A rotary air preheater heat transfer performance detection device and a use method thereof

Abstract

The application relates to the technical field of preheater detection, and discloses a rotary air preheater heat exchange performance detection device and a use method, which comprises a preheater shell, a temperature detection module is arranged on the preheater shell, the temperature detection module comprises temperature sensors arranged in an annular mode along an axial sealing downstream area of the rotary air preheater and used for collecting local temperature data of a flue gas side, the temperature detection module is connected with a sensor rotating module, the sensor rotating module is used for driving the annularly arranged temperature sensors to rotate around a preheater central shaft, and the preheater central shaft arranged in the preheater shell divides an internal space into the flue gas side and an air side. The rotary air preheater heat exchange performance detection device and method realize full-circumferential coverage monitoring of an axial sealing downstream area with high air leakage, the design that sensors alternately contact the flue gas side and the air side is combined, measurement drift caused by continuous high temperature is eliminated by using air natural cooling, and the precision of local temperature detection is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of preheater testing technology, and in particular to a device for testing the heat exchange performance of a rotary air preheater and its usage method. Background Technology

[0002] Rotary air preheaters are key equipment in boiler systems of thermal power plants for recovering waste heat from flue gas and improving combustion efficiency. They utilize a rotor to drive heat storage elements that alternately contact high-temperature flue gas and low-temperature air, achieving heat transfer from flue gas to air. This significantly reduces exhaust gas temperature and increases supply air temperature, thereby reducing fuel consumption. To ensure stable heat exchange performance, core indicators such as air leakage rate and heat transfer efficiency must be monitored during operation. Current technologies often employ oxygen content analysis or flow difference methods for air leakage detection, while temperature detection typically uses fixed sensors to collect the overall temperature of the flue gas or air, combined with heat transfer formulas to assess heat exchange efficiency. These methods, through the integration of data acquisition, processing, and analysis modules, form a relatively mature detection system, which is widely used in the performance monitoring of small and medium-sized rotary air preheaters.

[0003] However, when dealing with large-diameter rotary air preheaters, such as those arranged in a single row at 21.9m, existing detection technologies struggle to cover the entire circumference of high-leakage areas like axial seals due to the fixed arrangement of temperature sensors. This can easily lead to misjudgments because some leaks are missed. Furthermore, the impact of leaks on the local temperature field exhibits significant spatial variability, and existing methods often rely on overall parameters, making it difficult to accurately locate leak areas and analyze their causes. In addition, traditional detection methods do not consider the impact of flue gas velocity changes on leakage characteristics. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing technology cannot verify the correlation between air leakage and pressure difference through operating condition adjustment. To this end, we propose a rotary air preheater heat exchange performance testing device and its usage method.

[0005] To achieve the above objectives, this application adopts the following technical solution: a rotary air preheater heat exchange performance testing device, including a preheater shell, a temperature detection module is provided on the preheater shell, the temperature detection module includes a temperature sensor arranged in a ring along the axial sealed downstream region of the rotary air preheater, used to collect local temperature data on the flue gas side, the temperature detection module is connected to a sensor rotation module, used to drive the ring-arranged temperature sensor to rotate around the central axis of the preheater, the central axis of the preheater provided inside the preheater shell divides the internal space into a flue gas side and an air side, so that each temperature sensor alternately contacts the flue gas side and the air side;

[0006] The sensor rotation module is electrically connected to the positioning module and is used to obtain the rotation angle and current area of ​​the temperature sensor in real time. The preheater shell is provided with a flue gas inlet and a flue gas side, as well as an air inlet and an air side. The flue gas inlet pipe is provided with a flue gas flow rate adjustment module to adjust the flue gas flow rate entering the preheater to a preset value. The flue gas inlet pipe is provided with a flow rate detection module to detect and feedback the current flue gas flow rate in real time.

[0007] The temperature detection module, positioning module, and flow rate detection module are electrically connected to a data processing module, which receives temperature data, sensor position data, and flow rate data, and generates a temperature change chart. The data processing module is electrically connected to a leakage detection module, which determines the leakage status based on the temperature data and flow rate data. It identifies temperature anomalies in a single set of temperature sensors through initial detection, confirms the anomaly by rotating the temperature sensors to determine leakage, and analyzes the cause of leakage by combining the temperature change differences under high and low flow rates.

[0008] Preferably, in the temperature detection module, there are 16 temperature sensors arranged in a ring, and the circumferential angle between adjacent temperature sensors is equal; each temperature sensor is covered with a high-temperature resistant and corrosion-resistant protective sleeve, the protective sleeve is made of ceramic, and the probe end of the temperature sensor extends out of the sleeve to directly contact the flue gas flow.

[0009] Preferably, the rotation angle fed back by the positioning module in real time ensures that the temperature sensor completes the switch from the flue gas side to the air side exactly every 180° rotation; the positioning module includes 8 positioning marks evenly arranged along the rotation path and a photoelectric sensor that works in conjunction with them, used to control the detection accuracy of the rotation angle within ±1°.

[0010] Preferably, in the air leakage judgment module, the air leakage cause analysis logic includes: if the abnormal temperature amplitude at high flow rate is lower than that at normal flow rate, and the abnormal temperature amplitude at low flow rate is higher than that at normal flow rate, then it is determined that the air leakage is mainly caused by excessive sealing gap.

[0011] A method for using a rotary air preheater heat exchange performance testing device includes the following steps:

[0012] S1: Initialization, start the temperature detection module, so that the ring-shaped temperature sensor rotates around the central axis of the preheater at a preset speed under the drive of the sensor rotation drive module. The positioning module records the sensor position synchronously, and the data processing module establishes the reference temperature distribution curve under normal working conditions through Formula 1.

[0013] Formula 1: ,in Circumferential angle The reference temperature at that location Number of rotation cycles for continuous acquisition , For the first Angle within a cycle Temperature readings at the location;

[0014] S2: Initial test, flue gas temperature in the downstream area of ​​the axial seal is collected by a temperature sensor. When Formula 2 is satisfied, it is judged as a suspected air leak;

[0015] Formula 2: ,in, The preset temperature anomaly threshold, For the detection time;

[0016] S3: Recheck and confirm. Driven by the sensor rotation drive module, the temperature sensor rotates one revolution. The positioning module synchronously records the detection area of ​​each sensor. The air leakage judgment module uses Formula 3 to calculate the proportion of abnormal temperature sensors.

[0017] Formula 3: ,in This represents the number of sensors exhibiting abnormal temperatures. For the total number of sensors, if Furthermore, the overlap of abnormal regions detected by the two rotations is high. This confirms the presence of an air leak. This is the preset minimum abnormality percentage threshold. The preset minimum overlap threshold, It is the ratio of the number of overlapping regions to the total number of abnormal regions.

[0018] S4: High and low flow rate verification:

[0019] During the high-flow-rate stage, the flue gas velocity is adjusted to [a certain value] via the flue gas velocity regulation module. The flow rate detection module confirmed. Then, the temperature sensor is driven to rotate one more revolution, collecting and recording temperature data at high flow rates. ,in It is a high flow rate multiple factor. Normal flow rate This refers to the allowable fluctuation value of the flow rate;

[0020] During the low-flow-rate stage, the flue gas flow rate is adjusted to [a certain value] via the flue gas flow rate regulation module. The flow rate detection module confirmed. Then, the temperature sensor is driven to rotate one more revolution, collecting and recording temperature data at low flow rates. ,in For low flow rate multiples, , This refers to the allowable fluctuation value of the flow rate;

[0021] S5: Result Judgment. The air leakage judgment module analyzes and compares air leakage characteristics, using the following formula:

[0022] Locating the area of ​​air leakage: ;

[0023] Quantification of air leakage intensity: ;

[0024] Analysis of the causes of air leakage, through comparison and , and The differences, among which This represents the average temperature drop at high flow rates. The average temperature drop at low speed is output as the heat transfer performance test result.

[0025] Preferably, the calculation of the reference temperature distribution curve satisfies , The number of sensor rotation cycles for continuous data acquisition is defined as the time it takes for the temperature sensor to complete one full rotation around the central axis of the preheater. Based on the preheater design flue gas temperature fluctuation range, historical normal operating temperature deviation data, and temperature thresholds set according to relevant industry testing standards, only when the first... Any circular angle within a period Temperature readings at the location satisfy Only then can the periodic data be included in the calculation range of the reference temperature distribution curve to eliminate the influence of abnormal data such as instantaneous airflow fluctuations and occasional sensor interference on the stability of the reference curve; the complete formula for calculating the reference temperature distribution curve is as follows:

[0026] ,in Circumferential angle The reference temperature at that location , For the first circumferential angle within one effective rotation cycle Temperature readings at the location.

[0027] Preferably, the condition for determining suspected air leakage is that the temperature detected by any temperature sensor is lower than the benchmark threshold for three consecutive sampling cycles.

[0028] Preferably, the .

[0029] Preferably, the And the high flow rate is stable for a long time. ,in The preset minimum settling time, .

[0030] Preferably, the , ;

[0031] Air leakage strength passed Grading: When There was a slight air leak at the time. At that time, the air leakage was moderate. It was severely leaking air at the time. and The preset grading threshold, and .

[0032] The technical effects and advantages of this invention are as follows:

[0033] This invention achieves full-circumferential coverage monitoring of high-risk areas for air leakage downstream of the axial seal through a ring-shaped, rotatable temperature sensor. The design, which alternates sensor contact with the flue gas and air sides, utilizes natural air cooling to eliminate measurement drift caused by sustained high temperatures, significantly improving the accuracy of local temperature detection. A dual verification logic of initial detection and rotational re-checking, combined with quantitative judgment of the proportion of abnormal sensors and regional overlap, effectively reduces the risk of misjudgment caused by single sensor failure or environmental interference, ensuring the reliability of leakage detection. An innovative high- and low-flow-rate adjustment verification step is introduced. By comparing the differences in temperature anomaly amplitude under different flow rates, the cause of leakage can be accurately distinguished, and the leakage intensity can be graded and quantified by combining the average temperature drop, providing direct and specific guidance for sealing system optimization. The overall solution is particularly suitable for large-diameter, single-row rotary air preheaters, breaking through the coverage limitations of traditional fixed monitoring methods, significantly improving the efficiency and depth of heat exchange performance detection, and has significant practical value for improving the economic efficiency and safety of boiler operation. Attached Figure Description

[0034] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts:

[0035] Figure 1 This is a schematic diagram of the preheater shell of the present invention;

[0036] Figure 2 This is a front view structural diagram of the flue gas inlet of the present invention;

[0037] Figure 3 This is a top view of the flue gas side and air side of the present invention.

[0038] Legend: 1. Preheater shell; 2. Flue gas inlet; 3. Flue gas side; 4. Air inlet; 5. Air side; 6. Temperature sensor. Detailed Implementation

[0039] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0040] Reference Figures 1-3 As shown, the present invention provides a technical solution: a device for testing the heat exchange performance of a rotary air preheater, including a preheater shell 1, a temperature detection module on the preheater shell 1, the temperature detection module including temperature sensors 6 arranged in a ring along the axial sealing downstream region of the rotary air preheater, the number of temperature sensors 6 arranged in the ring in the temperature detection module is 16, and the circumferential included angle between adjacent temperature sensors 6 is equal; each temperature sensor 6 is covered with a high temperature resistant and corrosion-resistant protective sleeve, the protective sleeve is made of ceramic, the probe end of the temperature sensor 6 extends out of the sleeve to directly contact the flue gas flow, and is used to collect local temperature data on the flue gas side; the temperature detection module is connected to a sensor rotation module, which is used to drive the ring-arranged temperature sensors to rotate around the central axis of the preheater; the central axis of the preheater set inside the preheater shell 1 divides the internal space into a flue gas side 3 and an air side 5, so that each temperature sensor alternately contacts the flue gas side 3 and the air side 5;

[0041] It achieves full circumferential coverage of the downstream area of ​​the axial seal without dead angles, solving the problem of missed detection of local air leakage points due to the limited monitoring range of traditional fixed sensors; the ceramic protective sleeve is resistant to high temperature and corrosion, and the probe end directly contacts the flue gas, avoiding the sleeve's obstruction of temperature conduction and ensuring the authenticity of the collected data; the temperature sensor's 6-rotation design allows one corner to alternately contact the flue gas side and the air side, and the low-temperature airflow on the air side can quickly remove the sensor's residual heat, eliminating measurement drift caused by continuous high temperature, solving the problem of accuracy decay of traditional sensors under long-term high temperature environment, and significantly improving the stability and repeatability of temperature detection.

[0042] The sensor rotation module is electrically connected to the positioning module. The rotation angle fed back by the positioning module in real time ensures that the temperature sensor 6 completes the switch from the flue gas side 3 to the air side 5 exactly every time it rotates 180°. The positioning module includes 8 positioning marks evenly arranged along the rotation path and photoelectric sensors that work with them. It is used to control the detection accuracy of the rotation angle within ±1° and to obtain the rotation angle and current location of the temperature sensor 6 in real time. The interior of the preheater shell 1 is provided with flue gas inlet 2 and flue gas side 3, as well as air inlet 4 and air side 5. The inlet pipe of flue gas inlet 2 is provided with a flue gas flow rate adjustment module to adjust the flue gas flow rate entering the preheater to a preset value. The inlet pipe of flue gas inlet 2 is provided with a flow rate detection module to detect and feed back the current flue gas flow rate in real time.

[0043] The temperature detection module, positioning module, and flow rate detection module are electrically connected to a data processing module, which receives temperature data, sensor position data, and flow rate data, and generates a temperature change chart. The data processing module is also electrically connected to a leakage detection module, which determines the leakage status based on the temperature and flow rate data. The leakage detection module's leakage cause analysis logic includes: if the abnormal temperature amplitude at high flow rate is lower than the normal flow rate, and the abnormal temperature amplitude at low flow rate is higher than the normal flow rate, then the leakage is determined to be mainly caused by excessive sealing gap. The module identifies temperature anomalies in a single set of temperature sensors 6 through initial detection, confirms the anomaly by rotating temperature sensor 6 to determine leakage, and analyzes the cause of leakage by combining the temperature change differences at high and low flow rates.

[0044] The data processing module integrates multi-dimensional data and generates visual charts to intuitively present the correlation between temperature distribution and leakage areas, solving the problems of scattered traditional detection data and difficulty in quickly locating leakage locations. Through dual verification of the proportion of abnormal sensors (e.g., ≥60%) and regional overlap (e.g., ≥70%), the risk of misjudgment caused by a single set of temperature sensors or local dust accumulation is significantly reduced, improving the reliability of leakage judgment. Secondly, the introduction of temperature anomaly comparison under high and low flow rates accurately distinguishes between two causes of leakage: excessive sealing gap and seal damage. This solves the limitation of traditional detection that can only determine the existence of leakage but cannot clarify the cause, providing a direct basis for targeted optimization of the sealing system and significantly improving the guiding value of the detection results for engineering practice.

[0045] A method for using a rotary air preheater heat exchange performance testing device includes the following steps:

[0046] S1: Initialize and start the temperature detection module. The ring-shaped temperature sensor 6 is driven by the sensor rotation drive module to rotate around the central axis of the preheater at a preset speed. The positioning module records the sensor position synchronously. The data processing module establishes the reference temperature distribution curve under normal operating conditions through Formula 1.

[0047] Formula 1: ,in Circumferential angle The reference temperature at that location This refers to the number of sensor rotation cycles collected continuously. A single rotation cycle is defined as the time it takes for the temperature sensor to complete one full rotation around the central axis of the preheater. Based on the preheater design flue gas temperature fluctuation range, historical normal operating temperature deviation data, and temperature thresholds set according to relevant industry testing standards, only when the first... Any circular angle within a period Temperature readings at the location satisfy Only then can the periodic data be included in the calculation range of the reference temperature distribution curve to eliminate the influence of abnormal data such as instantaneous airflow fluctuations and occasional sensor interference on the stability of the reference curve; the complete formula for calculating the reference temperature distribution curve is as follows:

[0048] ,in Circumferential angle The reference temperature at that location , For the first circumferential angle within one effective rotation cycle Temperature readings at the location.

[0049] S2: Initial test, temperature sensor 6 is used to collect the flue gas temperature in the downstream area of ​​the axial seal. When Formula 2 is met, it is judged as a suspected air leak. The judgment condition for suspected air leak is that the temperature detected by any temperature sensor 6 is lower than the benchmark threshold for three consecutive sampling cycles.

[0050] Formula 2: ,in, The preset temperature anomaly threshold, For the detection time;

[0051] S3: Recheck and confirm. Driven by the sensor rotation drive module, the temperature sensor 6 rotates one revolution. The positioning module synchronously records the detection area of ​​each sensor. The air leakage judgment module uses formula three to calculate the proportion of abnormal temperature sensors 6.

[0052] Formula 3: ,in This represents the number of sensors exhibiting abnormal temperatures. For the total number of sensors, if Furthermore, the overlap of abnormal regions detected by the two rotations is high. This confirms the presence of an air leak. This is the preset minimum abnormality percentage threshold. The preset minimum overlap threshold, This is the ratio of the number of overlapping regions to the total number of anomalous regions. .

[0053] S4: High and low flow rate verification:

[0054] During the high-flow-rate stage, the flue gas velocity is adjusted to [a certain value] via the flue gas velocity regulation module. The flow rate detection module confirmed. Then, the temperature sensor 6 is driven to rotate one more revolution, collecting and recording temperature data at high flow rates. ,in It is a high flow rate multiple factor. Normal flow rate This refers to the allowable fluctuation value of the flow rate;

[0055] During the low-flow-rate stage, the flue gas flow rate is adjusted to [a certain value] via the flue gas flow rate regulation module. The flow rate detection module confirmed. Then, drive temperature sensor 6 to rotate one more revolution to collect and record temperature data at low flow rates. ,in For low flow rate multiples, , This refers to the allowable fluctuation value of the flow rate. And the high flow rate is stable for a long time. ,in The preset minimum settling time, , , ;

[0056] Air leakage strength passed Grading: When There was a slight air leak at the time. At that time, the air leakage was moderate. It was severely leaking air at the time. and The preset grading threshold, and ;

[0057] S5: Result Judgment. The air leakage judgment module analyzes and compares air leakage characteristics, using the following formula:

[0058] Locating the area of ​​air leakage: ;

[0059] Quantification of air leakage intensity: ;

[0060] Analysis of the causes of air leakage, through comparison and , and The differences, among which This represents the average temperature drop at high flow rates. The average temperature drop at low speed is output as the heat transfer performance test result.

[0061] Working Principle: During initialization, after the temperature detection module is activated, the ring-shaped temperature sensors 6, driven by the sensor rotation drive module, begin to rotate around the preheater's central axis at a preset speed. This speed is consistent with the preheater rotor speed, ensuring that the sensors can synchronously monitor temperature changes during rotor rotation. Simultaneously, the positioning module records the rotation angle and location (flue gas side 3 or air side 5) of each temperature sensor 6 in real time. The data processing module collects temperature data from multiple consecutive rotation cycles and integrates this data to generate a baseline temperature distribution curve under normal operating conditions. This step solves the problem of the baseline temperature being easily affected by instantaneous fluctuations in traditional detection. The averaging of multi-cycle data makes the baseline curve more stable, providing a precise reference for subsequent anomaly detection and effectively improving the initial accuracy of the detection.

[0062] Next, an initial test is performed. Temperature sensor 6 continuously collects the flue gas temperature in the downstream area of ​​the axial seal during rotation. When the temperature detected by any temperature sensor 6 is lower than the benchmark threshold for three consecutive sampling cycles, the system determines it as a suspected air leak. This step, by limiting the continuous sampling cycle, avoids misjudging air leaks due to instantaneous temperature fluctuations, solves the problem of insufficient reliability of single instantaneous data, and improves the accuracy of suspected air leak judgment.

[0063] Secondly, the sensor rotation drive module drives temperature sensor 6 to rotate one full revolution, while the positioning module simultaneously records the detection area of ​​each sensor. The air leakage judgment module counts the number of temperature sensors 6 with abnormal temperatures during the rotation and calculates the percentage of abnormal sensors. When the percentage of abnormal sensors reaches a preset minimum abnormal percentage threshold, and the overlap of the abnormal areas detected by two rotations reaches a preset minimum overlap threshold, air leakage is confirmed. This step, through full-circumference rotation detection and dual threshold judgment, solves the problem of misjudgment caused by single sensor failure or local interference, significantly improving the reliability of air leakage judgment.

[0064] During the high-flow-rate phase, the flue gas velocity is adjusted to a high multiple of the normal flow rate by the flue gas velocity adjustment module. After the flow rate detection module confirms that the flow rate is stable within the allowable fluctuation range and remains stable for a preset minimum time, the temperature sensor 6 is driven to rotate one more revolution to collect and record the temperature data under the high flow rate. During the low-flow-rate phase, the flue gas velocity is similarly adjusted to a low multiple of the normal flow rate. After confirming that the flow rate meets the standard, the temperature sensor 6 is driven to rotate one more revolution to collect the temperature data under the low flow rate. This step creates different operating conditions by changing the flue gas velocity, solving the problem that traditional detection methods cannot analyze leakage characteristics through changes in operating conditions, and providing crucial data for subsequent leakage cause determination.

[0065] In the result judgment, the leakage detection module combines temperature data under normal, high, and low flow rates to locate the leakage area. It quantifies the leakage intensity by calculating the average temperature drop in the abnormal area and analyzes the cause of the leakage (such as excessive sealing gaps or damaged seals) based on the difference between the average temperature drop at high and low flow rates and that at normal flow rate. Finally, it outputs the heat exchange performance test results. This step transforms leakage judgment from qualitative to quantitative analysis, overcoming the limitations of traditional detection methods that cannot clearly identify the specific situation and cause of leakage. It provides accurate evidence for targeted optimization of the preheater sealing system, significantly enhancing the guiding role of detection in equipment maintenance and heat exchange efficiency improvement.

[0066] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A device for testing the heat exchange performance of a rotary air preheater, characterized in that, The preheater shell is provided with a temperature detection module, the temperature detection module comprises temperature sensors arranged in an annular manner along a downstream region of the rotary air preheater in a sealing manner in an axial direction, and is used for collecting local temperature data of a flue gas side; the temperature detection module is connected with a sensor rotation module, which is used for driving the annularly arranged temperature sensors to rotate around a preheater central shaft; the preheater central shaft arranged in the preheater shell divides an internal space into a flue gas side and an air side, so that each temperature sensor alternately contacts the flue gas side and the air side; The sensor rotation module is electrically connected with a positioning module, which is used for acquiring a rotation angle of the temperature sensor and a current region in which the temperature sensor is located in real time; the internal space of the preheater shell is provided with a flue gas inlet and the flue gas side and an air inlet and the air side; an inlet pipeline of the flue gas inlet is provided with a flue gas flow rate adjusting module, which is used for adjusting a flue gas flow rate entering the preheater to a preset value; the flue gas inlet pipeline is provided with a flow rate detection module, which is used for detecting and feeding back a current flue gas flow rate in real time; The temperature detection module, the positioning module and the flow rate detection module are electrically connected with a data processing module, which is used for receiving temperature data, sensor position data and flow rate data, and generating a temperature change chart; the data processing module is electrically connected with a leakage determination module, which determines a leakage state based on the temperature data and the flow rate data; a single group of temperature sensors is identified to be abnormal in temperature through initial detection, and the abnormality is confirmed through rotation review of the temperature sensors to determine the leakage; a leakage reason is analyzed based on a temperature change difference under high and low flow rates; in the leakage determination module, the leakage reason analysis logic comprises: if a temperature abnormality amplitude under high flow rate is lower than that under normal flow rate, and a temperature abnormality amplitude under low flow rate is higher than that under normal flow rate, it is determined that the leakage is mainly caused by a too large sealing gap.

2. The device for detecting heat exchange performance of a rotary air preheater according to claim 1, characterized in that: In the temperature detection module, the number of the annularly arranged temperature sensors is 16, and a circumferential included angle between adjacent temperature sensors is equal; each temperature sensor is provided with a high-temperature-resistant and corrosion-resistant protective sleeve pipe; the protective sleeve pipe is made of ceramic; and a probe end of the temperature sensor protrudes out of the sleeve pipe to directly contact a flue gas flow.

3. The device for detecting heat exchange performance of a rotary air preheater according to claim 1, characterized in that: The rotation angle fed back by the positioning module is such that the temperature sensor completes switching from the flue gas side to the air side exactly when the temperature sensor rotates 180°; the positioning module comprises eight positioning marks arranged uniformly along a rotation path and photoelectric sensors matched with the positioning marks, and is used for controlling detection accuracy of the rotation angle to be within ±1°.

4. A method of using a rotary air preheater heat transfer performance detection device, characterized by: The device for detecting heat exchange performance of the rotary air preheater is applied to the rotary air preheater, and comprises the following steps: S1: initialization, starting the temperature detection module, rotating the annularly arranged temperature sensors around the preheater central shaft at a preset rotation speed under the driving of the sensor rotation driving module, and synchronously recording sensor positions by the positioning module; the data processing module establishes a reference temperature distribution curve under normal working conditions by formula one; Formula one: wherein is the reference temperature at the angle of the circumference, is the number of rotation cycles collected continuously , is the temperature detection value at the angle in the th cycle; S2: Initial detection, collecting flue gas temperature of the downstream region of the axial seal by temperature sensor When formula two is satisfied, it is determined as suspected air leakage; Equation two: wherein, is a preset temperature anomaly threshold value, is a detection time; S3: review and confirmation, rotating the temperature sensors one circle under the driving of the sensor rotation driving module, synchronously recording detection regions of the sensors by the positioning module, and calculating a proportion of abnormal temperature sensors by the leakage determination module through formula three; Formula three: wherein is the number of sensors with temperature anomalies, is the total number of sensors, if and the overlap degree of the abnormal areas detected twice , it is confirmed that there is air leakage, is a preset minimum anomaly proportion threshold value, is a preset minimum overlap threshold value, is the ratio of the number of overlapping areas to the total number of abnormal areas; S4: high and low flow rate verification: During the high-flow-rate stage, the flue gas velocity is adjusted to [a certain value] via the flue gas velocity regulation module. The flow rate detection module confirmed. Then, the temperature sensor is driven to rotate one more revolution, collecting and recording temperature data at high flow rates. ,in It is a high flow rate multiple factor. Normal flow rate This refers to the allowable fluctuation value of the flow rate; During the low-flow-rate stage, the flue gas flow rate is adjusted to [a certain value] via the flue gas flow rate regulation module. The flow rate detection module confirmed. Then, the temperature sensor is driven to rotate one more revolution, collecting and recording temperature data at low flow rates. ,in For low flow rate multiples, , This refers to the allowable fluctuation value of the flow rate; S5: result judgment, the air leakage judgment module compares and analyzes the air leakage characteristics, and the formula is as follows: Air leakage area positioning: ; Air leakage intensity quantification: ; Wind leakage reason analysis is carried out by comparing the differences between and , and , wherein is the average temperature drop at high flow rate, is the average temperature drop at low flow rate, and the heat exchange performance detection result is output.

5. The method of using a rotary air preheater heat transfer performance detection device of claim 4, wherein: The calculation of the reference temperature distribution curve satisfies , This refers to the number of sensor rotation cycles collected continuously. A single rotation cycle is defined as the time it takes for the temperature sensor to complete one full rotation around the central axis of the preheater. Based on the preheater design flue gas temperature fluctuation range, historical normal operating temperature deviation data, and temperature thresholds set according to relevant industry testing standards, only when the first... Any circular angle within a period Temperature readings at the location satisfy Only then can the periodic data be included in the calculation range of the reference temperature distribution curve to eliminate the influence of abnormal data such as instantaneous airflow fluctuations and occasional sensor interference on the stability of the reference curve; the complete formula for calculating the reference temperature distribution curve is as follows: wherein is the circumferential angle at the reference temperature, , is the temperature detection value at the circumferential angle in the i-th effective rotation period. in the i-th effective rotation period.

6. The method of using a rotary air preheater heat transfer performance detection device of claim 4, wherein: The determination condition of the suspected air leakage is that the temperature detected by any temperature sensor is lower than the reference threshold value for 3 consecutive sampling periods.

7. The method of using a rotary air preheater heat transfer performance detection device of claim 5, wherein: The .

8. The method of using a rotary air preheater heat transfer performance detection device of claim 4, wherein: The , and high flow rate stability duration wherein is a preset minimum stability time, .

9. The method of using a rotary air preheater heat transfer performance detection device of claim 4, wherein: The , ; Air leakage intensity is determined by Classification: when air leakage is slight, air leakage is moderate, air leakage is severe, and are preset classification thresholds, and .

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