Water injection control system and method based on gas turbine inter-stage flow field parameter measurement

Abstract

This invention discloses a water injection control system and method based on the measurement of interstage flow field parameters in a gas turbine, relating to the field of gas turbine control technology. It includes: an interstage flow field measurement module for acquiring interstage flow field parameters via a compressor interstage flow field parameter measurement device; a droplet evaporation calculation module for obtaining parameters of the interstage flow field during dry compression through dry compression tests and parameters of the interstage flow field during wet compression through wet compression tests, and calculating the droplet evaporation rate; and a humidification water injection control module for controlling and adjusting the water injection rate based on a comparison between the droplet evaporation rate and a given water injection rate. This invention can quantitatively represent how much liquid water evaporates into gaseous water during the compression process in the compressor after water injection in a gas turbine, and establishes a quantitative wet compression measurement and evaluation system to regulate the water injection rate.

Description

Technical Field

[0001] This invention relates to the field of gas turbine control technology, and in particular to a water injection control system and method based on the measurement of interstage flow field parameters of a gas turbine. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Wet compression, as a technology that can improve the output power of gas turbines, has been the subject of extensive theoretical research and computational simulation analysis. However, due to the complex wet compression process and the difficulties in actual experiments, a key question remains: how much liquid water evaporates and transforms into gaseous water after being sprayed during the compression process inside the compressor? Few studies have provided clear conclusions.

[0004] The difficulty of this problem lies in two aspects. First, the calculations are not accurate enough. Theoretical analysis and numerical simulations cannot quantify and accurately measure the impact of the harsh operating conditions inside the gas turbine, such as high speed, high pressure, and high temperature, on the droplets. Second, the measurement is difficult. The evaporation rate of the droplets is difficult to measure directly. At the same time, the confined space inside the gas turbine and the high temperature and high pressure working environment limit the placement of experimental measurement probes.

[0005] This issue is important for two reasons. On the one hand, water injection can increase the unit's output. For example, when the weather is hot, the efficiency of the gas turbine decreases and the output decreases. At this time, the power plant load is high, and water injection can increase the gas turbine's work capacity to increase power generation. On the other hand, excessive water injection can also have adverse effects on the gas turbine. Excessive water injection can lead to reduced compressor efficiency, a decrease in the total pressure recovery coefficient of the combustion chamber, incomplete combustion, a narrowing of the flameout boundary, an increase in turbine flow pressure, and a reduction in intake flow.

[0006] Therefore, how to establish a quantitative wet compression measurement and evaluation system, and use it to regulate the water injection volume, thereby improving the operating efficiency of the gas turbine, has become an urgent technical problem to be solved. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a water injection control system and method based on the measurement of interstage flow field parameters of a gas turbine. This system can quantitatively represent how much liquid water evaporates and transforms into gaseous water during the compression process in the compressor after water injection in the gas turbine. It also establishes a quantitative wet compression measurement and evaluation system to regulate the water injection volume.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution: The first aspect of this invention provides a water injection control system based on the measurement of interstage flow field parameters of a gas turbine, comprising: The interstage flow field measurement module is used to collect interstage flow field parameters through the compressor interstage flow field parameter measurement device; The droplet evaporation calculation module is used to obtain the parameters of the interstage flow field in the dry compression process through dry compression test, obtain the parameters of the interstage flow field in the wet compression process through wet compression test, calculate the droplet evaporation, and then summarize the overall evaporation of the droplets in each stage of the compressor during the wet compression process. The humidification spray control module is used to control and adjust the spray volume based on the comparison between the total droplet evaporation rate and the given spray volume.

[0009] Furthermore, the flow field parameters for the dry compression test include the total pressure, static pressure, and total temperature of the incoming flow, as well as the total pressure and static temperature of each stage of stationary blades.

[0010] Furthermore, the total pressure and static temperature of the stationary blades are measured using an interstage flow field parameter measuring device, which includes several probes and pressure measuring tubes.

[0011] Furthermore, the probe is a leaf-shaped probe, which is integrally welded to the stationary blade. The total pressure and static temperature data measured by the probe are connected to the outside through a pressure measuring tube with an outer diameter of 1 mm.

[0012] Furthermore, the probe includes four total pressure probes and two static pressure probes. The total pressure probes are positioned facing the incoming flow at the front of the stationary blade, while the static pressure probes are positioned facing away from the incoming flow at the rear of the stationary blade.

[0013] Furthermore, the droplet evaporation calculation module for each stage includes a wet compression test module, which is configured to set the initial water injection volume, maintain the core engine speed of the gas turbine at a constant speed, and conduct a wet compression test to obtain the parameters of the interstage flow field during the wet compression process.

[0014] Furthermore, the formula for calculating the amount of water vapor evaporated in a single stage is: , In the formula, It represents the ratio of droplet temperature to fluid temperature. M represents the ratio of droplet velocity to fluid velocity. w C represents the mass of the droplet. w V represents the specific heat capacity of water. in V out Let represent the inlet and outlet gas velocities, respectively, and L be the latent heat of vaporization of water. Let n be the amount of water vapor evaporation in the nth infinitesimal segment. Indicates the mass of dry air. Indicates the mass of water vapor. The specific heat at constant pressure of air. The specific heat at constant pressure of water vapor; The water vapor content (total evaporation rate of each stage of the compressor) after the Nth infinitesimal segment : .

[0015] A second aspect of the present invention provides a method for controlling the water injection volume based on the measurement of interstage flow field parameters of a gas turbine, comprising the following steps: Interstage flow field parameters are collected using a compressor interstage flow field parameter measurement device; The parameters of the interstage flow field in the dry compression process are obtained by dry compression test, and the parameters of the interstage flow field in the wet compression process are obtained by wet compression test. The evaporation rate of the droplets is calculated, and then the overall evaporation rate of the droplets in each stage of the compressor during the wet compression process is summarized. The water spray volume is controlled and adjusted based on the comparison between the total evaporation of droplets and the given spray volume.

[0016] Furthermore, the specific steps for controlling and adjusting the water spray volume based on the comparison between the droplet evaporation rate and the given spray volume are as follows: If the given water spray rate minus the calculated evaporation rate is greater than 0.1 kg / s, it indicates that the current water spray rate is greater than the set threshold, and the water supply rate will be reduced by 0.05 kg / s. If the difference between the given water spray volume and the calculated evaporation volume is less than 0.1 kg / s, then the absolute value of the difference between the two is compared. If the absolute value is also less than 0.1, it indicates that the current water spray volume is less than the set threshold, and the water spray volume is increased by 0.05 kg / s.

[0017] Furthermore, to prevent the cycle from continuing indefinitely, the process of increasing and decreasing the water volume is counted. If the increase and decrease are both adjusted more than 9 times, the adjustment is stopped and the water volume is kept constant.

[0018] The above one or more technical solutions have the following beneficial effects: This invention discloses a water spray control system and method based on the measurement of interstage flow field parameters of a gas turbine. Based on the measurement and calculation of interstage flow field parameters, a water spray control system for humidification spray is proposed, which can quantitatively describe the evaporation in the compressor after water spraying, and provide a basis for the adjustment of water spray volume.

[0019] The wet compression water injection control system can provide a basis for humidification of the gas turbine, ensuring that the water injection volume meets the humidification needs of the compressor, avoiding excessive water injection, and improving the operating efficiency of the gas turbine.

[0020] Based on this control method, the impact of water spraying on gas turbines can be further analyzed to ensure the operating status of gas turbines during long-term water spraying afterburners and improve the service life of gas turbines.

[0021] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0023] Figure 1 This is a structural diagram of the compressor interstage flow field parameter measuring device in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram illustrating the principle of the compressor interstage flow field parameter measurement scheme in Embodiment 1 of the present invention; Figure 3 This is a TS diagram of the wet compression process in Embodiment 1 of the present invention; Figure 4 This is a flowchart of the water injection volume control method based on the measurement of interstage flow field parameters of a gas turbine in Embodiment 2 of the present invention. Detailed Implementation

[0024] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. Example 1: Embodiment 1 of the present invention provides a water injection control system based on the measurement of interstage flow field parameters of a gas turbine, comprising: The interstage flow field measurement module is used to collect interstage flow field parameters through the compressor interstage flow field parameter measurement device. Taking the dry compression test as an example, the flow field parameters of the dry compression test include the total pressure, static pressure, and total temperature of the incoming flow, as well as the total pressure and static temperature of each stage stationary blade.

[0026] In this embodiment, the total pressure and static temperature of the stationary blades are measured using a compressor interstage flow field parameter measuring device, such as... Figure 1As shown, the compressor interstage flow field parameter measurement device includes several probes and pressure measuring tubes. The probes are blade-shaped and are integrally welded to the stationary blade. The probes are positioned 2 mm from the leading or trailing edge of the stationary blade, and the connection to the blade is achieved through welding.

[0027] The total pressure and static temperature data measured by the probes are connected to the outside via a pressure measuring tube with an outer diameter of 1 mm. Most of the tube is partially embedded in the pressure surface of the blade, with the remaining portion used for connection to the outside. The probes include four total pressure probes and two static pressure probes. The total pressure probes are positioned facing the incoming flow at the front of the stationary blade, while the static temperature probes are positioned facing away from the incoming flow at the rear of the stationary blade. This design allows for more accurate measurement of the static temperature and reduces the influence of incoming droplets on the temperature probes (water droplets wetting the probe surface can lead to inaccurate temperature measurements).

[0028] In this embodiment, the compressor stage measurement scheme is as follows: Figure 2 As shown, firstly, the Pitot tube and total temperature probe are placed in the air intake to obtain the total pressure, static pressure, and total temperature of the incoming flow, from which the outgoing airflow can be deduced. Then, the total pressure and static temperature of each stage of stationary blades are obtained through the blade-shaped probe. These parameters are summarized and input into the arithmetic unit, and then the evaporation rate of each stage of droplets is calculated by the droplet evaporation rate calculation module, thereby confirming the water supply.

[0029] The droplet evaporation calculation module is used to obtain the parameters of the interstage flow field in the dry compression process through dry compression test, obtain the parameters of the interstage flow field in the wet compression process through wet compression test, calculate the droplet evaporation, and then summarize the overall evaporation of the droplets in each stage of the compressor during the wet compression process.

[0030] In this embodiment, the droplet evaporation calculation module at each stage includes a dry compression test module, which is used to calculate the polytropic index of the compressor dry compression process.

[0031] First, a dry compression test was conducted. For ease of description, the relative humidity of the incoming air in the dry compression test was 0. The total pressure, static pressure, and static temperature of the dry compression process were measured by the interstage flow field measurement module.

[0032] By combining the relationship between total temperature and total pressure with the density formula, the inflow velocity and density can be obtained. Then, the inflow flow rate can be calculated through iteration. Finally, the total temperature formula is obtained as follows: , , , .

[0033] In the formula, P* represents the total fluid pressure, and P represents the static fluid pressure. Indicates fluid density, Indicates fluid velocity. Indicates the inflow rate, T* represents the total fluid temperature, T represents the static fluid temperature, Cp represents the isobaric specific heat capacity, and A in Indicates the area of ​​the import. The gas constant is =287J / (Kg·K).

[0034] The total pressure and static temperature at the outlet are obtained, and the outlet area can be measured. The outlet velocity can then be calculated, and the outlet total temperature can be obtained using the same method as for calculating the inlet total temperature. Let Tr be the ratio of the outlet to the inlet total temperature, and Pr be the ratio of the outlet to the inlet total pressure. Then, the polytropic index of the dry compression process of the compressor is... It can be represented as: .

[0035] In this embodiment, the droplet evaporation calculation module also includes a wet compression test module, which is configured to set the initial water injection volume, keep the gas turbine core engine speed constant, and conduct a wet compression test to obtain the parameters of the interstage flow field during the wet compression process.

[0036] Figure 3 The TS diagram of the wet compression process is given, which divides the wet compression process into two parts: one is the compression process of dry air and water vapor, and the other is the isobaric evaporation and heat absorption process of droplets.

[0037] For the wet compression process, the total pressure and static temperature after wet compression within each micro-segment can be obtained using the compressor stage flow field parameter measurement device. However, for the total temperature after dry compression within each micro-segment... It can be obtained from the following equation: , In the formula, This is the polytropic index for the dry compression process of the compressor. The specific heat at constant pressure of air. The specific heat at constant pressure of water vapor. Indicates the mass of dry air. P represents the mass of water vapor. rn The total pressure ratio is the ratio of the total pressure of the current stage to the total pressure of the previous stage. For the actual compressibility factor of water vapor, it is taken empirically. =1.4, because the water vapor content is relatively small compared to the air volume, the error in this value has little impact on the overall calculation. This represents the static temperature after the previous stage of wet compression, obtained through experimental measurement. In this embodiment, the micro-element segment consists of the moving blades and stationary blades of each stage.

[0038] For the isobaric evaporation and endothermic process of a single-stage wet-compressed droplet, the amount of water vapor evaporation can be calculated using the following formula: , In the formula, Indicates enthalpy of vaporization. Indicates the dry compression temperature. This indicates the temperature after isobaric heat absorption. It represents the ratio of droplet temperature to fluid temperature. This represents the ratio of droplet velocity to fluid velocity. In this embodiment, it is assumed that... =0.1, =0.9, M w C represents the mass of the droplet. w V represents the specific heat capacity of water. in V out Let L represent the inlet and outlet gas velocities, respectively, and L be the latent heat of vaporization of water, a constant value of 2.3 x 10^6. Let n be the amount of water vapor evaporation in the nth infinitesimal segment. Indicates the mass of dry air. Indicates the mass of water vapor. The specific heat at constant pressure of air. The specific heat at constant pressure of water vapor. This indicates the static temperature after the previous wet compression stage.

[0039] The water vapor content after the Nth infinitesimal segment (i.e., the total evaporation rate of each stage of the compressor) : .

[0040] The humidification spray control module is used to control and adjust the spray volume based on the comparison between the total droplet evaporation rate and the given spray volume.

[0041] In this embodiment, if the given water spray volume minus the calculated evaporation volume is greater than 0.1 kg / s, it indicates that the current water spray volume is greater than the set threshold, and the water supply volume will be reduced by 0.05 kg / s. If the difference between the given water spray volume and the calculated evaporation volume is less than 0.1 kg / s, then the absolute value of the difference between the two is compared. If the absolute value is also less than 0.1, it indicates that the current water spray volume is less than the set threshold, and the water spray volume is increased by 0.05 kg / s.

[0042] To avoid continuous cycling, the process of increasing and decreasing the water spray volume is counted. If both increases and decreases exceed 9 times, the adjustment is stopped, and the water spray volume remains constant. If the absolute value of the calculated result is greater than 0.1, it indicates an error in the model input, or that the gas turbine may be experiencing some unknown state. In this case, the test should be stopped, and the control system input should be checked for correctness, and any abnormalities in the gas turbine should be examined.

[0043] Example 2: Embodiment 2 of the present invention provides a method for controlling the water injection volume based on the measurement of interstage flow field parameters of a gas turbine, such as... Figure 4 As shown, it includes the following steps: Step 1: Collect interstage flow field parameters using the compressor interstage flow field parameter measurement device.

[0044] Step 2: Obtain the parameters of the interstage flow field in the dry compression process through dry compression test, obtain the parameters of the interstage flow field in the wet compression process through wet compression test, calculate the evaporation rate of droplets, and then summarize the overall evaporation rate of droplets in each stage of the compressor during the wet compression process.

[0045] In this embodiment, for a specific rotational speed, a dry compression test (without water injection) is first conducted. The gas turbine is started and accelerated to the specified speed, and the interstage flow field parameters of the dry compression test are obtained, thereby calculating the polytropic index of dry compression. Next, a wet compression test is conducted. The initial water injection volume is set to b. i =1, j=1, keep the rotational speed constant, and obtain the flow field parameters between stages in the wet compression test.

[0046] The amount of water evaporation is calculated based on the flow field parameters between stages in the dry compression test and the flow field parameters between stages in the wet compression test.

[0047] Step 3: Control and adjust the water spray volume based on the comparison between the total droplet evaporation rate and the given spray volume. The specific steps are as follows: If the given water spray rate minus the calculated evaporation rate is greater than 0.1 kg / s, it indicates that the current water spray rate is greater than the set threshold, and the water supply rate will be reduced by 0.05 kg / s. If the difference between the given water spray volume and the calculated evaporation volume is less than 0.1 kg / s, then the absolute value of the difference between the two is compared. If the absolute value is also less than 0.1, it indicates that the current water spray volume is less than the set threshold, and the water spray volume is increased by 0.05 kg / s.

[0048] To avoid continuous cycling, the process of increasing and decreasing the water spray volume is counted. If both increases and decreases exceed 9 times, the adjustment is stopped, and the water spray volume remains constant. If the absolute value of the calculated result is greater than 0.1, it indicates an error in the model input, or that the gas turbine may be experiencing some unknown state. In this case, the test should be stopped, and the control system input should be checked for correctness, and any abnormalities in the gas turbine should be examined.

[0049] The steps involved in the above embodiment two correspond to those in embodiment one. For specific implementation details, please refer to the relevant description section of embodiment one.

[0050] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0051] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A water spray control system based on the measurement of interstage flow field parameters of a gas turbine, characterized in that, include: The interstage flow field measurement module is used to collect interstage flow field parameters through the compressor interstage flow field parameter measurement device; The module for calculating the evaporation rate of droplets at each stage is used to obtain parameters of the interstage flow field during the dry compression process through dry compression tests to calculate the polytropic index of the compressor's dry compression process, and to obtain parameters of the interstage flow field during the wet compression process through wet compression tests, and to calculate the evaporation rate of droplets in each micro-element, thereby calculating the total droplet evaporation rate of each stage of the compressor during the wet compression process. Each micro-element consists of the moving and stationary blades of each stage. The wet compression process is divided into two parts: one is the compression process of dry air and water vapor, and the other is the isobaric evaporation and heat absorption process of droplets. For the isobaric evaporation and heat absorption process of droplets in a single-stage wet compression, the evaporation rate of droplets in each micro-element is calculated. For the wet compression process, the total pressure and static temperature inside each micro-element after wet compression are obtained by the compressor interstage flow field parameter measurement device. The humidification spray control module is used to control and adjust the spray volume based on the comparison between the total droplet evaporation rate and the given spray volume.

2. The water injection control system based on the measurement of interstage flow field parameters of a gas turbine as described in claim 1, characterized in that, The flow field parameters for the dry compression test include the total pressure, static pressure, and total temperature of the incoming flow, as well as the total pressure and static temperature of each stage of stationary blades.

3. The water injection control system based on the measurement of interstage flow field parameters of a gas turbine as described in claim 1, characterized in that, The total pressure and static temperature of the stationary blades are measured using an interstage flow field parameter measuring device for compressors. The device includes several probes and pressure measuring tubes.

4. The water injection control system based on the measurement of interstage flow field parameters of a gas turbine as described in claim 3, characterized in that, The probe is a leaf-shaped probe, which is integrally welded to the stationary blade. The total pressure and static temperature data measured by the probe are connected to the outside through a pressure measuring tube with an outer diameter of 1 mm.

5. The water injection control system based on the measurement of interstage flow field parameters of a gas turbine as described in claim 4, characterized in that, The probes include four total pressure probes and two static temperature probes. The total pressure probes are positioned facing the incoming flow at the front of the stationary blade, while the static temperature probes are positioned facing away from the incoming flow at the rear of the stationary blade.

6. The water injection control system based on the measurement of interstage flow field parameters of a gas turbine as described in claim 1, characterized in that, The droplet evaporation calculation module includes a wet compression test module, which is configured to set the initial water injection volume and conduct a wet compression test while keeping the core engine speed of the gas turbine constant, so as to obtain the parameters of the interstage flow field during the wet compression process.

7. A method for controlling water injection volume based on the measurement of interstage flow field parameters of a gas turbine, characterized in that, Includes the following steps: Interstage flow field parameters are collected using a compressor interstage flow field parameter measurement device; The parameters of the interstage flow field in the dry compression process are obtained through dry compression tests to calculate the polytropic index of the compressor's dry compression process. The parameters of the interstage flow field in the wet compression process are obtained through wet compression tests, and the evaporation rate of droplets in each micro-element is calculated, thereby calculating the total droplet evaporation rate of each stage of the compressor during wet compression. Each micro-element consists of the moving and stationary blades of each stage. The wet compression process is divided into two parts: the compression process of dry air and water vapor, and the isobaric evaporation and heat absorption process of droplets. For the isobaric evaporation and heat absorption process of droplets in a single-stage wet compression, the evaporation rate of droplets in each micro-element is calculated. For the wet compression process, the total pressure and static temperature inside each micro-element after wet compression are obtained using a compressor interstage flow field parameter measuring device. The water spray volume is controlled and adjusted based on the comparison between the total droplet evaporation rate and the given spray volume.

8. The water injection volume control method based on the measurement of interstage flow field parameters of a gas turbine as described in claim 7, characterized in that, The specific steps for controlling and adjusting the water spray volume based on the comparison between the total droplet evaporation rate and the given spray volume are as follows: If the given water spray rate minus the calculated evaporation rate is greater than 0.1 kg / s, it indicates that the current water spray rate is greater than the set threshold, and the water spray rate will be reduced by 0.05 kg / s. If the given water spray rate minus the calculated evaporation rate is less than 0.1 kg / s, then the absolute value of the difference between the two is compared. If the absolute value of the difference is also less than 0.1 kg / s, it indicates that the current water spray rate is less than the set threshold, and the water spray rate is increased by 0.05 kg / s.

9. The water injection volume control method based on the measurement of interstage flow field parameters of a gas turbine as described in claim 8, characterized in that, To prevent the cycle from continuing indefinitely, the process of increasing and decreasing the water volume is counted. If the increase and decrease are both adjusted more than 9 times, the adjustment is stopped and the water volume is kept constant.

Images