Design method of steel structure hyperbolic cooling tower

Abstract

The invention relates to a design method of a steel structure hyperbolic cooling tower, which comprises the following steps of: drawing concentric circles based on the bottom radius, the top radius and the throat radius of the cooling tower, taking one point on each circle, enabling three points to be collinear, enabling a connecting line of the points on two large circles to be tangent to a smaller circle, and drawing a plane geometry relation graph by taking the circle center of the concentric circles as an original point of a coordinate system; an equation set is listed according to a plane geometrical relation graph, coordinates of points on two large circles can be obtained by solving the equation set, namely, bus and endpoint coordinates and reverse bus and endpoint coordinates of the cooling tower can be obtained, n arrays are made by the reverse buses and the bus around the central axis of the cooling tower, m intersection points are formed by a set after the reverse buses are arrayed and the bus, and m intersection points are formed by the intersection points and the bus. The number of layers of the cooling tower is m-1, and the difference of Z-direction coordinates of adjacent intersection points is the layer height of each layer of the cooling tower; the set behind the bus array and the set behind the reverse bus array form n intersection points at the elevation of each layer, and the intersection points of the two sets of each layer are connected in sequence to form a closed state.

Description

Technical Field

[0001] The invention belongs to the technical field of cooling tower design, and particularly relates to a design method of a steel structure hyperbolic cooling tower. Background Art

[0002] The application of steel-structured natural ventilation indirect air-cooling towers in my country's engineering field is gradually increasing. There are many structural forms of steel cooling towers, including straight-tube-conical section and hyperbolic shapes, and single-layer reticulated shell, double-layer reticulated shell, cross-truss, and other structural systems. However, the design methods for hyperbolic steel cooling towers are still relatively simple, making it difficult to obtain the final structure through efficient variable parameter analysis.

[0003] The traditional design method for hyperbolic cooling towers involves calculating the outline of the hyperbola using mathematical equations and then manually lofting the structural model using CAD software. This traditional design method is extremely inefficient. Later, some scholars and engineers significantly improved work efficiency through programming, but this method is usually based on a hyperbolic surface obtained by rotating the hyperbola calculated by mathematical equations around its central axis. At least three parameters must be pre-specified: the number of cooling tower floors, the height of each floor, and the number of circumferential divisions. As disclosed in announcement number CN112380747B, "A design method for a hyperbolic steel structure cooling tower", a geometric model is first established based on the design parameters of the cooling tower (design parameters include: hyperbolic geometric parameters of the tower, number of circumferential divisions, longitudinal division height, lattice shell thickness, structural form, length size and node form of each rod), and then the load and load condition combination calculations are performed on each node and rod in the geometric model according to the calculation parameters (calculation parameters include: structural deadweight, wind load, temperature action parameters, seismic action parameters, partial coefficients and combination coefficients of load combinations) to obtain the load conditions, and a finite element model is generated based on the geometric model and load conditions. Then, the internal force analysis and stability analysis of the finite element model are performed. If the analysis results are unqualified, the above-mentioned design parameters need to be modified and the above steps need to be repeated. The above-mentioned existing design methods have the problem that the relationship between the various design parameters is difficult to coordinate and the efficiency of variable parameter analysis is low. Summary of the Invention

[0004] The present invention discloses a design method for a steel structure hyperbolic cooling tower. The method can quickly establish a line model required for structural design without solving a quadratic hyperbolic equation, which can significantly improve modeling efficiency. In addition, the method only requires defining one parameter to quickly implement variable parameter analysis of the structure, which can significantly improve the efficiency of variable parameter analysis and quickly obtain the optimal structural model of the hyperbolic cooling tower.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A design method for a steel structure hyperbolic cooling tower includes the following contents:

[0007] Step 1) obtaining process control parameters of the hyperbolic cooling tower: bottom radius R1 of the cooling tower, throat radius R0 of the cooling tower, top radius R2 of the cooling tower, and total height H of the cooling tower;

[0008] Step 2) Based on the process control parameters in step 1), a plane geometric relationship diagram is drawn, namely:

[0009] 2.1) Based on R1, R2, and R0, draw three concentric circles, namely the bottom circle, the top circle, and the throat circle. Establish an XYZ coordinate system with the center O of the concentric circles as the origin of the coordinate system;

[0010] 2.2) Determine a point on each of the three concentric circles so that the three points are collinear. Point A is on the bottom circle, point B is on the top circle, and point C is on the throat circle, so that the line AB is tangent to the throat circle.

[0011] Step 3) Based on the plane geometric relationship diagram in step 2), the three-dimensional coordinates of point B are obtained by solving the equation group. The line AB is the projection of the cooling tower's busbar on the plane. The projection of the reverse busbar on the plane is obtained by making the line AB symmetrical about the X axis, thereby determining the coordinates of the two endpoints of the busbar and the reverse busbar;

[0012] Step 4) Assuming the central axis of the cooling tower to be a Z-direction straight line passing through the origin O, an array of n reverse busbars is formed around the central axis of the cooling tower. The combination of the reverse busbar array and the busbar forms m intersections. The number of floors of the cooling tower is m-1. The difference between the Z-direction coordinates of adjacent intersections is the floor height of each floor of the cooling tower.

[0013] Step 5) The busbars of the cooling tower are arranged into an array of n numbers around the central axis of the cooling tower. The combination of the busbar array and the combination of the reverse busbar array is the main component of the cooling tower. The two combinations form n intersections at each elevation of the cooling tower. The number of circumferential divisions of each layer is n-1. The intersections of the two combinations on each layer are connected in sequence to form a closed circumferential rod of the cooling tower.

[0014] Furthermore, after step 5), step 6) is also included, namely, modeling the widening platform and the reinforcement ring to obtain a cooling tower structural line model.

[0015] Furthermore, after step 6), step 7) is also included, i.e., applying load and optimizing the cross section of the cooling tower structure line model to check whether the various indicators of the cooling tower structure meet the design requirements. If they meet the requirements, the design work is completed. If not, adjust the parameter n and re-execute steps 1) to 6) until all structural indicators are qualified.

[0016] Furthermore, in step 2), let the plane coordinates of point B be (x2, y2), the plane coordinates of point A be (x1, y1), the distance between point A and point B be L1, the angle between line AB and line OA be θ, draw a perpendicular line from point B to line OA, and the distance from the foot of the perpendicular to point A is m1.

[0017] Furthermore, in step 3), the following set of equations can be listed based on the plane geometric relationship diagram:

[0018] x2 = R1-m1 (1)

[0019] m1 = L1cosθ (2)

[0020]

[0021] y2 = L1sinθ (5)

[0022] sinθ = R0 / R1 (6)

[0023] Based on the above equations, the plane coordinate value of point B can be obtained. According to the total height H of the cooling tower, the Z-axis coordinate value of point B can be obtained, thereby obtaining the actual busbar of the cooling tower and the three-dimensional coordinate values ​​of the two endpoints of the busbar.

[0024] Furthermore, in step 6), the intersections of the rear set of busbar arrays and the rear set of reverse busbar arrays in step 5) are divided into m arrays according to different Z-axis coordinates, and the coordinate information of each intersection in each array is assigned;

[0025] The designer determines the location of the widening platform, extracts the coordinate information of each intersection point at the widening platform location, offsets the extracted intersection points outward, and closes the lines connecting the offset points to complete the modeling of the widening platform.

[0026] The designer determines the location of the reinforcement ring, extracts the coordinate information of each intersection point at the location of the reinforcement ring, offsets the extracted intersection points inward, and closes the lines connecting the offset points to complete the modeling of the reinforcement ring.

[0027] Furthermore, the widening platform is arranged on the second layer of the cooling tower structure.

[0028] Furthermore, in step 7), the cooling tower structure line model is imported into the structural design software, loads are applied, component cross-sections and material properties are assigned, and then structural index calculations are performed.

[0029] The present invention can quickly establish the structural line model of the cooling tower based on the four process control parameters of the cooling tower, while the existing technology needs to obtain it by solving the quadratic hyperbola equation. Compared with the existing technology, the present invention simplifies the modeling parameters of the hyperbola cooling tower and improves the modeling efficiency of the cooling tower structural line model. Only one parameter (i.e., the array number n) needs to be defined to quickly realize the variable parameter analysis of the structure, which significantly improves the efficiency of the variable parameter analysis and can obtain the optimal structural model in the shortest time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the structure of a 12-layer hyperbolic cooling tower exemplified in the embodiment;

[0031] Figure 2 Schematic diagram of the plane parameterization of the hyperbolic cooling tower in the embodiment;

[0032] Figure 3 This is a design flow chart of the steel structure hyperbolic cooling tower of the present invention. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0034] This embodiment proposes a new design method for a steel structure hyperbolic cooling tower. The structure of the hyperbolic cooling tower is as follows: Figure 1 As shown, Figure 1 The top of the cooling tower is the outlet, the throat is the thinnest part of the cooling tower, and the total size from the bottom to the top is the total height H of the cooling tower. The bottom, top and throat can form three concentric circles on the plane. Figures 1 to 3 The design method of this embodiment is described as follows:

[0035] Step 1) According to the process design of the cooling tower, the following four process control parameters of the hyperbolic cooling tower can be obtained: the bottom radius R1 of the cooling tower, the throat radius R0 of the cooling tower, the top radius R2 of the cooling tower, and the total height H of the cooling tower.

[0036] Step 2) Based on the process control parameters in step 1), draw Figure 2 The plane geometric relationship diagram shown in the figure is as follows:

[0037] Step 2.1) Draw three concentric circles based on R1, R2, and R0, namely the bottom circle, top circle, and throat circle, and establish an XYZ coordinate system with the center O of the concentric circles as the origin of the coordinate system;

[0038] Step 2.2) Determine a point on each of the three concentric circles and make the three points collinear. Point A is on the bottom circle, point B is on the top circle, and point C is on the throat circle. The line connecting points AB is tangent to the throat circle. Connect point A and point B. The line AB is the projection of the cooling tower's generatrix on the plane. Let the plane coordinates of point B be (x2, y2) and the plane coordinates of point A be (x1, y1). From Figure 2 It can be seen that y1=0, x1=R1, and the specific values ​​of x2 and y2 are unknown;

[0039] Step 2.3) Let the distance between point A and point B be L1. Connect the origin O and point A. Let the angle between line AB and line OA be θ. Draw a perpendicular from point B to line OA. Let the distance from the foot of the perpendicular to point A be m1.

[0040] Step 3) According to mathematical knowledge, a straight line in space can be rotated around a certain axis to obtain a single-leaf hyperbolic shape, and the hyperbolic cooling tower is also an axisymmetric shape even if it is centrally symmetrical. Therefore, based on the plane geometric relationship diagram in step 2) (i.e. Figure 2 The geometric relationship shown in the figure) can be listed as follows:

[0041] x2 = R1-m1 (1)

[0042] m1 = L1cosθ (2)

[0043]

[0044] y2 = L1sinθ (5)

[0045] sinθ = R0 / R1 (6)

[0046] In the above equations, only x2, y2, m1, L1, sinθ and cosθ are unknown. These six unknowns can be solved by the above six equations, so the plane coordinate value of point B can be obtained. Since the total height H of the cooling tower is known, the Z coordinate value of point B is H. The three-dimensional coordinates of points A and B are also known, so the actual busbar of the cooling tower and the three-dimensional coordinates of the two end points of the busbar can be obtained. Connect line AB along Figure 2 The projection of the reverse generatrix on the plane can be obtained by taking the X-axis symmetry into account. Therefore, the three-dimensional coordinates of the actual reverse generatrix and its two endpoints are also known.

[0047] Step 4) Assume that the central axis of the cooling tower is a Z-direction straight line passing through the origin O, and form an array of reverse busbars around the central axis of the cooling tower. Assume that the number of arrays is n. The set of reverse busbar arrays will have multiple intersections with the busbars of the cooling tower. The number of intersections is set to m. According to the statistical value of m, the number of floors of the cooling tower can be obtained as m-1. The subtraction of the Z-direction coordinates of adjacent intersections among each intersection is the floor height of each floor of the cooling tower.

[0048] Step 5) The busbars of the cooling tower are arrayed in an n-number around the central axis of the cooling tower. The combination of the busbar array and the combination of the reverse busbar array is the main component of the cooling tower. At the same time, the two combinations have multiple intersections at each elevation of the cooling tower. The number of intersections on each layer is the parameter n, and the number of circumferential divisions of each layer is obtained as n-1. The intersections of the two combinations on each layer are connected in sequence and closed to form the circumferential rods of the cooling tower.

[0049] Step 6) Through steps 1) to 5) above, the main component lines of the hyperbolic cooling tower have been obtained. Subsequently, the structural modeling of the widening platform and reinforcement ring needs to be completed to obtain the final cooling tower structural line model. The structural modeling of the widening platform and reinforcement ring can be completed using conventional procedures in the prior art. This step is not the focus of the technical solution improvement of the present invention. The improvement of the present invention mainly revolves around steps 1) to 5) above. Steps 1) to 5) can be programmed, and the main component lines of the cooling tower can be automatically obtained by simply inputting the process control parameters and the parameter n.

[0050] During the specific execution of this step, the intersections of the two sets in step 5) are divided into m arrays according to different Z-coordinates, and the intersections in each array are numbered (i.e., the coordinates of the intersections). The designer defines the positions of the widening platform and the reinforcement ring based on process requirements and engineering experience (in this embodiment, the widening platform is set on the second floor of the cooling tower, and the position of the widening platform is determined specifically according to the process design), and extracts the coordinate information of each intersection at the position of the widening platform and the position of the reinforcement ring. The modeling of the widening platform and the reinforcement ring can be completed by using the offset and connection method (the intersection points extracted for the widening platform are offset outward and the offset points are connected to close the lines; the intersection points extracted for the reinforcement ring are offset inward and the offset points are connected to close the lines).

[0051] Step 7) importing the cooling tower structure line model obtained in step 6) into a general structural design software, applying loads, assigning component cross-sections and material properties, and then calculating the cooling tower structure indicators to determine whether the calculated indicators of the cooling tower structure meet the design requirements. If all indicators meet the requirements, the design work of the cooling tower is completed; if there are indicators that do not meet the requirements, adjust the parameter n, and then re-execute the above steps 1) to 6) until all indicators of the cooling tower structure meet the requirements. After repeated iterative calculations, the calculation is completed.

[0052] The following is a design example of a 12-story steel structure hyperbolic cooling tower for a project:

[0053] Known process parameters: the bottom diameter of the cooling tower is 70,000 mm, the throat diameter is 38,090 mm, the outlet diameter (top diameter) is 40,910 mm, and the total height of the cooling tower is 90,000 mm.

[0054] 1. According to equations (1) to (6), the coordinates of point A are (35000, 0, 0), and the coordinates of point B are (6324.191433, 19452.805138, 90000), both in mm.

[0055] 2. With point A as the starting point and point B as the end point, draw line segment AB to obtain the hyperbolic generatrix. Then, with point A as the base point and the X-axis as the axis of symmetry, mirror the hyperbolic generatrix to obtain the reverse generatrix.

[0056] 3. Define parameter n = 30;

[0057] 4. Let the central axis of the cooling tower be a Z-direction straight line passing through the origin. Array the reverse busbars around the central axis of the cooling tower. The number of arrays is n = 30. The set of reverse busbars after the array has m intersections with the hyperbolic busbars. After extracting all the intersections and counting the total number of intersections, we get m = 13. Therefore, when the parameter n = 30, the cooling tower has 12 floors.

[0058] 5. Array the hyperbolic busbars around the central axis of the cooling tower. The number of arrays is n = 30. The set of reverse busbars after the array has multiple intersections with the set of hyperbolic busbars. Group these intersections according to different Z-coordinates to obtain 13 arrays [a n1 ]~[a n13 ], each array contains the coordinate information of 13 points, among which the array [a n1 ] are all 0, and are arranged from bottom to top along the Z coordinates. n13 ]The Z coordinates of the points are all 90000;

[0059] 6. Set the array [a n1 ]~[a n13 ] are sorted in clockwise direction, and the point numbers in each array are n1, n2, n3...n30, excluding the array [a n1 ], connect [a n2 ]~[a n13 All points in the array can form 12 closed loops, which are the structural ring beams of the cooling tower. To facilitate construction and installation, these 12 loops are offset 500 degrees inward along their respective radial directions to form 12 new closed loops and a new point array [a n2 ']~[a n13'], the points in each new array are numbered n1', n2', n3'...n30', and then all n1 and n1', n2 and n2', n3 and n3'..., and so on;

[0060] 7. According to the process requirements, the widening platform is set on the second floor of the cooling tower structure. Based on engineering experience, reinforcement rings are set on the 5th, 8th and 11th floors of the cooling tower structure respectively. Grasshopper programming is used to construct the cooling tower structure line model;

[0061] 8. Change the parameter n, set n = 25 and n = 35 respectively. Through the program written in steps 1 to 7 above, three cooling tower structure line models can be obtained. Import the three cooling tower structure line models into the general structural design software, apply loads respectively and assign component cross-section and material properties, and then perform structural calculations. Select the solution with the best cost-effectiveness to draw the construction drawing and complete the final hyperbolic cooling tower design. Similarly, more parameters n can be changed to select the optimal structural solution.

[0062] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A design method for a steel structure hyperbolic cooling tower, characterized in that: It includes the following: Step 1) obtaining the process control parameters of the hyperbolic cooling tower: the bottom radius R1 of the cooling tower, the throat radius R0 of the cooling tower, the top radius R2 of the cooling tower, and the total height H of the cooling tower; Step 2) Based on the process control parameters in step 1), a plane geometric relationship diagram is drawn, namely: 2.1) Based on R1, R2, and R0, three concentric circles are drawn, namely the bottom circle, the top circle, and the throat circle, and an XYZ coordinate system is established with the center O of the concentric circles as the origin of the coordinate system; 2.2) Determine a point on each of the three concentric circles so that the three points are collinear, where point A is on the bottom circle, point B is on the top circle, and point C is on the throat circle, satisfying that the line AB is tangent to the throat circle; Step 3) Based on the plane geometric relationship diagram in step 2), the three-dimensional coordinates of point B are obtained by solving the equation group. The AB line is the projection of the busbar of the cooling tower on the plane. The projection of the reverse busbar on the plane can be obtained by making the AB line symmetrical about the X axis, so as to determine the coordinates of the two endpoints of the busbar and the reverse busbar; Step 4) Assuming the central axis of the cooling tower as a Z-direction straight line passing through the origin O, the reverse busbars are arrayed in n numbers around the central axis of the cooling tower, the set of the reverse busbar arrays and the busbars form m intersections, the number of floors of the cooling tower is m-1, and the difference between the Z-direction coordinates of adjacent intersections is the floor height of each floor of the cooling tower; Step 5) The busbars of the cooling tower are arranged in an array of n numbers around the central axis of the cooling tower. The combination of the busbar array and the combination of the reverse busbar array are the main components of the cooling tower. The two combinations form n intersections at each elevation of the cooling tower. The number of annular divisions of each layer is n-1. The intersections of the two combinations of each layer are connected in sequence to form a closed annular rod of the cooling tower.

2. The design method of a steel structure hyperbolic cooling tower according to claim 1, characterized in that: After step 5), the method further includes step 6), namely, modeling the widening platform and the reinforcing ring to obtain a cooling tower structural line model.

3. The design method of a steel structure hyperbolic cooling tower according to claim 2, characterized in that: After step 6), step 7) is also included, i.e., applying load and optimizing the cross section of the cooling tower structure line model, and checking whether various indicators of the cooling tower structure meet the design requirements. If they meet the requirements, the design work is completed. If not, adjust the parameter n and re-execute steps 1) to 6) until various indicators of the structure are qualified.

4. The design method of a steel structure hyperbolic cooling tower according to claim 1, characterized in that: In step 2), let the plane coordinates of point B be (x2, y2), the plane coordinates of point A be (x1, y1), the distance between point A and point B be L1, the angle between line AB and line OA be θ, draw a perpendicular line from point B to line OA, and the distance from the foot of the perpendicular to point A is m1.

5. The design method of a steel structure hyperbolic cooling tower according to claim 4, characterized in that: In step 3), the following set of equations can be listed according to the plane geometric relationship diagram: x2 = R1-m1 (1) m1 = L1cosθ (2) y2 = L1sinθ (5) sinθ = R0 / R1 (6) Based on the above equations, the plane coordinate value of point B can be obtained. According to the total height H of the cooling tower, the Z-axis coordinate value of point B can be obtained, thereby obtaining the actual busbar of the cooling tower and the three-dimensional coordinate values ​​of the two endpoints of the busbar.

6. The design method of a steel structure hyperbolic cooling tower according to claim 2, characterized in that: In the step 6), the intersections of the rear set of the busbar array and the rear set of the reverse busbar array in step 5) are divided into m arrays according to different Z-direction coordinates, and the coordinate information of each intersection in each array is assigned; The designer determines the location of the widening platform, extracts the coordinate information of each intersection point at the location of the widening platform, offsets the extracted intersection points outwards and closes the lines connecting the offset points to complete the modeling of the widening platform; The designer determines the position of the reinforcement ring, extracts the coordinate information of each intersection point at the position of the reinforcement ring, shifts the extracted intersection points inward and closes the lines connecting the shifted points to complete the modeling of the reinforcement ring.

7. The design method of a steel structure hyperbolic cooling tower according to claim 6, characterized in that: The widening platform is arranged on the second floor of the cooling tower structure.

8. The design method of a steel structure hyperbolic cooling tower according to claim 2, characterized in that: In the step 7), the cooling tower structure line model is imported into the structural design software, loads are applied, component cross-sections and material properties are assigned, and then structural index calculations are performed.

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