CN-121766213-B - Uniaxial tracking type photovoltaic array snow distribution coefficient calculation method based on wind-induced snow drift numerical simulation

CN121766213BCN 121766213 BCN121766213 BCN 121766213BCN-121766213-B

Abstract

The invention discloses a calculation method of snow distribution coefficient on a single-axis tracking type photovoltaic array based on wind-induced snow drift numerical simulation, which belongs to the technical field of snow analysis on a photovoltaic panel and comprises the following steps of establishing a geometric model of the single-axis tracking type photovoltaic array and acquiring initial snow depth data; the method comprises the steps of simulating a wind field near a single-axis tracking type photovoltaic array to simulate wind-induced snow drift, obtaining snow depth data on a photovoltaic panel, calculating snow distribution coefficients of all points on the photovoltaic panel, determining the most unfavorable working condition, converting total pressure and total torque generated by uneven snow load obtained through numerical simulation into equivalent snow load superposed by uniformly distributed snow load, and calculating the equivalent snow distribution coefficients. According to the invention, the influence of wind-induced snow drift on the photovoltaic panel is analyzed by adopting an improved Euler-Euler simulation method, so that the snow distribution coefficient with engineering applicability is obtained, and a reference is provided for the design of the single-axis tracking photovoltaic bracket system under the snow load condition.

Inventors

ZHOU XUANYI
DING SHAN
GUO ZHENSHAN

Assignees

同济大学

Dates

Publication Date: 20260512
Application Date: 20260303

Claims (7)

1. A calculation method of snow distribution coefficient on a single-axis tracking type photovoltaic array based on wind-induced snow drift numerical simulation is characterized by comprising the following steps: Step 1, establishing a geometric model of a single-axis tracking type photovoltaic array according to geometric parameters of a single-axis tracking type photovoltaic array prototype, and acquiring initial snow depth data; determining a calculation domain of the geometric model, carrying out grid division, carrying out discretization on the calculation domain, and generating a structured grid or an unstructured grid meeting calculation requirements; Step 2, simulating a wind field near the single-axis tracking type photovoltaic array by adopting ANSYS/FLUENT software, and realizing simulation of wind-induced snow drift by combining a snow phase transportation equation; step 3, obtaining snow depth data on the photovoltaic panel in the single-axis tracking type photovoltaic array, and calculating snow distribution coefficients of each point on the photovoltaic panel through the following formula , ; Wherein x is the projection distance of each point on the photovoltaic panel from the windward end, the unit is m, S (x) is the snow depth at the x position, the unit is m, S 0 is the ground snow depth, and the unit is m; Step 4, when a plurality of working conditions exist, determining the most unfavorable working conditions by comparing torque coefficients and pressure coefficients under different working conditions; Step 5, obtaining total pressure F total and total torque T total generated by uneven snow load through numerical simulation: ; ; Wherein, the The unit is kN/m 2 ; the snow distribution coefficient of each point of the photovoltaic panel; the snow load at each point on the photovoltaic panel is given in kN/m 2 ; The unit is m, which is the distance from each snow load to the center point of the photovoltaic panel; converting the uneven snow load into an equivalent snow load with superimposed two uniformly distributed snow loads on the left and right sides of a main beam in a single-axis tracking type photovoltaic array through the equivalent relationship of pressure and torque; ; ; F T and F U are concentrated forces corresponding to two uniform forces, F T generates torque on a main beam, F T acts at a position 0.25C 0 away from the center of the photovoltaic panel, F U acts at the center of the photovoltaic panel, and C 0 is the projection length of the chord length of the photovoltaic panel; adding the two equivalent uniform snow loads corresponding to F T and F U , and calculating the equivalent snow distribution coefficients at the two sides of the center of the main beam And (3) with ; ; ; Wherein, the T And U To simplify the two snow distribution coefficients corresponding to F T and F U generated in the process; When a plurality of working conditions exist, only the least favorable working condition selected in the step 4 is calculated.
2. The method for calculating the snow distribution coefficient on the single-axis tracking type photovoltaic array based on the wind-induced snow drift numerical simulation according to claim 1, wherein in the step 1, the geometric parameters of the single-axis tracking type photovoltaic array prototype comprise the row number of photovoltaic panels, the chord length of each row of photovoltaic panels and the center-to-ground height of the photovoltaic panels.
3. The method for calculating the snow distribution coefficient on the single-axis tracking type photovoltaic array based on the wind-induced snow drift numerical simulation is characterized in that in the step 2, in the process of simulating the wind-induced snow drift, a Reynolds time average method is adopted for the air phase, a realizable k-epsilon model is adopted for the turbulence model, a quasi-stationary calculation method is adopted for dividing the wind-induced snow blowing process into a plurality of equal-duration stages, the boundary of the particle surface is updated after the calculation of each stage is completed, and then the calculation of the next stage is carried out based on the new boundary.
4. The method for calculating the snow distribution coefficient on the single-axis tracking type photovoltaic array based on the wind-induced snow drift numerical simulation according to claim 3, wherein in the step 2, the transportation equation of the snow phase is as follows: ; ; Wherein phi is the snow concentration, u j is the wind speed, w f is the sedimentation speed of snow particles, D t is the turbulence diffusion coefficient, v t is the motion turbulence viscosity, sc t is the turbulence Schmitt number, x j is the distance in the j direction, and t is the time.
5. The method for calculating the snow distribution coefficient on the single-axis tracking type photovoltaic array based on the wind-induced snow drift numerical simulation according to claim 4, wherein in the step 2, the snow distribution on the surface of the photovoltaic panel calculates the snow surface flux q through an erosion/deposition model, and the snow surface flux comprises a fluid erosion flux q ero,ae , a splash deposition flux q dep and a splash erosion flux q ero,sp , wherein the erosion flux q ero comprises a fluid erosion flux q ero,ae and a splash erosion flux q ero,sp ; ; The fluid erosion flux q ero,ae is the mass of particles per unit time, per unit area, that are activated by the fluid, calculated as follows: ; Wherein d p is the particle diameter, ρ p is the particle density, ρ a is the air density, u * is the friction speed, u *t is the threshold friction speed; The splash deposition flux q dep is defined as the mass of vertically downward passing snow particles per unit time and unit area, calculated by the product of the snow concentration and the vertical sedimentation velocity of the particles, i.e ; The splash erosion flux q ero,sp reflects the mass flux resulting from new particle take-off due to collisions between snow particles, the take-off number obeying a binomial distribution of parameters m and p: ; ; ; Wherein U im is the incident speed of the particles, and theta im is the incident angle of the particles; after the snow surface flux q is obtained, the change amount of the depth of the snow surface in unit time is calculated by the following method, and then the redistribution of accumulated snow on the photovoltaic panel is obtained: ; Wherein, the packing density of the rho b snow particles is expressed as kg/m 3 .
6. The method for calculating snow distribution coefficient on a single-axis tracking type photovoltaic array based on wind-induced snow drift numerical simulation as set forth in claim 5, wherein the correction of the threshold friction speed of snow particles on a photovoltaic panel is required under the condition of a slope surface, namely ; Wherein u *t,θ is the corrected threshold friction speed, θ is the inclination angle of the photovoltaic panel, positive when facing the wind, and α is the snow surface angle of repose.
7. The method for calculating the snow distribution coefficient on the single-axis tracking type photovoltaic array based on the wind-induced snow drift numerical simulation according to any one of claims 1 to 6, wherein in the step 4, the calculation formulas of the pressure coefficient C P and the torque coefficient C M are as follows: ; ; Wherein C 0 is the projection length of the chord length of the photovoltaic panel, the unit is m, and y (x) is the distance from the x position to the center point on the photovoltaic panel, and the unit is m.

Description

Uniaxial tracking type photovoltaic array snow distribution coefficient calculation method based on wind-induced snow drift numerical simulation Technical Field The invention belongs to the technical field of snow analysis on photovoltaic panels, and particularly relates to a method for calculating snow distribution coefficients on a single-axis tracking type photovoltaic array based on wind-induced snow drift numerical simulation. Background With technological progress and improvement of environmental awareness, solar energy is widely utilized as a clean, safe and renewable energy source, and the global photovoltaic industry is rapidly developed. The single-axis tracking type photovoltaic system is widely applied because of simple structure, low cost and capability of remarkably improving the power generation efficiency. However, the photovoltaic bracket has lighter dead weight and is easy to generate structural damage under the action of snow. Therefore, how to reasonably consider snow load in design has become a key technical problem in the design of tracking type photovoltaic brackets. The currently disclosed research documents are few, and systematic research on snow distribution rules on the surface of the photovoltaic bracket is lacked. In the building structure load specification (GB 50009-2012) of China, corresponding snow distribution coefficients are not provided for a photovoltaic structure. While US12289080B2 discloses a structural design scheme that comprehensively considers wind load and snow load, no specific calculation method or coefficient is proposed for the snow distribution characteristics of the photovoltaic array surface. Because of the significant differences in geometry and arrangement of the photovoltaic array from the building, the surrounding flow field features are also different, resulting in complex non-uniformity in snow distribution. The direct adoption of the snow load distribution coefficient of the building structure may cause design errors, thereby affecting the safety and economy of the bracket structure. Therefore, it is necessary to research a snow distribution coefficient calculating method for a single-axis tracking type photovoltaic bracket so as to realize more reasonable and accurate structural design. Disclosure of Invention In order to solve the problems, the invention provides a calculation method for snow distribution coefficients on a single-axis tracking type photovoltaic array based on wind-induced snow drift numerical simulation. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: A calculation method of snow distribution coefficient on a single-axis tracking type photovoltaic array based on wind-induced snow drift numerical simulation comprises the following steps: Step 1, establishing a geometric model of a single-axis tracking type photovoltaic array according to geometric parameters of a single-axis tracking type photovoltaic array prototype, and acquiring initial snow depth data; Determining a calculation domain of the geometric model, carrying out grid division, carrying out discretization processing on the calculation domain, and generating a structured grid or an unstructured grid meeting the calculation precision requirement so as to ensure the accuracy and stability of a numerical simulation result. Step 2, simulating a wind field near the single-axis tracking type photovoltaic array by adopting ANSYS/FLUENT software, and realizing simulation of wind-induced snow drift by combining a snow phase transportation equation; step 3, obtaining snow depth data on the photovoltaic panel in the single-axis tracking type photovoltaic array, and calculating snow distribution coefficients of each point on the photovoltaic panel through the following formula , ; Wherein x is the projection distance of each point on the photovoltaic panel from the windward end, the unit is m, S (x) is the snow depth at the x position, the unit is m, S 0 is the ground snow depth, and the unit is m; Step 4, when a plurality of working conditions exist, determining the most unfavorable working conditions by comparing torque coefficients and pressure coefficients under different working conditions; The calculation formula of the pressure coefficient C P and the torque coefficient C M is as follows: ; ; Wherein C 0 is the projection length of the chord length of the photovoltaic panel, and the unit is m, and y (x) is the distance from the x position to the central point on the photovoltaic panel, and the unit is m; Step 5, obtaining total pressure F total and total torque T total generated by uneven snow load through numerical simulation: ; ; Wherein, the The unit is kN/m 2; the snow distribution coefficient of each point of the photovoltaic panel; the snow load at each point on the photovoltaic panel is given in kN/m 2; The unit is m, which is the distance from each snow load to the center point of the photovoltaic panel; convert