Heavy-duty gas turbine exhaust gas temperature measurement correction method and device

Abstract

The invention relates to the technical field of gas turbine testing, and discloses a heavy-duty gas turbine exhaust temperature measurement correction method and device, and the method comprises the steps: collecting real-time temperature data through a total temperature probe array, and calculating an exhaust cross section temperature average value; the running state and the exhaust downstream temperature of the gas turbine are collected, and running parameters and reference temperature data are obtained; according to the size relation between the adjustable guide vane angle and a preset adjustable guide vane angle inflection point value, a corresponding regression model is selected to calculate a temperature correction coefficient; and performing correction calculation on the exhaust section temperature average value by using the temperature correction coefficient to obtain the final exhaust temperature. According to the method, the preset adjustable guide vane angle inflection point value is called, the regression relation with the adjustable guide vane angle or the relative load rate as the core variable is matched, and therefore deviation generated when a single model is used for fitting exhaust flow field distortion in the full working condition range is reduced, and the accuracy of obtaining the final exhaust temperature is improved.

Description

Technical Field

[0001] This invention relates to the field of gas turbine testing technology, specifically to a method and apparatus for measuring and correcting the exhaust temperature of a heavy-duty gas turbine. Background Technology

[0002] Gas turbine exhaust temperature is a crucial parameter for evaluating unit performance, monitoring operational status, and ensuring unit safety. Accurate acquisition and processing of exhaust temperature data are fundamental for calculating thermal efficiency and analyzing combustion chamber operating conditions during gas turbine testing and daily operation. To obtain representative exhaust temperatures, multiple temperature measurement points are typically arranged circumferentially and radially in layers along a specific cross-section of the gas turbine exhaust channel. This multi-point measurement reflects the overall temperature level of the exhaust flow field.

[0003] In practical applications of heavy-duty gas turbines, the large cross-sectional dimensions of the exhaust diffuser channel mean that long-length total temperature probes extending deep into the channel are prone to vibration under the impact of high-temperature and high-velocity airflow. Furthermore, traditional fixed installation methods restrict the probe's free expansion after heating, easily generating thermal stress on the probe body, leading to structural deformation or damage. In addition, the exhaust flow field of gas turbines is non-uniform; the swirling intensity and flow regime of the airflow change under different operating conditions, resulting in uneven distribution of mass flow rate density across the cross-section. Existing data processing methods often use simple arithmetic averages, failing to fully consider the impact of velocity distribution differences on enthalpy statistics, and lack dynamic correction mechanisms for different flow field morphologies (such as the switching between swirling and axial flow), leading to deviations between exhaust temperature data obtained over a wide load range and the actual values.

[0004] Therefore, improving the structural reliability of temperature measurement devices in large-size flow channels, and combining flow field characteristics to perform weighted calculations and dynamic corrections on the measurement data to obtain accurate final exhaust temperatures, are problems that need to be solved in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and apparatus for measuring and correcting exhaust temperature in heavy-duty gas turbines. This method solves the problems of insufficient structural reliability of existing temperature measuring devices in large-size exhaust channels, as well as low accuracy of exhaust temperature measurement due to non-uniform exhaust flow field and lack of dynamic correction mechanisms for changes in flow field morphology.

[0006] To address the above problems, the present invention provides the following technical solution: This invention provides a method for correcting the measurement of exhaust temperature in heavy-duty gas turbines, employing the following technical solution: A method for correcting exhaust temperature measurement in a heavy-duty gas turbine includes: collecting real-time temperature data from multiple measuring points using a total temperature probe array arranged on the exhaust cross-section of the gas turbine, and processing the real-time temperature data to obtain an average exhaust cross-section temperature; collecting real-time operating status data of the gas turbine and temperature data of the downstream region of the exhaust to obtain gas turbine operating parameters and reference temperature data, wherein the gas turbine operating parameters include at least the adjustable guide vane angle, relative load rate, and ambient temperature; calling a preset inflection point value of the adjustable guide vane angle, and selecting a corresponding regression model to calculate a temperature correction coefficient based on the relationship between the adjustable guide vane angle and the inflection point value in the gas turbine operating parameters; and using the temperature correction coefficient to correct the average exhaust cross-section temperature to obtain the final exhaust temperature.

[0007] By employing the aforementioned technical solution, a multi-point array measurement was used to cover a large-scale exhaust channel cross-section, acquiring two-dimensional temperature field data containing radial and circumferential information. This solves the problem that single-point or sparse measurements cannot characterize complex flow field properties. Furthermore, addressing the nonlinear hydrodynamic characteristics of the exhaust flow field in heavy-duty gas turbines that vary with operating conditions, this method establishes a correction logic based on operating condition partitioning. By introducing the inflection point of the adjustable guide vane angle as a criterion for the switch from swirling flow dominance to axial flow dominance, appropriate regression models are matched under different flow field mechanisms. This piecewise correction strategy overcomes the deficiency of insufficient fitting accuracy of a single linear model over a wide load range, reduces systematic deviations in temperature measurement caused by flow field distortion and changes in swirling intensity, and achieves accurate correction of exhaust temperature across the entire operating range.

[0008] Furthermore, in obtaining the average temperature of the exhaust section, a mass-weighted average calculation strategy is adopted for all measuring points. This strategy includes: using fluid dynamics simulation to extract the local mass flow density values ​​at the physical location of the measuring points, and normalizing them to obtain the mass weighting coefficient for each measuring point; and weighting the real-time temperature data of the measuring points according to the mass weighting coefficient to obtain the average temperature of the exhaust section.

[0009] By adopting the above technical solution, fluid dynamics factors are introduced into the temperature calculation process, correcting the physical bias caused by the traditional arithmetic average method when the flow velocity distribution is uneven. Within the gas turbine exhaust cylinder, local mass flow density varies at different radii and circumferential positions, resulting in different enthalpies carried by each measuring point. Mass weighting increases the weight of measuring point data in high-velocity, high-flux regions in the average value calculation, while reducing the influence of measuring points in low-velocity regions. This makes the calculated average temperature more consistent with the thermodynamic law of conservation of energy, improving the physical accuracy and representativeness of the exhaust cross-section average temperature data, and providing reliable basic data for subsequent bias correction.

[0010] Furthermore, in obtaining the average temperature of the exhaust section, a simplified measurement point combination averaging calculation strategy is adopted. This strategy includes: selecting the data of the measurement points of the 2nd, 5th, and 8th radial rings to represent the entire exhaust section, where the 2nd ring is located in the root region of the flow channel, the 5th ring is located in the middle region of the flow channel, and the 8th ring is located in the tip region of the flow channel; averaging the real-time temperature data of all the measurement points of the selected 2nd, 5th, and 8th rings to obtain the average temperature of the exhaust section.

[0011] By adopting the above technical solution, a balance is struck between data processing volume and measurement representativeness while meeting the real-time requirements of the control system. The combination of measurement points at three specific radial locations—the root, middle, and tip—can cover the main characteristic distribution of the radial temperature gradient in the exhaust flow field. Compared to full-point calculation, this strategy reduces the number of data channels involved in real-time computation, lowers the computational load on the controller, and is suitable for engineering applications with high requirements for dynamic response speed or limited hardware resources, achieving an optimized configuration of computational efficiency and measurement accuracy.

[0012] Furthermore, the downstream region of the exhaust gas is selected as the exhaust volute inlet downstream of the inner cone of the gas turbine exhaust diffuser or the transition section of the waste heat boiler inlet; the reference temperature data is obtained by simultaneously collecting temperature data through multiple thermocouples arranged in the downstream region of the exhaust gas, and calculating the average value of the collected multiple temperature data to obtain the reference temperature data.

[0013] By employing the above technical solution, the natural mixing effect of the exhaust diffuser and volute structure on the airflow is utilized. After the exhaust flow undergoes a long downstream flow and diffusion process, the temperature and velocity fields tend to become homogenized, eliminating the local distortion caused by the strong upstream swirling flow. The multi-point average temperature collected at this time can serve as reference data reflecting the total energy level of the gas turbine exhaust. Using this downstream stable data to calibrate the measurement results of the complex upstream section ensures the physical accuracy and stability of the regression target of the corrected model.

[0014] Furthermore, the inflection point value of the adjustable guide vane angle is a predetermined fixed value, which is obtained by: establishing a hydrodynamic simulation model of the gas turbine exhaust flow field, simulating the flow field state under different adjustable guide vane angles, and extracting the critical angle when the exhaust flow changes from a swirling state to an axial flow state as the inflection point value of the adjustable guide vane angle; the temperature correction coefficient is defined as the difference between the reference temperature data and the average temperature of the exhaust section.

[0015] By employing the aforementioned technical solution, complex changes in flow field topology are quantified into directly readable geometric parameters for the control system. Critical angles are determined through simulation, defining the boundaries of different fluid dynamic mechanisms. Simultaneously, the temperature correction coefficient is defined as the deviation between the measured and reference values, establishing a correction direction aimed at eliminating system errors. This gives subsequent regression calculations clear physical meaning and a mathematical convergence objective.

[0016] Furthermore, when the adjustable guide vane angle in the gas turbine operating parameters is less than or equal to the inflection point value of the adjustable guide vane angle, it is determined to be a low load or small angle operating condition range, and the temperature correction coefficient is calculated using the first piecewise regression model; the first piecewise regression model is a regression relationship on the temperature correction coefficient established based on the adjustable guide vane angle and the ambient temperature.

[0017] By employing the aforementioned technical solution, a model was developed for the specific aerodynamic behavior of the exhaust flow field under low-load or small-angle operating conditions. Within this range, the compressor inlet guide vanes are partially closed, resulting in strong residual swirling in the turbine exhaust, with the swirling intensity directly controlled by the guide vane angle. Simultaneously, changes in ambient temperature alter the intake air density and mass flow rate, thereby affecting the flow field structure. A regression model with guide vane angle and ambient temperature as core independent variables was constructed, accurately decoupling the intrinsic correlation between flow field swirling distortion and temperature measurement deviation under this operating condition, thus improving the correction accuracy under low-load conditions.

[0018] Furthermore, when the adjustable guide vane angle in the gas turbine operating parameters is greater than the inflection point value of the adjustable guide vane angle, it is determined to be a high load or large angle operating condition range, and the temperature correction coefficient is calculated using the second piecewise regression model; the second piecewise regression model is a regression relationship on the temperature correction coefficient established based on the relative load rate and the ambient temperature.

[0019] By adopting the above technical solution, the transformation of exhaust flow field characteristics under high-load conditions is adapted. When the guide vane angle opens beyond the inflection point, the exhaust flow gradually transforms into axial flow, and the marginal influence of guide vane angle changes on the flow field morphology weakens. At this point, the combustion chamber temperature rise level becomes the dominant factor affecting exhaust temperature distribution, and the relative load rate is directly related to the combustion chamber temperature rise. Switching to a regression model with relative load rate and ambient temperature as independent variables can more sensitively reflect the impact of changes in combustion conditions on exhaust temperature deviation, avoiding the fitting failure of a single model after changes in the flow field mechanism.

[0020] Furthermore, the steps for obtaining the final exhaust temperature specifically include: superimposing the average exhaust cross-sectional temperature with the temperature correction coefficient to obtain a corrected summation value; and using a first-order inertial filtering algorithm to smooth the corrected summation value to obtain the final exhaust temperature.

[0021] By employing the above technical solution, both steady-state accuracy correction and dynamic signal processing are integrated. Algebraic superposition eliminates systematic measurement bias (DC component) caused by the flow field structure, making the measured value approximate the true thermodynamic temperature. The first-order inertial filtering algorithm effectively suppresses high-frequency random noise (AC component) caused by airflow turbulence and combustion pulsation. Through reasonable configuration of filtering parameters, while ensuring a smooth and stable output signal, low-frequency trend signals reflecting changes in unit operating conditions are preserved, ensuring that the final temperature data meets the control system's dual requirements for signal-to-noise ratio and dynamic tracking capability.

[0022] Furthermore, the process includes the following steps: transmitting the final exhaust temperature as a process control variable to the gas turbine control system in real time; the gas turbine control system substitutes the final exhaust temperature into the exhaust temperature control curve logic and compares it with the set value; when it deviates from the set value, it outputs a command to adjust the opening of the fuel regulating valve or correct the angle of the compressor inlet adjustable guide vane.

[0023] By adopting the above technical solution, the engineering application of high-precision temperature measurement data in closed-loop control has been realized. Accurate exhaust temperature feedback enables the control system to precisely calculate the average metal temperature of the turbine blades, thereby allowing the unit to operate at turbine inlet temperature levels closer to the design limits while preventing overheating damage.

[0024] The present invention also provides a heavy-duty gas turbine exhaust temperature measuring device, which adopts the following technical solution: A heavy-duty gas turbine exhaust temperature measurement device includes: an exhaust cylinder outer casing; 15 nine-point total temperature probes arranged in a circumferential array on the exhaust cross section; an inner cone of an exhaust diffuser located at the center of the exhaust flow channel; an inner support ring plate disposed on the inner end of the nine-point total temperature probes; auxiliary temperature measuring points arranged in the downstream region of the exhaust flow field; and a data acquisition system, which is connected to the nine-point total temperature probes and the auxiliary temperature measuring points respectively, for acquiring temperature signals; wherein, the nine-point total temperature probe includes a probe rod and nine temperature sensing node assemblies arranged along the length direction; a fairing is disposed outside the temperature sensing node assemblies. The fairing has an air inlet on the side facing the airflow and an exhaust outlet on the side away from the airflow. The end of the 9-point total temperature probe near the outer casing of the exhaust cylinder is fixed by a flange, and the end that extends into the inner side of the exhaust channel has an integrally formed connecting stud. The inner support ring plate has a segmented structure, with every three adjacent 9-point total temperature probes forming a group. The connecting studs of each group of 9-point total temperature probes pass through the corresponding mounting holes on the inner support ring plate and are locked in place. The inner support ring plate is installed on the inner cone or bearing support of the exhaust diffuser through a floating connection mechanism, which is configured to allow the inner support ring plate to move radially.

[0025] By adopting the above technical solutions, the comprehensiveness of the measurement and the reliability of the device are guaranteed from the hardware structure perspective. A fine three-dimensional temperature measurement grid is constructed by arranging high-density temperature sensing nodes on the exhaust cross-section, ensuring the spatial resolution of the raw data. In terms of mechanical structure, to address the issue of long probes in large exhaust channels being susceptible to airflow excitation and thermal stress, a support mode with fixed outer ends and grouped inner ends is adopted. The inner support ring plate couples the free ends of multiple probes, improving the overall structural stiffness and natural frequency of the probe group and avoiding the airflow excitation frequency range. Simultaneously, the floating connection mechanism design allows the inner support ring plate to freely expand and contract radially as the components expand due to heat, releasing the thermal stress generated on the probe rod due to rapid start-up and shutdown of the gas turbine or load changes.

[0026] This invention provides a method and apparatus for measuring and correcting the exhaust temperature of a heavy-duty gas turbine. It offers the following advantages: 1. This invention calls a preset adjustable guide vane angle inflection point value and, based on the relationship between the adjustable guide vane angle and the inflection point value in the gas turbine operating parameters, selects either a first piecewise regression model or a second piecewise regression model for calculation. Considering the characteristics of the exhaust flow field of heavy-duty gas turbines switching between swirling and axial flow states, it matches regression relationships with the adjustable guide vane angle or relative load rate as the core variables, thereby reducing the deviation caused by using a single model to fit the exhaust flow field distortion across the entire operating range and improving the accuracy of the final exhaust temperature.

[0027] 2. This invention collects real-time temperature data from multiple measuring points using a total temperature probe array arranged on the exhaust cross section of a gas turbine. It then employs a mass-weighted average calculation strategy across all measuring points to obtain the average exhaust cross section temperature. By utilizing fluid dynamics simulation to extract the local mass flow density values ​​at the physical locations of the measuring points and normalizing them to obtain the mass weighting coefficients, the calculation results can reflect the differences in the contribution of measuring points in different flow velocity regions to the overall enthalpy, thereby improving the representativeness of the average exhaust cross section temperature as a physical benchmark data.

[0028] 3. This invention uses an inner support ring plate to fix one end of a 9-point total temperature probe array distributed circumferentially into the inner side of the exhaust channel. The inner support ring plate is then installed on the inner cone or bearing support of the exhaust diffuser via a floating connection mechanism. This improves the overall rigidity of the probe array and avoids structural damage caused by airflow vibration. At the same time, it allows the inner support ring plate to move radially to accommodate thermal expansion, eliminating the thermal stress generated on the probe rod due to temperature changes during gas turbine operation and ensuring the structural integrity of the measuring device in high-temperature and high-flow-rate environments. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall installation structure of the exhaust temperature measuring device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the 9-point total temperature probe of the present invention; Figure 3 This is a schematic diagram of the internal support ring plate in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the temperature sensing node assembly according to an embodiment of the present invention; Figure 5 This is a flowchart of a gas turbine exhaust temperature measurement correction method according to an embodiment of the present invention.

[0030] Among them, 1. Exhaust cylinder outer casing; 2. 9-point total temperature probe; 3. Exhaust diffuser inner cone; 4. Inner support ring plate; 5. Probe rod; 6. Temperature sensing node assembly. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This invention provides a heavy-duty gas turbine exhaust temperature measuring device, which is installed inside the exhaust passage of the gas turbine. For example... Figure 1 As shown, the device mainly includes an outer casing 1 for the exhaust cylinder as an external support, an array of 9 total temperature probes 2 distributed on the exhaust cross section, an inner cone 3 of the exhaust diffuser located in the center of the exhaust channel, an inner support ring plate 4 for internal fixation, auxiliary measuring points located downstream of the exhaust, and a data acquisition system.

[0033] like Figure 2 As shown, the main structure of the 9-point total temperature probe 2 includes a probe rod 5. To adapt to the high-temperature and high-speed airflow environment within the gas turbine exhaust channel, the probe rod 5 is made of a high-temperature resistant alloy material, such as Inconel 625 or 310S stainless steel. The cross-section of the probe rod 5 is designed to be streamlined or airfoil-like to reduce resistance to the exhaust flow field and wake interference. Nine temperature-sensing node components 6 are arranged along the length of the probe rod 5. The distribution of these nine measuring points follows the principle of equal annular area of ​​the flow channel in the measurement section. In specific implementation, with the center of the gas turbine exhaust channel as the center, the exhaust channel cross-section is divided into nine concentric rings of equal area, and each temperature-sensing node component 6 is arranged at the center radius of the corresponding ring. This distribution ensures that the flow area represented by each measuring point has a consistent weight when calculating the average temperature.

[0034] like Figure 4As shown, to reduce radiation and velocity errors during measurement, each temperature sensing node assembly 6 employs a shroud design. The shroud utilizes a double-layer cylindrical or Venturi tube structure, with an air inlet on the side facing the airflow and an exhaust outlet on the side facing away from the airflow, and radiation-shielding exhaust holes on the shroud wall. The sensing element inside the probe uses a K-type thermocouple, with the thermocouple's sensing end located at the center of the shroud. This shroud structure, on the one hand, reduces the velocity of the high-speed airflow entering the interior, creating a relatively stagnant zone around the thermocouple node, converting the kinetic energy of the airflow into internal energy, thereby converting dynamic temperature into static temperature for measurement; on the other hand, its double-layer wall structure shields against high-temperature radiation from the combustion chamber flame and cold radiation from the exhaust cylinder wall. Through this design, the probe structure can adapt to complex airflow angle changes in the exhaust flow field, ensuring a temperature measurement accuracy better than ±1% even under conditions where the exhaust airflow deflection angle fluctuates within ±30°.

[0035] Regarding the installation layout of the probe array, such as Figure 1 As shown, 15 of the aforementioned 9-point total temperature probes 2 are evenly arranged circumferentially on the outer casing 1 of the exhaust cylinder, forming a total of 135 temperature measurement points. To address the vibration problem of the long probes under high-speed airflow, a flange-fixed structure combined with a double-support simply supported beam is adopted for probe fixation. Specifically, a mounting flange is provided at the root of the 9-point total temperature probe 2, i.e., the end closest to the outer casing 1 of the exhaust cylinder. This mounting flange is bolted to the boss on the outer casing 1 of the exhaust cylinder, achieving rigid support and sealing on the outside of the probe. The head of the 9-point total temperature probe 2, i.e., the end extending into the exhaust channel, has an integrally machined connecting stud. An inner support ring plate 4 is provided on the hub side of the exhaust channel, which serves as the inner support point of the probe.

[0036] like Figure 1 and Figure 3 As shown, in terms of connection method, every three adjacent 9-point total temperature probes 2 are grouped together. Correspondingly, the inner support ring plate 4 adopts a segmented structure, with the connecting studs of the three probes in each group, integrally machined at their front ends, passing through the corresponding mounting holes on the inner support ring plate 4 and tightened by high-temperature resistant nuts. This grouped connection method enhances the local integrity of the probe group and ensures the reliability of probe installation. The inner support ring plate 4 is installed on the inner cone 3 of the exhaust diffuser or on the bearing support via a floating connection mechanism. This floating connection mechanism allows the inner support ring plate 4 to move freely in the radial direction. When the probe rod 5 undergoes axial elongation due to heat, the inner support ring plate 4 moves radially accordingly, thereby eliminating the thermal expansion stress of the probe rod 5 and preventing the probe from bending and deforming due to heat resistance. At the same time, this double-supported simply supported beam structure increases the first-order natural frequency of the probe, effectively preventing structural damage caused by airflow excitation.

[0037] In addition, auxiliary temperature measuring points are arranged in the downstream region of the exhaust flow field. This downstream region is selected at the exhaust volute inlet after the exhaust diffuser outlet or the transition section at the waste heat boiler inlet. At this location, the flow field mixing degree is higher than that of the exhaust cylinder cross-section, and the temperature distribution is relatively uniform. This invention uses the temperature data collected at this location to correct the measurement data of the upstream torus.

[0038] In terms of signal transmission and processing, the signal leads of all 9-point total temperature probes 2 and auxiliary measuring points are connected to a data acquisition instrument located in the ambient temperature zone, such as the EX1048A thermocouple data acquisition instrument. The acquisition frequency is set to 50Hz. The data acquisition instrument connects to the background data acquisition and analysis system via TCP / IP communication protocol to achieve real-time synchronous transmission of temperature data.

[0039] See attached document Figure 5 This invention provides a method for correcting the measurement of exhaust temperature in heavy-duty gas turbines, comprising the following steps: S100 collects real-time temperature data from multiple measuring points through a total temperature probe array arranged on the exhaust section of the gas turbine, and calculates the average temperature of the exhaust section. S200 collects gas turbine operating parameters and reference temperature data of the downstream area of ​​the exhaust gas. The operating parameters include at least the adjustable guide vane angle, relative load rate and ambient temperature. S300, determine the inflection point value of the adjustable guide vane angle, and select the corresponding characteristic parameters and regression model to calculate the temperature correction coefficient based on the relationship between the current adjustable guide vane angle and the inflection point value; S400, the average temperature of the exhaust section is corrected using the temperature correction coefficient to obtain the final exhaust temperature.

[0040] The above steps will be explained in detail below with reference to specific embodiments.

[0041] See attached document Figure 5 Step S100 specifically includes the following sub-steps: S110, the real-time temperature measurement data of all total temperature probe measuring points on the exhaust section of the gas turbine is synchronously acquired through the data acquisition system. Specifically, the data acquisition system reads the electrical signals of the thermocouples in the 135 temperature sensing node assemblies 6 of 15 nine-point total temperature probes 2 arranged on the exhaust section at a set sampling frequency (e.g., 50Hz) using a thermocouple acquisition instrument (e.g., EX1048A), and converts the electrical signals into temperature values. The definition of the first... The first on the probe Temperature measurement data at each measuring point are as follows: ,in The value ranges from 1 to 15, representing the probe number distributed circumferentially. The value ranges from 1 to 9, representing the measurement point number distributed radially.

[0042] S120, according to the preset calculation strategy, the real-time temperature measurement data is processed to calculate the average temperature of the exhaust section.

[0043] Before calculating the average value, the system first performs data validity checks and cleaning to eliminate the influence of sensor malfunctions or abnormal interference. Specific criteria include: For measurement range exceeding the limit, if the temperature at the measuring point exceeds the preset physical range (e.g., below 0℃ or above 700℃), it will be marked as invalid. For deviation consistency judgment, if the deviation between the reading of a certain measuring point and the average value of a single probe exceeds the preset standard deviation (e.g., 3σ), it is marked as an outlier. The system only uses valid data in subsequent calculations and deducts the number of invalid measuring points from the denominator.

[0044] After confirming the validity of the data, the calculation strategies implemented include arithmetic average calculation of all measurement points, quality-weighted average calculation of all measurement points, and simplified measurement point combination average calculation.

[0045] When using the arithmetic mean calculation strategy across all measurement points, the data acquisition and analysis system performs equal-weighted summation of temperature measurement data from 135 measurement points and takes the average value. The calculation formula is as follows: ; in, This represents the arithmetic mean of all temperature measurements taken at 135 points across 15 probes.

[0046] When employing a full-point mass-weighted average calculation strategy, a mass-weighting coefficient is introduced to reflect the differences in exhaust mass flow rate distribution at different measuring point locations. The mass-weighting coefficient is obtained as follows: a gas turbine exhaust flow path model is established using fluid dynamics simulation software; flow field calculations are performed under ISO basic load design conditions; local mass flow rate density values ​​are extracted from the physical locations of the aforementioned 135 measuring points; and these local mass flow rate density values ​​are normalized to obtain the mass-weighting coefficient corresponding to each measuring point. At this point, the formula for calculating the average temperature of the exhaust section is as follows: ; in, This represents the quality-weighted average of all temperature measurement data from 135 measurement points across 15 probes. For the first The first probe The mass weighting coefficients corresponding to each measuring point.

[0047] The quality weighting coefficient The physical significance lies in correcting the energy measurement deviation caused by uneven exhaust velocity distribution. Due to the working characteristics of the last-stage turbine blades in a gas turbine, there are significant differences in velocity at different radii of the exhaust cylinder cross-section (typically, the velocity is lower at the root and tip, and higher in the middle). If only an arithmetic average is used, the contribution of the low-velocity region to the overall exhaust energy will be overestimated. By introducing local mass flow density as a weight, the calculated... Thermodynamically, it is closer to the weighted average temperature of the true enthalpy of gas turbine exhaust.

[0048] S130, in embodiments where it is necessary to reduce the number of measuring points or hardware costs, a simplified measuring point combination averaging calculation strategy is adopted. This strategy selects specific toroidal measuring points that can represent the characteristics of the exhaust flow field for calculation based on the flow field analysis results, instead of using all 135 measuring points.

[0049] A preferred simplified approach is the three-ring representation method, where measurement data from the 2nd, 5th, and 8th radial rings represent the entire exhaust cross-section. The 2nd ring is located at the root region of the flow channel, the 5th ring at the middle region, and the 8th ring at the tip region. This combination of three rings comprehensively covers the radial temperature distribution characteristics of the main flow channel. In this case, a total of 45 measurement points are used in the calculation, and the formula for calculating the average exhaust cross-section temperature is as follows: ; in, This represents the arithmetic mean of temperature measurement data from 45 measurement points across rings 2, 5, and 8. , , They represent the first Temperature measurement data at the 2nd, 5th, and 8th measuring points on the probe.

[0050] Another preferred simplification method is the single-ring representation method, which selects only the measurement data of the 5th radial ring to represent the entire exhaust cross-section. The 5th ring is located on the geometric center annular surface of the exhaust channel, where the influence of the hub wake and casing boundary layer is relatively small, and its temperature level is highly correlated with the overall average temperature. In this case, the total number of measurement points involved in the calculation is 15, and the formula for calculating the average exhaust cross-section temperature is as follows: ; in, This represents the arithmetic mean of temperature measurement data from 15 measuring points in the 5th ring. Indicates the first Temperature measurement data at the 5th measuring point on the probe.

[0051] The specific circuit connections and signal conditioning processes of the data acquisition hardware involved in the above steps are well-known technologies to those skilled in the art and will not be elaborated upon here. Through the above sub-steps, the system can obtain characteristic temperature values ​​reflecting the thermal state of the gas turbine exhaust, providing basic data for subsequent temperature correction.

[0052] Step S200 specifically includes the following sub-steps: S210, Obtain the reference temperature for correcting the average temperature of the exhaust section. Auxiliary temperature measuring points are arranged in the region downstream of cone 3 inside the gas turbine exhaust diffuser, i.e., at the exhaust volute inlet after the exhaust diffuser outlet or the transition section at the waste heat boiler inlet. In this region, relative to the gas turbine exhaust cylinder section, the airflow has undergone deceleration, pressurization, and free drift processes through the diffuser, resulting in more thorough flow mixing and better temperature distribution uniformity than the upstream exhaust section. Temperature data is simultaneously collected by multiple high-precision thermocouples arranged in this region, and the arithmetic average of the collected temperature data is calculated to obtain the reference temperature measurement value for the uniformly mixed downstream flow field of the exhaust, denoted as [reference temperature value]. This reference temperature measurement value Although it lags behind the measurement data of the exhaust section total temperature probe in terms of time response, it can more accurately reflect the overall exhaust enthalpy level of the gas turbine under steady-state conditions, and therefore serves as the true benchmark for verifying and correcting exhaust section temperature measurements.

[0053] S220, synchronously reads key operating parameters related to the current operating status from the gas turbine control system. These key operating parameters include at least the adjustable guide vane angle, relative load rate, and ambient temperature.

[0054] The adjustable guide vane angle is denoted as This refers to the opening angle of the adjustable guide vanes at the compressor inlet. This parameter directly determines the mass flow rate of air entering the gas turbine, thereby changing the residual swirl intensity and streamline distribution of the turbine exhaust.

[0055] The relative load factor is denoted as This refers to the ratio of the actual current output power of a gas turbine to its rated power under basic load conditions. This parameter reflects the power load level of the gas turbine and is strongly correlated with the overall distribution gradient of the exhaust temperature field.

[0056] Atmospheric ambient temperature is denoted as This refers to the atmospheric temperature at the gas turbine inlet. As a boundary condition of the thermodynamic cycle, this parameter affects the compressor's reduced speed and pressure ratio, thereby correcting the exhaust temperature field.

[0057] S230, in the data acquisition and analysis system, the average exhaust cross-sectional temperature obtained in step S100 is ( , , or (and the reference temperature measurement obtained in this step) and key operating parameters ( , , Timestamp alignment is performed to ensure that the data used in subsequent correction calculations all correspond to the gas turbine operating state at the same time or within the same steady-state time window, thereby eliminating calculation errors caused by data transmission delays or asynchronous acquisition. The specific implementation of the control system data communication interface is well-known to those skilled in the art and will not be elaborated upon here.

[0058] Step S300 specifically includes the following sub-steps: S310, Define the temperature correction factor and establish the basic deviation relationship. The reference temperature measurement value obtained in system calculation step S200. The difference between the average exhaust cross-section temperature calculated in step S100 and the average temperature in step S100 is defined as the temperature correction factor. The calculation formula is as follows: ; in, This represents the average exhaust section temperature calculated in the preceding steps, specifically corresponding to the arithmetic mean of all measurement points. Weighted average of all measurement points Simplified combined average or Any one of them.

[0059] S320 determines the operating condition boundary point for the exhaust flow field characteristics of the gas turbine, i.e. Inflection point. The system retrieves stored historical runtime data or fluid simulation data to construct a temperature correction factor. Adjustable guide vane angle The characteristic curve changes. Analyze the slope variation or standard deviation distribution characteristics of this characteristic curve to identify the critical angle value at which the exhaust flow field transitions from a strongly swirling unsteady state to a regular axial flow steady state. Set this critical angle value as... Inflection point, denoted as .

[0060] This inflection point corresponds, in fluid dynamics, to the transition of the gas turbine exhaust flow field from a strongly swirling state to an axial flow-dominated state. At low loads (small... At a certain angle, the exhaust gas flow at the turbine's final stage outlet has a large tangential velocity component, resulting in a high-intensity swirling structure in the exhaust flow field. At this point, the flow field is extremely sensitive to changes in flow rate caused by variations in guide vane opening. However, at high loads (large... At a certain angle, the airflow gradually shifts to axial outflow, and the flow field structure tends to be uniform and stable, mainly affected by the overall work load. Identifying this inflection point and performing segmented corrections solves the technical challenge that a single model cannot take into account the flow field characteristics under all working conditions.

[0061] In the actual control logic, the adjustable guide vane angle collected in real time will be... With preset The comparison is used to determine the current flow field operating condition range of the gas turbine.

[0062] S330, when the adjustable guide vane angle is collected in real time Less than or equal to At this point, the gas turbine is determined to be operating under low load or small angle conditions. Within this range, the exhaust flow rate is relatively low and significantly affected by the guide vane opening. The flow field in the exhaust support wake region exhibits strong instability, and the temperature correction coefficient is primarily related to the adjustable guide vane angle and the ambient atmospheric temperature. The system uses the first piecewise regression model to calculate the temperature correction coefficient, and the calculation formula is as follows: ; in, This is a temperature correction factor. The adjustable guide vane angle at the current moment. The current atmospheric temperature. The first angle coefficient, The first ambient temperature coefficient, This is the first intercept constant. The above coefficients... , and The historical operational data is obtained in advance and stored in the system through binary linear regression analysis or least squares fitting.

[0063] S340, when the adjustable guide vane angle is collected in real time Greater than When the gas turbine is in a high-load or large-angle operating range, it is determined that the gas turbine is operating within this range. Within this range, the exhaust flow rate increases with increasing load, the flow field structure tends to stabilize, and the influence of changes in the adjustable guide vane angle on the flow field morphology weakens. The temperature correction coefficient is mainly related to the relative load factor of the gas turbine and the ambient atmospheric temperature. The system uses a second-piece regression model to calculate the temperature correction coefficient, and the calculation formula is as follows: ; in, This is a temperature correction factor. The relative load factor at the current moment. The current atmospheric temperature. The load factor is the load factor. The second ambient temperature coefficient, This is the second intercept constant. The above coefficients... , and Similarly, the historical operating data under large-angle conditions are obtained in advance through binary linear regression analysis or least squares fitting and stored in the system.

[0064] The aforementioned coefficients are obtained using an offline modeling and online correction strategy. Specifically, during the gas turbine commissioning or performance testing phase, an operational sequence covering the entire operating range is artificially constructed. The collected historical dataset is then trained using a multiple linear regression algorithm or machine learning algorithm (such as support vector regression, SVR) to solve for the set of coefficients that minimizes the sum of squared residuals. This set of coefficients is then stored in the system to ensure the real-time nature of the online calculations.

[0065] Through the above steps, the present invention can automatically switch the correction model according to different operating conditions of the gas turbine, thereby accurately capturing the deviation pattern between the measured value of the exhaust section and the actual enthalpy value in the entire operating range.

[0066] See attached document Figure 5 Step S400 specifically includes the following sub-steps: S410, Perform the final correction and smoothing calculation for the exhaust temperature. The data acquisition and analysis system calls the average exhaust cross-sectional temperature obtained in step S100. And the temperature correction coefficient calculated in step S300 based on the current operating conditions. The two are algebraically superimposed to obtain the corrected summation value, denoted as . The calculation formula is as follows: ; in, This indicates the instantaneous temperature value for which only spatial and operational condition corrections have been completed. This represents the average temperature of the exhaust section. This is the temperature correction factor determined based on the current adjustable guide vane angle and load condition.

[0067] To prevent control signal jitter caused by random noise in the raw measurement data or high-frequency turbulent fluctuations in the airflow, the system... Time-domain smoothing is performed, and the result after processing is defined as the final exhaust temperature, denoted as . A first-order inertial filtering algorithm is used, and the formula is as follows: ; in: Indicates the current sampling time; The final exhaust temperature calculated at the current sampling time and after filtering (i.e., the final output of this step); This is the corrected summation value calculated at the current sampling time (i.e., the input to the filtering algorithm); This represents the final exhaust temperature output by the system at the previous sampling time. The filter coefficient (ranging from 0.1 to 0.3) is used to adjust the signal's response speed and smoothness.

[0068] S420 will calculate the final exhaust temperature The temperature data is transmitted in real time to the gas turbine control system as a process control variable. The data acquisition and analysis system establishes a data connection with the gas turbine controller (TCS) or distributed control system (DCS) through hard-wired communication (e.g., 4-20mA analog signal) or industrial Ethernet communication, and updates the temperature data at a refresh frequency no less than the control logic scan cycle, replacing the traditional single-point measurement value or simple average value as the core input parameter of the control system.

[0069] S430, the gas turbine control system utilizes the final exhaust temperature Execute combustion adjustment and protection logic. Specifically, the control system will... The values ​​are substituted into the gas turbine exhaust temperature control (OTC) logic and compared with the preset exhaust temperature setpoint. When When the value deviates from the setpoint, the control system outputs commands to adjust the opening of the fuel regulating valve or correct the angle of the compressor inlet adjustable guide vanes to maintain stable turbine exhaust energy. In addition, the control system will also... Used for over-temperature protection logic, when the value exceeds the preset alarm threshold or trip threshold, an alarm or emergency shutdown procedure is triggered to prevent damage to the exhaust diffuser and rear flue due to local overheating.

[0070] Compared to traditional uncorrected or simply averaging measurement schemes, this invention, through the aforementioned multi-dimensional correction strategy, eliminates systematic measurement errors introduced by uneven exhaust flow swirl distribution and changes in operating conditions. This ensures that the exhaust temperature data obtained by the control system remains highly consistent with the actual exhaust energy level of the thermodynamic cycle. This allows the gas turbine to operate at temperatures closer to its design limits (i.e., reducing the safety margin reserved to address measurement uncertainties), thereby improving the gas turbine's thermal efficiency and the overall output of the combined cycle while ensuring safety.

[0071] By applying the corrected temperature data, measurement deviations caused by uneven swirling flow distribution were eliminated, ensuring that the gas turbine operates under true thermodynamic boundary conditions across the entire operating range. The PID control algorithm and specific protection logic configuration within the control system are well-known techniques to those skilled in the art and will not be elaborated upon here.

[0072] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0073] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0074] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0075] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0076] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0077] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0078] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0079] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for correcting the exhaust temperature of a heavy-duty gas turbine, characterized in that, Includes the following steps: S100. Collect real-time temperature data at multiple measuring points by a total temperature probe array arranged on the exhaust section of the gas turbine, and calculate and process the real-time temperature data to obtain the average temperature of the exhaust section. S200: Collect real-time operating status data of the gas turbine and temperature data of the downstream area of ​​the exhaust gas to obtain gas turbine operating parameters and reference temperature data. The gas turbine operating parameters include at least the adjustable guide vane angle, relative load rate and ambient temperature. S300: Call the preset adjustable guide vane angle inflection point value, and select the corresponding regression model to calculate the temperature correction coefficient based on the relationship between the adjustable guide vane angle and the adjustable guide vane angle inflection point value. S400. The average temperature of the exhaust section is corrected using the temperature correction coefficient to obtain the final exhaust temperature.

2. The method for correcting the exhaust temperature of a heavy-duty gas turbine according to claim 1, characterized in that, In step S100, the process of obtaining the average temperature of the exhaust section adopts a mass-weighted average calculation strategy for all measuring points. The full-point mass weighted average calculation strategy includes: using fluid dynamics simulation to extract the local mass flow density values ​​at the physical location of the measuring points, and normalizing them to obtain the mass weighting coefficient for each measuring point; Calculate the product of the real-time temperature data of each measuring point and its corresponding mass weighting coefficient; sum all the products to obtain the average temperature of the exhaust section.

3. The method for correcting the exhaust temperature of a heavy-duty gas turbine according to claim 1, characterized in that, In step S100, the process of obtaining the average temperature of the exhaust section adopts a simplified measurement point combination averaging calculation strategy. The simplified measurement point combination averaging calculation strategy includes: selecting the data of the measurement points of the radial 2nd ring, 5th ring, and 8th ring to represent the entire exhaust cross section, wherein the 2nd ring is located in the root region of the flow channel, the 5th ring is located in the middle region of the flow channel, and the 8th ring is located in the tip region of the flow channel; performing an arithmetic average calculation on the real-time temperature data of all the measurement points of the selected 2nd ring, 5th ring, and 8th ring to obtain the average temperature of the exhaust cross section.

4. The method for correcting the exhaust temperature of a heavy-duty gas turbine according to claim 1, characterized in that, In step S200, the downstream region of the exhaust gas is selected as the exhaust volute inlet downstream of the inner cone of the gas turbine exhaust diffuser or the transition section of the waste heat boiler inlet. The reference temperature data is obtained by simultaneously collecting temperature data using multiple thermocouples arranged in the downstream region of the exhaust gas, and calculating the arithmetic average of the collected temperature data to obtain the reference temperature data.

5. The method for correcting the exhaust temperature of a heavy-duty gas turbine according to claim 1, characterized in that, In step S300, the adjustable guide vane angle inflection point value is a predetermined fixed value, and the method for obtaining the adjustable guide vane angle inflection point value is as follows: A fluid dynamics simulation model of the gas turbine exhaust flow field is established to simulate the flow field state under different adjustable guide vane angles. The critical angle at which the exhaust flow changes from a swirling state to an axial flow state is extracted as the inflection point value of the adjustable guide vane angle. The temperature correction factor is defined as the difference between the reference temperature data and the average temperature of the exhaust section.

6. The method for correcting the exhaust temperature of a heavy-duty gas turbine according to claim 5, characterized in that, In step S300, when the adjustable guide vane angle is less than or equal to the inflection point value of the adjustable guide vane angle, it is determined to be a low load or small angle operating condition range, and the temperature correction coefficient is calculated using the first piecewise regression model. The calculation process of the first piecewise regression model is as follows: the product of the adjustable guide vane angle and the first angle coefficient, the product of the atmospheric ambient temperature and the first ambient temperature coefficient, and the first intercept constant are summed to obtain the temperature correction coefficient.

7. The method for correcting the exhaust temperature of a heavy-duty gas turbine according to claim 5, characterized in that, In step S300, when the adjustable guide vane angle is greater than the inflection point value of the adjustable guide vane angle, it is determined to be a high load or large angle operating condition range, and the temperature correction coefficient is calculated using the second piecewise regression model. The calculation process of the second piecewise regression model is as follows: the product of the relative load rate and the load rate coefficient, the product of the atmospheric ambient temperature and the second ambient temperature coefficient, and the second intercept constant are summed to obtain the temperature correction coefficient.

8. The method for correcting the exhaust temperature of a heavy-duty gas turbine according to claim 1, characterized in that, The S400 step specifically includes: The average temperature of the exhaust section is algebraically superimposed with the temperature correction coefficient to obtain the corrected summation value; The corrected summation value is smoothed using a first-order inertial filtering algorithm to obtain the final exhaust temperature; The calculation process of the first-order inertial filtering algorithm is as follows: the product of the current corrected summation value and the filter coefficient is summed with the product of the final exhaust temperature output at the previous time and the complement of the filter coefficient to obtain the final exhaust temperature at the current time.

9. The method for correcting the exhaust temperature of a heavy-duty gas turbine according to claim 1, characterized in that, It also includes the following steps: The final exhaust temperature is transmitted to the gas turbine control system in real time as a process control variable. The gas turbine control system substitutes the final exhaust temperature into the exhaust temperature control curve logic and compares it with the set value. When it deviates from the set value, it outputs a command to adjust the opening of the fuel regulating valve or correct the angle of the adjustable guide vane at the compressor inlet.

10. A heavy-duty gas turbine exhaust temperature measuring device, characterized in that, A method for correcting the exhaust temperature of a heavy-duty gas turbine as described in any one of claims 1 to 9 includes: Exhaust cylinder outer casing (1); Fifteen nine-point total temperature probes are arranged in a circumferential array on the exhaust section (2); The inner cone of the exhaust diffuser located in the center of the exhaust channel (3); The inner support ring plate (4) is set on the inner end of the 9-point total temperature probe (2). Auxiliary temperature measuring points are arranged in the downstream region of the exhaust flow field; And a data acquisition system, which is connected to the 9-point total temperature probe (2) and the auxiliary temperature measuring point respectively, for acquiring temperature signals; The 9-point total temperature probe (2) includes a probe rod (5) and 9 temperature sensing node assemblies (6) arranged along the length direction; the temperature sensing node assembly (6) is provided with a shroud, which has an air inlet on the side facing the airflow and an exhaust outlet on the side facing away from the airflow. The 9-point total temperature probe (2) is fixed by a flange at one end near the outer casing (1) of the exhaust cylinder, and the other end, which extends into the inner side of the exhaust channel, is integrally formed with a connecting stud. The inner support ring plate (4) is a segmented structure. Every three adjacent 9-point total temperature probes (2) are divided into a group. The connecting studs of each group of 9-point total temperature probes (2) pass through the corresponding mounting holes on the inner support ring plate (4) and are locked and fixed. The inner support ring plate (4) is mounted on the inner cone (3) of the exhaust diffuser or the bearing support via a floating connection mechanism, the floating connection mechanism being configured to allow the inner support ring plate (4) to move radially.

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