Device with heat exchanger flow resistance diagnosis function and control method thereof

Abstract

The invention belongs to the technical field of valve control, and particularly relates to a device with a heat exchanger flow resistance diagnosis function and a control method thereof. The valve comprises an actuator, a V-shaped ball valve, a first pressure sensor, a second pressure sensor and a first temperature sensor. The method comprises the steps that input data of an actuator are obtained in real time, the instantaneous flow rate and the Reynolds coefficient are calculated, the real-time flow state is obtained according to the Reynolds coefficient, an attenuation model is established through the resistance coefficient and the logarithmic average temperature difference, an alarm threshold value is set, and early warning is conducted on the scaling critical point of the primary side of the heat exchanger in advance. By means of the actuator with the functions of operation data collection, data analysis and scaling early warning, deep fusion of state monitoring of the valve and the heat exchanger is achieved; different from single pressure difference alarm, the influence of flow fluctuation on the pressure difference is eliminated through a resistance coefficient, the accuracy of scaling judgment is improved in combination with the logarithmic temperature difference LMTD, and'flow resistance + heat transfer 'two-dimensional verification is formed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of valve control, and particularly relates to a device with heat exchanger flow resistance diagnosis function and a control method thereof. BACKGROUND

[0002] In an industrial cooling circulating water and chilled water system, a large number of heat exchangers at the end rely on heat exchange between primary refrigerant and secondary process medium to achieve temperature control. To achieve precise temperature control, a temperature control type dynamic balance valve is usually installed on the primary side return water pipeline of the heat exchanger, and the secondary side water supply temperature is monitored in real time to control the primary side flow in the opposite direction, so that the output temperature of the secondary side meets the process set value.

[0003] However, after long-term operation of the heat exchanger, scale, biological sludge or particle deposits inevitably accumulate on the inner wall of the flow passage, significantly reducing the heat transfer efficiency. In this process, to compensate for the heat transfer attenuation, the control system increases the valve opening to increase the primary side flow, which increases the valve opening and masks the performance degradation of the heat exchanger, and increases the primary side pumping energy consumption.

[0004] Currently, there are mainly two lagging methods for heat transfer attenuation. One is to install a differential pressure sensor on the primary supply and return water pipeline, and use the primary side differential pressure alarm method, but it only triggers when the heat exchanger is severely blocked, and cannot capture the early gradual change process of scale formation. The other way is to clean regularly, but this way may cause "excessive cleaning" or "insufficient cleaning", and also cannot dynamically match the real health status of the equipment.

[0005] Chinese invention patent CN111322447A dynamic flow balance and energy control integrated valve control method and valve realizes hydraulic balance control and energy control by integrating pressure / temperature sensor and orifice plate flow measurement, but does not involve heat exchanger flow resistance diagnosis function. SUMMARY

[0006] In view of the problems that the existing technology differential pressure sensor cannot capture early data of scale formation and regular cleaning of scale cannot dynamically match the health status of the equipment, the application discloses a device with heat exchanger flow resistance diagnosis function and a control method thereof.

[0007] A device with heat exchanger flow resistance diagnosis function, comprising a valve and a heat exchanger,

[0008] The valve comprises an actuator, a V-shaped ball valve, a first pressure sensor, a second pressure sensor and a first temperature sensor, the lower end of the actuator is fixedly connected with the upper end wall of the V-shaped ball valve body through a support, and the first pressure sensor and the first temperature sensor are installed at both ends of the V-shaped ball valve.

[0009] The heat exchanger comprises a primary side water supply pipe, a primary side return water pipe, a secondary side water supply pipe, a secondary side return water pipe, a second temperature sensor and a third pressure sensor are installed on the primary side water supply pipe of the heat exchanger, the valve is installed on the primary side return water pipe, a third temperature sensor is installed on the secondary side water supply pipe, and a fourth temperature sensor is installed on the secondary side return water pipe of the heat exchanger, and signals of the first temperature sensor, the second temperature sensor, the third temperature sensor, the fourth temperature sensor, the first pressure sensor, the second pressure sensor and the third pressure sensor are transmitted to the input interface of the actuator through signal lines.

[0010] Optionally, the actuator comprises a controller.

[0011] A control method of a device with a heat exchanger flow resistance diagnosis function, comprising the following steps:

[0012] Real-time input data of the actuator are acquired, instantaneous flow is calculated, and real-time flow rate is calculated according to the input data of the actuator and the instantaneous flow, wherein the input data of the actuator include water temperature value and pressure value;

[0013] According to the real-time water temperature value, corresponding data are matched from a preset water temperature-property table to obtain a Reynolds coefficient, the Reynolds coefficient is compared with a preset threshold value, and a real-time flow state is obtained, wherein the real-time flow state includes laminar flow state, transition flow state and turbulent flow state;

[0014] When the real-time flow state is the turbulent flow state, a resistance coefficient is calculated according to the instantaneous flow of the heat exchanger and the pressure value, and the resistance coefficient at the initial stage of operation is calibrated to obtain a design resistance coefficient;

[0015] A logarithmic mean temperature difference is calculated according to the water temperature value, and the logarithmic mean temperature difference at the initial stage of operation is calibrated to obtain a design logarithmic mean temperature difference;

[0016] An attenuation model is established through the resistance coefficient and the logarithmic mean temperature difference, an alarm threshold value is set, and a critical point of primary side fouling of the heat exchanger is warned in advance.

[0017] As an implementable manner, the input data of the actuator further include valve opening, pre-valve pressure value, post-valve pressure value, water supply temperature value and return water temperature value.

[0018] As an implementable manner, the calculation formula of the instantaneous flow is as follows:

[0019] Wherein, Q represents the instantaneous flow, represents the valve opening, ΔP S represents the pre-valve and post-valve pressure difference, and K, a, b, c, d, e, f, g, h, i and j are dimensionless constants, respectively.

[0020] The calculation formula of the instantaneous energy is:

[0021] W=Q / 3600*C*|T2-T1|

[0022] Wherein, W represents the instantaneous energy, Q represents the instantaneous flow, C represents the specific heat capacity of water, and |T2-T1| represents the water supply and return temperature difference.

[0023] As an implementable manner, the calculation formula of the instantaneous flow rate is:

[0024] v=Q / A

[0025] Wherein, v represents the instantaneous flow rate, Q represents the instantaneous flow, and A represents the corresponding pipe cross-sectional area.

[0026] The calculation formula of the Reynolds coefficient is:

[0027] Re=vDp / μ

[0028] Wherein, Re represents the Reynolds coefficient, v represents the instantaneous flow rate, D represents the inner diameter of the primary side pipe of the heat exchanger, p represents the density, and μ represents the dynamic viscosity.

[0029] As an implementable manner, the comparison of the Reynolds coefficient with the first preset threshold value and the second preset threshold value to obtain the real-time flow state comprises:

[0030] If Re<the first preset threshold value, the real-time flow state is judged to be "laminar flow state";

[0031] If the first preset threshold value<Re<the second preset threshold value, the real-time flow state is judged to be "transitional flow state";

[0032] If Re>the second preset threshold value, the real-time flow state is judged to be "turbulent flow state".

[0033] As an implementable manner, the calculation formula of the resistance coefficient K value is:

[0034] K=ΔP / Q 2

[0035] Wherein, ΔP represents the pressure difference of the primary side supply and return water of the heat exchanger, i.e. ΔP=P1-P2, P1 represents the primary side supply water pressure value of the heat exchanger, P2 represents the secondary side return water pressure value of the heat exchanger, and Q represents the instantaneous flow;

[0036] The design resistance coefficient is obtained by calibrating the resistance coefficient at the initial stage of operation, comprising the following steps:

[0037] When the controller detects that the real-time flow state is "turbulent flow state" at the initial stage of operation after the system installation is completed, the resistance coefficient value is calculated;

[0038] The resistance coefficient in a preset time period is recorded automatically, and the average value of the resistance coefficient is calculated;

[0039] The average value of the resistance coefficient is calibrated as the design resistance coefficient and is recorded.

[0040] As an implementable manner, the logarithmic mean temperature difference is calculated according to the water temperature value, and the design logarithmic mean temperature difference is calibrated according to the logarithmic mean temperature difference in the initial operation period, including the following steps:

[0041] The logarithmic mean temperature difference is calculated according to the water temperature value;

[0042] In the initial operation period after the system installation is completed, the controller automatically records the logarithmic mean temperature difference in a preset time period while calibrating the design resistance coefficient;

[0043] The average value of the logarithmic mean temperature difference is calculated, and the average value of the logarithmic mean temperature difference is calibrated as the design logarithmic mean temperature difference and is recorded.

[0044] The calculation formula of the logarithmic mean temperature difference is:

[0045] LMTD = [(T1-T3)-(T2-T4)] / ln[(T1-T3) / (T2-T4)]

[0046] Wherein, LMTD represents the logarithmic mean temperature difference, T1 represents the temperature value detected by the first temperature sensor, T2 represents the temperature value detected by the second temperature sensor, T3 represents the temperature value detected by the third temperature sensor, and T4 represents the temperature value detected by the fourth temperature sensor.

[0047] As an implementable manner, the decay model is established through the resistance coefficient and the logarithmic mean temperature difference, the alarm threshold is set, and the critical point of the fouling of the primary side of the heat exchanger is warned in advance, including the following steps:

[0048] The controller brings the exponential decay model of the resistance coefficient by storing the historical resistance coefficient and the logarithmic mean temperature difference;

[0049] The critical point of the fouling is predicted, that is, the remaining days are calculated, and the early warning is entered;

[0050] The critical point of the fouling is verified by the logarithmic mean temperature difference;

[0051] The calculation formula of the exponential decay model is:

[0052] K(t) = K s ·e rt

[0053] Wherein, K(t) represents the resistance coefficient calculated by the exponential decay model, Ks represents the design resistance coefficient, t is the running time, and r represents the growth coefficient;

[0054] The calculation formula of the fouling critical point is:

[0055]

[0056] Wherein, Ka represents the alarm threshold, r represents the growth coefficient, and t represents the current time. 临界 The fouling critical point,

[0057] The remaining days calculation formula is:

[0058] Delta t=t 临界 -t 当前

[0059] Wherein, Delta t represents the remaining days, t represents the fouling critical point, and t represents the current time. 临界 represents the fouling critical point, t represents the current time. 当前 represents the current time.

[0060] The present application has remarkable technical effects due to the adoption of the above technical scheme:

[0061] 1. The present application realizes the deep integration of valve and heat exchanger state monitoring through the executor with the functions of operation data acquisition, data analysis and fouling early warning.

[0062] 2. The present application eliminates the influence of flow fluctuation on pressure difference through the resistance coefficient K value, and combines the logarithmic mean temperature difference LMTD to improve the accuracy of fouling judgment and form "flow resistance + heat transfer" two-dimensional verification. BRIEF DESCRIPTION OF DRAWINGS

[0063] The following drawings are examples of the specific embodiments of the present application:

[0064] Figure 1 It is the overall structure diagram of the device with the heat exchanger flow resistance diagnosis function described in the embodiments of the present application.

[0065] Figure 2 It is the input signal interface diagram of the device with the heat exchanger flow resistance diagnosis function described in the embodiments of the present application.

[0066] Figure 3 It is the A view of the device with the heat exchanger flow resistance diagnosis function described in the embodiments of the present application.

[0067] Figure 4 It is the control method flow chart of the device with the heat exchanger flow resistance diagnosis function described in the embodiments of the present application. DETAILED DESCRIPTION

[0068] The application will be further described in connection with the accompanying drawings and examples. The following examples are illustrative of specific embodiments of the application and are not meant to limit the application.

[0069] Example 1

[0070] A device with heat exchanger flow resistance diagnosis function, as shown in Figure 1 and Figure 3 The valve comprises:

[0071] The actuator 5, the V-shaped ball valve 6, the first pressure sensor 7, the second pressure sensor 14 and the first temperature sensor 8, the lower end of the actuator 5 is fixedly connected with the upper end wall of the V-shaped ball valve body 6 through a support, and the first pressure sensor 7 and the first temperature sensor 8 are installed at both ends of the V-shaped ball valve 6.

[0072] The heat exchanger 9 is connected with the primary side water supply pipe 1, the primary side water return pipe 2, the secondary side water supply pipe 3 and the secondary side water return pipe 4 in sequence, the first temperature sensor 10 and the third pressure sensor 11 are installed on the primary side water supply pipe, the valve is installed on the primary side water return pipe, the third temperature sensor 12 is installed on the secondary side water supply pipe, and the fourth temperature sensor 13 is installed on the secondary side water return pipe of the heat exchanger, the signals of the first temperature sensor 8, the second temperature sensor 10, the third temperature sensor 12, the fourth temperature sensor 13, the first pressure sensor 7 and the second pressure sensor 11 are transmitted to the input interface of the actuator through signal lines, and the actuator comprises a controller.

[0073] The fifth temperature sensor 15 of the V-shaped ball valve body 6 is connected to the existing PT1000 platinum resistance input interface PT1 for collecting PT1000 signals, the first pressure sensor 7 before the valve is connected to the analog input interface AI2, the second pressure sensor 14 after the valve is connected to the existing analog input interface AI3, the analog input interface collects DC4-20mA signals, the first temperature sensor 10, the third temperature sensor 12 and the fourth temperature sensor 13 of the primary side of the heat exchanger are also connected to the existing PT1000 platinum resistance input interfaces PT2-PT4 for collecting PT1000 signals, and the third pressure sensor 11 of the primary side of the heat exchanger is connected to the existing input universal port AI1, which can select one of DC4-20mA, 0-20mA, 0-10V, 2-10V and PT1000 signals as an input signal, and the current input universal port adopts input analog DC4-20mA signals. The corresponding connection mode is shown in Figure 2 and Figure 3

[0074] Example 2

[0075] ​A control method for a device with heat exchanger flow resistance diagnosis function of claim 1, as shown in the figure, comprising the following steps: Figure 4

[0076] S100, real-time acquisition of input data of the actuator, calculation of instantaneous flow rate, and calculation of real-time flow rate according to the input data of the actuator and the instantaneous flow rate, the input data of the actuator including water temperature value and pressure value;

[0077] S200, according to the real-time water temperature value, matching the corresponding data from the preset water temperature-property table to obtain the Reynolds coefficient, comparing the Reynolds coefficient with the preset threshold value to obtain the real-time flow state, and the real-time flow state including laminar flow state, transition flow state and turbulent flow state;

[0078] S300, when the real-time flow state is "turbulent flow state", calculating the resistance coefficient according to the instantaneous flow rate and pressure value of the heat exchanger, and calibrating the resistance coefficient at the initial stage of operation to obtain the design resistance coefficient;

[0079] S400, calculating the logarithmic mean temperature difference according to the water temperature value, and calibrating the logarithmic mean temperature difference at the initial stage of operation to obtain the design logarithmic mean temperature difference;

[0080] S500, establishing an attenuation model through the resistance coefficient and the logarithmic mean temperature difference, setting an alarm threshold and giving an early warning for the critical point of primary side fouling of the heat exchanger.

[0081] In this embodiment, the input data of the actuator further includes valve opening, pre-valve pressure value, post-valve pressure value, water supply temperature value and return water temperature value.

[0082] In this embodiment, the real-time acquisition of input data of the actuator, calculation of instantaneous flow rate, and calculation of real-time flow rate according to the input data of the actuator and the instantaneous flow rate in step S100 specifically includes the following steps:

[0083] S110: real-time acquisition of input data of the actuator, calculation of instantaneous flow rate;

[0084] S120: calculation of real-time flow rate according to the input data of the actuator and the instantaneous flow rate.

[0085] The calculation formula of the instantaneous flow rate is:

[0086]

[0087] Wherein, Q represents the instantaneous flow rate, represents the valve opening, ΔP S represents the pressure difference before and after the valve, K, a, b, c, d, e, f, g, h, i, j are dimensionless constants respectively;

[0088] ​The calculation formula of the instantaneous energy is:

[0089] W=Q / 3600*C*|T2-T1|

[0090] Wherein, W represents the instantaneous energy, Q represents the instantaneous flow, C represents the specific heat capacity of water, and |T2-T1| represents the water supply and return temperature difference. The instantaneous energy is used for valve display, which refers to the energy provided by the primary side of the heat exchanger / theoretically maximum energy that can be obtained by the secondary side.

[0091] The calculation formula of the instantaneous flow rate is:

[0092] v=Q / A

[0093] Wherein, v represents the instantaneous flow rate, Q represents the instantaneous flow, and A represents the corresponding pipe cross-sectional area.

[0094] In the embodiment, the controller is used to select the pipe diameter D of the valve. Generally, the marked diameter on the V-type ball valve is selected. If the diameter is observed before and after the valve, the marked diameter on the V-type ball valve is enlarged by 1 gear. After selecting the corresponding diameter D, the heat exchanger primary side pipe diameter is DN200, then D=0.2m, A=πD 2 / 4=0.031416m 2 , and if the instantaneous flow Q provided by the current valve is 150m 3 / h, then the corresponding instantaneous flow rate v=Q / A=150 / 3600 / 0.031416=1.326m / s.

[0095] In the embodiment, in step S200, the real-time water temperature value is used to match the corresponding data from the preset water temperature-property table to obtain the Reynolds coefficient. The Reynolds coefficient is compared with the preset threshold value to obtain the real-time flow state, including:

[0096] The calculation formula of the Reynolds coefficient is:

[0097] Re=vDρ / μ

[0098] Wherein, Re represents the Reynolds coefficient, v represents the instantaneous flow rate, D represents the heat exchanger primary side pipe diameter, ρ represents the density, and μ represents the dynamic viscosity.

[0099] In the embodiment, the current valve detects that the water temperature is 35℃, and the current property parameters are obtained by interpolation from Table 1. The density ρ is 994.1kg / m 3 , and the dynamic viscosity μ is 0.723*10 -3 Pa·s.

[0100] Table 1

[0101] Water temperature t (°C) Density p (kg / m3) 3 ​ Dynamic viscosity μ (10 -3 Pa-s) 0 999.9 1.792 5 1000 1.519 10 999.7 1.308 15 999.1 1.14 20 998.2 1.005 25 997.1 0.894 30 995.7 0.801 35 994.1 0.723 40 992.2 0.656 45 990.2 0.599 50 988.1 0.549 60 983.2 0.469 70 977.8 0.406 80 971.8 0.357 90 965.3 0.318 100 958.4 0.284

[0102] The comparison of the Reynolds coefficient with the first preset threshold value and the second preset threshold value obtains a real-time flow state. In the embodiment, the first preset threshold value is 2000, and the second preset threshold value is 4000. Then:

[0103] If Re < 2000, the real-time flow state is determined to be a "laminar flow state";

[0104] If 2000 < Re < 4000, the real-time flow state is determined to be a "transitional flow state";

[0105] If Re > 4000, the real-time flow state is determined to be a "turbulent flow state".

[0106] In the embodiment, when the real-time flow state is a "turbulent flow state" in step S300, the resistance coefficient is calculated according to the instantaneous flow and pressure value of the heat exchanger, and the design resistance coefficient is calibrated according to the resistance coefficient at the initial stage of operation, including:

[0107] The resistance coefficient K value calculation formula is:

[0108] K = ΔP / Q 2

[0109] Wherein, ΔP represents the water supply and return pressure difference of the primary side of the heat exchanger, that is, ΔP = P1-P2, P1 represents the water supply pressure value of the primary side of the heat exchanger, P2 represents the return water pressure value of the secondary side of the heat exchanger, and Q represents the instantaneous flow.

[0110] The design resistance coefficient is calibrated according to the resistance coefficient at the initial stage of operation, including the following steps:

[0111] When the real-time flow state is "turbulent flow state" detected by the controller at the initial stage of operation after the system installation is completed, the resistance coefficient value is calculated;

[0112] The resistance coefficient in a preset time period is automatically recorded, and the average value of the resistance coefficient is calculated;

[0113] The average value of the resistance coefficient is calibrated as the design resistance coefficient for entry.

[0114] In the embodiment, the logarithmic mean temperature difference is calculated according to the water temperature value in step S400, and the design logarithmic mean temperature difference is calibrated according to the logarithmic mean temperature difference at the initial stage of operation, including the following steps:

[0115] S410: Calculate the logarithmic mean temperature difference according to the water temperature value;

[0116] S420: At the initial stage of operation after the system installation is completed, the controller automatically records the logarithmic mean temperature difference in a preset time period while calibrating the design resistance coefficient;

[0117] S430: Calculate the average of the logarithmic mean temperature difference, and calibrate the average of the logarithmic mean temperature difference as the design logarithmic mean temperature difference for entry;

[0118] The calculation formula of the logarithmic mean temperature difference is:

[0119] LMTD = [(T1-T3)-(T2-T4)] / ln[(T1-T3) / (T2-T4)]

[0120] Wherein, LMTD (Logarithmic Mean Temperature Difference, Logarithmic Mean Temperature Difference) represents the logarithmic mean temperature difference, T1 represents the temperature value detected by the first temperature sensor, T2 represents the temperature value detected by the second temperature sensor, T3 represents the temperature value detected by the third temperature sensor, and T4 represents the temperature value detected by the fourth temperature sensor.

[0121] In this embodiment, the step S500 of establishing the attenuation model by the resistance coefficient and the logarithmic mean temperature difference, setting the alarm threshold and early warning of the fouling critical point of the primary side of the heat exchanger comprises the following steps:

[0122] S510: The controller brings the exponential attenuation model of the resistance coefficient by storing the historical resistance coefficient and the logarithmic mean temperature difference;

[0123] S520: Predict the fouling critical point, that is, calculate the remaining days, and enter the early warning in advance;

[0124] S530: Assist in verifying the fouling critical point by the logarithmic mean temperature difference;

[0125] The calculation formula of the exponential attenuation model is:

[0126] K(t) = K s ·e rt

[0127] Wherein, K(t) represents the resistance coefficient calculated by the exponential attenuation model, Ks represents the design resistance coefficient, t is the running time, and r represents the growth coefficient;

[0128] The growth coefficient is obtained by linear least squares fitting according to the actual calculation of the resistance coefficient K value, and r is refitted every 7 days to ensure that the current attenuation model adapts to the change of the fouling rate.

[0129] The calculation formula of the fouling critical point is:

[0130]

[0131] Wherein, Ka represents the alarm threshold, r represents the growth coefficient, and t represents the time. 临界Critical fouling point,

[0132] The remaining days calculation formula is:

[0133] Delta t=t 临界 -t 当前

[0134] Wherein, Delta t represents the remaining days, t 临界 represents the critical fouling point, t 当前 represents the current time.

[0135] LMTD auxiliary verification: when the resistance coefficient K reaches the alarm threshold Ka, it indicates that there is fouling in the heat exchanger at this time, that is, partial blockage.If the current LMTD value is less than the design LMTD value, it is confirmed that the current critical fouling point is effective, otherwise the "model exception" prompt is triggered.

[0136] The depth fusion of valve and heat exchanger state monitoring is realized by the executor with the functions of operation data acquisition, data analysis and fouling early warning; by distinguishing from single differential pressure alarm and regular cleaning, the influence of flow fluctuation on differential pressure is eliminated by the resistance coefficient K value, combined with the logarithmic temperature difference LMTD, the accuracy of fouling judgment can be improved, and the "flow resistance + heat transfer" two-dimensional verification is formed.

[0137] The present application is described with reference to flowcharts and / or block diagrams in accordance with the method, terminal device (system) and computer program product of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of the flows and / or blocks in the flowchart and / or block diagram can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device realize the functions specified in the flow Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The functions specified in one or more flows and / or blocks.

[0138] These computer program instructions can also be stored in a computer readable storage medium which can guide the computer or other programmable data processing terminal device to work in a specific way, so that the instructions stored in the computer readable storage medium generate a product including instruction devices, which realize the functions specified in the flow Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The functions specified in one or more flows and / or blocks.

[0139] These computer program instructions can also be loaded into a computer or other programmable data processing terminal device, so that a series of operational steps are performed on the computer or other programmable terminal device to generate a computer-implemented process, so that the instructions executed on the computer or other programmable terminal device provide steps for implementing the function specified in the flowchart Figure 1 one flow or multiple flows and / or the function specified in the block Figure 1 one flow or multiple flows and / or the function specified in the block

[0140] It should be noted that:

[0141] The phrase "one embodiment" or "an embodiment" as used throughout this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Therefore, the appearances of the phrase "one embodiment" or "an embodiment" throughout the specification are not necessarily all referring to the same embodiment.

[0142] Furthermore, it should be noted that the specific embodiments described in this specification and the shapes of the parts thereof, the names thereof, etc. can be different. Any equivalent or simple change made to the configuration, features, and principles described in the patent concept of the present application is included in the scope of the present application. Those skilled in the art can make various modifications or supplements to the specific embodiments described or replace them with similar means, as long as they do not deviate from the structure of the present application or exceed the scope defined by the claims.

Claims

1. A device with heat exchanger flow resistance diagnostic function, comprising a valve and a heat exchanger, characterized in that, The valve includes an actuator, a V-type ball valve, a first pressure sensor, a second pressure sensor, and a first temperature sensor. The lower end of the actuator is fixedly connected to the upper wall of the V-type ball valve body via a bracket. The first pressure sensor and the first temperature sensor are installed at both ends of the V-type ball valve. The heat exchanger includes a primary side water supply pipe, a primary side water return pipe, a secondary side water supply pipe, and a secondary side water return pipe. A second temperature sensor and a third pressure sensor are installed on the primary side water supply pipe of the heat exchanger. The valve is installed on the primary side water return pipe. A third temperature sensor is installed on the secondary side water supply pipe. A fourth temperature sensor is installed on the secondary side water return pipe of the heat exchanger. The signals from the first, second, third, and fourth temperature sensors, as well as the first, second, and third pressure sensors, are all transmitted to the input interface of the actuator via signal lines.

2. The device with heat exchanger flow resistance diagnosis function according to claim 1, characterized in that, The actuator includes a controller.

3. A control method for a device having a heat exchanger flow resistance diagnostic function as described in claim 1, characterized in that, Includes the following steps: The system acquires the actuator's input data in real time, calculates the instantaneous flow rate, and calculates the real-time flow velocity based on the actuator's input data and the instantaneous flow rate. The actuator's input data includes water temperature and pressure values. Based on the real-time water temperature value, the corresponding data is matched from the preset water temperature-physical property table to obtain the Reynolds coefficient. The Reynolds coefficient is compared with the first preset threshold and the second preset threshold to obtain the real-time flow state, which includes laminar flow state, transitional flow state and turbulent flow state. When the real-time flow state is "turbulent state", the resistance coefficient is calculated based on the instantaneous flow rate and pressure value of the heat exchanger, and the resistance coefficient at the initial stage of operation is calibrated to obtain the design resistance coefficient. The logarithmic mean temperature difference is calculated based on the water temperature value, and the design logarithmic mean temperature difference is obtained by calibrating based on the logarithmic mean temperature difference during the initial stage of operation. A degradation model is established using the resistance coefficient and logarithmic mean temperature difference. An alarm threshold is set, and an early warning is given for the critical point of fouling on the primary side of the heat exchanger.

4. The control method of the device with heat exchanger flow resistance diagnosis function according to claim 3, characterized in that, The actuator input data also includes valve opening, upstream pressure, downstream pressure, supply water temperature, and return water temperature.

5. The control method of the device with heat exchanger flow resistance diagnosis function according to claim 4, characterized in that, The formula for calculating the instantaneous flow rate is: Where Q represents instantaneous flow rate, Indicates the valve opening degree, ΔP S This represents the pressure difference before and after the valve, where K, a, b, c, d, e, f, g, h, i, and j are dimensionless constants. The formula for calculating instantaneous energy is: W = Q / 3600 * C * |T2 - T1| Where W represents instantaneous energy, Q represents instantaneous flow rate, C represents the specific heat capacity of water, and |T2-T1| represents the temperature difference between the supply and return water.

6. The control method of the device with heat exchanger flow resistance diagnosis function according to claim 5, characterized in that, The formula for calculating the instantaneous flow velocity is: v = Q / A Where v represents the instantaneous flow velocity, Q represents the instantaneous flow rate, and A represents the corresponding pipe cross-sectional area; The formula for calculating the Reynolds coefficient is as follows: Re = vDρ / μ Where Re represents the Reynolds coefficient, v represents the instantaneous flow velocity, D represents the inner diameter of the primary side pipe of the heat exchanger, ρ represents the density, and μ represents the dynamic viscosity.

7. The control method of the device with heat exchanger flow resistance diagnosis function according to claim 6, characterized in that, The step of comparing the Reynolds coefficient with a first preset threshold and a second preset threshold to obtain the real-time flow state includes: If Re < the first preset threshold, then the real-time flow state is determined to be "laminar flow state"; If the first preset threshold < Re < the second preset threshold, then the real-time flow state is determined to be "transitional flow state"; If Re > the second preset threshold, then the real-time flow state is determined to be "turbulent state".

8. The control method of the device with heat exchanger flow resistance diagnosis function according to claim 4, characterized in that, The formula for calculating the drag coefficient K is as follows: K=ΔP / Q 2 Wherein, ΔP represents the pressure difference between the primary and return water on the heat exchanger, i.e., ΔP=P1-P2, where P1 represents the primary water supply pressure of the heat exchanger, P2 represents the secondary water return pressure of the heat exchanger, and Q represents the instantaneous flow rate. The calibration of the resistance coefficient during the initial stage of operation to obtain the design resistance coefficient includes the following steps: In the initial stage of operation after the system is installed, the controller calculates the resistance coefficient value based on the detected real-time flow state as "turbulent state". Automatically record the resistance coefficient within a preset time period and calculate the average resistance coefficient; The average value of the drag coefficient is calibrated and entered as the design drag coefficient.

9. The control method of the device with heat exchanger flow resistance diagnosis function according to claim 8, characterized in that, The process of calculating the logarithmic mean temperature difference based on the water temperature value and calibrating it based on the logarithmic mean temperature difference during the initial stage of operation to obtain the design logarithmic mean temperature difference includes the following steps: Calculate the logarithmic mean temperature difference based on the water temperature value; During the initial operation of the system after installation, the controller automatically records the logarithmic average temperature difference over a preset time period while calibrating the design resistance coefficient. The average value of the logarithmic mean temperature difference is calculated, and the average value of the logarithmic mean temperature difference is calibrated and entered as the design logarithmic mean temperature difference. The formula for calculating the logarithmic mean temperature difference is: LMTD=[(T1-T3)-(T2-T4)] / ln[(T1-T3) / (T2-T4)] Wherein, LMTD represents the logarithmic mean temperature difference, T1 represents the temperature value detected by the first temperature sensor, T2 represents the temperature value detected by the second temperature sensor, T3 represents the temperature value detected by the third temperature sensor, and T4 represents the temperature value detected by the fourth temperature sensor.

10. The control method of the device with heat exchanger flow resistance diagnosis function according to claim 9, characterized in that, The process of establishing a degradation model using the resistance coefficient and logarithmic mean temperature difference, setting an alarm threshold, and providing early warning of the critical point of fouling on the primary side of the heat exchanger includes the following steps: The controller stores historical drag coefficients and logarithmic mean temperature differences, and then inputs them into an exponential decay model of the drag coefficient. Predict the scaling critical point, i.e. calculate the remaining days, and issue an early warning in advance; The scaling critical point was further verified by using the logarithmic mean temperature difference. The calculation formula for the exponential decay model is as follows: K(t))=K s ·e rt Where K(t) represents the drag coefficient calculated by the exponential decay model, Ks represents the design drag coefficient, t is the running time, and r represents the growth coefficient; The formula for calculating the scaling critical point is: Where Ka represents the alarm threshold, r represents the growth coefficient, and t represents the alarm threshold. 临界 Indicates the critical point of scaling. The formula for calculating the remaining days is: Δt=t 临界 -t 当前 Where Δt represents the number of days remaining, t 临界 Indicates the scaling critical point, t 当前 Indicates the current time.

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