A calculation method for temperature rise of warm wastewater

Abstract

The present invention relates to the field of environmental engineering technology, and discloses a method for calculating the temperature rise of warm wastewater, the method comprising: determining the position of each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the initial temperature rise of each drain outlet, the comprehensive heat dissipation coefficient and the attenuation coefficient of the water surface; determining the equivalent distance of the calculation point from each drain outlet; calculating the correction factor of each drain outlet, and calculating the temperature rise of the calculation point according to the equivalent distance of the calculation point from each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient, the initial temperature rise of each drain outlet and the correction factor of each drain outlet. The present invention can calculate the temperature rise of a single drain outlet and multiple drain outlets respectively, and takes into account the mutual influence between heat sources, nonlinear effects and spatial attenuation effects, thereby improving the calculation accuracy of the temperature rise of warm wastewater, and providing a reliable basis for engineering design and decision-making.

Description

Technical Field

[0001] The invention relates to the technical field of environmental engineering, and in particular to a method for calculating the temperature rise of warm wastewater. Background Art

[0002] Power plants discharge a large amount of cooling water into the sea, which will cause the water temperature of the sea near the outlet to rise. The spread of warm wastewater will affect the marine biological environment and may also have an adverse impact on the water intake system of the power plant itself. Therefore, how to accurately calculate the spread range of warm wastewater and its impact on the surrounding environment is one of the key issues in power plant operations.

[0003] In the prior art, a method combining numerical simulation and physical model is usually used to predict the diffusion of warm drainage water. However, the prediction method of warm drainage diffusion through the model is complex, time-consuming and requires professional software and knowledge. Many existing simplified methods (such as simple linear superposition) usually assume that the influence of each heat source is independent, and assume that thermal conductivity and other physical parameters are constants, ignoring the interaction between heat sources and nonlinear effects. This assumption may be valid when the distance between heat sources is far or the number of heat sources is small, but it will lead to large errors in complex situations.

[0004] Therefore, there is an urgent need for a calculation method for the temperature rise of warm drainage water, which can calculate the temperature rise of a single drain outlet and multiple drain outlets separately, and take into account the mutual influence, nonlinear effect and spatial attenuation effect between heat sources, so as to improve the calculation accuracy of the temperature rise of warm drainage water and provide a reliable basis for engineering design and decision-making. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for calculating the temperature rise of warm drainage water, which can calculate the temperature rise of a single drain outlet and multiple drain outlets respectively, and takes into account the mutual influence, nonlinear effect and spatial attenuation effect between heat sources, thereby improving the calculation accuracy of the temperature rise of warm drainage water and providing a reliable basis for engineering design and decision-making.

[0006] The present invention provides a method for calculating the temperature rise of warm wastewater, comprising the following steps:

[0007] S1. Determine the location of each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the initial temperature rise of each drain outlet, the comprehensive heat dissipation coefficient of the water surface and the attenuation coefficient;

[0008] S2. Determine the equivalent distance between the calculation point and each drainage outlet according to the position of the calculation point;

[0009] S3. Calculate the contribution ratio of each drainage outlet to the temperature rise of the calculation point based on the equivalent distance from the calculation point to each drainage outlet, the radius of the equivalent temperature area of ​​each drainage outlet, the initial temperature rise and attenuation coefficient of each drainage outlet;

[0010] S4, remove the drains whose temperature rise contribution ratio is less than the preset threshold, and determine whether the number of remaining drains is 1; if the number of remaining drains is not 1, proceed to S5; if the number of remaining drains is 1, proceed to S7;

[0011] S5. Calculate the correction factor of each drain outlet, and calculate the temperature rise of the calculation point caused by each drain outlet according to the equivalent distance of the calculation point from each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient, the initial temperature rise of each drain outlet and the correction factor of each drain outlet;

[0012] S6. Superimpose the temperature rise of the calculation point caused by each drain outlet to obtain the total temperature rise of the calculation point;

[0013] S7. Calculate the temperature rise of the calculation point based on the equivalent distance from the calculation point to the drain outlet, the radius of the equivalent temperature area of ​​the drain outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient and the initial temperature rise of the drain outlet.

[0014] Furthermore, in S1, the position of each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the initial temperature rise of each drain outlet, the comprehensive heat dissipation coefficient of the water surface and the attenuation coefficient are determined, wherein the calculation method of the radius of the equivalent temperature area of ​​each drain outlet is as follows:

[0015] ;

[0016] Among them, R o,i represents the radius of the equivalent temperature area of ​​the i-th drain outlet, Q i represents the drainage flow of the ith drainage outlet, and D represents the water depth of the calculation area.

[0017] Furthermore, in S1, the position of each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the initial temperature rise of each drain outlet, the comprehensive heat dissipation coefficient of the water surface and the attenuation coefficient are determined, wherein the calculation method of the comprehensive heat dissipation coefficient of the water surface is as follows:

[0018] ;

[0019] ;

[0020] Among them, K S represents the comprehensive heat dissipation coefficient of the water surface, ω represents the total heat flux of the water surface, T S represents the water surface temperature, ω br represents the water surface back radiation flux, ω e represents the turbulent heat exchange between the water surface and the atmosphere, ω c represents the evaporation flux from the water surface.

[0021] Furthermore, in S2, the equivalent distance between the calculation point and each drainage outlet is determined according to the position of the calculation point, and the calculation formula is as follows:

[0022] ;

[0023] Among them, R i represents the equivalent distance from the calculation point to the i-th drain outlet, R i ' represents the distance between the calculation point and the i-th drainage outlet, D i ' represents the average water depth along the path between the calculation point and the i-th drainage outlet, represents the angle between the major axis of the water flow and the line connecting the nearest water channel to the water intake and discharge outlet, b' represents the ratio of the major and minor axis lengths of the water flow under the action of waves and tidal currents, and θ represents the openness of the water body diffusion;

[0024] The calculation formula for the ratio of the major axis to the minor axis of water flow under the action of waves and tidal currents is as follows:

[0025] ;

[0026] ;

[0027] ;

[0028] Among them, b represents the ratio of the major and minor axis lengths of the water flow under the action of the tide, u represents the average flow velocity of the tide, w represents the water flow velocity caused by waves, U and V represent the flow velocity components in two orthogonal directions of the water flow, L represents the wavelength, H represents the wave height, and T represents the wave period.

[0029] Furthermore, in S3, the contribution ratio of each drainage outlet to the temperature rise of the calculation point is calculated according to the equivalent distance from the calculation point to each drainage outlet, the radius of the equivalent temperature area of ​​each drainage outlet, the initial temperature rise and the attenuation coefficient of each drainage outlet. The calculation process of the temperature rise contribution ratio of each drainage outlet is as follows:

[0030] S31, judging whether the equivalent distance from the calculation point to the drain outlet is less than or equal to the radius of the equivalent temperature area of ​​the drain outlet; if the equivalent distance from the calculation point to the drain outlet is less than or equal to the radius of the equivalent temperature area of ​​the drain outlet, entering S32; if the equivalent distance from the calculation point to the drain outlet is greater than the radius of the equivalent temperature area of ​​the drain outlet, entering S33;

[0031] S32, taking the initial temperature rise of the drain outlet as the temperature rise contribution of the drain outlet to the calculation point;

[0032] The calculation formula for the initial temperature rise of the drain outlet is as follows:

[0033] T 贡献,i =T o,i =T i -Tambient ;

[0034] Among them, T i represents the current temperature of the i-th drain outlet, T ambient represents the background condition temperature;

[0035] S33. The calculation formula for the contribution of the drain outlet to the temperature rise of the calculation point is as follows:

[0036] T 贡献,i =T o,i ·exp(-e·(R i -R o,i ));

[0037] Among them, T 贡献,i represents the contribution of the ith drain outlet to the temperature rise of the calculation point, T o,i represents the initial temperature rise of the i-th drain outlet, e represents the attenuation coefficient, R i represents the equivalent distance from the calculation point to the i-th drain outlet, R o,i represents the radius of the equivalent temperature area of ​​the i-th drain outlet;

[0038] S34. Calculate the total temperature rise contribution according to the temperature rise contribution of each drain outlet, and calculate the temperature rise contribution ratio of each drain outlet according to the temperature rise contribution of each drain outlet and the total temperature rise contribution.

[0039] Furthermore, in S5, the calculation process of the correction factor of each drainage outlet is as follows:

[0040] ;

[0041] Among them, F i represents the correction factor of the i-th drain outlet, I ij represents the interaction term of the j-th drain outlet on the i-th drain outlet, i≠j;

[0042] The calculation formula of the interaction term of the jth drain outlet on the ith drain outlet is as follows:

[0043] ;

[0044] Among them, β represents the proportionality coefficient, α represents the temperature dependence coefficient, and Y j represents the thermal power of the jth drain outlet, r ij represents the distance between the i-th drain outlet and the j-th drain outlet, (x p ,y p ,z p ) represents the position coordinates of the calculation point, (x j ,y j ,z j ) represents the location coordinates of the jth drain outlet, and σ represents the standard deviation of the heat source influence range.

[0045] Further, in S5, the temperature rise of the calculation point caused by each drainage outlet is calculated according to the equivalent distance of the calculation point from each drainage outlet, the radius of the equivalent temperature area of ​​each drainage outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient, the initial temperature rise of each drainage outlet and the correction factor of each drainage outlet. The calculation formula is as follows:

[0046] ;

[0047] Among them, T up,i represents the temperature rise at the calculation point caused by the i-th drain outlet, K S Indicates the comprehensive heat dissipation coefficient of the water surface, F i Represents the correction factor of the i-th drain outlet.

[0048] Further, in S7, the temperature rise of the calculation point is calculated according to the equivalent distance of the calculation point from the drain outlet, the radius of the equivalent temperature area of ​​the drain outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient and the initial temperature rise of the drain outlet. The calculation formula is as follows:

[0049] ;

[0050] Among them, T up,i represents the temperature rise at the calculation point caused by the i-th drain outlet, T o,i represents the initial temperature rise of the i-th drain outlet, e represents the attenuation coefficient, K S Represents the comprehensive heat dissipation coefficient of the water surface, R i represents the equivalent distance from the calculation point to the i-th drain outlet, R o,i Represents the radius of the equivalent temperature area of ​​the i-th drain outlet.

[0051] The embodiments of the present invention have the following technical effects:

[0052] The present invention calculates the temperature rise contribution of each drain outlet and determines whether the calculation point is affected by one heat source or multiple heat sources based on the relationship between these contributions and a preset threshold value, so that the calculation process is more flexible and efficient, and can be adjusted according to different application scenarios, thereby improving the reliability and practicality of the results while maintaining the simplicity of calculation. In the case of multiple heat sources, interaction terms are introduced and correction factors are used to adjust the temperature rise caused by each drain outlet, taking into account the interaction and nonlinear effects between the heat sources, which can more accurately reflect the actual physical phenomena and provide a more reliable temperature estimation method in complex situations, thereby improving the calculation accuracy of the temperature rise of warm drainage water and providing a reliable basis for engineering design and decision-making. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 It is a flow chart of a method for calculating temperature rise of warm wastewater provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0056] The present invention proposes a method for calculating the temperature rise of warm wastewater. Figure 1 is a flow chart of a method for calculating the temperature rise of warm wastewater provided by an embodiment of the present invention, see Figure 1 , specifically including:

[0057] S1. Determine the location of each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the initial temperature rise of each drain outlet, the comprehensive heat dissipation coefficient of the water surface and the attenuation coefficient.

[0058] Specifically, the equivalent temperature area of ​​the drain outlet is near the drain outlet, where heat dissipation is small and the temperature is considered to be the same as the drain outlet. It is defined as the radius of the cylinder, which is related to the discharge volume and the average water depth of the calculation domain. The land boundary restricts the flow of water bodies, and the influence is expressed by the openness of the water area. The greater the openness, the greater the heat dissipation path. Similarly, the change in water depth is also corrected by parameters to make the capacity of the deep water area larger. The above factors are reflected in the equivalent radius. Since this value is related to the exponential coefficient, the empirical value of the mixing zone is used here, which is equivalent to the radius of the cylinder formed by the 10-minute drainage water body. The calculation method of the radius of the equivalent temperature area of ​​each drain outlet is as follows:

[0059] ;

[0060] Among them, R o,i represents the radius of the equivalent temperature area of ​​the i-th drain outlet, Q i represents the drainage flow of the ith drainage outlet, and D represents the water depth of the calculation area.

[0061] The calculation method of the comprehensive heat dissipation coefficient of the water surface is as follows:

[0062] ;

[0063] ;

[0064] Among them, K S represents the comprehensive heat dissipation coefficient of the water surface, ω represents the total heat flux of the water surface, T S represents the water surface temperature, ω br represents the water surface back radiation flux, ω e represents the turbulent heat exchange between the water surface and the atmosphere, ω c represents the evaporation flux from the water surface.

[0065] Furthermore, the empirical formula for the comprehensive heat dissipation coefficient of the water surface is such as the Gunneberg formula:

[0066] ;

[0067] Among them, T S = represents the water surface temperature, and U represents the wind speed. Under normal circumstances, the heat dissipation caused by the first item of water surface back radiation accounts for 10-20% of the total dissipation. The influence of wind speed on the heat dissipation coefficient is very obvious. In the calculation and application of this formula, the natural average water temperature is used as the water surface temperature, and the wind speed is taken as the average value of the whole year.

[0068] The calculation formula for the initial temperature rise of each drain outlet is as follows:

[0069] T 贡献,i =T o,i =T i -T ambient ;

[0070] Among them, T i represents the current temperature of the i-th drain outlet, T ambient Represents the background condition temperature.

[0071] Specifically, the attenuation coefficient e indicates that the farther away from the drain outlet, the smaller the temperature rise. The specific value of the attenuation coefficient e is determined based on experiments. In this embodiment, e=-0.018 or e=-0.025. When calculating the maximum temperature rise of the calculation point, e=-0.018 is used, and when calculating the average temperature rise of the calculation point, e=-0.025 is used. Among them, the average temperature rise is mainly used to evaluate the impact of the reheated drainage on the water intake of the power plant itself, and the maximum temperature rise is mainly used for environmental assessment requirements.

[0072] S2. According to the position of the calculation point, determine the equivalent distance between the calculation point and each drainage outlet.

[0073] Specifically, the calculation formula is as follows:

[0074] ;

[0075] Among them, R i represents the equivalent distance from the calculation point to the i-th drain outlet, R i ' represents the distance between the calculation point and the i-th drainage outlet, D i ' represents the average water depth along the path between the calculation point and the i-th drainage outlet, It represents the angle between the long axis of the water flow and the line connecting the water channel closest to the water intake and drainage outlet. When the water flows mostly from the drainage outlet away from the water intake, it is taken as an obtuse angle. b' represents the ratio of the long and short axes of the water flow under the action of waves and tides. θ represents the openness of the water body diffusion.

[0076] Specifically, the magnitude of tidal power makes the diffusion speed different. The changes in hydrodynamics and boundaries make the diffusion of water and heat not regularly present circular radiation. For example, the land boundary restricts the flow of water, and it is also believed that there is no heat exchange. The reciprocating tidal current makes the temperature contour lines caused by warm discharge appear strip-shaped or elliptical distribution. The change in water depth makes the heat dissipation capacity different, and the capacity of deep water areas is larger. The effect of waves is mainly manifested in the acceleration of water mixing speed, including horizontal and vertical directions. The greater the wave height and the longer the period, the more obvious the mixing effect. Because the water particles under the action of waves are reciprocating motion, the effect on the long-distance transport of water is not great, so it is considered as a factor in accelerating the lateral diffusion of tidal currents.

[0077] The calculation formula for the ratio of the major axis to the minor axis of water flow under the action of waves and tidal currents is as follows:

[0078] ;

[0079] ;

[0080] ;

[0081] Among them, b represents the ratio of the major and minor axis lengths of the water flow under the action of the tide, u represents the average flow velocity of the tide, w represents the water flow velocity caused by waves, U and V represent the flow velocity components in two orthogonal directions of the water flow, L represents the wavelength, H represents the wave height, and T represents the wave period.

[0082] S3. Calculate the contribution ratio of each drainage outlet to the temperature rise of the calculation point based on the equivalent distance from the calculation point to each drainage outlet, the radius of the equivalent temperature area of ​​each drainage outlet, the initial temperature rise and attenuation coefficient of each drainage outlet.

[0083] Specifically, the calculation process of the temperature rise contribution ratio of each drainage outlet is as follows:

[0084] S31. Determine whether the equivalent distance between the calculation point and the drain outlet is less than or equal to the radius of the equivalent temperature area of ​​the drain outlet.

[0085] If the equivalent distance between the calculation point and the drain outlet is less than or equal to the radius of the equivalent temperature zone of the drain outlet, in this case, the calculation point is located in the equivalent temperature zone of the drain outlet, the temperature can be considered uniform, and the process goes to S32. If the equivalent distance between the calculation point and the drain outlet is greater than the radius of the equivalent temperature zone of the drain outlet, in this case, the calculation point is outside the equivalent temperature zone of the drain outlet, the temperature will decay with the increase of distance, so it is necessary to calculate the temperature rise contribution based on the attenuation coefficient, and the process goes to S33.

[0086] S32. The initial temperature rise of the drain outlet is taken as the temperature rise contribution of the drain outlet to the calculation point.

[0087] S33. The calculation formula for the contribution of the drain outlet to the temperature rise of the calculation point is as follows.

[0088] T 贡献,i =T o,i ·exp(-e·(R i -R o,i ));

[0089] Among them, T 贡献,i represents the contribution of the ith drain outlet to the temperature rise of the calculation point, T o,i represents the initial temperature rise of the i-th drain outlet, e represents the attenuation coefficient, R i represents the equivalent distance from the calculation point to the i-th drain outlet, R o,i Represents the radius of the equivalent temperature area of ​​the i-th drain outlet.

[0090] S34. Calculate the total temperature rise contribution according to the temperature rise contribution of each drain outlet, and calculate the temperature rise contribution ratio of each drain outlet according to the temperature rise contribution of each drain outlet and the total temperature rise contribution.

[0091] Specifically, the calculation formula for the temperature rise contribution ratio of each drainage outlet is as follows:

[0092] ;

[0093] ;

[0094] Among them, T 总贡献 Denotes the total temperature rise contribution, C i represents the temperature rise contribution ratio of the i-th drain outlet, and n represents the total number of drain outlets.

[0095] S4. Remove the drain outlets whose temperature rise contribution ratio is less than a preset threshold, and determine whether the number of remaining drain outlets is 1.

[0096] Specifically, if the number of remaining drain outlets is not 1, proceed to S5; if the number of remaining drain outlets is 1, proceed to S7.

[0097] Among them, the preset threshold can be set according to the actual situation, such as 0.05 or 0.1, to screen out the drains that contribute very little to the temperature rise of the calculation point. If the contribution to the temperature rise of the calculation point is very small, it means that the drain has little effect on the temperature rise of the calculation point and can be ignored, which can significantly reduce the amount of calculation, improve the calculation efficiency, and take into account the calculation accuracy. If the number of remaining drains is 1, the calculation formula of a single drain is used to calculate the temperature rise of the calculation point. If the number of remaining drains is not 1, it means that the number of drains that affect the temperature of the calculation point is greater than 1, and there is mutual influence between heat sources. The temperature rise of the calculation point cannot be calculated by simple superposition, and the calculation formula of multiple drains is used to calculate the temperature rise of the calculation point.

[0098] S5. Calculate the correction factor of each drain outlet, and calculate the temperature rise of the calculation point caused by each drain outlet based on the equivalent distance from the calculation point to each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient, the initial temperature rise of each drain outlet and the correction factor of each drain outlet.

[0099] Specifically, in simple models, we usually assume that the influence of each heat source on the calculation point is linearly superimposed. That is, the total temperature rise is a simple addition of the individual contributions of each heat source. However, in actual situations, the presence of multiple heat sources will lead to nonlinear changes in the temperature field, especially when the heat source is close or the heat source intensity is large. By introducing a correction factor, the temperature rise contribution of each heat source not only reflects its own characteristics, but also takes into account the influence of other surrounding heat sources, thereby combining the independent contribution of each drain outlet with the influence of other drain outlets to more accurately estimate the total temperature rise of the calculation point.

[0100] The calculation process of the correction factor for each drain outlet is as follows:

[0101] ;

[0102] Among them, F i represents the correction factor of the i-th drain outlet, I ij It represents the interaction term of the j-th drain outlet on the ith drain outlet, i≠j. The interaction between multiple heat sources is considered by introducing the interaction term, and the nonlinear effect of thermal conductivity changing with temperature is considered in the interaction term.

[0103] The calculation formula of the interaction term of the jth drain outlet on the ith drain outlet is as follows:

[0104] ;

[0105] Among them, β represents the proportionality coefficient, α represents the temperature dependence coefficient, and Y j represents the thermal power of the jth drain outlet, r ij represents the distance between the i-th drain outlet and the j-th drain outlet, (xp ,y p ,z p ) represents the position coordinates of the calculation point, (x j ,y j ,z j ) represents the position coordinates of the jth drain outlet, σ represents the standard deviation of the heat source influence range, which is usually related to the influence range of the drain outlet and can be determined based on experience or experimental data. represents the distance dependence, indicating that the closer the distance between the heat sources, the stronger the interaction; represents the temperature dependence term, which takes into account the effect of the change in the temperature of the heat source on the heat conduction. When the temperature increases, it may lead to an increase in thermal conductivity, thereby enhancing the interaction; Represents the spatial attenuation term, which describes how the influence of a heat source on a distant point decays rapidly with increasing distance.

[0106] Furthermore, during the heat diffusion process, the heat from the high temperature area is transferred to the low temperature area. Generally speaking, the farther away from the drain outlet, the smaller the temperature rise. As the diffusion range increases, the temperature decreases and the temperature difference also decreases. Therefore, the temperature difference can be expressed as an exponential function.

[0107] The calculation formula for the temperature rise at the calculation point caused by each drainage outlet is as follows:

[0108] ;

[0109] Among them, T up,i represents the temperature rise at the calculation point caused by the i-th drain outlet, K S Indicates the comprehensive heat dissipation coefficient of the water surface, F i Represents the correction factor of the i-th drain outlet.

[0110] S6. Add the temperature rise of the calculation point caused by each drain outlet to obtain the total temperature rise of the calculation point.

[0111] Specifically, the calculation formula for the total temperature rise of the calculation point is as follows:

[0112] ;

[0113] Among them, T up Represents the total temperature rise at the calculation point.

[0114] S7. Calculate the temperature rise of the calculation point based on the equivalent distance from the calculation point to the drain outlet, the radius of the equivalent temperature area of ​​the drain outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient and the initial temperature rise of the drain outlet.

[0115] Specifically, the calculation formula for the temperature rise of the calculation point is as follows:

[0116] ;

[0117] Among them, T up,i represents the temperature rise at the calculation point caused by the i-th drain outlet, T o,i represents the initial temperature rise of the i-th outlet. When the water intake is affected by the temperature discharge, the water intake temperature rise must also be added. e represents the attenuation coefficient, K S Represents the comprehensive heat dissipation coefficient of the water surface, R i represents the equivalent distance from the calculation point to the i-th drain outlet, R o,i Represents the radius of the equivalent temperature area of ​​the i-th drain outlet.

[0118] Furthermore, the calculated results are compared with the measured data to verify the accuracy of the calculation method. If there is a deviation, the attenuation coefficient e and the equivalent temperature zone radius R can be adjusted according to the actual situation. o,i etc. and recalculate to improve the calculation accuracy.

[0119] The present invention calculates the temperature rise contribution of each drain outlet and determines whether the calculation point is affected by one heat source or multiple heat sources based on the relationship between these contributions and a preset threshold value, so that the calculation process is more flexible and efficient, and can be adjusted according to different application scenarios, thereby improving the reliability and practicality of the results while maintaining the simplicity of calculation. In the case of multiple heat sources, interaction terms are introduced and correction factors are used to adjust the temperature rise caused by each drain outlet, taking into account the interaction and nonlinear effects between the heat sources, which can more accurately reflect the actual physical phenomena and provide a more reliable temperature estimation method in complex situations, thereby improving the calculation accuracy of the temperature rise of warm drainage water and providing a reliable basis for engineering design and decision-making.

[0120] It should be noted that the terms used in the present invention are only for describing specific embodiments, rather than limiting the scope of the present application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular, but may also include the plural. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of more restrictions, the elements defined by the sentence "include one..." do not exclude the presence of other identical elements in the process, method or device including the elements.

[0121] It should also be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating the temperature rise of warm wastewater, characterized in that: The steps include: S1. Determine the location of each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the initial temperature rise of each drain outlet, the comprehensive heat dissipation coefficient of the water surface and the attenuation coefficient; S2. Determine the equivalent distance between the calculation point and each drainage outlet according to the position of the calculation point; S3, calculating the contribution ratio of each drain outlet to the temperature rise of the calculation point according to the equivalent distance from the calculation point to each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the initial temperature rise of each drain outlet and the attenuation coefficient; Specifically include: S31, judging whether the equivalent distance from the calculation point to the drain outlet is less than or equal to the radius of the equivalent temperature area of ​​the drain outlet; if the equivalent distance from the calculation point to the drain outlet is less than or equal to the radius of the equivalent temperature area of ​​the drain outlet, proceeding to S32; if the equivalent distance from the calculation point to the drain outlet is greater than the radius of the equivalent temperature area of ​​the drain outlet, proceeding to S33; S32, taking the initial temperature rise of the drain outlet as the temperature rise contribution of the drain outlet to the calculation point; The calculation formula of the initial temperature rise of the drain outlet is as follows: T 贡献,i =T o,i =T i -T ambient ; Among them, T i represents the current temperature of the i-th drain outlet, T ambient represents the background condition temperature; S33. The calculation formula of the contribution of the drain outlet to the temperature rise of the calculation point is as follows: T 贡献,i =T o,i ·exp(-e·(R i -R o,i )); Among them, T 贡献,i represents the contribution of the ith drain outlet to the temperature rise of the calculation point, T o,i represents the initial temperature rise of the i-th drain outlet, e represents the attenuation coefficient, R i represents the equivalent distance from the calculation point to the i-th drain outlet, R o,i represents the radius of the equivalent temperature area of ​​the i-th drain outlet; S34, calculating the total temperature rise contribution according to the temperature rise contribution of each drain outlet, and calculating the temperature rise contribution ratio of each drain outlet according to the temperature rise contribution of each drain outlet and the total temperature rise contribution; S4, remove the drain outlets whose temperature rise contribution ratio is less than the preset threshold, and determine whether the number of remaining drain outlets is 1; if the number of remaining drain outlets is not 1, proceed to S5; if the number of remaining drain outlets is 1, proceed to S7; S5, calculating the correction factor of each drain outlet, and calculating the temperature rise of the calculation point caused by each drain outlet according to the equivalent distance of the calculation point from each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient, the initial temperature rise of each drain outlet and the correction factor of each drain outlet; The calculation process of the correction factor of each drainage outlet is as follows: ； Among them, F i represents the correction factor of the i-th drain outlet, I ij represents the interaction term of the j-th drain outlet on the i-th drain outlet, i≠j; The calculation formula of the interaction term of the jth drain outlet on the ith drain outlet is as follows: ； Among them, β represents the proportionality coefficient, α represents the temperature dependence coefficient, and Y j represents the thermal power of the jth drain outlet, r ij represents the distance between the i-th drain outlet and the j-th drain outlet, (x p ,y p ,z p ) represents the position coordinates of the calculation point, (x j ,y j ,z j ) represents the position coordinates of the jth drain outlet, σ represents the standard deviation of the heat source influence range; The calculation formula for the temperature rise caused by each drain outlet is as follows: ； Among them, T up,i represents the temperature rise of the calculation point due to the i-th drain outlet, K S Indicates the comprehensive heat dissipation coefficient of the water surface, F i represents the correction factor of the i-th drain outlet; S6, superimposing the temperature rise of the calculation point caused by each drain outlet to obtain the total temperature rise of the calculation point; S7. Calculate the temperature rise of the calculation point according to the equivalent distance of the calculation point from each drain outlet, the radius of the equivalent temperature area of ​​the drain outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient and the initial temperature rise of the drain outlet.

2. The method for calculating the temperature rise of warm wastewater according to claim 1, characterized in that: In S1, the position of each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the initial temperature rise of each drain outlet, the comprehensive heat dissipation coefficient of the water surface and the attenuation coefficient are determined, wherein the calculation method of the radius of the equivalent temperature area of ​​each drain outlet is as follows: ； Among them, R o,i represents the radius of the equivalent temperature area of ​​the i-th drain outlet, Q i represents the drainage flow of the i-th drainage outlet, and D represents the water depth of the calculation area.

3. The method for calculating the temperature rise of warm wastewater according to claim 2, characterized in that: In S1, the position of each drain outlet, the radius of the equivalent temperature area of ​​each drain outlet, the initial temperature rise of each drain outlet, the comprehensive heat dissipation coefficient of the water surface and the attenuation coefficient are determined, wherein the calculation method of the comprehensive heat dissipation coefficient of the water surface is as follows: ； ； Among them, K S represents the comprehensive heat dissipation coefficient of the water surface, ω represents the total heat flux of the water surface, T S represents the water surface temperature, ω br represents the water surface back radiation flux, ω e represents the turbulent heat exchange between the water surface and the atmosphere, ω c represents the evaporation flux from the water surface.

4. A method for calculating the temperature rise of warm wastewater according to claim 3, characterized in that: In S2, the equivalent distance between the calculation point and each drainage outlet is determined according to the position of the calculation point, and the calculation formula is as follows: ； Among them, R i represents the equivalent distance from the calculation point to the i-th drain outlet, R i ' represents the distance between the calculation point and the i-th drainage outlet, D i ' represents the average water depth along the path between the calculation point and the i-th drainage outlet, represents the angle between the major axis of the water flow and the line connecting the nearest water channel to the water intake and discharge outlet, b' represents the ratio of the major and minor axis lengths of the water flow under the action of waves and tidal currents, and θ represents the openness of the water body diffusion; The calculation formula for the ratio of the major axis to the minor axis of water flow under the action of waves and tidal currents is as follows: ； ； ； Among them, b represents the ratio of the major and minor axis lengths of the water flow under the action of the tide, u represents the average flow velocity of the tide, w represents the water flow velocity caused by waves, U and V represent the flow velocity components in two orthogonal directions of the water flow, L represents the wavelength, H represents the wave height, and T represents the wave period.

5. The method for calculating the temperature rise of warm wastewater according to claim 4, characterized in that: In S7, the temperature rise of the calculation point is calculated according to the equivalent distance of the calculation point from each drain outlet, the radius of the equivalent temperature area of ​​the drain outlet, the comprehensive heat dissipation coefficient of the water surface, the attenuation coefficient and the initial temperature rise of the drain outlet. The calculation formula is as follows: ； Among them, T up,i represents the temperature rise of the calculation point due to the i-th drain outlet, T o,i represents the initial temperature rise of the i-th drain outlet, e represents the attenuation coefficient, K S Represents the comprehensive heat dissipation coefficient of the water surface, R i represents the equivalent distance from the calculation point to the i-th drain outlet, R o,i Represents the radius of the equivalent temperature area of ​​the i-th drain outlet.

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