Calculation method for space temperature gradient of simply-supported U-shaped aqueduct

Abstract

The invention discloses a method for calculating the space temperature gradient of a simply-supported U-shaped aqueduct, and belongs to the technical field of water conveyance project structure design processes. According to the calculation method for the space temperature gradient of the simply-supported U-shaped aqueduct, direct values are conveniently designed and calculated, design and calculation are based on data, and the structure is safe, reasonable and reliable. The calculation method comprises the steps of obtaining the gradient temperature difference of the sunny side of the aqueduct in summer, obtaining the gradient temperature difference of the nightside of the aqueduct in summer and obtaining the temperature difference of the cooling surface during cooling in winter. And respectively calculating the space temperature gradient T of the sunny side of the simply-supported U-shaped aqueduct in the heating state, the space temperature gradient T of the nightside of the simply-supported U-shaped aqueduct in the heating state and the space temperature gradient T of the simply-supported U-shaped aqueduct in the cooling state according to the following linear functional expressions. T is the summer aqueduct sunny side gradient temperature difference, the summer aqueduct nightside gradient temperature difference and the cooling surface temperature difference in winter cooling which are obtained before calculation, and x is the distance between the aqueduct calculation point position and the outer surface.

Description

Technical Field

[0001] The invention relates to a calculation method, in particular to a calculation method for the spatial temperature gradient of a simply supported U-shaped aqueduct, and belongs to the technical field of design process of water conveyance engineering structures. Background Art

[0002] Aqueduct is a water conveyance structure with high crack resistance requirements. Generally, the water-facing surface is required to meet the first-level crack resistance standard. The structure must have good crack resistance to ensure safe operation. During summer operation, affected by temperature, sunshine, water and other temperature boundary factors, the surface of the structure will heat up rapidly due to the increase in temperature and solar radiation, while the water body will heat up slowly, resulting in a "hot concrete and cold water" situation. Therefore, a positive temperature difference will be formed between the outer surface of the concrete and the water body. The temperature difference will cause the concrete cross section to produce temperature self-stress. After research, this temperature stress has a significant effect. The temperature rise can make the tensile stress generated in the circumferential direction of the water-facing surface of the structure reach about 1.6MPa to 2.7MPa. Often, the positive temperature difference condition will control the circumferential crack resistance of the inner wall of the structure. During winter operation, due to the occurrence of cold waves, the surface of the structure will cool down rapidly, while the water body will cool down slowly, resulting in a situation where the concrete is cold and the water is hot. Therefore, a negative temperature difference will be formed between the outer surface of the concrete and the water body. The negative temperature difference will cause the longitudinal tensile stress on the outer surface of the structure, reduce the longitudinal prestress of the structure, and affect the longitudinal crack resistance of the outer wall of the structure. Only by reasonably determining the temperature boundary can the safety of the engineering structure be guaranteed.

[0003] The prior art background has the following disadvantages:

[0004] 1) No normative basis: Due to the rapid development of the water conservancy industry and the rapid application of large prestressed concrete aqueducts, the normative regulations of the water conservancy industry are relatively lagging, and no guidance is given for the load value of the temperature gradient, and no clear temperature value model is given.

[0005] 2) Complex temperature boundaries: Specifically,

[0006] 1. Water temperature boundary: The water body is transported along the channel from the water intake. The water temperature at the water intake is the initial water temperature. As the water body flows along the channel, it passes through buildings such as aqueducts, open channels, tunnels, etc. The channel axis is long, and the water temperature will change with the external temperature, sunlight intensity, etc. Therefore, the water temperature boundary is complex and difficult to determine.

[0007] 2. Temperature boundary. The temperature boundary varies according to the geographical location of the structure. At the same time, due to the influence of the intensity of solar radiation at that time, it changes every moment of the day. At the same time, the temperature boundary also affects the water temperature boundary.

[0008] 3) Difficulty in design: Since there is no standard basis for the value of temperature gradient and the temperature boundary is complex, it is difficult to determine a reasonable temperature mode, which makes the design difficult. The design requires a reasonable temperature gradient mode for structural calculations. The correct gradient mode can ensure the control of structural temperature stress, ensure the durability of the structure, and ensure the safety of the structure. An unreasonable temperature gradient mode will make the temperature gradient of the structure too large, resulting in material waste; or make the temperature gradient of the structure too small, and the temperature stress of the structure is not effectively controlled, causing temperature cracks on the water-facing surface, affecting the durability of the structure. Due to the presence of water, the steel bars are corroded along the cracks, which in turn affects the safety of the structure. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct, which is convenient for design calculation and direct value acquisition, makes the design calculation based on a basis, and has a safe, reasonable and reliable structure.

[0010] The technical solution adopted to solve the above technical problems is: a method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct, the calculation method comprising the steps of obtaining the gradient temperature difference of the sunny side of the aqueduct in summer, obtaining the gradient temperature difference of the shady side of the aqueduct in summer, obtaining the temperature difference of the cooling side during winter cooling, and respectively calculating the spatial temperature gradient T of the sunny side of the simply supported U-shaped aqueduct under the heating state, the spatial temperature gradient T of the shady side under the heating state, and the spatial temperature gradient T of the cooling state according to the following linear function formula.

[0011] The linear function is

[0012] In the formula, △T is the gradient temperature difference on the sunny side of the aqueduct in summer, the gradient temperature difference on the shady side of the aqueduct in summer, and the temperature difference on the cooling surface during winter cooling, respectively, and x is the distance from the calculation point of the aqueduct to the outer surface.

[0013] Furthermore, the gradient temperature difference on the sunny side of the aqueduct in summer is calculated according to the following steps:

[0014] Before calculation, first determine the average temperature T1 of the water body at the water intake when the temperature is highest in summer based on the environmental impact assessment data of the reservoir area, determine the surface temperature T2 of the water body at the water intake based on the environmental impact assessment data of the reservoir area, and determine the average temperature T3 of the atmosphere at the water intake location based on the meteorological data of previous years; then calculate the temperature difference △1=T2-T1 between the water body at the water intake and the surface water body at the water intake in summer, calculate the temperature difference △2=T3-T2 between the water body at the water intake and the surface water body at the water intake in summer, and determine the maximum temperature difference △3=△1+△2 at the water intake in summer; then determine the temperature rise △4 on the sunny side of the aqueduct and the temperature rise △5 on the shady side caused by solar radiation in summer, and finally calculate and determine the gradient temperature difference △6=△3+△4 on the sunny side of the aqueduct in summer.

[0015] The preferred method of the above scheme is that when determining the temperature rise △4 on the sunny side and △5 on the shady side of the aqueduct caused by summer solar radiation, it is necessary to first determine the sunny side and shady side of the aqueduct according to the solar radiation angle, and then calculate the temperature rise △4 on the sunny side and △5 on the shady side respectively according to the solar radiation theory.

[0016] When determining the sunny side and the sun-facing side of the aqueduct, the sunny side is the structural surface directly exposed to the sun, and the sun-facing side is defined as the sun-facing side when the angle between the tangent line of the structural surface and the horizontal plane is less than 45°.

[0017] Furthermore, the gradient temperature difference on the sun-facing side of the aqueduct in summer is calculated according to the following steps: before the calculation, the average temperature T1 of the water body at the water intake when the temperature is the highest in summer is determined based on the environmental impact assessment data of the reservoir area, the surface temperature T2 of the water body at the water intake is determined based on the environmental impact assessment data of the reservoir area, and the average temperature T3 of the atmosphere at the water intake location is determined based on the meteorological data of previous years; then the temperature difference △1=T2-T1 between the water body at the water intake and the surface water body at the water intake in summer is calculated, the temperature difference △2=T3-T2 between the water body at the water intake and the surface water body at the water intake in summer is calculated, and the maximum temperature difference △3=△1+△2 at the water intake in summer is determined; then the temperature rise △4 on the sunny side and the temperature rise △5 on the sun-facing side of the aqueduct caused by summer solar radiation are determined, and finally the gradient temperature difference △7=△3+△5 ​​on the sun-facing side of the aqueduct in summer is calculated.

[0018] The preferred method of the above scheme is that when determining the temperature rise △4 on the sunny side and △5 on the shady side of the aqueduct caused by summer solar radiation, it is necessary to first determine the sunny side and shady side of the aqueduct according to the solar radiation angle, and then calculate the temperature rise △4 on the sunny side and △5 on the shady side respectively according to the solar radiation theory.

[0019] When determining the sunny side and the sun-facing side of the aqueduct, the sunny side is the structural surface directly exposed to the sun, and the sun-facing side is defined as the sun-facing side when the angle between the tangent line of the structural surface and the horizontal plane is less than 45°.

[0020] Furthermore, the temperature difference of the cooling surface during winter cooling is calculated according to the following steps:

[0021] Before calculation, first determine the water temperature T4 of the water intake during winter cooling based on the reservoir area environmental impact assessment data, determine the lowest temperature T5 during winter cooling based on historical meteorological data, and then calculate and determine the temperature difference △8=T5-T4 of the cooling surface during winter cooling.

[0022] The preferred method of the above scheme is that before using the linear function to calculate the spatial temperature gradient T of the sun-facing side of the simply supported U-shaped aqueduct under the heating state, the spatial temperature gradient T of the sun-facing side under the heating state, and the spatial temperature gradient T of the sun-facing side under the cooling state, it is necessary to first construct the aqueduct temperature gradient model. The specific requirements are as follows:

[0023] The linear gradient temperature model is adopted, and the cross-sectional temperature transitions from the outer surface of the tank body to the inner wall of the tank body facing the water;

[0024] When the temperature rises, the sun-facing side and the sun-facing side of the trough body have different temperature gradients;

[0025] When cooling, the outer surface of the tank body is kept at the same temperature.

[0026] Furthermore, when using a linear function to calculate the spatial temperature gradient T on the sun-facing side of the simply supported U-shaped aqueduct under the heating state, the spatial temperature gradient T on the sun-facing side under the heating state, and the spatial temperature gradient T on the cooling state, the temperature influence depth x of the aqueduct body is determined according to the following requirements:

[0027] When x≤40cm, the temperature changes linearly within the range of thickness H; when x>40cm, the temperature is 0 within the range of thickness Hx.

[0028] The beneficial effect of the present invention is that the calculation method provided by the present application first obtains the gradient temperature difference of the sunny side of the aqueduct in summer, the gradient temperature difference of the shady side of the aqueduct in summer, and the temperature difference of the cooling side during winter cooling, and finally calculates the spatial temperature gradient T of the sunny side of the simply supported U-shaped aqueduct in the heating state, the spatial temperature gradient T of the shady side in the heating state, and the spatial temperature gradient T of the cooling state according to the following linear function formula, and the linear function formula is In the formula, △T is the gradient temperature difference of the sunny side of the aqueduct in summer, the gradient temperature difference of the back-sun side of the aqueduct in summer, and the temperature difference of the cooling surface during winter cooling, respectively, and x is the distance between the calculation point of the aqueduct and the outer surface. In this way, in the subsequent design calculation of the U-shaped aqueduct, the linear function formula can be directly used for calculation to obtain the temperature gradient value of the aqueduct under various working conditions in the design space position, so as to directly obtain the value of the design calculation, so as to achieve the purpose of making the design calculation based on evidence and the designed structure safe, reasonable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a simplified diagram of the temperature gradient model involved in the method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct of the present invention, wherein H temperature affects the depth;

[0030] Figure 2 It is a simplified diagram of the division of the sunny side and the non-sun side of the aqueduct involved in the calculation method of the spatial temperature gradient of the simply supported U-shaped aqueduct of the present invention;

[0031] Figure 3 for Figure 2 Simplified schematic diagram of the aqueduct temperature rise gradient pattern under working conditions;

[0032] Figure 4 A simplified diagram of aqueduct cooling division involved in the invention of a method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct;

[0033] Figure 5 for Figure 4 Simplified schematic diagram of the aqueduct temperature rise gradient pattern under operating conditions. DETAILED DESCRIPTION

[0034] like Figure 1 to Figure 5 The figure shows a method for calculating the spatial temperature gradient of a simple supported U-shaped aqueduct provided by the present invention, which is convenient for design calculation and direct value acquisition, so that the design calculation has a basis to rely on, and the structure is safe, reasonable and reliable. The calculation method includes obtaining the gradient temperature difference of the sunny side of the aqueduct in summer, obtaining the gradient temperature difference of the shady side of the aqueduct in summer, obtaining the temperature difference of the cooling side during winter cooling, and calculating the spatial temperature gradient T of the sunny side of the simple supported U-shaped aqueduct in the heating state, the spatial temperature gradient T of the shady side in the heating state, and the spatial temperature gradient T of the cooling state according to the following linear function formula. The linear function formula is In the formula, △T is the gradient temperature difference of the sunny side of the aqueduct in summer, the gradient temperature difference of the shady side of the aqueduct in summer, and the temperature difference of the cooling surface during winter cooling, respectively, and x is the distance between the calculation point of the aqueduct and the outer surface. The calculation method provided in the present application first obtains the gradient temperature difference of the sunny side of the aqueduct in summer, the gradient temperature difference of the shady side of the aqueduct in summer, and the temperature difference of the cooling surface during winter cooling, and finally calculates the spatial temperature gradient T of the sunny side of the simply supported U-shaped aqueduct under the heating state, the spatial temperature gradient T of the shady side under the heating state, and the spatial temperature gradient T of the shady side under the cooling state according to the above linear function. In this way, in the subsequent design calculation of the U-shaped aqueduct, the linear function can be directly used to perform calculations to obtain the temperature gradient value of the aqueduct under various working conditions in the design space position, so as to facilitate the direct value acquisition of the design calculation, so as to achieve the purpose of making the design calculation based on evidence and the designed structure safe, reasonable and reliable. Correspondingly, in order to facilitate the acquisition of the gradient temperature difference of the aqueduct under corresponding working conditions, the gradient temperature difference of the sunny side of the aqueduct in summer in this application is calculated according to the following steps. Before the calculation, the average temperature T1 of the water body at the water intake when the temperature is the highest in summer is determined according to the environmental impact assessment data of the reservoir area, the surface layer temperature T2 of the water body at the water intake is determined according to the environmental impact assessment data of the reservoir area, and the average temperature T3 of the atmosphere at the water intake location is determined according to the meteorological data of previous years; then the temperature difference △1=T2-T1 between the water body at the water intake and the surface water body at the water intake in summer is calculated, the temperature difference △2=T3-T2 between the water body at the water intake and the surface water body at the water intake in summer is calculated, and the maximum temperature difference △3=△1+△2 of the water intake in summer is determined; then the temperature rise △4 on the sunny side of the aqueduct and the temperature rise △5 on the shady side caused by summer solar radiation are determined, and finally the gradient temperature difference △6=△3+△4 on the sunny side of the aqueduct in summer is calculated. More specifically, when determining the temperature rise △4 on the sunny side and △5 on the shady side of the aqueduct caused by summer solar radiation, it is necessary to first determine the sunny side and shady side of the aqueduct based on the solar radiation angle, and then calculate the sunny side temperature rise △4 and shady side temperature rise △5 respectively according to the solar radiation theory. Among them, when determining the sunny side and shady side of the aqueduct, the sunny side is the structural surface directly exposed to the sun, and when the angle between the tangent of the structural surface and the horizontal plane is less than 45°, it is defined as the shady side. The gradient temperature difference of the shady side of the aqueduct in summer in this application is calculated according to the following steps. Before the calculation, the average temperature T1 of the water body at the water intake when the temperature is the highest in summer is determined according to the environmental impact assessment data of the reservoir area, the surface temperature T2 of the water body at the water intake is determined according to the environmental impact assessment data of the reservoir area, and the average temperature T3 of the atmosphere at the water intake location is determined according to the meteorological data of previous years; then the temperature difference △1=T2-T1 between the water body at the water intake and the surface water body at the water intake in summer is calculated, the temperature difference △2=T3-T2 between the water body at the water intake and the surface water body at the water intake in summer is calculated, and the maximum temperature difference △3=△1+△2 of the water intake in summer is determined; then the temperature rise △4 on the sunny side of the aqueduct and the temperature rise △5 on the shady side caused by summer solar radiation are determined, and finally the gradient temperature difference △7=△3+△5 ​​on the shady side of the aqueduct in summer is calculated.Correspondingly, when determining the temperature rise △4 on the sunny side and △5 on the shady side of the aqueduct caused by solar radiation in summer, it is necessary to first determine the sunny side and shady side of the aqueduct based on the solar radiation angle, and then calculate the sunny side temperature rise △4 and shady side temperature rise △5 respectively according to the solar radiation theory. Among them, when determining the sunny side and shady side of the aqueduct, the sunny side is the structural surface directly exposed to the sun, and when the angle between the tangent line of the structural surface and the horizontal plane is less than 45°, it is defined as the shady side.

[0035] Furthermore, the temperature difference of the cooling surface during winter cooling in this application is calculated and obtained according to the following steps. Before the calculation, the water temperature T4 of the water intake during winter cooling is determined based on the environmental impact assessment data of the reservoir area, and the lowest temperature T5 during winter cooling is determined based on the meteorological data of previous years, and then the temperature difference △8 of the cooling surface during winter cooling is calculated to determine. 8 = T5-T4. Correspondingly, before using a linear function to calculate the spatial temperature gradient T of the sun-facing side of the simply supported U-shaped aqueduct under the heating state, the spatial temperature gradient T of the sun-facing side under the heating state, and the spatial temperature gradient T of the sun-facing side under the cooling state, it is necessary to construct the aqueduct temperature gradient model first. The specific requirements are as follows: using a linear gradient temperature model, the cross-sectional temperature transitions from the outer surface of the trough body to the inner wall of the trough body facing the water; when heating, the sun-facing side and the sun-facing side of the trough body take different temperature gradients; when cooling, the outer surface of the trough body takes the same temperature.

[0036] At the same time, when the linear function is used to calculate the spatial temperature gradient T on the sunny side of the simply supported U-shaped aqueduct under the heating state, the spatial temperature gradient T on the shady side under the heating state, and the spatial temperature gradient T under the cooling state, the temperature influence depth x of the trough body is determined according to the following requirements: when x≤40cm, the temperature changes linearly within the range of thickness H; when x>40cm, the temperature is 0 within the range of thickness Hx.

[0037] It should be pointed out that the calculation method of this application is not applicable to the U-shaped aqueduct structure with an external paved insulation layer, but it can also be applied to the open simply supported rectangular aqueduct.

[0038] The technical solution of the present application is further described below through specific embodiments:

[0039] The water conservancy industry specifications do not provide for the temperature gradient load of aqueducts, and the design calculation cannot be performed in accordance with the specifications. The present invention aims to combine the geographical environment of the aqueduct building and the water temperature of the aqueduct water body to provide a U-shaped aqueduct spatial temperature gradient model, which is convenient for design calculations and can directly obtain values, so that the design calculations have a basis to rely on, the structure is safe, reasonable and reliable, the design efficiency is improved, and the design verification process is simplified. Since the U-shaped aqueduct is a spatial thin-walled structure, the distribution of its temperature along the thin wall can be simplified to a linear function. The temperature stress calculated by this linear function can still guide the design verification, and it has been applied to a certain aqueduct project in a certain irrigation area.

[0040] Embodiment 1

[0041] Technical solution: Provide a spatial temperature gradient model suitable for a simply supported U-shaped aqueduct, which is the following linear function:

[0042]

[0043] Among them, the process of obtaining △T is as follows: T1, T2, and T4 can be determined according to the environmental impact assessment report of the reservoir where the water intake is located. T3 and T5 can be determined according to the meteorological data of previous years. The temperature rise of the sunny side △4 and the temperature rise of the shady side △5 can be determined according to the current solar radiation theory calculation. The sunny side is the surface of the structure directly exposed to the sun. When the angle between the tangent line of the structure surface and the horizontal plane is less than 45°, it can be defined as the shady side.

[0044] The specific process is:

[0045] Determine the average water temperature T1 at the water intake when the temperature is highest in summer.

[0046] Determine the surface temperature T2 of the water at the water intake.

[0047] According to 1) and 2), the temperature difference between the water body at the water intake and the surface water body at the water intake in summer is determined as △1=T2-T1.

[0048] Determine the average atmospheric temperature T3 at the water intake location.

[0049] According to 2) and 4), determine the temperature difference between the water body at the water intake and the surface water body at the water intake in summer △2 = T3-T2.

[0050] Determine the maximum temperature difference at the water intake in summer △3=△1+△2.

[0051] Determine the sunny side and shady side of the aqueduct according to the solar radiation angle.

[0052] Determine the temperature rise of △4 on the sunny side and △5 on the shady side of the aqueduct caused by summer solar radiation.

[0053] To simplify the theory, the temperature difference of the water body along the channel in summer is ignored. According to 6) and 8), the gradient temperature difference on the sunny side of the aqueduct in summer is determined as △6=△3+△4, and the gradient temperature difference on the shady side is determined as △7=△3+△5.

[0054] Determine the water temperature T4 at the water intake during winter cooling.

[0055] Determine the lowest temperature T5 when the temperature drops in winter.

[0056] To simplify the theory, the temperature difference of the cooling water along the channel in summer is ignored, and the temperature difference of the cooling surface during winter cooling is determined according to 10) and 11) as △8 = T5-T4.

[0057] A structural temperature gradient model is constructed. The temperature gradient model adopts a linear gradient temperature model, and the cross-sectional temperature transitions from the outer surface of the trough body to the water-facing surface of the inner wall of the trough body.

[0058] When the temperature rises, the sunny side and the shady side of the trough body have different temperature gradients.

[0059] When cooling, the outer surface of the tank body is kept at the same temperature.

[0060] The temperature of the groove body affects the depth A≤40cm. When A≤40cm, the temperature changes linearly within the range of thickness A. When A>40cm, the temperature is 0 within the range of thickness HA.

[0061] A spatial temperature gradient pattern of a simply supported U-shaped aqueduct is provided, and its function form is as follows:

[0062]

[0063] Wherein, △T is the temperature of the sun-facing side or the sun-facing side, and its value is shown in Table 1. x is the distance between the structural calculation point and the outer surface, that is, the above-mentioned A value range.

[0064] Table 1 △T value table:

[0065] .

Claims

1. Calculation method for spatial temperature gradient of simply supported U-shaped aqueduct, Features: The calculation method includes the steps of obtaining the gradient temperature difference of the sunny side of the aqueduct in summer, obtaining the gradient temperature difference of the shady side of the aqueduct in summer, obtaining the temperature difference of the cooling side during winter cooling, and respectively calculating the spatial temperature gradient T of the sunny side of the simply supported U-shaped aqueduct under the heating state, the spatial temperature gradient T of the shady side under the heating state, and the spatial temperature gradient T of the cooling state according to the following linear function formula. The linear function is In the formula, △T is the gradient temperature difference on the sunny side of the aqueduct in summer, the gradient temperature difference on the shady side of the aqueduct in summer, and the temperature difference on the cooling surface during winter cooling, respectively, and x is the distance from the calculation point of the aqueduct to the outer surface.

2. The method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct according to claim 1, Features: The gradient temperature difference on the sunny side of the aqueduct in summer is calculated according to the following steps: Before calculation, determine the average water temperature T at the water intake when the temperature is highest in summer based on the environmental impact assessment data of the reservoir area. 1 , determine the surface temperature T of the water body at the water intake based on the environmental impact assessment data of the reservoir area 2 And the average atmospheric temperature T at the water intake location is determined based on historical meteorological data 3 ; Then calculate the temperature difference between the water body at the water intake and the surface water body at the water intake in summer △1=T 2 -T 1 , calculate the temperature difference between the water body at the water intake and the surface water body at the water intake in summer △2=T 3 -T 2 , and determine the maximum temperature difference of the water intake in summer △3=△1+△2; then determine the temperature rise △4 on the sunny side of the aqueduct and the temperature rise △5 on the shady side caused by summer solar radiation, and finally calculate and determine the gradient temperature difference △6=△3+△4 on the sunny side of the aqueduct in summer.

3. The method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct according to claim 2, Features: When determining the temperature rise of the sunny side △4 and the temperature rise of the shady side △5 on the aqueduct side caused by summer solar radiation, it is necessary to first determine the sunny side and the shady side of the aqueduct according to the solar radiation angle, and then calculate the temperature rise of the sunny side △4 and the temperature rise of the shady side △5 respectively according to the solar radiation theory. When determining the sunny side and the sun-facing side of the aqueduct, the sunny side is the structural surface directly exposed to the sun, and the sun-facing side is defined as the sun-facing side when the angle between the tangent line of the structural surface and the horizontal plane is less than 45°.

4. The method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct according to claim 1, Features: The gradient temperature difference on the back side of the aqueduct in summer is calculated according to the following steps. Before the calculation, the average water temperature T of the water intake when the temperature is the highest in summer is determined based on the environmental impact assessment data of the reservoir area. 1 , determine the surface temperature T of the water body at the water intake based on the environmental impact assessment data of the reservoir area 2 And the average atmospheric temperature T at the water intake location is determined based on historical meteorological data 3 ; Then calculate the temperature difference between the water body at the water intake and the surface water body at the water intake in summer △1=T 2 -T 1 , calculate the temperature difference between the water body at the water intake and the surface water body at the water intake in summer △2=T 3 -T 2 , and determine the maximum temperature difference of the water intake in summer △3=△1+△2; then determine the temperature rise △4 on the sunny side of the aqueduct and the temperature rise △5 on the shady side caused by summer solar radiation, and finally calculate and determine the gradient temperature difference △7=△3+△5 ​​on the shady side of the aqueduct in summer.

5. The method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct according to claim 4, Features: When determining the temperature rise of the sunny side △4 and the temperature rise of the shady side △5 on the aqueduct side caused by summer solar radiation, it is necessary to first determine the sunny side and the shady side of the aqueduct according to the solar radiation angle, and then calculate the temperature rise of the sunny side △4 and the temperature rise of the shady side △5 respectively according to the solar radiation theory. When determining the sunny side and the sun-facing side of the aqueduct, the sunny side is the structural surface directly exposed to the sun, and the sun-facing side is defined as the sun-facing side when the angle between the tangent line of the structural surface and the horizontal plane is less than 45°.

6. The method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct according to claim 1, 2, 3, 4 or 5, Features: The temperature difference of the cooling surface during winter cooling is calculated according to the following steps: Before calculation, determine the water temperature T of the water intake during winter cooling based on the reservoir area environmental assessment data. 4 , according to the meteorological data of previous years, determine the lowest temperature T during winter cooling 5 , and then calculate and determine the temperature difference of the cooling surface during winter cooling △8=T 5 -T 4 .

7. The method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct according to claim 6, Features: Before using the linear function to calculate the spatial temperature gradient T on the sun-facing side of the simply supported U-shaped aqueduct under the heating state, the spatial temperature gradient T on the sun-facing side under the heating state, and the spatial temperature gradient T on the cooling state, it is necessary to construct the aqueduct temperature gradient model. The specific requirements are as follows: The linear gradient temperature model is adopted, and the cross-sectional temperature transitions from the outer surface of the tank body to the inner wall of the tank body facing the water; When the temperature rises, the sun-facing side and the sun-facing side of the trough body have different temperature gradients; When cooling, the outer surface of the tank body is kept at the same temperature.

8. The method for calculating the spatial temperature gradient of a simply supported U-shaped aqueduct according to claim 7, Features: When using linear function formula to calculate the spatial temperature gradient T on the sun-facing side of the simply supported U-shaped aqueduct under the heating state, the spatial temperature gradient T on the sun-facing side under the heating state, and the spatial temperature gradient T on the cooling state, the temperature influence depth x of the aqueduct body is determined according to the following requirements: When x≤40cm, the temperature changes linearly within the range of thickness H; when x>40cm, the temperature is 0 within the range of thickness Hx.

Images