Intelligent control system and control method for mass concrete cooling circulation pipe

Abstract

The invention provides an intelligent control system and method for a mass concrete cooling circulation pipe, and the system and method achieve the precise control of the internal temperature of concrete through an integrated network platform, a controller and communication equipment. Inner and outer ring cooling pipe sets are arranged, and the cooling water flow is monitored and adjusted in real time through a flow adjusting valve and a temperature sensor so as to control the temperature difference inside and outside concrete. The system is further provided with a cooling device, a filtering device, a water level gauge and other functional parts, and high efficiency and safety of cooling water circulation are guaranteed. By establishing a heat conduction equation, setting boundary conditions and introducing a cooling efficiency factor, the system can predict the change rule of the concrete temperature so as to formulate a reasonable cooling plan. The problem of concrete cracking caused by temperature stress can be effectively prevented, operation of a cooling system is optimized, energy consumption is reduced, and construction quality and efficiency are improved. An advanced temperature control solution is provided for mass concrete construction, and the reliability and economical efficiency of an engineering project are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete construction, and in particular to an intelligent control system and a control method for a large-volume concrete cooling circulation pipe. Background Art

[0002] In concrete construction projects, the hydration reaction of concrete after pouring is a complex and critical process. The hydration reaction releases a large amount of heat, causing the temperature inside and outside the concrete to rise to varying degrees. Since the outside of the concrete is in contact with the air, its temperature rise rate is relatively slow, while the temperature rise inside is particularly significant due to the hydration reaction. The existence of this internal and external temperature difference will cause the temperature difference to gradually increase in the early stage, which will have an adverse effect on the structural performance and service life of the concrete.

[0003] In order to effectively control the temperature difference between the inside and the outside and prevent the internal temperature from being too high, it has become a common method to arrange metal pipes in the concrete structure in advance and introduce cooling water after pouring. The circulation of cooling water can effectively remove the heat inside the concrete, lower the temperature, and thus reduce the temperature difference between the inside and the outside. However, in the middle and late stages, as the hydration reaction slows down, the temperature rise trend gradually slows down, and eventually the temperature begins to drop. At this stage, how to reasonably and automatically adjust the flow rate and flow of cooling water and control the cooling rate has become an important technical issue.

[0004] Traditional methods for adjusting process parameters of cooling water pipes mostly rely on manual monitoring and manual collection of field data. This method has many disadvantages, such as poor monitoring data accuracy, low temperature control efficiency, and great influence by human factors. Alternatively, optical fiber sensors are used, whose detection data is not only less accurate but also more easily damaged. This not only increases the difficulty and cost of construction, but may also have an adverse effect on the temperature control effect of concrete. Summary of the invention

[0005] The main purpose of the present invention is to provide an intelligent control system and control method for a large-volume concrete cooling circulation pipe, which can solve the problems of inaccurate detection data and easy damage of equipment in traditional methods, and can accurately predict and precisely control the concrete temperature, especially reducing or even avoiding the problem of concrete cracking caused by excessive temperature difference between inside and outside.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: an intelligent control system for a large-volume concrete cooling circulation pipe, including a network platform, the network platform is provided with a controller and a communication device;

[0007] A main pipe is also provided, which is used to connect the water inlet device, and is connected to a plurality of water inlet branches. A flow regulating valve and a first temperature sensor are provided on each water inlet branch. The controller is used to be electrically connected to a second temperature sensor provided in the mass concrete to receive temperature data in the mass concrete, and to issue an action instruction to control the flow regulating valve after the instruction is calculated by the network platform.

[0008] A communication device is also provided for sending and receiving data and instructions wirelessly.

[0009] In a preferred solution, the main pipes are divided into two groups, and the corresponding water inlet branches are divided into two groups, and the two groups of water inlet branches are respectively connected to the outer ring cooling pipe group and the inner ring cooling pipe group to control the temperature difference between the inside and outside of the large volume concrete;

[0010] An independent outer ring cooling pipe group and an inner ring cooling pipe group are provided in the mass concrete;

[0011] The outer cooling pipe group is close to the surface of the mass concrete that is easy to dissipate heat, and the inner cooling pipe group is far away from the surface of the mass concrete that is easy to dissipate heat;

[0012] Second temperature sensors are provided on the outer ring and the inner ring of the mass concrete, and the second temperature sensors are electrically connected to the controller in a wireless manner.

[0013] In a preferred solution, each main pipe is connected to a water distributor, wherein the water distributor for supplying water to the inner ring cooling pipe group is provided with a cooling device.

[0014] In a preferred solution, the return water pipes of the inner ring cooling pipe group and the outer ring cooling pipe group are connected to the return water storage tank, and the return water storage tank is connected to the main pipe through a water pump;

[0015] The return water storage tank is provided with a filtering device, and the pipeline connected to the water pump is located downstream of the filtering device.

[0016] There is also a water level gauge to maintain the water level in the return water storage tank;

[0017] A third temperature sensor is provided at the connection between the outer ring cooling pipe group and the inner ring cooling pipe group and the internal concrete pipe and on the return water pipe to detect the return water temperature and evaluate the cooling rate;

[0018] A flow meter is also installed on the return pipe to detect return water loss and determine whether the pipeline is broken.

[0019] A control method using the above-mentioned intelligent control system for cooling circulation pipes of large-volume concrete comprises the following steps:

[0020] S1. Establish heat conduction equation: According to the density, specific heat capacity, thermal conductivity and cement hydration heat release rate of concrete, establish heat conduction equation to describe the process of heat transfer inside concrete;

[0021] S2. Setting boundary conditions: according to the convective heat transfer coefficient of the concrete surface and the ambient temperature, set the convective heat transfer boundary conditions to describe the heat exchange between the concrete surface and the environment;

[0022] S3. Introduce cooling efficiency factor: quantify the cooling effect of cooling water pipe on concrete temperature reduction by experimental measurement or estimation based on engineering experience;

[0023] S4. Solve the prediction formula: Combine the heat conduction equation, boundary conditions and cooling efficiency factor to derive the prediction formula of concrete temperature. Solve the prediction formula by numerical method to obtain the variation law of concrete temperature over time.

[0024] The above steps can realize the prediction of concrete temperature based on heat conduction and convection heat transfer.

[0025] In the preferred solution, in step S1, establishing the heat conduction equation specifically includes, first, making the following assumptions on the model: the temperature distribution inside the concrete is uniform, that is, the temperature remains consistent in the same area; the heat of cement hydration is the main heat source inside the concrete, and its release rate changes with time; the cooling water pipe reduces the concrete temperature through convection heat transfer; the ambient temperature has a significant impact on the concrete surface temperature;

[0026] Based on the principle of heat conduction, the heat conduction equation for the temperature distribution inside the concrete is established.

[0027]

[0028] ρ represents the density of concrete, which indicates the mass of concrete per unit volume, in kg / m 3 ;

[0029] c represents the specific heat capacity of concrete, which indicates the heat required to raise or lower the temperature of a unit mass of concrete by 1 degree Celsius, in units of kJ / kg.℃;

[0030] T represents the temperature of the concrete, the main variable for prediction;

[0031] t represents time, because temperature changes with time;

[0032] k represents the thermal conductivity of concrete, which indicates the rate of heat transfer inside the concrete, and its unit is kJ / mh℃;

[0033] Q(t) represents the cement hydration heat release rate, that is, the change of heat released by cement during the hardening process with time;

[0034] Through the above equation, we can get the temperature distribution of concrete at different times and different locations.

[0035] In the preferred solution, in step S2, the boundary conditions are set according to the convective heat transfer coefficient of the concrete surface and the ambient temperature to describe the heat exchange between the concrete surface and the environment. The specific formula is as follows:

[0036]

[0037] Where k is the thermal conductivity of concrete, n is the normal direction of the concrete surface, h represents the convective heat transfer coefficient between the concrete surface and the environment, T s Indicates the temperature of the concrete surface, T env is the ambient temperature, represents the heat flux on the concrete surface along the normal direction n, is the temperature gradient along the normal direction, that is, the rate of temperature change. The negative sign indicates that heat flows from the inside of the concrete to the external environment;

[0038] The heat exchange boundary conditions between the inner wall of the cooling water pipe and the concrete are:

[0039]

[0040] Among them, h w represents the convective heat transfer coefficient between the inner wall of the cooling water pipe and the concrete, T w is the cooling water temperature, T c is the temperature of the concrete near the cooling water pipe.

[0041] In a preferred solution, in step S3, the cooling efficiency factor η(t) is introduced considering the effect of the cooling water pipe on reducing the temperature of the concrete, which specifically includes the following sub-steps: The formula is as follows:

[0042] S31. Design a series of experiments using cooling water pipes with different flow rates and diameters, and ensure that the performance parameters of the concrete remain consistent in all experiments;

[0043] S32. Monitor and record the temperature changes of concrete at different flow rates and pipe diameters;

[0044] S33. Analyze the experimental data and establish the mathematical relationship between the cooling efficiency factor and the cooling water pipe flow rate and pipe diameter:

[0045]

[0046] Here, a is a constant used to adjust the fitting degree of the expression.

[0047] A pipe is the surface area of ​​the cooling water pipe, which can be calculated from the diameter and length of the cooling water pipe; Q is the flow rate of cooling water; ΔTw is the difference between the temperature of cooling water and the initial temperature of concrete; V concrete is the volume of concrete; ρ is the density of concrete; c is the specific heat capacity of concrete; ΔT c is the difference between the initial temperature of the concrete and the ambient temperature; N is an index used to describe the rate at which the cooling efficiency factor changes with time.

[0048] In a preferred solution, in step S4, the prediction formula is solved, and the temperature distribution is solved by a numerical method in combination with the heat conduction equation, boundary conditions and cooling efficiency factor to obtain the concrete temperature prediction formula:

[0049]

[0050] Where T(t) is the temperature of the concrete at time (t); T {initial} is the initial temperature of concrete; Q {total} is the total heat of cement hydration; V concrete is the concrete volume; η(t) is the cooling efficiency factor.

[0051] The preferred solution includes the following steps:

[0052] Step 1: The network platform imports historical experience data, formulates a cooling plan by predicting the temperature of the concrete, supplies water to the outer ring cooling pipe group and the inner ring cooling pipe group respectively, and collects data from temperature sensors at various locations;

[0053] Also includes the adjustment steps:

[0054] Step 2: If the predicted temperature rise rate exceeds the preset value, the flow rates of the outer ring cooling tube group and the inner ring cooling tube group are increased simultaneously;

[0055] If the predicted temperature difference between the inside and outside exceeds the preset value, the flow rate of the inner ring cooling tube group is increased and the flow rate of the outer ring cooling tube group is reduced;

[0056] If the predicted heating rate of the inner ring cooling tube group exceeds the preset value and the flow rate has reached the maximum value, the cooling device is started to cool the water supply.

[0057] If the predicted heating rate is stable and the temperature difference between the inner and outer rings does not exceed the preset value, the flow rates of the outer ring cooling tube group and the inner ring cooling tube group are gradually reduced to save energy.

[0058] If the flow difference between the outer ring cooling tube group and the inner ring cooling tube group exceeds expectations, the flow of the corresponding cooling tube group is controlled and an alarm is issued to request manual processing.

[0059] The present invention adopts a scheme of centralized intelligent control of the water inlet flow rate according to the temperature of the mass concrete, greatly improving the intelligent degree of temperature control of the mass concrete, reducing the probability of cracking of the mass concrete, and improving the strength of the mass concrete. The intelligent control method adopted can predict the temperature change of the mass concrete in advance, realize early prevention and treatment, further ensure the construction quality of the mass concrete, reduce the probability of manual processing errors, and reduce labor intensity. It can predict the situation of pipeline rupture, give early warning, avoid the formation of weak cavities inside the concrete due to the flushing of cooling water, and take remedial measures in advance before the next warehouse of concrete is poured. In addition, the present invention establishes a prediction model for the concrete temperature based on heat conduction and convection heat transfer. By comprehensively considering the heat conduction inside the concrete, the convection heat transfer between the surface and the environment, and the influence of the cooling water pipe, the temperature change of the concrete can be accurately predicted. The model uses the heat conduction equation to describe the internal heat transfer, sets the boundary conditions to reflect the heat exchange between the surface and the environment, and determines the cooling efficiency factor through experiments. Combined with these factors, the numerical method is used to solve the prediction formula to obtain the law of concrete temperature change over time. This model not only takes into account multiple influencing factors, but also has high prediction accuracy. It has important guiding significance for temperature control in concrete construction, and helps to optimize the construction process and ensure project quality.

[0060] The beneficial effects of the present invention are:

[0061] 1) The system achieves precise control of the cooling process through a network platform and controller. It can dynamically adjust the cooling water flow rate according to real-time temperature data, effectively control the internal temperature of large-volume concrete, especially the temperature difference between the inside and outside, and prevent cracking caused by temperature stress.

[0062] 2) The system can automatically formulate a cooling plan based on historical experience and prediction algorithms, and optimize the cooling effect, reduce energy consumption and improve work efficiency by intelligently regulating the flow of the inner and outer ring cooling pipe groups.

[0063] 3) By setting up inner and outer ring cooling pipe groups, the system can better control the temperature difference between the inside and outside of the concrete, avoiding quality problems caused by excessive temperature difference.

[0064] 4) The system is equipped with a variety of sensors to monitor water temperature and flow, as well as water level gauges to maintain the water level in the tank. These features help to automate the entire cooling process and can promptly detect and deal with potential problems, such as return pipe ruptures.

[0065] 5) Using the temperature prediction method and the actual collected data, the system can continuously adjust the cooling strategy to make the cooling process more scientific and reasonable, while providing valuable experience data for subsequent similar projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0067] Figure 1 is a temperature envelope diagram of the internal concrete of the cap in the embodiment of the present invention;

[0068] Figure 2 is a temperature time course curve when the flow rate of the outer ring of the platform is adjusted in the embodiment of the present invention;

[0069] Figure 3 This is an overall structural diagram of an intelligent circulating pipe cooling control system device in an embodiment of the present invention;

[0070] Figure 4 is a three-dimensional diagram of an intelligent circulating pipe cooling control device in an embodiment of the present invention;

[0071] Figure 5 1 is a front view of a box of an intelligent circulating pipe cooling control device according to an embodiment of the present invention;

[0072] Figure 6 This is a left view of the box of the intelligent circulating pipe cooling control device in the embodiment of the present invention;

[0073] Figure 7 This is a right view of the box of the intelligent circulating pipe cooling control device in the embodiment of the present invention;

[0074] Figure 8 is a cross-sectional view of an intelligent circulating pipe cooling control device in an embodiment of the present invention;

[0075] Fig. 9 It is an internal pipeline diagram of the intelligent circulating pipe cooling control device in an embodiment of the present invention;

[0076] Fig.10 This is a simplified structural diagram of an intelligent circulating pipe cooling control system device in an embodiment of the present invention;

[0077] In the figure: box body 1; first through hole 101; second through hole 102; branch pipe through hole 103; electric control box 2; display screen 3; ventilation fan 4; main pipe 5; first main pipe 51; second main pipe 52; water level gauge 6; water inlet branch pipe 7; outer ring water inlet branch pipe 701; inner ring water inlet branch pipe 702; flow regulating valve 8; flow meter 9; first temperature sensor 10; main valve 11; quick connector 12; cooling device 13; water distributor 14; first water distributor 141; second water distributor 142; water pump 15; return water storage tank 16; large volume concrete 17; outer ring cooling pipe group 18; inner ring cooling pipe group 19; network platform 20; communication equipment 21; filtering device 22; second temperature sensor 23; third temperature sensor 24. DETAILED DESCRIPTION

[0078] Embodiment 1:

[0079] like Figures 1 to 10 As shown, an intelligent control system for a large volume concrete cooling circulation pipe is characterized by: comprising a network platform 20, the network platform 20 is provided with a controller and a communication device 21;

[0080] A main pipe 5 is also provided, and the main pipe 5 is used to connect the water inlet device. The main pipe 5 is connected to a plurality of water inlet branches 7. A flow regulating valve 8 and a first temperature sensor 10 are provided on each water inlet branch 7. The controller is used to be electrically connected to a second temperature sensor 23 provided in the mass concrete 17 to receive temperature data in the mass concrete 17, and after the network platform 20 calculates the instructions, the controller issues an action instruction to control the flow regulating valve 8;

[0081] A communication device 21 is also provided for sending and receiving data and instructions in a wireless manner.

[0082] The present invention provides an intelligent control system for large-volume concrete cooling circulation pipes. By integrating a network platform, a controller and communication equipment, it realizes accurate monitoring and automatic adjustment of the internal temperature of concrete, can dynamically adjust the cooling water flow rate according to the temperature data collected in real time, effectively control the internal temperature of concrete, and avoid structural damage caused by temperature changes. The independent inner and outer ring cooling pipe design in the system can finely manage the temperature difference inside and outside the concrete, further enhancing the safety and stability of the structure. In addition, the system also has an automatic alarm mechanism, which can promptly notify the operator when an abnormal situation is detected, thereby ensuring the construction quality and efficiency, not only improving the temperature control accuracy in large-volume concrete construction, but also improving the reliability and economy of the overall construction through intelligent means.

[0083] In the preferred embodiment, the main pipe 5 is divided into two groups, including a first main pipe 51 and a second main pipe 52, and the corresponding water inlet branch pipes are divided into two groups, including an outer ring water inlet branch pipe 701 and an inner ring water inlet branch pipe 702. The two groups of water inlet branch pipes 7 are respectively connected to the outer ring cooling pipe group 18 and the inner ring cooling pipe group 19 to control the temperature difference between the inside and outside of the large volume concrete 17.

[0084] The first main pipe 51 and the second main pipe 52 extend out of the casing 1 through the first through hole 101 and the second through hole 102 respectively, and are used to connect to the water inlet device. By arranging the outer ring water inlet branch pipe 701 and the inner ring water inlet branch pipe 702, one end of the outer ring water inlet branch pipe 701 and the inner ring water inlet branch pipe 702 extend out of the casing 1 through the branch pipe through hole 103 and are connected to the condensation pipe inside the concrete, and the other end is connected to the outer ring cooling pipe group 18 and the inner ring cooling pipe group 19, so as to accurately control the flow rate and temperature of the cooling water introduced into the inner outer ring concrete and the inner ring concrete, so as to control the temperature difference between the inside and outside of the large volume concrete 17.

[0085] In the preferred embodiment, the main pipe 5 is respectively used to connect a water distributor 14, wherein the water distributor 14 for supplying water to the inner ring cooling pipe group 19 is provided with a cooling device 13. The water distributor 14 includes a first water distributor 141 and a second water distributor 142.

[0086] The first main pipe 51 and the second main pipe 52 are respectively used to connect the first water distributor 141 and the second water distributor 142. The first water distributor 141 and the second water distributor 142 are respectively connected to the outer ring cooling tube group 18 and the inner ring cooling tube group 19. The second water distributor 142 connected to the inner ring cooling tube group 19 is provided with a cooling device 13 for controlling the temperature of cooling water entering the inner ring cooling tube group 19.

[0087] The preferred solution is Figure 3 In the embodiment, an independent outer ring cooling pipe group 18 and an inner ring cooling pipe group 19 are provided in the mass concrete 17; the outer ring cooling pipe group 18 and the inner ring cooling pipe group 19 are both provided as independent pipes, which can conveniently and accurately control the temperature of the concrete pipes entering the outer ring and the inner ring.

[0088] The outer ring cooling pipe group 18 is close to the surface of the large volume concrete 17 that is easy to dissipate heat, and the inner ring cooling pipe group 19 is far away from the surface of the large volume concrete 17 that is easy to dissipate heat; by setting the outer ring cooling pipe group 18 and the inner ring cooling pipe group 19, the problem of easy cracks in the concrete due to the large inside and outside of the concrete is alleviated, and the concrete at different positions is cooled according to the actual situation.

[0089] Temperature sensors 10 are provided on the outer and inner rings of the mass concrete 17. The temperature sensors 10 are electrically connected to the controller in a wireless manner to measure the temperature of the cooling water inside the concrete.

[0090] The preferred solution is Figure 3 In the embodiment, the return pipes of the inner cooling pipe group 19 and the outer cooling pipe group 18 are connected to the return water storage tank 16, and the return water storage tank 16 is connected to the main pipe 5 through the water pump 15. The cooling water is introduced into the main pipe 5 by the water pump 15, and the cooling water enters the cooling pipe inside the concrete through the concrete inner cooling pipe group 19 and the outer cooling pipe group 18, and then enters the return water storage tank 16 through the return pipe, so that water resources are reused and costs are saved.

[0091] The preferred solution is Figure 3 In the embodiment, the return water storage tank 16 is provided with a filter device 22, and the pipeline connected to the water pump 15 is located downstream of the filter device 22. The return water storage tank 16 is provided with a filter device 22, which can filter the cooling water entering the main pipe 5 in advance to avoid clogging the pipeline.

[0092] A water level meter 6 is also provided for maintaining the water level in the return water storage tank 16; the water level in the return water storage tank 16 can be measured to maintain the water level in the return water storage tank 16 normal.

[0093] A third temperature sensor 24 is provided at the connection between the outer ring cooling pipe group 18 and the inner ring cooling pipe group 19 and the internal concrete pipe and on the return water pipe to detect the return water temperature and evaluate the cooling rate.

[0094] Among them, a third temperature sensor 24 is set at the connection between the outer ring cooling pipe group 18 and the inner ring cooling pipe group 19 and the internal concrete pipe and on the return pipe, which can obtain the inlet temperature and outlet temperature of the inner outer ring concrete and inner ring concrete pipes, providing data support for the subsequent prediction of concrete temperature.

[0095] A flow meter 9 is also provided on the return water pipe to detect the return water loss and determine whether the pipeline is broken.

[0096] Embodiment 2:

[0097] Further illustrate with reference to Example 1, Figure 1-10 As shown, the present invention also provides a concrete temperature prediction method, comprising the following steps:

[0098] S1. Establish heat conduction equation: According to the density, specific heat capacity, thermal conductivity and cement hydration heat release rate of concrete, establish heat conduction equation to describe the process of heat transfer inside concrete;

[0099] S2. Setting boundary conditions: according to the convective heat transfer coefficient of the concrete surface and the ambient temperature, set the convective heat transfer boundary conditions to describe the heat exchange between the concrete surface and the environment;

[0100] S3. Introduce cooling efficiency factor: quantify the cooling effect of cooling water pipe on concrete temperature reduction by experimental measurement or estimation based on engineering experience;

[0101] S4. Solve the prediction formula: Combine the heat conduction equation, boundary conditions and cooling efficiency factor to derive the prediction formula of concrete temperature. Solve the prediction formula by numerical method to obtain the variation law of concrete temperature over time.

[0102] The above steps can realize the prediction of concrete temperature based on heat conduction and convection heat transfer.

[0103] The concrete temperature prediction method provided by the present invention can accurately simulate the temperature change law of concrete after pouring by establishing a heat conduction equation, setting boundary conditions and introducing a cooling efficiency factor, and solving the prediction formula in combination with a numerical method. This method can not only help engineers understand in advance the heat distribution generated by the cement hydration reaction inside the concrete, but also effectively control the internal temperature of the concrete through dynamic adjustment of the cooling water pipe, avoiding problems such as cracks caused by excessive temperature differences. In this way, the quality and durability of large-volume concrete structures can be significantly improved, while optimizing the operating efficiency of the cooling system, reducing unnecessary energy consumption, and ensuring the safety and efficiency of the construction process.

[0104] In the preferred embodiment, in step S1, establishing the heat conduction equation specifically includes, first, making the following assumptions on the model: the temperature distribution inside the concrete is uniform, that is, the temperature remains consistent in the same area; the heat of cement hydration is the main heat source inside the concrete, and its release rate changes with time; the cooling water pipe reduces the concrete temperature through convective heat transfer; the ambient temperature has a significant impact on the concrete surface temperature;

[0105] Based on the principle of heat conduction, the heat conduction equation for the temperature distribution inside the concrete is established.

[0106]

[0107] ρ is the density of concrete, which indicates the mass of concrete per unit volume, in kg / m 3 ;

[0108] c represents the specific heat capacity of concrete, which indicates the heat required to raise or lower the temperature of a unit mass of concrete by 1 degree Celsius, in units of kJ / kg.℃;

[0109] T is the temperature of the concrete, the main variable for prediction;

[0110] t is time, because temperature changes with time;

[0111] k is the thermal conductivity of concrete, which indicates the rate of heat transfer inside the concrete, and its unit is kJ / mh℃;

[0112] Q(t) is the heat release rate of cement hydration, that is, the change of heat released by cement during the hardening process over time;

[0113] Through the above equation, the temperature distribution of concrete at different times and locations is obtained.

[0114] By establishing a heat conduction equation and making reasonable assumptions, it is possible to accurately simulate the change of temperature inside concrete over time and space. This method allows engineers to predict the heat distribution inside the concrete due to cement hydration before construction, and how the cooling water pipe affects the temperature of the concrete through heat exchange. This not only helps prevent concrete cracking caused by temperature stress, but also guides construction personnel to optimize the layout and operation of the cooling system to ensure the integrity and safety of large-volume concrete structures. In addition, by accurately controlling the temperature, it is also possible to improve construction efficiency and reduce material waste, thereby achieving effective cost control while ensuring project quality.

[0115] In the preferred embodiment, in step S2, the boundary conditions are set according to the convective heat transfer coefficient of the concrete surface and the ambient temperature to describe the heat exchange between the concrete surface and the environment. The specific formula is as follows:

[0116]

[0117] Where k is the thermal conductivity of concrete, n is the normal direction of the concrete surface, h represents the convective heat transfer coefficient between the concrete surface and the environment, T s Indicates the temperature of the concrete surface, T env is the ambient temperature, represents the heat flux on the concrete surface along the normal direction n, is the temperature gradient along the normal direction, that is, the rate of temperature change. The negative sign indicates that heat flows from the inside of the concrete to the external environment;

[0118] The heat exchange boundary conditions between the inner wall of the cooling water pipe and the concrete are:

[0119]

[0120] Among them, h w represents the convective heat transfer coefficient between the inner wall of the cooling water pipe and the concrete, T w is the cooling water temperature, T c is the temperature of the concrete near the cooling water pipe.

[0121] (h(T s -T env )) represents the heat transfer due to convection heat transfer. Where n is the convection heat transfer coefficient, which describes the rate of heat transfer between the concrete surface and the surrounding environment. T s is the temperature of the concrete surface, (T env ) is the ambient temperature. The form of this expression shows that when the concrete surface temperature is higher than the ambient temperature, heat will flow from the concrete surface to the environment; conversely, when the concrete surface temperature is lower than the ambient temperature, heat will flow from the environment to the concrete surface.

[0122] By setting the above boundary conditions, the heat exchange between concrete and the external environment is taken into account, so as to more accurately predict the temperature distribution inside the concrete. In practical applications, the value of the convective heat transfer coefficient h needs to be measured or estimated according to the specific situation. It is affected by many factors, such as wind speed, roughness of the concrete surface, etc.

[0123] In the preferred embodiment, in step S3, the cooling efficiency factor η(t) is introduced considering the effect of cooling water pipe on reducing the concrete temperature, which specifically includes the following sub-steps: The formula is as follows:

[0124] S31. Design a series of experiments using cooling water pipes with different flow rates and diameters, and ensure that the performance parameters of the concrete remain consistent in all experiments;

[0125] S32. Monitor and record the temperature changes of concrete at different flow rates and pipe diameters;

[0126] S33. Analyze the experimental data and establish the mathematical relationship between the cooling efficiency factor and the cooling water pipe flow rate and pipe diameter:

[0127]

[0128] Here, a is a constant used to adjust the fitting degree of the expression.

[0129] A pipe is the surface area of ​​the cooling water pipe, which can be calculated from the diameter and length of the cooling water pipe; Q is the flow rate of cooling water; ΔT w is the difference between the temperature of cooling water and the initial temperature of concrete; V concrete is the volume of concrete; ρ is the density of concrete; c is the specific heat capacity of concrete; ΔT c is the difference between the initial temperature of the concrete and the ambient temperature; N is an index used to describe the rate at which the cooling efficiency factor changes with time.

[0130] By introducing a cooling efficiency factor and conducting experimental measurements, the effect of cooling water pipes on reducing concrete temperature can be accurately quantified. This process involves designing experiments with different flow rates and pipe diameters, monitoring temperature changes, and analyzing data to establish a mathematical relationship between the cooling efficiency factor and cooling parameters. Doing so enables engineers to optimize the configuration of the cooling system based on actual working conditions, ensuring that the cooling effect is optimal, thereby effectively controlling the temperature of large-volume concrete after pouring, avoiding structural defects caused by temperature stress, and improving construction quality and safety.

[0131] In the preferred solution, the prediction formula is solved, and the temperature distribution is solved by numerical method in combination with the heat conduction equation, boundary conditions and cooling efficiency factor to obtain the concrete temperature prediction formula:

[0132]

[0133] Where T(t) is the temperature of the concrete at time (t); T {initial} is the initial temperature of concrete; Q {total} is the total heat of cement hydration; V concrete is the concrete volume; η(t) is the cooling efficiency factor.

[0134] By combining the heat conduction equation, boundary conditions and cooling efficiency factors, and using numerical methods to solve the temperature distribution, an accurate concrete temperature prediction formula can be obtained. This allows construction personnel to accurately predict the temperature changes of concrete at different time points before construction, so as to better control the temperature gradient inside the concrete and avoid quality problems such as cracks caused by temperature stress. By optimizing the cooling strategy, the integrity and durability of the concrete structure are ensured, while improving construction efficiency and reducing costs. This method provides a scientific basis for large-volume concrete construction and enhances the reliability and economy of engineering projects.

[0135] Embodiment 3:

[0136] Further illustrate with reference to Example 1 and Example 2, Figure 1-10 As shown, the present invention also provides a control method for a large-volume concrete cooling circulation pipe intelligent control system, which is characterized by comprising the following steps:

[0137] Step 1: The network platform 20 imports historical experience data, formulates a cooling plan through any of the above concrete temperature prediction methods, supplies water to the outer ring cooling pipe group 18 and the inner ring cooling pipe group 19 respectively, and collects data from the temperature sensors 10 at various positions;

[0138] Also includes the adjustment steps:

[0139] Step 2: If the predicted temperature rise rate exceeds the preset value, the flow rates of the outer ring cooling tube group 18 and the inner ring cooling tube group 19 are increased simultaneously;

[0140] If the predicted temperature difference between the inner and outer rings exceeds the preset value, the flow rate of the inner ring cooling tube group 19 is increased and the flow rate of the outer ring cooling tube group 18 is reduced;

[0141] If it is predicted that the heating rate of the inner ring cooling tube group 19 exceeds the preset value and the flow rate has reached the maximum value, the cooling device 13 is started to cool the water supply.

[0142] If the predicted heating rate is stable and the temperature difference between the inner and outer rings does not exceed the preset value, the flow rates of the outer ring cooling tube group 18 and the inner ring cooling tube group 19 are gradually reduced to save energy consumption;

[0143] If the flow difference between the outer ring cooling tube group 18 and the inner ring cooling tube group 19 exceeds expectations, the flow of the corresponding cooling tube group is controlled, and an alarm is issued to request manual processing.

[0144] Embodiment 4:

[0145] Further description is given in combination with Example 1, Example 2 and Example 3. Figure 1-10 As shown in . In order to highlight the research problem, the minor factors that affect the hydration heat process of mass concrete are ignored. The assumptions in the analysis are: 1) Mass concrete is an isotropic homogeneous body; 2) The concrete of the same layer is poured into the mold at the same temperature, and it is poured at one time; 3) Solar radiation is not considered; 4) The volume of steel bars and cooling pipes is not considered; 5) The effect of self-weight on temperature stress is ignored.

[0146] In order to facilitate the analysis of the influence of a single thermal parameter factor, the reference values ​​of the parameters required for the numerical analysis of the temperature field are set according to the actual project. When conducting a single factor influence analysis, only that parameter is changed, while other unchanged material and environmental parameters take the reference values ​​as shown in Tables 1 and 2.

[0147] Table 1 Environmental condition parameter reference values

[0148]

[0149] Table 2 Reference values ​​of thermophysical properties of materials

[0150]

[0151]

[0152] The plane size of the model is 36m in diameter and 8.0m in height. It is poured twice along the height (3m+5m). A total of 10 layers of cooling water pipes are arranged. The horizontal spacing of the cooling water pipes is 0.8m and the vertical spacing is 1.0m. According to the symmetry of the structure, 1 / 4 of the pedestal is taken for temperature stress calculation. The calculation takes into account the influence of the cooling water pipes. The maximum temperature envelope diagram inside the finite element is shown in the figure below: Figure 1 shown.

[0153] The calculated flow rate is 0m 3 / h、1.5m 3 / h、2.0m 3 / h and 2.5m 3 / h, the temperature field changes at the center point of the concrete pouring layer, and the results are shown in Table 3.

[0154] It can be seen from Table 3 that the peak temperature of the center point of the first layer of concrete of the foundation reaches 67.8℃ without cooling water pipes. 3 / h, which also reduces the peak temperature to 64.2℃. When the cooling water flow rate is controlled at 2.0m 3 / h and 2.5m 3 / h, the core temperature peaks were reduced to 63.1°C and 61.7°C respectively. At the same time, the core temperature peak time was delayed with the use of cooling water pipes and the increase of cooling water flow rate.

[0155] The maximum flow rate is calculated to be 2.5m 3 / h, verify the change of the temperature difference between the inner and outer surface of the concrete by adjusting the opening of the inner and outer ring flow control valves, such as Figure 2 shown.

[0156] from Figure 2 It can be seen that without adjusting the flow rate of the outer ring of concrete, the temperature difference between the inner and outer surfaces of the concrete is close to 17.5°C. According to the change of the internal temperature of the concrete, the temperature difference between the inner and outer surfaces is reduced to 12.8°C after adjusting the opening of the inner and outer ring flow regulating valves. It can be seen that adjusting the opening of the outer ring flow valve can significantly reduce the temperature difference between the inner and outer surfaces.

[0157] Table 3 Concrete temperature field parameters

[0158]

[0159] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An intelligent control system for large-volume concrete cooling circulation pipes, characterized by: It comprises a network platform (20), wherein the network platform (20) is provided with a controller and a communication device (21); A main pipe (5) is also provided, the main pipe (5) is used to connect to the water inlet device, the main pipe (5) is connected to a plurality of water inlet branch pipes (7), each of the water inlet branch pipes (7) is provided with a flow control valve (8) and a first temperature sensor (10), the controller is used to be electrically connected to a second temperature sensor (23) provided in the mass concrete (17) to receive temperature data in the mass concrete (17), and issue an action instruction to control the flow control valve (8) after the instruction is calculated by the network platform (20); A communication device (21) is also provided for sending and receiving data and instructions in a wireless manner.

2. The intelligent control system for cooling circulation pipes of large volume concrete according to claim 1 is characterized in that: The main pipe (5) is divided into two groups, and the corresponding water inlet branch pipes are divided into two groups. The two groups of water inlet branch pipes (7) are respectively connected to the outer ring cooling pipe group (18) and the inner ring cooling pipe group (19) to control the temperature difference between the inside and outside of the mass concrete (17); An independent outer ring cooling pipe group (18) and an inner ring cooling pipe group (19) are provided in the mass concrete (17); The outer cooling pipe group (18) is close to the surface of the mass concrete (17) that is easy to dissipate heat, and the inner cooling pipe group (19) is far away from the surface of the mass concrete (17) that is easy to dissipate heat; Second temperature sensors (23) are provided on both the outer ring and the inner ring of the mass concrete (17), and the second temperature sensors (23) are electrically connected to the controller in a wireless manner.

3. The intelligent control system for cooling circulation pipes of large-volume concrete according to claim 1 is characterized in that: The main pipes (5) are respectively connected to a water distributor (14), wherein the water distributor (14) for supplying water to the inner ring cooling pipe group (19) is provided with a cooling device (13).

4. The intelligent control system for cooling circulation pipes of large volume concrete according to claim 1 is characterized in that: The return pipes of the inner ring cooling pipe group (19) and the outer ring cooling pipe group (18) are connected to the return water storage tank (16), and the return water storage tank (16) is connected to the main pipe (5) through a water pump (15); The return water storage tank (16) is provided with a filtering device (22), and the pipeline connected to the water pump (15) is located downstream of the filtering device (22). A water level gauge (6) is also provided to maintain the water level in the return water storage tank (16); A third temperature sensor (24) is provided at the connection point between the outer ring cooling pipe group (18) and the inner ring cooling pipe group (19) and the internal concrete pipe and on the return water pipe to detect the return water temperature and evaluate the cooling rate; A flow meter (9) is also provided on the return water pipe to detect the return water loss and determine whether the pipe is broken.

5. A control method using the intelligent control system for mass concrete cooling circulation pipes according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Establish heat conduction equation: According to the density, specific heat capacity, thermal conductivity and cement hydration heat release rate of concrete, establish heat conduction equation to describe the process of heat transfer inside concrete; S2. Setting boundary conditions: according to the convective heat transfer coefficient of the concrete surface and the ambient temperature, set the convective heat transfer boundary conditions to describe the heat exchange between the concrete surface and the environment; S3. Introduce cooling efficiency factor: quantify the cooling effect of cooling water pipe on concrete temperature reduction by experimental measurement or estimation based on engineering experience; S4. Solve the prediction formula: Combine the heat conduction equation, boundary conditions and cooling efficiency factor to derive the prediction formula of concrete temperature. Solve the prediction formula by numerical method to obtain the variation law of concrete temperature over time. The above steps can realize the prediction of concrete temperature based on heat conduction and convection heat transfer.

6. According to claim 5, a control method using a large volume concrete cooling circulation pipe intelligent control system is characterized in that: In step S1, establishing the heat conduction equation specifically includes, first, making the following assumptions on the model: the temperature distribution inside the concrete is uniform, that is, the temperature remains consistent in the same area; the heat of cement hydration is the main heat source inside the concrete, and its release rate changes with time; the cooling water pipe reduces the concrete temperature through convective heat transfer; the ambient temperature has a significant impact on the concrete surface temperature; Based on the principle of heat conduction, the heat conduction equation for the temperature distribution inside the concrete is established. ρ represents the density of concrete, which indicates the mass of concrete per unit volume, in kg / m 3 ; c represents the specific heat capacity of concrete, which indicates the heat required to raise or lower the temperature of a unit mass of concrete by 1 degree Celsius, in units of kJ / kg.℃; T represents the temperature of the concrete, the main variable for prediction; t represents time, because temperature changes with time; k represents the thermal conductivity of concrete, which indicates the rate of heat transfer inside the concrete, and its unit is kJ / mh℃; Q(t) represents the cement hydration heat release rate, that is, the change of heat released by cement during the hardening process with time; Through the above equation, we can get the temperature distribution of concrete at different times and different locations.

7. The control method of the intelligent control system for cooling circulation pipes of large-volume concrete according to claim 5 is characterized in that: In step S2, the boundary conditions are set according to the convective heat transfer coefficient of the concrete surface and the ambient temperature to describe the heat exchange between the concrete surface and the environment. The specific formula is as follows: Where k is the thermal conductivity of concrete, n is the normal direction of the concrete surface, h represents the convective heat transfer coefficient between the concrete surface and the environment, T s Indicates the temperature of the concrete surface, T env is the ambient temperature, represents the heat flux on the concrete surface along the normal direction n, is the temperature gradient along the normal direction, that is, the rate of temperature change. The negative sign indicates that heat flows from the inside of the concrete to the external environment; The heat exchange boundary conditions between the inner wall of the cooling water pipe and the concrete are: Among them, h w represents the convective heat transfer coefficient between the inner wall of the cooling water pipe and the concrete, T w is the cooling water temperature, T c is the temperature of the concrete near the cooling water pipe.

8. The control method of the intelligent control system for cooling circulation pipes of large-volume concrete according to claim 5 is characterized in that: In step S3, the cooling efficiency factor η(t) is introduced considering the effect of cooling water pipe on reducing the temperature of concrete, which specifically includes the following sub-steps: The formula is as follows: S31. Design a series of experiments using cooling water pipes with different flow rates and diameters, and ensure that the performance parameters of the concrete remain consistent in all experiments; S32. Monitor and record the temperature changes of concrete at different flow rates and pipe diameters; S33. Analyze the experimental data and establish the mathematical relationship between the cooling efficiency factor and the cooling water pipe flow rate and pipe diameter: Among them, a is a constant used to adjust the fitting degree of the expression; A pipe is the surface area of ​​the cooling water pipe, which can be calculated from the diameter and length of the cooling water pipe; Q is the flow rate of cooling water; ΔT w is the difference between the temperature of cooling water and the initial temperature of concrete; V concrete is the volume of concrete; ρ is the density of concrete; c is the specific heat capacity of concrete; ΔT c is the difference between the initial temperature of the concrete and the ambient temperature; N is an index used to describe the rate at which the cooling efficiency factor changes with time.

9. The control method of claim 5 using an intelligent control system for cooling circulation pipes of large-volume concrete, characterized in that: In step S4, the prediction formula is solved, and the temperature distribution is solved by numerical method in combination with the heat conduction equation, boundary conditions and cooling efficiency factor to obtain the concrete temperature prediction formula: Where T(t) is the temperature of the concrete at time (t); T {initial} is the initial temperature of concrete; Q {total} is the total heat of cement hydration; V concrete is the concrete volume; η(t) is the cooling efficiency factor.

10. A control method using a large volume concrete cooling circulation pipe intelligent control system according to any one of claims 5 to 9, characterized in that: The following steps are involved: Step 1: The network platform (20) imports historical experience data, formulates a cooling plan by predicting the temperature of the concrete, supplies water to the outer ring cooling pipe group (18) and the inner ring cooling pipe group (19), and collects data from temperature sensors (10) at various positions; Also includes the adjustment steps: Step 2: if the predicted temperature rise rate exceeds the preset value, the flow rates of the outer ring cooling tube group (18) and the inner ring cooling tube group (19) are increased simultaneously; If the predicted temperature difference between the inside and outside exceeds a preset value, the flow rate of the inner ring cooling tube group (19) is increased, and the flow rate of the outer ring cooling tube group (18) is reduced; If it is predicted that the temperature rise rate of the inner ring cooling tube group (19) exceeds a preset value and the flow rate has reached a maximum value, the cooling device (13) is started to cool the water supply. If the predicted heating rate is stable and the temperature difference between the inside and outside does not exceed the preset value, the flow rates of the outer ring cooling tube group (18) and the inner ring cooling tube group (19) are gradually reduced to save energy consumption; If the flow rate difference between the outer ring cooling tube group (18) and the inner ring cooling tube group (19) exceeds expectations, the flow rate of the corresponding cooling tube group is controlled and an alarm is issued to request manual processing.

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