is an X-Y planeP,YP0), unit vector of incident solar ray at point P of
Figure DEST_PATH_IMAGE012
And unit vector of reflected ray from P to A
Figure 100002_DEST_PATH_IMAGE013
Respectively by formula
Figure 100002_DEST_PATH_IMAGE015
And
Figure 100002_DEST_PATH_IMAGE017
calculating;
s16: in that
Figure DEST_PATH_IMAGE012A
And
Figure DEST_PATH_IMAGE013A
in the plane of the drawing there is shown,
Figure DEST_PATH_IMAGE018
is a normal vector of the mirror surface,
Figure DEST_PATH_IMAGE012AA
、
Figure DEST_PATH_IMAGE013AA
and
Figure DEST_PATH_IMAGE018A
the included angle is
Figure 100002_DEST_PATH_IMAGE019
Then can obtain
Figure 100002_DEST_PATH_IMAGE021
，
Figure 100002_DEST_PATH_IMAGE023
，
Figure 100002_DEST_PATH_IMAGE025
，
Figure DEST_PATH_IMAGE026
，
Figure DEST_PATH_IMAGE028
，
Figure 100002_DEST_PATH_IMAGE029
Wherein
Figure DEST_PATH_IMAGE030
The pitch angle of the normal vector of the mirror surface at the preset position of the heliostat at the preset time,
Figure 100002_DEST_PATH_IMAGE031
a second azimuth angle of the normal vector of the mirror surface at the preset position of the heliostat at the preset time.
Preferably, step S2 includes:
s21: establishing a calculation model of the heliostat;
s22: creating a watershed computing grid around the heliostat according to the computing model;
s23: calculating and acquiring mirror surface wind pressure through computational fluid dynamics under a computational grid;
s24: extracting the wind pressure values of the mirror surface control points, selecting a first preset number of extraction points in each wind load control area, and finally calculating the wind pressure value of the control point according to the wind pressure average value of the first preset number of points;
s25: and applying the calculated wind pressure value editing ANSYS command at the corresponding moment to the heliostat finite element model to perform structural deformation calculation to obtain the mirror surface deformation information of the heliostat.
Preferably, in step S2, the surface wind pressure of the heliostat at a preset time is obtained through a CFD calculation software ANSYS-Fluent simulation, the surface wind pressure is converted into an actual load applied to the finite element structure, and the actual load is written into an ANSYS command and applied to the finite element structure to perform structural deformation calculation to obtain the mirror deformation information of the heliostat.
Preferably, step S3 includes:
s31: dividing the single mirror surface into a plurality of preset areas with the control point as the center;
s32: extracting the coordinate values of the preset area after the first preset number of end points are deformed by Ansys calculation, and utilizing
Figure DEST_PATH_IMAGE032
Three end points forming a plane N1From the coordinates of the three end points, N can be derived1Normal vector of plane
Figure 100002_DEST_PATH_IMAGE033
；
S33: in N1Selecting a second preset number of deformation points in the area, wherein each point shares N1Vector of plane normal
Figure DEST_PATH_IMAGE033A
And calculating the relation between the reflection line corresponding to each deformation point and a heat absorption area on the heat collection tower by utilizing a vector relation through a pitch angle and an azimuth angle in a heliostat field coordinate system.
Preferably, step S3 further includes:
s34: according to the reflection principle, the reflection coefficient can be in N1Selected points within a region
Figure 100002_DEST_PATH_IMAGE035
And incident light
Figure DEST_PATH_IMAGE036
By the formula
Figure 100002_DEST_PATH_IMAGE037
、
Figure DEST_PATH_IMAGE038
Calculating the vector of the reflected light
Figure 100002_DEST_PATH_IMAGE039
And calculating a reflected light equation and calculating the number of points on the light loss receiving area, and calculating the effective reflecting surface of the mirror surface of the area through the number of points on the area surface to finally obtain the light condensation efficiency.
Preferably, S32: extracting the coordinate values of the deformed four endpoints of the preset area by Ansys calculation, wherein
Figure DEST_PATH_IMAGE040
Three end points forming a plane N1From the coordinates of the three end points, N can be derived1Normal vector of plane
Figure DEST_PATH_IMAGE033AA
。
Preferably, S24: extracting the wind pressure value of the mirror control point, selecting 4 extraction points in each wind load control area, and finally calculating the wind pressure value of the control point according to the wind pressure mean value of the 4 extraction points
Figure 100002_DEST_PATH_IMAGE041
，
Figure DEST_PATH_IMAGE042
Wherein
Figure 100002_DEST_PATH_IMAGE043
Corresponds to the first
Figure DEST_PATH_IMAGE044
The mirror is
Figure 100002_DEST_PATH_IMAGE045
Arrange first
Figure DEST_PATH_IMAGE046
And (4) a control point.
Preferably, the vector is passed in step S34
Figure 100002_DEST_PATH_IMAGE047
Calculating the equation of the reflected ray
Figure DEST_PATH_IMAGE048
Calculating the number of points on the receiving region by calculating the light loss, and calculating the effective reflection area of the mirror surface in the region by point number
Figure 100002_DEST_PATH_IMAGE049
By the formula
Figure DEST_PATH_IMAGE050
Calculating the reflection area
Figure 100002_DEST_PATH_IMAGE051
By the formula
Figure DEST_PATH_IMAGE052
Calculating the light condensing efficiency, wherein
Figure 100002_DEST_PATH_IMAGE053
Is the area of the mirror surface in the region,
Figure DEST_PATH_IMAGE054
the total number of points in the area is,
Figure 100002_DEST_PATH_IMAGE055
to reflect the number of points of the light in the receiving area,
Figure DEST_PATH_IMAGE056
the light condensing efficiency.
The heliostat condensing efficiency evaluation method under the wind load effect can solve the problem that structural deformation caused by wind load in the existing evaluation method needs to evaluate condensing efficiency, is not limited to verification evaluation after a heliostat field is built, can carry out calculation based on local meteorological data for priori evaluation, carries out evaluation before the heliostat field is built, can obtain the surface deformation information of the heliostat under the wind load effect by arranging a displacement sensor on the surface of the heliostat after the heliostat field is built, can still adopt the method to carry out long-term monitoring on condensing efficiency, and can provide calculation basis for the light and heat power station for evaluating the condensing efficiency of the heliostat in advance and monitoring afterwards.
Drawings
FIG. 1 is an equatorial coordinate system of the present invention;
FIG. 2 is a horizon coordinate system in accordance with the present invention;
FIG. 3 is a schematic diagram of the heliostat field single mirror elevation and azimuth calculation of the invention;
FIG. 4 is a schematic diagram of a computational model in the present invention;
FIG. 5 is a diagram illustrating an overall partitioning of a computational grid in the present invention;
FIG. 6 is a schematic diagram of computational grid heliostat local meshing in the present invention;
FIG. 7 is a schematic view of an integral mirror in the present invention;
fig. 8 is a schematic diagram of a partial mirror surface in the global mirror surface in the present invention.
Detailed Description
The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.
Referring to fig. 1, fig. 2, fig. 3, fig. 4, fig. 5, fig. 6, fig. 7, and fig. 8, the method for evaluating the light condensing efficiency of a heliostat under the action of wind load in the present embodiment includes the following steps:
s1: acquiring a pitch angle and a second azimuth angle of the heliostat at preset time through a first azimuth angle and a height angle of the sun relative to the earth at preset time;
s2: acquiring surface wind pressure of the heliostat at preset time, converting the surface wind pressure into an actual load applied to the finite element structure, and applying the actual load to the finite element structure to perform structural deformation calculation to acquire mirror surface deformation information of the heliostat;
s3: and extracting the coordinates of the deformation points in the subareas according to the mirror surface deformation information, establishing a heliostat field space coordinate system according to the coordinates of the deformation points, calculating the relation between a reflection line corresponding to the deformation points and a heat absorption area on the heat collection tower by utilizing a vector relation through a pitch angle and an azimuth angle under the heliostat field space coordinate system, and acquiring the light condensation efficiency caused by wind load when the heliostat is in preset time.
The heliostat condensing efficiency evaluation method under the wind load effect can solve the problem that structural deformation caused by wind load in the existing evaluation method is required for condensing efficiency evaluation, the evaluation method is not limited to verification evaluation after a heliostat field is built, calculation can be carried out on the basis of local meteorological data for priori evaluation before the heliostat field is built, after the heliostat field is built, a displacement sensor is arranged on the surface of the heliostat, after the surface deformation information of the heliostat under the wind load effect is obtained, long-term condensation efficiency monitoring can still be carried out by adopting the method, and calculation basis of heliostat condensing efficiency pre-evaluation and post-monitoring can be provided for a photo-thermal power station.
Referring to fig. 1 and 2, step S1 includes:
s11: introducing an equatorial coordinate system and a horizon coordinate system;
s12: by the formula
Figure DEST_PATH_IMAGE001A
Calculating declination angle
Figure DEST_PATH_IMAGE002A
Wherein n represents a preset date in the year, and n represents the day of the year when counted by taking 1 month and 1 day as a starting point, and 2019 is taken as an example: spring minutes n = 80; summer solstice n = 172; autumn divided day n = 266; winter solstice day n = 356;
s13: by the formula
Figure DEST_PATH_IMAGE003A
Calculating a first azimuth angle of the sun relative to the earth at a preset time
Figure DEST_PATH_IMAGE004A
And by formula
Figure DEST_PATH_IMAGE005A
Calculating the altitude angle of the sun relative to the earth at a preset time
Figure DEST_PATH_IMAGE006A
Wherein
Figure DEST_PATH_IMAGE007A
Representing the geographical latitude at a preset location,
Figure DEST_PATH_IMAGE008A
representing the angle of time
Figure DEST_PATH_IMAGE010A
，
Figure DEST_PATH_IMAGE011A
The time is shown and corresponds to 24 hours.
Referring to fig. 3, step S1 further includes:
s14: establishing a space coordinate system which takes the bottom of a heat absorption tower as an origin of coordinate axes, the height direction of the heat absorption tower as a Z axis and the ground plane of the heliostat as an X-Y plane;
s15: determining the central position of the heat absorption tower as the point A (0, 0, Z) in the space coordinate systemA) Determining a P point (X) of a predetermined heliostat in a heliostat field whose center is an X-Y planeP,YP0), unit vector of incident solar ray at point P of
Figure DEST_PATH_IMAGE012AAA
And unit vector of reflected ray from P to A
Figure DEST_PATH_IMAGE013AAA
Respectively by formula
Figure DEST_PATH_IMAGE015A
And
Figure DEST_PATH_IMAGE017A
calculating;
s16: in that
Figure DEST_PATH_IMAGE012AAAA
And
Figure DEST_PATH_IMAGE013AAAA
in the plane of the drawing there is shown,
Figure DEST_PATH_IMAGE018AA
is a normal vector of the mirror surface,
Figure DEST_PATH_IMAGE012AAAAA
、
Figure DEST_PATH_IMAGE013AAAAA
and
Figure DEST_PATH_IMAGE018AAA
the included angle is
Figure DEST_PATH_IMAGE019A
Then can obtain
Figure DEST_PATH_IMAGE021A
，
Figure DEST_PATH_IMAGE023A
，
Figure DEST_PATH_IMAGE025A
，
Figure DEST_PATH_IMAGE026A
，
Figure DEST_PATH_IMAGE028A
，
Figure DEST_PATH_IMAGE029A
Wherein
Figure DEST_PATH_IMAGE030A
The pitch angle of the normal vector of the mirror surface at the preset position of the heliostat at the preset time,
Figure DEST_PATH_IMAGE031A
a second azimuth angle of the normal vector of the mirror surface at the preset position of the heliostat at the preset time.
Referring to fig. 4, 5 and 6, step S2 includes:
s21: establishing a calculation model of the heliostat;
s22: creating a watershed computing grid around the heliostat according to the computing model;
s23: calculating and acquiring mirror surface wind pressure through computational fluid dynamics under a computational grid;
s24: extracting the wind pressure values of the mirror control points, selecting a first preset number of extraction points in each wind load control area, and finally calculating the wind pressure value of the control point according to the wind pressure average value of the first preset number of extraction points;
s25: and applying the calculated wind pressure value editing ANSYS command at the corresponding moment to the heliostat finite element model to perform structural deformation calculation to obtain the mirror surface deformation information of the heliostat.
In step S2, surface wind pressure of the heliostat at a preset time is obtained through CFD calculation software ANSYS-Fluent simulation, the surface wind pressure is converted into an actual load applied to the finite element structure, and the actual load is compiled into an ANSYS command and applied to the finite element structure to perform structural deformation calculation to obtain mirror surface deformation information of the heliostat.
Referring to fig. 7 and 8, step S3 includes:
s31: dividing a single mirror into a plurality of preset areas with a control point as the center, such as a whole partition area diagram in FIG. 7, and dividing the whole mirror into a plurality of areas, such as a simulation area of A11 in FIG. 8;
s32: extracting the coordinate values of the preset area after the first preset number of end points are deformed by Ansys calculation, and utilizing
Figure DEST_PATH_IMAGE032A
Three end points forming a plane N1From the coordinates of the three end points, N can be derived1Normal vector of plane
Figure DEST_PATH_IMAGE033AAA
；
S33: in N1Selecting a second preset number of deformation points in the region, wherein the second preset number is large enough to improve the precision, and the points share the normal vector
Figure DEST_PATH_IMAGE033AAAA
And calculating the relation between the reflection line corresponding to each deformation point and a heat absorption area on the heat collection tower by utilizing a vector relation through a pitch angle and an azimuth angle in a heliostat field coordinate system.
Step S3 further includes:
s34: according to the reflection principle, the reflection coefficient can be in N1Selected points within a region
Figure DEST_PATH_IMAGE035A
And incident light
Figure DEST_PATH_IMAGE036A
By the formula
Figure DEST_PATH_IMAGE037A
、
Figure DEST_PATH_IMAGE038A
Calculating the vector of the reflected light
Figure DEST_PATH_IMAGE039A
And calculating a reflected light equation and calculating the number of points on the light loss receiving area, and calculating the effective reflecting surface of the mirror surface of the area through the number of points on the area surface to finally obtain the light condensation efficiency.
S32: extracting the coordinate values of the deformed four endpoints of the preset area by Ansys calculation, wherein
Figure DEST_PATH_IMAGE040A
Three end points forming a plane N1From the coordinates of the three end points, N can be derived1Normal vector of plane
Figure DEST_PATH_IMAGE033AAAAA
。
S24: extracting the wind pressure value of the mirror control point, selecting 4 extraction points in each wind load control area in order to reduce the error, and finally calculating the wind pressure value of the control point according to the wind pressure mean value of the 4 extraction points
Figure DEST_PATH_IMAGE041A
，
Figure DEST_PATH_IMAGE042A
Wherein
Figure DEST_PATH_IMAGE043A
Corresponds to the first
Figure DEST_PATH_IMAGE044A
The mirror is
Figure DEST_PATH_IMAGE045A
Arrange first
Figure DEST_PATH_IMAGE046A
And (4) a control point.
Passing the vector in step S34
Figure DEST_PATH_IMAGE047A
Calculating the equation of the reflected ray
Figure DEST_PATH_IMAGE048A
Calculating the number of points on the receiving region by calculating the light loss, and calculating the effective reflection area of the mirror surface in the region by point number
Figure DEST_PATH_IMAGE049A
By the formula
Figure DEST_PATH_IMAGE050A
Calculating the reflection area
Figure DEST_PATH_IMAGE051A
By the formula
Figure DEST_PATH_IMAGE052A
Calculating the light condensing efficiency, wherein
Figure DEST_PATH_IMAGE053A
Is the area of the mirror surface in the region,
Figure DEST_PATH_IMAGE054A
the total number of points in the area is,
Figure DEST_PATH_IMAGE055A
to reflect the number of points of the light in the receiving area,
Figure DEST_PATH_IMAGE056A
the light condensing efficiency. The plane formed by the three endpoints is used by calculating the mirror surface by partitioning and taking the deformation coordinates of the endpoints of the partitions as the calculation reference. The method avoids the artificial consideration of the mirror surface deformation into the curved surface bending deformation in the heliostat deformation represented by the integral node curved surface reconstructionAnd the defects that only the endpoint coordinates of each partition mirror surface are changed by wind load in the calculation process, and the partition mirror surface keeps the flatness in the calculation process.
The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Claims (5)

1. A heliostat light condensation efficiency evaluation method under the action of wind load is characterized by comprising the following steps:
s1: acquiring a pitch angle and a second azimuth angle of the heliostat at preset time through a first azimuth angle and a height angle of the sun relative to the earth at preset time;
s2: acquiring surface wind pressure of the heliostat at preset time, converting the surface wind pressure into an actual load applied to the finite element structure, and applying the actual load to the finite element structure to perform structural deformation calculation to acquire mirror surface deformation information of the heliostat;
s3: extracting deformation point coordinates in the subareas according to the mirror surface deformation information, establishing a heliostat field space coordinate system according to the deformation point coordinates, calculating the relation between a reflection line corresponding to the deformation point and a heat absorption area on the heat collection tower by utilizing a vector relation through a pitch angle and an azimuth angle under the heliostat field space coordinate system, and acquiring the light condensation efficiency caused by wind load when the heliostat is in preset time;
step S1 includes:
s11: introducing an equatorial coordinate system and a horizon coordinate system;
s12: by the formula
Figure DEST_PATH_IMAGE001
Calculating declination angle
Figure 737495DEST_PATH_IMAGE002
Wherein n represents a preset date in the year;
s13: by the formula
Figure DEST_PATH_IMAGE003
Calculating a first azimuth angle of the sun relative to the earth at a preset time
Figure 454915DEST_PATH_IMAGE004
And by formula
Figure DEST_PATH_IMAGE005
Calculating the altitude angle of the sun relative to the earth at a preset time
Figure 302655DEST_PATH_IMAGE006
Wherein
Figure DEST_PATH_IMAGE007
Representing the geographical latitude at a preset location,
Figure 54710DEST_PATH_IMAGE008
representing the angle of time
Figure DEST_PATH_IMAGE009
，
Figure 58264DEST_PATH_IMAGE010
Represents a time of day;
step S1 further includes:
s14: establishing a space coordinate system which takes the bottom of a heat absorption tower as an origin of coordinate axes, the height direction of the heat absorption tower as a Z axis and the ground plane of the heliostat as an X-Y plane;
s15: determining the central position of the heat absorption tower as the point A (0, 0, Z) in the space coordinate systemA) Determining a P point (X) of a predetermined heliostat in a heliostat field whose center is an X-Y planeP,YP0), unit vector of incident solar ray at point P of
Figure DEST_PATH_IMAGE011
And reflected lightUnit vector from P to A
Figure 262980DEST_PATH_IMAGE012
Respectively by formula
Figure DEST_PATH_IMAGE013
And
Figure 648831DEST_PATH_IMAGE014
calculating;
s16: in that
Figure DEST_PATH_IMAGE015
And
Figure 255393DEST_PATH_IMAGE016
in the plane of the drawing there is shown,
Figure DEST_PATH_IMAGE017
is a normal vector of the mirror surface,
Figure DEST_PATH_IMAGE019
、
Figure DEST_PATH_IMAGE021
and
Figure 638970DEST_PATH_IMAGE022
the included angle is
Figure DEST_PATH_IMAGE023
Then can obtain
Figure 580250DEST_PATH_IMAGE024
，
Figure DEST_PATH_IMAGE025
，
Figure 520524DEST_PATH_IMAGE026
，
Figure DEST_PATH_IMAGE027
，
Figure 699701DEST_PATH_IMAGE028
，
Figure DEST_PATH_IMAGE029
Wherein
Figure 67229DEST_PATH_IMAGE030
The pitch angle of the normal vector of the mirror surface at the preset position of the heliostat at the preset time,
Figure DEST_PATH_IMAGE031
a second azimuth angle of the normal vector of the mirror surface at the preset position of the heliostat at the preset time;
step S3 includes:
s31: dividing the single mirror surface into a plurality of preset areas with the control point as the center;
s32: extracting the coordinate values of the preset area after the first preset number of end points are deformed by Ansys calculation, and utilizing
Figure 495805DEST_PATH_IMAGE032
Three end points forming a plane N1From the coordinates of the three end points, N can be derived1Normal vector of plane
Figure DEST_PATH_IMAGE033
；
S33: in N1Selecting a second preset number of deformation points in the area, wherein each point shares N1Vector of plane normal
Figure 974191DEST_PATH_IMAGE034
Calculating the relation between a reflection line corresponding to each deformation point and a heat absorption area on the heat collection tower by utilizing a vector relation through a pitch angle and an azimuth angle in a heliostat field coordinate system;
step S2 includes:
s21: establishing a calculation model of the heliostat;
s22: creating a watershed computing grid around the heliostat according to the computing model;
s23: calculating and acquiring mirror surface wind pressure through computational fluid dynamics under a computational grid;
s24: extracting the wind pressure values of the mirror surface control points, selecting a first preset number of extraction points in each wind load control area, and finally calculating the wind pressure values of the control points according to the wind pressure average value of the first preset number of extraction points;
s25: applying the calculated wind pressure value editing ANSYS command at the corresponding moment to a heliostat finite element model for structural deformation calculation to obtain the mirror surface deformation information of the heliostat;
s24: extracting the wind pressure value of the mirror control point, selecting 4 extraction points in each wind load control area, and finally calculating the wind pressure value of the control point according to the wind pressure mean value of the 4 extraction points
Figure DEST_PATH_IMAGE035
，
Figure 70192DEST_PATH_IMAGE036
Wherein
Figure DEST_PATH_IMAGE037
Corresponds to the first
Figure 608620DEST_PATH_IMAGE038
The mirror is
Figure DEST_PATH_IMAGE039
Arrange first
Figure 275225DEST_PATH_IMAGE040
And (4) a control point.
2. The method for evaluating the condensing efficiency of the heliostat according to claim 1 under the action of wind load is characterized in that: in step S2, surface wind pressure of the heliostat at a preset time is obtained through CFD calculation software ANSYS-Fluent simulation, the surface wind pressure is converted into an actual load applied to the finite element structure, and the actual load is compiled into an ANSYS command and applied to the finite element structure to perform structural deformation calculation to obtain mirror surface deformation information of the heliostat.
3. The method according to claim 1, wherein the step S3 further includes:
s34: according to the reflection principle, the reflection coefficient can be in N1Selected points within the area
Figure DEST_PATH_IMAGE041
And incident light
Figure 806569DEST_PATH_IMAGE042
By the formula
Figure DEST_PATH_IMAGE043
、
Figure 507809DEST_PATH_IMAGE044
Calculating the vector of the reflected light
Figure DEST_PATH_IMAGE045
And calculating a reflected light equation and calculating the number of points on the light loss receiving area, and calculating the effective reflecting surface of the mirror surface of the area through the number of points on the area surface to finally obtain the light condensation efficiency.
4. The method for evaluating the condensing efficiency of the heliostat according to claim 1 under the action of wind load is characterized in that: s32: extracting the coordinate values of the deformed four endpoints of the preset area by Ansys calculation, wherein
Figure 737845DEST_PATH_IMAGE046
Three end points forming a plane N1From the coordinates of the three end points, N can be derived1Normal vector of plane
Figure 157325DEST_PATH_IMAGE034
。
5. The method for evaluating the condensing efficiency of the heliostat according to claim 3 under the action of wind load is characterized in that: passing the vector in step S34
Figure DEST_PATH_IMAGE047
Calculating the equation of the reflected ray
Figure 243093DEST_PATH_IMAGE048
Calculating the number of points on the receiving region by calculating the light loss, and calculating the effective reflection area of the mirror surface in the region by point number
Figure DEST_PATH_IMAGE049
By the formula
Figure 48107DEST_PATH_IMAGE050
Calculating the reflection area
Figure DEST_PATH_IMAGE051
By the formula
Figure 193917DEST_PATH_IMAGE052
Calculating the light condensing efficiency, wherein
Figure DEST_PATH_IMAGE053
Is the area of the mirror surface in the region,
Figure 835114DEST_PATH_IMAGE054
the total number of points in the area is,
Figure DEST_PATH_IMAGE055
to reflect the number of points of the light in the receiving area,
Figure 708261DEST_PATH_IMAGE056
the light condensing efficiency.
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