Pressure optimization control method and system for multi-nozzle steam ejector

Abstract

The invention relates to the technical field of injection control, and particularly discloses a pressure optimization control method and system for a multi-nozzle steam injector. Basic structure parameters and operation parameters of all nozzles of the multi-nozzle steam ejector are obtained firstly, then the critical ejection ratio is calculated according to the basic structure parameters, the steam margin coefficient is obtained according to the operation parameters and the preset critical pressure, then the turbulence intensity factor and the pressure fluctuation coefficient are obtained by combining the critical ejection ratio and the steam margin coefficient, and the fluctuation coefficient is compared with the preset threshold value; if the comparison exceeds the threshold value, the opening degree is calculated and adjusted according to the real-time flow deviation and the pressure balance degree, the opening degree of each nozzle is adjusted after the back pressure change sensitivity coefficient is corrected, the flow and the pressure are balanced, and coupling interference is reduced.

Description

Technical Field

[0001] This invention relates to the field of jet control technology, and in particular to a pressure optimization control method and system for a multi-nozzle steam ejector. Background Technology

[0002] Steam ejectors, as highly efficient and energy-saving devices that use high-pressure working steam to eject low-pressure fluids, are widely used in many industrial fields such as chemical, power, and refrigeration. Their core principle is to utilize the expansion and acceleration of working steam in the nozzle to create a low-pressure zone in the mixing chamber, drawing in the ejected fluid, which is then pressurized and discharged after mixing in the diffuser section. In recent years, to meet the demands of high-flow-rate ejection or improved efficiency, multi-nozzle steam ejector structures have gradually gained attention. Compared to single-nozzle structures, multi-nozzle designs can provide a more uniform flow field distribution, a larger flow area, and potential efficiency improvements. However, when multiple nozzles operate simultaneously, slight differences in manufacturing tolerances, installation deviations, inlet steam parameters (pressure, temperature, dryness), or uneven transmission of downstream back pressure fluctuations can easily lead to inconsistencies in the actual operating conditions (such as flow rate and outlet pressure) of each nozzle. This inconsistency can cause poor coupling and interference between nozzles, especially near critical operating conditions. Pressure fluctuations in one nozzle can easily be transmitted and amplified through the common mixing chamber and diffuser section, affecting the stable operation of other nozzles. Therefore, a pressure optimization control method for multi-nozzle steam ejectors is needed to solve the above problems. Summary of the Invention

[0003] The purpose of this invention is to provide a pressure optimization control method and system for a multi-nozzle steam ejector to solve the technical problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A pressure optimization control method for a multi-nozzle steam ejector includes: Obtain the operating parameters of each nozzle on a multi-nozzle steam ejector, wherein the operating parameters include basic structural parameters and operational parameters; The critical ejection ratio is obtained based on the aforementioned basic structural parameters; The steam state parameters of each nozzle are obtained based on the operating parameters, and multiple steam margin coefficients are obtained based on the steam state parameters of each nozzle and the preset critical pressure value. Multiple turbulence intensity factors are obtained based on multiple steam margin coefficients and the critical ejection ratio, and multiple pressure fluctuation coefficients are obtained based on multiple steam margin coefficients and multiple turbulence intensity factors; The pressure fluctuation coefficients are compared sequentially with preset thresholds; If the pressure fluctuation coefficient is greater than a preset threshold, it is determined that the nozzle needs to be optimized for control, and the nozzle adjustment opening of each nozzle is obtained. Based on the nozzle adjustment opening of each nozzle, pressure optimization control is performed on the opening of multiple basic nozzles.

[0005] Preferably, the step of obtaining the critical ejection ratio based on the basic structure parameters includes: Based on the aforementioned basic structural parameters, the number of nozzles, throat diameter, outlet diameter, diffusion angle (the angle between the inner walls of the diffuser section of the steam ejector), and the correlation coefficient of steam properties are obtained. The throat diameter ratio is obtained based on the throat diameter and the outlet diameter; Obtain the cavity volume that steam can occupy in the injector mixing chamber; The critical ejection ratio is obtained based on the number of nozzles, the throat diameter ratio, the diffusion angle, the cavity volume, and the correlation coefficient of the steam properties.

[0006] Preferably, the step of obtaining multiple steam margin coefficients based on the steam state parameters of each nozzle and a preset critical pressure value includes: Obtain the steam inlet pressure and outlet back pressure of each nozzle; The pressure difference is obtained based on the steam inlet pressure of each nozzle and the preset critical pressure value; Multiple steam margin coefficients are obtained based on the pressure difference between each nozzle and the outlet back pressure.

[0007] Preferably, the step of obtaining multiple pressure fluctuation coefficients based on multiple steam margin coefficients and multiple turbulence intensity factors includes: Get the bias number; Multiple pressure fluctuation coefficients are obtained based on the bias number, multiple steam margin coefficients, and multiple turbulence intensity factors, wherein the calculation formula is as follows: ; in, This represents the pressure fluctuation coefficient from the 0th to the nth. This represents the o-th steam margin coefficient. Let $\frac{0}{0}$ represent the $o$-th turbulence intensity factor, and $o$ represent the nozzle number, where $o = 1...n$. This represents the bias number.

[0008] Preferably, the step of obtaining the nozzle adjustment opening of each nozzle includes: Obtain the metering time period for each nozzle, wherein the metering time period includes the start time and the end time; The flow rate of each nozzle at multiple times within a metering time period is obtained, and the average flow rate of each nozzle within the metering time period is calculated based on the multiple flow rate values, the start time, and the end time. Calculate the real-time flow deviation of each nozzle at each moment based on the flow rate value of each nozzle at each moment and its corresponding average flow rate. Obtain the nozzle outlet pressure of each nozzle, including the continuous nozzle outlet pressure and the instantaneous nozzle outlet pressure; The pressure balance is obtained based on the continuous nozzle outlet pressure and the instantaneous nozzle outlet pressure; The nozzle adjustment opening of each nozzle is obtained based on the real-time flow deviation and pressure equalization of each nozzle.

[0009] Preferably, the step of pressure optimization control of the openings of multiple basic nozzles based on the nozzle adjustment opening of each nozzle includes: Obtain the rate of change of back pressure at the outlet of each nozzle and the degree of steam superheat; The back pressure change sensitivity coefficient is obtained based on the back pressure change rate and steam superheat of each nozzle. The nozzle adjustment opening is corrected based on the back pressure change sensitivity coefficient to obtain multiple corrected nozzle adjustment openings; The opening of the multiple base nozzles is adjusted according to the opening of the multiple correction nozzles to achieve optimized pressure control.

[0010] This application also provides a pressure optimization control system for a multi-nozzle steam ejector, including: The first acquisition module is used to acquire the operating parameters of each nozzle on the multi-nozzle steam ejector, wherein the operating parameters include basic structural parameters and operating parameters; The second acquisition module is used to acquire the critical ejection ratio based on the basic structure parameters; The third acquisition module is used to acquire the steam state parameters of each nozzle according to the operating parameters, and to acquire multiple steam margin coefficients according to the steam state parameters of each nozzle and the preset critical pressure value. The fourth acquisition module is used to acquire multiple turbulence intensity factors based on multiple steam margin coefficients and the critical ejection ratio, and to acquire multiple pressure fluctuation coefficients based on multiple steam margin coefficients and multiple turbulence intensity factors; The comparison module is used to sequentially compare multiple pressure fluctuation coefficients with preset thresholds; If the pressure fluctuation coefficient is greater than a preset threshold, it is determined that the nozzle needs to be optimized for control, and the nozzle adjustment opening of each nozzle is obtained. Based on the nozzle adjustment opening of each nozzle, pressure optimization control is performed on the opening of multiple basic nozzles.

[0011] Preferably, the second acquisition module includes: The first acquisition unit is used to acquire the number of nozzles, throat diameter, outlet diameter, diffusion angle, and steam property correlation coefficient based on the basic structural parameters. The second acquisition unit is used to acquire the throat diameter ratio based on the throat diameter and the outlet diameter; The third acquisition unit is used to acquire the cavity volume that steam can occupy in the injector mixing chamber; The fourth acquisition unit is used to acquire the critical ejection ratio based on the number of nozzles, the throat diameter ratio, the diffusion angle, the cavity volume, and the correlation coefficient of the steam properties.

[0012] This application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the above-described method.

[0013] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0014] The beneficial effects of this application are as follows: This invention first obtains the basic structural parameters and operating parameters of each nozzle of the multi-nozzle steam ejector, then calculates the critical ejection ratio (maximum ejection ratio for stable operation) based on the basic structural parameters, and then obtains the turbulence intensity factor (flow turbulence degree) and pressure fluctuation coefficient (fluctuation risk) based on the operating parameters and the preset critical pressure steam margin coefficient. The fluctuation coefficient is compared with the preset threshold. If the comparison exceeds the threshold, the opening is adjusted based on the real-time flow deviation and pressure balance. After correction by the back pressure change sensitivity coefficient, the opening of each nozzle is adjusted to balance the flow and pressure and reduce coupling interference. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a method flow according to an embodiment of this application.

[0016] Figure 2 This is a schematic diagram of the system structure according to an embodiment of this application.

[0017] Figure 3 This is a schematic diagram of the internal structure of a computer device according to an embodiment of this application.

[0018] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] like Figures 1-3 As shown, this application provides a pressure optimization control method for a multi-nozzle steam ejector, comprising: S1. Obtain the operating parameters of each nozzle on the multi-nozzle steam ejector, wherein the operating parameters include basic structural parameters and operating parameters; S2. Obtain the critical ejection ratio based on the basic structural parameters; S3. Obtain the steam state parameters of each nozzle according to the operating parameters, and obtain multiple steam margin coefficients according to the steam state parameters of each nozzle and the preset critical pressure value. S4. Obtain multiple turbulence intensity factors based on multiple steam margin coefficients and the critical ejection ratio, and obtain multiple pressure fluctuation coefficients based on multiple steam margin coefficients and multiple turbulence intensity factors; S5. The pressure fluctuation coefficients are compared with preset thresholds in sequence; If the pressure fluctuation coefficient is greater than a preset threshold, it is determined that the nozzle needs to be optimized for control, and the nozzle adjustment opening of each nozzle is obtained. Based on the nozzle adjustment opening of each nozzle, pressure optimization control is performed on the opening of multiple basic nozzles.

[0021] As described in steps S1-S5 above, when multiple nozzles operate simultaneously, slight differences in manufacturing tolerances, installation deviations, inlet steam parameters (pressure, temperature, dryness), or uneven transmission of downstream back pressure fluctuations can easily lead to inconsistencies in the actual operating states (e.g., flow rate, outlet pressure) of each nozzle. This inconsistency can cause poor coupling and interference between nozzles, especially when approaching critical operating conditions. Pressure fluctuations in one nozzle can easily be transmitted and amplified through the common mixing chamber and diffuser section, affecting the stable operation of other nozzles. This invention obtains the operating parameters of each nozzle on a multi-nozzle steam ejector. These operating parameters include basic structural parameters and operational parameters. Operational parameters (e.g., steam inlet pressure, outlet back pressure, flow rate of each nozzle) are collected through sensors (e.g., pressure sensors, flow sensors); basic structural parameters (e.g., number of nozzles, throat diameter, outlet diameter, diffusion angle) are obtained through equipment design documents or measurements. These operating parameters form the basis for subsequent analysis. Furthermore, the basic structural parameters determine the inherent characteristics of the ejector (e.g., upper limit of ejection capacity), while the operational parameters reflect the real-time operating state (e.g., whether the current pressure is close to the critical value). Then, the critical ejector ratio is obtained based on the aforementioned basic structural parameters. The critical ejector ratio is the maximum ejector ratio (the ratio of ejector fluid flow rate to working steam flow rate) that allows the ejector to operate stably. Its calculation requires consideration of the number of nozzles, the ratio of throat diameter to outlet diameter (throat ratio), diffusion angle, mixing chamber volume, and steam property correlation coefficients (such as steam density and specific heat capacity) from the basic structural parameters. Thus, the critical ejector ratio represents the "stability boundary" of the ejector; exceeding this value will lead to unstable operating conditions (such as rapid flow fluctuations). The basic structural parameters directly determine this boundary. For example, a larger throat ratio (a narrower throat relative to the outlet) results in more significant steam acceleration in the nozzle, leading to a higher critical ejector ratio. Next, the steam state parameters of each nozzle are obtained based on the operating parameters. Then, multiple steam margin coefficients are obtained based on the steam state parameters of each nozzle and the preset critical pressure value. The steam state parameters include the steam inlet pressure and outlet back pressure of each nozzle. The preset critical pressure value is the critical operating pressure of that nozzle model (e.g., 0.6 MPa in the design manual). The steam margin coefficient is calculated using the formula "(inlet pressure - preset critical pressure value) / outlet back pressure," reflecting the degree of deviation between the actual pressure and the critical pressure. In this way, the steam margin coefficient quantifies the "safety margin" of the nozzle deviating from the critical state. A larger coefficient indicates that the inlet pressure is much higher than the critical pressure, the steam energy is sufficient, and it is not prone to fluctuations; a smaller coefficient indicates that it is close to the critical state and the risk of fluctuations is high. For example, the inlet pressure of nozzle 1 is 0.8 MPa, the preset critical pressure is 0.6 MPa, and the outlet back pressure is 0.3 MPa. Its steam margin coefficient is (0.8-0.6) / 0.3≈0.67, indicating that there is a certain margin; if the inlet pressure drops to 0.65 MPa, the margin coefficient is (0.65-0.6) / 0.3≈0.17, which is close to the critical state and the risk of fluctuations increases. Next, multiple turbulence intensity factors are obtained based on multiple steam margin coefficients and the critical ejection ratio, and multiple pressure fluctuation coefficients are obtained based on multiple steam margin coefficients and multiple turbulence intensity factors. Among them, the turbulence intensity factor reflects the degree of turbulence in the steam flow within the nozzle and is related to the steam margin coefficient and the critical ejection ratio (when the margin coefficient is small and close to the critical ejection ratio, the fluid flow is more turbulent and the factor value is high). The pressure fluctuation coefficient can comprehensively quantify the amplitude and risk of pressure fluctuation. In this way, the turbulence intensity factor reflects the flow stability, while the pressure fluctuation coefficient is the core indicator for judging whether the nozzle may cause overall fluctuations—the larger the coefficient, the higher the pressure fluctuation risk of the nozzle and the easier it is to interfere with other nozzles. Finally, the pressure fluctuation coefficients are compared with preset thresholds in turn. The preset thresholds are set according to the requirements for stable operation of the injector (e.g., the threshold is determined to be 0.5 under a certain working condition through experiments). The pressure fluctuation coefficients of each nozzle are compared with the thresholds one by one. The threshold is the "red line" for determining whether intervention is needed. If the coefficient exceeds the threshold, it means that the pressure fluctuation of the nozzle may affect the overall stability and needs to be controlled immediately; if it does not exceed the threshold, no adjustment is needed. If the pressure fluctuation coefficient is greater than a preset threshold, it is determined that the nozzle needs optimized control. The nozzle adjustment opening of each nozzle is obtained, and pressure optimization control is performed on the openings of multiple basic nozzles based on the nozzle adjustment openings of each nozzle. The nozzle adjustment opening is calculated by combining the real-time flow deviation (the difference between the actual flow and the average flow) and the pressure balance (the consistency between the continuous outlet pressure and the instantaneous outlet pressure) within the metering time period, reflecting the adjustment range (such as opening or closing the nozzle valve). The optimized control is achieved by adjusting the opening (by combining the back pressure sensitivity coefficient obtained from the outlet back pressure change rate and steam superheat) to adjust the basic opening of each nozzle, so that the flow and pressure tend to be consistent. In this way, by precisely adjusting the opening, the steam flow and pressure of each nozzle are balanced, reducing coupling interference caused by inconsistent states. For example, if the flow of a certain nozzle is too high and the pressure is too low, the flow is reduced by closing the opening to match the pressure of other nozzles.

[0022] In one embodiment, step S2, which involves obtaining the critical ejection ratio based on the infrastructure parameters, includes: S201. Obtain the number of nozzles, throat diameter, outlet diameter, diffusion angle, and steam property correlation coefficient based on the aforementioned basic structural parameters; S202. Obtain the throat diameter ratio based on the throat diameter and the outlet diameter; S203. Obtain the cavity volume that steam can occupy in the injector mixing chamber; S204. The critical ejection ratio is obtained based on the number of nozzles, the throat diameter ratio, the diffusion angle (the angle between the inner walls of the diffuser section of the steam ejector), the cavity volume, and the steam property correlation coefficient, wherein the calculation formula is: ; in, Indicates the critical ejection ratio. This represents the correlation coefficient of steam properties. Indicates the number of nozzles. Indicates the throat diameter ratio. The diffuse angle is represented by V, and the cavity volume is represented by V.

[0023] As described in steps S201-S204 above, this invention obtains the number of nozzles, throat diameter, outlet diameter, diffusion angle (the angle between the inner walls of the diffuser section of the steam ejector), and steam property correlation coefficient based on the aforementioned basic structural parameters. The number of nozzles is determined during design (e.g., 4 nozzles); the throat diameter (the diameter at the narrowest point of the nozzle) and outlet diameter (the diameter at the end of the diffuser section of the nozzle) are measured using vernier calipers; the diffusion angle is the angle between the inner walls of the diffuser section, and the steam property correlation coefficient is obtained by comparing the working steam type (e.g., saturated steam, superheated steam) with a preset reference table. In this scheme, the diffusion angle... Increasing the diffusion angle improves fluid mixing. When in the range of [0°, 90°], Monotonically increasing, but excessively large values ​​may lead to flow separation. The formula only reflects the positive effect and needs to be limited. (To avoid separation zones), for example, the property coefficient of saturated steam is taken as 0.85. These parameters are the basis for determining the "geometric boundary" and "fluid characteristics" of the ejector. For example, the more nozzles there are, the larger the total flow area and the stronger the potential ejection capability, but the more complex the flow field interference also becomes. An excessively large diffusion angle will lead to fluid separation (increasing energy loss), while an excessively small angle will result in low efficiency in converting kinetic energy into pressure energy. Both need to be quantified through parameters. For example, the basic structural parameters of a multi-nozzle steam ejector are: 3 nozzles, throat diameter 10mm, outlet diameter 20mm, diffusion angle 10°, and working steam is superheated steam (steam property correlation coefficient 0.9). These parameters directly determine the "physical limits" of its fluid flow. Next, the throat diameter ratio is obtained based on the throat diameter and the outlet diameter. The throat diameter ratio reflects the degree of "contraction-expansion" of the nozzle: the smaller the throat diameter ratio (the wider the outlet is relative to the throat), the more complete the deceleration process of the steam in the diffusion section, the better the pressure recovery effect, and the higher the critical ejection ratio may be; conversely, if the throat diameter ratio is too large, the diffusion effect is weak and the critical ejection ratio decreases. Then, the cavity volume that steam can occupy in the injector mixing chamber is obtained, where the cavity volume is the internal space volume of the mixing chamber (if the mixing chamber is cylindrical, the volume = π × radius² × length), or it can be measured by water injection. The mixing chamber is the core area for mixing the working steam and the ejector fluid. If the cavity volume is too small, the two fluids will not mix sufficiently (forming local high or low pressure zones, causing fluctuations); if the volume is too large, the fluid will remain in the mixing chamber for too long, increasing energy loss (reducing ejection efficiency). Therefore, the contribution of the cavity volume can be weakened by using the square root (diminishing marginal returns). Thus, the cavity volume is a key "spatial parameter" affecting the critical ejection ratio. Finally, the critical ejection ratio is obtained based on the number of nozzles, the throat diameter ratio, the diffusion angle, the cavity volume, and the correlation coefficient of steam properties. The critical ejection ratio is a core indicator for the stable operation of a multi-nozzle steam ejector, defined as the ratio of the maximum ejector fluid flow rate to the working steam flow rate that the ejector can stably eject. When the actual ejection ratio approaches or exceeds the critical ejection ratio, the ejector is prone to entering unstable operating conditions (such as turbulent flow field and severe pressure fluctuations). Secondly, by comprehensively considering the above parameters, the maximum stable ejection capability of the ejector is accurately determined. This critical value is a "quantitative scale" for judging whether the ejector is approaching an unstable state. The closer the actual ejection ratio is to this value, the higher the risk of pressure fluctuations between nozzles. Simultaneously, by comprehensively extracting the number of nozzles, throat diameter, outlet diameter, diffusion angle, cavity volume, and correlation coefficient of steam properties from the basic structural parameters, the critical ejection ratio is calculated through multi-parameter coupling, comprehensively covering the influence of geometric structure, flow field interference, energy conversion, and fluid characteristics, ensuring that the critical value is consistent with the actual operating conditions.

[0024] In one embodiment, step S3, which involves obtaining multiple steam margin coefficients based on the steam state parameters of each nozzle and a preset critical pressure value, includes: S301. Obtain the steam inlet pressure and outlet back pressure of each nozzle; S302. Obtain the pressure difference value based on the steam inlet pressure of each nozzle and the preset critical pressure value; S303. Obtain multiple steam margin coefficients based on the pressure difference between each nozzle and the outlet back pressure.

[0025] As described in steps S301-S304 above, this invention first acquires the steam inlet pressure and outlet back pressure of each nozzle. Specifically, the steam inlet pressure is measured by installing a pressure sensor (e.g., a piezoelectric pressure sensor with an accuracy of ±0.5%) at the steam pipe inlet of each nozzle to collect pressure data in real time (unit: MPa). The outlet back pressure is measured by installing a pressure sensor at the outlet end of each nozzle (near the mixing chamber inlet) to collect downstream back pressure data (unit: MPa). Thus, the inlet pressure reflects the driving energy, and the outlet back pressure reflects the flow resistance; both together determine the pressure gradient and velocity distribution within the nozzle. For example, insufficient inlet pressure or excessive back pressure will lead to insufficient steam expansion and a decrease in flow velocity. For instance, in the nozzle system, the sensor collects the following data: nozzle 1 has an inlet pressure of 0.7 MPa and an outlet back pressure of 0.3 MPa; nozzle 2 has an inlet pressure of 0.65 MPa and an outlet back pressure of 0.32 MPa. Then, the pressure difference is obtained based on the steam inlet pressure of each nozzle and the preset critical pressure value. The preset critical pressure value is determined through experiments or fluid simulation (such as CFD simulation) based on the nozzle's basic structural parameters (e.g., throat diameter, steam type). For example, the critical pressure value for a certain type of nozzle is 0.5 MPa (stored in the control system's parameter library). Next, the pressure difference is calculated using the formula: Pressure difference ΔP = Steam inlet pressure - Preset critical pressure value. This pressure difference directly reflects the "absolute margin" of the inlet pressure exceeding the critical pressure. A positive ΔP indicates that the current pressure is higher than the critical value, providing a certain safety margin; a negative ΔP or close to zero indicates that the pressure is lower than or close to the critical value, posing a risk of flow instability. Next, multiple steam margin coefficients are obtained based on the pressure difference of each nozzle and the outlet back pressure. The formula for calculating the steam margin coefficient is: Steam margin coefficient = Pressure difference / Outlet back pressure. The values ​​in this scheme are calculated after normalization. For example, the pressure difference is normalized by the outlet back pressure to eliminate the influence of different back pressure environments on the margin assessment. Thus, the steam margin coefficient is a quantitative indicator of "relative safety margin". The larger the steam margin coefficient value, the higher the margin of the inlet pressure relative to the critical pressure, and the smaller the inhibitory effect of the outlet back pressure, and the more stable the flow. The smaller the steam margin coefficient value, the closer it is to the critical state, and the higher the risk of pressure fluctuation.

[0026] In one embodiment, step S4, which involves obtaining multiple pressure fluctuation coefficients based on multiple steam margin coefficients and multiple turbulence intensity factors, includes: S401, Obtain the bias value; S402. Obtain multiple pressure fluctuation coefficients based on the bias number, multiple steam margin coefficients, and multiple turbulence intensity factors, wherein the calculation formula is: ; in, This represents the pressure fluctuation coefficient from the 0th to the nth. This represents the o-th steam margin coefficient. Let $\frac{0}{0}$ represent the $o$-th turbulence intensity factor, and $o$ represent the nozzle number, where $o = 1...n$. This represents the bias number.

[0027] As described in steps S401-S402 above, the present invention first obtains the bias number, where the bias number (A) is the inherent small pressure fluctuation value of the multi-nozzle steam ejector during stable operation, determined experimentally: under conditions of no load or low load (far from the critical ejection ratio) and consistent nozzle states, the pressure fluctuation data of each nozzle is continuously collected by a pressure sensor, and the statistical average value is taken as the bias number (the unit is consistent with the pressure fluctuation coefficient, and after dimensionless processing, it is usually 0.05-0.2). For example, the minimum average fluctuation value of a system under stable conditions is experimentally measured to be 0.1, so A=0.1. In this way, the bias number represents the "unavoidable basic fluctuation" of the system, which is used to correct the calculation results, avoid misjudging the inherent small fluctuation as a risk fluctuation that needs to be optimized, and at the same time, it can eliminate the inherent noise interference of the system, making the pressure fluctuation coefficient closer to the actual risk. Then, multiple pressure fluctuation coefficients are obtained based on the bias number, multiple steam margin coefficients, and multiple turbulence intensity factors, wherein a larger steam margin coefficient (higher safety margin) and a smaller turbulence intensity factor (more stable flow) are obtained. The smaller the term, the smaller the pressure fluctuation coefficient after superimposing the bias number (the lower the risk). At the same time, it couples "safety margin" with "flow turbulence" to directly quantify the "controllability" of pressure fluctuation. When the safety margin is high and the flow is stable, the fluctuation coefficient is small (low risk); conversely, the risk is high. In summary, in multi-nozzle steam ejectors, pressure fluctuations are the direct cause of system instability. The root cause of these fluctuations lies in the coupling effect between the turbulent characteristics of the steam flow and the degree to which the nozzle deviates from the critical state (i.e., steam margin). The turbulence intensity factor reflects the degree of turbulence in the steam flow within the nozzle and mixing chamber (the stronger the turbulence, the more inhomogeneous the flow field, and the more severe the pressure fluctuations). Its magnitude is related to the steam margin coefficient (distance from the critical state) and the critical ejection ratio (stability boundary)—the smaller the steam margin (closer to the critical state) and the lower the critical ejection ratio (narrower the stability boundary), the greater the turbulence intensity and the more severe the steam pressure fluctuations. Margin coefficient: quantifies the safety margin of the nozzle from the critical state (as explained in weight 3). The smaller the margin, the easier it is for turbulence to be amplified, and the higher the risk of pressure fluctuation. Pressure fluctuation coefficient: combines turbulence intensity (the "intensity source" of fluctuation) and steam margin (the "amplification condition" of fluctuation), and is corrected by the bias number (the inherent small fluctuation of the system). Finally, it quantifies the actual pressure fluctuation amplitude and risk level of each nozzle. Therefore, it is necessary to calculate the pressure fluctuation coefficient through this step in order to transform the "degree of flow turbulence" and "distance from the critical state" into quantitative indicators that can be directly used for judgment, laying the foundation for subsequent threshold comparison.

[0028] In one embodiment, step S5, which involves obtaining the nozzle adjustment opening of each nozzle, includes: S501. Obtain the metering time period for each nozzle, wherein the metering time period includes the start time and the end time; S502. Obtain the flow rate of each nozzle at multiple times within the metering time period, and calculate the average flow rate of each nozzle within the metering time period based on the multiple flow rate values, the start time, and the end time. S503. Calculate the real-time flow deviation of each nozzle at each moment based on the flow rate value of each nozzle at each moment and its corresponding average flow rate. S504. Obtain the nozzle outlet pressure of each nozzle, wherein the nozzle outlet pressure includes the continuous nozzle outlet pressure and the instantaneous nozzle outlet pressure. S505. Obtain the pressure balance based on the continuous nozzle outlet pressure and the instantaneous nozzle outlet pressure; S506. Obtain the nozzle adjustment opening of each nozzle based on the real-time flow deviation and pressure equalization of each nozzle.

[0029] As described in steps S501-S506 above, the present invention first obtains the metering time period for each nozzle. The metering time period includes a start time and an end time. The metering time period is set by the control system according to the stability requirements of the operating conditions, and is usually selected as the smallest time window that can reflect the dynamic changes in flow and pressure (e.g., 1 minute, start time t0=09:00:00, end time t1=09:00:60). This time period needs to cover at least 10 sampling points (to avoid errors caused by insufficient data). The data is collected in real time by flow sensors and pressure sensors installed at the outlet of each nozzle (sampling frequency 1-10Hz, i.e., 1-10 times per second). This introduces a time-dimensional metering window to avoid the randomness of a single instantaneous value (such as instantaneous flow jumps caused by sudden interference), so that subsequent analysis is based on "dynamic trends over a period of time", which is closer to the actual operating state. Then, the nozzle flow rates at multiple times within the metering time period are obtained, and the average flow rate of each nozzle within the metering time period is calculated based on the multiple flow rate values, the start time, and the end time. The calculation formula is as follows: ; in, Indicates average flow rate. Indicates the start time. Indicates the end time. This represents the flow rate value, and n represents the number of flow rate values, where n = 1, 2, 3...n; This average flow rate reflects the "baseline flow rate level" of the nozzle during the metering period, providing a reference for determining whether the instantaneous flow rate deviates from the normal range. Next, based on the flow rate value of each nozzle at each moment and its corresponding average flow rate, the real-time flow rate deviation of each nozzle at each moment is calculated, where the calculation formula is: ; in, Indicates real-time traffic deviation. This represents the l-th flow value. This indicates the number of flow values, where l represents the sequence number of the flow value. Indicates average flow rate; This real-time flow deviation quantifies the degree of deviation between the flow rate and the baseline level at a given moment. The larger the absolute value of the deviation, the more unstable the flow rate at that moment, and the more significant the interference with the flow field in the mixing chamber. Subsequently, the nozzle outlet pressure of each nozzle is acquired. The nozzle outlet pressure includes continuous nozzle outlet pressure and instantaneous nozzle outlet pressure. The instantaneous nozzle outlet pressure is the pressure value at a certain moment (e.g., the pressure at t=10:00:30, P_instant = 0.32MPa) acquired by a high-frequency pressure sensor (sampling frequency 10Hz) installed at the nozzle outlet. The continuous nozzle outlet pressure is the average of all instantaneous pressures within the measurement period (e.g., the average of 600 instantaneous pressures within 2 minutes, denoted as P_hold = 0.3MPa). Thus, the instantaneous pressure reflects the pressure state at a certain moment, while the continuous pressure reflects the average pressure level within the time period. The difference between the two directly reflects the pressure stability (the greater the difference, the more drastic the pressure fluctuation). For example, if the instantaneous pressure of the nozzle fluctuates between 0.28-0.35MPa within 2 minutes, the continuous pressure P_hold = 0.3MPa, and the instantaneous pressure P_instant = 0.35MPa, the significant difference indicates poor pressure stability. Simultaneously, the pressure equalization degree is obtained based on the continuous nozzle outlet pressure and the instantaneous nozzle outlet pressure. The pressure equalization degree is calculated by the relative deviation between the two, using the following formula: ,in, Indicates the degree of pressure balance. Indicates the instantaneous nozzle outlet pressure. E represents the continuous nozzle outlet pressure (dimensionless, ranging from 0 to 1). The closer E is to 1, the closer the instantaneous pressure is to the continuous pressure, and the more stable the pressure; the closer E is to 0, the more drastic the pressure fluctuation. Finally, the nozzle adjustment opening of each nozzle is obtained based on the real-time flow deviation and pressure equalization of each nozzle. This requires considering multiple base nozzle openings, where the base nozzle openings are preset initial nozzle openings, the real-time flow deviation of each nozzle, and the pressure equalization of each nozzle. Where H represents the nozzle adjustment opening and K1 represents the flow deviation weighting coefficient. This indicates the real-time flow deviation, where the adjustment direction is from... The sign of the deviation determines the opening; a positive deviation requires a smaller opening, while a negative deviation requires a larger opening. The pressure balance is represented by j(c), which represents the base nozzle opening. The adjustment range of the opening is positively correlated with the flow deviation (the amount of base nozzle opening that needs to be corrected) and the pressure stability (the urgency of adjusting the base nozzle opening). When the flow deviation is large and the pressure is unstable, a larger adjustment is required to quickly balance the pressure; otherwise, a fine adjustment is needed.

[0030] In one embodiment, step S5, which performs pressure optimization control on the openings of multiple base nozzles based on the nozzle adjustment opening of each nozzle, includes: S507. Obtain the outlet back pressure change rate and steam superheat of each nozzle; S508. Obtain the back pressure change sensitivity coefficient based on the back pressure change rate and steam superheat of each nozzle. S509. Correct the nozzle adjustment opening according to the back pressure change sensitivity coefficient to obtain multiple corrected nozzle adjustment openings; S5010. Adjust the opening of the multiple base nozzles according to the opening of the multiple correction nozzles to achieve pressure optimization control.

[0031] As described in steps S507-S5010 above, the present invention first obtains the outlet back pressure change rate and steam superheat of each nozzle. The outlet back pressure change rate is obtained by continuously collecting back pressure data (such as the basic nozzle opening) through a pressure sensor at the nozzle outlet (sampling frequency ≥10Hz). The basic nozzle opening PO1 at any time (Base nozzle opening PO2 at time), calculate the pressure change per unit time: back pressure change rate = (Unit: MPa / s), positive values ​​indicate pressure increase, negative values ​​indicate decrease. Steam superheat: The steam temperature (via a thermocouple sensor at the nozzle inlet, accuracy ±1℃ of the base nozzle opening) and the corresponding saturation temperature at that pressure must be collected simultaneously. Superheat base nozzle opening = base nozzle opening - actual temperature base nozzle opening - base nozzle opening saturation temperature (unit: ℃). These two factors together constitute the "operating condition sensitivity" of the base nozzle opening. The back pressure change rate of the base nozzle opening reflects the dynamic stability of the downstream pressure, while superheat reflects the phase change risk of the steam itself; both directly affect the safety of the opening adjustment. For example: The pressure sensor at nozzle opening 1 collects data within seconds showing a back pressure increase from 0.3 MPa to 0.32 MPa. The back pressure change rate is (0.32 - 0.3) / 1 = 0.02 MPa / s (rapid pressure increase). The actual steam temperature is 180℃, and the saturation temperature corresponding to a 0.7 MPa nozzle opening is 164℃. The superheat is 180 - 164 = 16℃ (moderate superheat). Next, the back pressure change sensitivity coefficient is obtained based on the outlet back pressure change rate and steam superheat of each nozzle. The back pressure change sensitivity coefficient (S) is calculated through empirical formulas or experimental models. The core logic is: the larger the absolute value of the outlet back pressure change rate (the more violent the pressure fluctuation), the larger S is; the smaller the steam superheat (closer to saturation), the larger S is (due to high phase change risk, the adjustment sensitivity is high). The formula is: Back pressure change sensitivity coefficient = Outlet back pressure change rate * a1 + Steam superheat * a2, where a1 and a2 are the weight values ​​corresponding to the outlet back pressure change rate and steam superheat. In this way, the sensitivity coefficient S quantifies "how much pressure fluctuation risk will be caused by a 1% opening adjustment under the current operating conditions". The larger S is, the stronger the pressure disturbance caused by the same opening adjustment, and the adjustment range needs to be reduced; the smaller S is, the more stable the operating conditions, and the adjustment can be carried out as planned. The outlet back pressure change rate reflects the dynamic stability of the downstream operating conditions, and its change will directly affect the flow resistance of steam in the nozzle and the coupling effect with other nozzles. For example, when the back pressure rises rapidly, steam expansion is hindered, which may cause flow fluctuations. In this case, the steam is highly sensitive to opening adjustments. Steam superheat reflects the phase change risk of the steam itself. The lower the superheat, the closer the steam is to saturation. Even a small pressure change may cause some steam to condense, thereby changing the steam's flow and pressure characteristics. It is also more sensitive to opening adjustments. Therefore, in this scheme, the weight of steam superheat is greater than that of the outlet back pressure change rate. Then, the nozzle adjustment opening is corrected according to the back pressure change sensitivity coefficient to obtain multiple corrected nozzle adjustment openings. The formula for calculating the corrected nozzle adjustment opening H1 is: H1=H / (1+S), where H is the nozzle adjustment opening in S506 and S is the back pressure change sensitivity coefficient. Finally, the openings of the multiple base nozzles are adjusted according to the openings of the multiple corrective nozzles to achieve optimized pressure control. The base nozzle opening refers to the initial opening of each nozzle (e.g., collected by an opening sensor or recorded by the control system as the current valve position, such as 30%). Based on the direction of the corrective nozzle opening (determined by the positive or negative flow deviation in S503; a positive deviation closes the valve, and a negative deviation opens it), the base opening is adjusted: final opening = base opening ± corrective nozzle opening. This applies the corrected "safe adjustment amount" to the actual valve, realizing the transformation from "theoretical calculation" to "physical execution." This ensures that the final opening of each nozzle balances the flow and pressure deviations and adapts to the sensitivity of real-time operating conditions, ultimately making the pressure of the multi-nozzle system tend to be stable and consistent.

[0032] This application also provides a pressure optimization control system for a multi-nozzle steam ejector, including: The first acquisition module is used to acquire the operating parameters of each nozzle on the multi-nozzle steam ejector, wherein the operating parameters include basic structural parameters and operating parameters; The second acquisition module is used to acquire the critical ejection ratio based on the basic structure parameters; The third acquisition module is used to acquire the steam state parameters of each nozzle according to the operating parameters, and to acquire multiple steam margin coefficients according to the steam state parameters of each nozzle and the preset critical pressure value. The fourth acquisition module is used to acquire multiple turbulence intensity factors based on multiple steam margin coefficients and the critical ejection ratio, and to acquire multiple pressure fluctuation coefficients based on multiple steam margin coefficients and multiple turbulence intensity factors; The comparison module is used to sequentially compare multiple pressure fluctuation coefficients with preset thresholds; If the pressure fluctuation coefficient is greater than a preset threshold, it is determined that the nozzle needs to be optimized for control, and the nozzle adjustment opening of each nozzle is obtained. Based on the nozzle adjustment opening of each nozzle, pressure optimization control is performed on the opening of multiple basic nozzles.

[0033] In one embodiment, the second acquisition module includes: The first acquisition unit is used to acquire the number of nozzles, throat diameter, outlet diameter, diffusion angle, and steam property correlation coefficient based on the basic structural parameters. The second acquisition unit is used to acquire the throat diameter ratio based on the throat diameter and the outlet diameter; The third acquisition unit is used to acquire the cavity volume that steam can occupy in the injector mixing chamber; The fourth acquisition unit is used to acquire the critical ejection ratio based on the number of nozzles, the throat diameter ratio, the diffusion angle, the cavity volume, and the correlation coefficient of the steam properties.

[0034] This application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the above-described method.

[0035] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0036] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in this application and in the embodiments can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual-speed SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0037] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0038] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A pressure optimization control method for a multi-nozzle steam ejector, characterized in that, include: Obtain the operating parameters of each nozzle on a multi-nozzle steam ejector, wherein the operating parameters include basic structural parameters and operational parameters; The critical ejection ratio is obtained based on the aforementioned basic structural parameters; The steam state parameters of each nozzle are obtained based on the operating parameters, and multiple steam margin coefficients are obtained based on the steam state parameters of each nozzle and the preset critical pressure value. Multiple turbulence intensity factors are obtained based on multiple steam margin coefficients and the critical ejection ratio, and multiple pressure fluctuation coefficients are obtained based on multiple steam margin coefficients and multiple turbulence intensity factors; The pressure fluctuation coefficients are compared sequentially with preset thresholds; If the pressure fluctuation coefficient is greater than a preset threshold, it is determined that the nozzle needs to be optimized. The basic nozzle opening of each nozzle on the multi-nozzle steam ejector is obtained, and the nozzle adjustment opening of each nozzle is obtained. Based on the nozzle adjustment opening of each nozzle, the pressure optimization control of the multiple basic nozzle openings is performed.

2. The pressure optimization control method for a multi-nozzle steam ejector according to claim 1, characterized in that, The step of obtaining the critical ejection ratio based on the basic structure parameters includes: The number of nozzles, throat diameter, outlet diameter, diffusion angle, and correlation coefficient of steam properties are obtained based on the aforementioned basic structural parameters. The throat diameter ratio is obtained based on the throat diameter and the outlet diameter; Obtain the cavity volume that steam can occupy in the injector mixing chamber; The critical ejection ratio is obtained based on the number of nozzles, the throat diameter ratio, the diffusion angle, the cavity volume, and the correlation coefficient of the steam properties.

3. The pressure optimization control method for a multi-nozzle steam ejector according to claim 1, characterized in that, The step of obtaining multiple steam margin coefficients based on the steam state parameters of each nozzle and the preset critical pressure value includes: Obtain the steam inlet pressure and outlet back pressure of each nozzle; The pressure difference is obtained based on the steam inlet pressure of each nozzle and the preset critical pressure value; Multiple steam margin coefficients are obtained based on the pressure difference between each nozzle and the outlet back pressure.

4. The pressure optimization control method for a multi-nozzle steam ejector according to claim 1, characterized in that, The step of obtaining multiple pressure fluctuation coefficients based on multiple steam margin coefficients and multiple turbulence intensity factors includes: Get the bias number; Multiple pressure fluctuation coefficients are obtained based on the bias number, multiple steam margin coefficients, and multiple turbulence intensity factors.

5. The pressure optimization control method for a multi-nozzle steam ejector according to claim 1, characterized in that, The step of obtaining the nozzle adjustment opening of each nozzle includes: Obtain the metering time period for each nozzle, wherein the metering time period includes the start time and the end time; The flow rate of each nozzle at multiple times within a metering time period is obtained, and the average flow rate of each nozzle within the metering time period is calculated based on the multiple flow rate values, the start time, and the end time. Calculate the real-time flow deviation of each nozzle at each moment based on the flow rate value of each nozzle at each moment and its corresponding average flow rate. Obtain the nozzle outlet pressure of each nozzle, including the continuous nozzle outlet pressure and the instantaneous nozzle outlet pressure; The pressure balance is obtained based on the continuous nozzle outlet pressure and the instantaneous nozzle outlet pressure; The nozzle adjustment opening of each nozzle is obtained based on the opening of multiple basic nozzles, the real-time flow deviation of each nozzle, and the pressure equalization.

6. The pressure optimization control method for a multi-nozzle steam ejector according to claim 1, characterized in that, The step of optimizing the pressure control of the openings of multiple basic nozzles based on the nozzle adjustment openings of each nozzle includes: Obtain the rate of change of back pressure at the outlet of each nozzle and the degree of steam superheat; The back pressure change sensitivity coefficient is obtained based on the back pressure change rate and steam superheat of each nozzle. The nozzle adjustment opening is corrected based on the back pressure change sensitivity coefficient to obtain multiple corrected nozzle adjustment openings; The opening of the multiple base nozzles is adjusted according to the opening of the multiple correction nozzles to achieve optimized pressure control.

7. A pressure optimization control system for a multi-nozzle steam ejector, characterized in that, include: The first acquisition module is used to acquire the operating parameters of each nozzle on the multi-nozzle steam ejector, wherein the operating parameters include basic structural parameters and operating parameters; The second acquisition module is used to acquire the critical ejection ratio based on the basic structure parameters; The third acquisition module is used to acquire the steam state parameters of each nozzle according to the operating parameters, and to acquire multiple steam margin coefficients according to the steam state parameters of each nozzle and the preset critical pressure value. The fourth acquisition module is used to acquire multiple turbulence intensity factors based on multiple steam margin coefficients and the critical ejection ratio, and to acquire multiple pressure fluctuation coefficients based on multiple steam margin coefficients and multiple turbulence intensity factors; The comparison module is used to sequentially compare multiple pressure fluctuation coefficients with preset thresholds; If the pressure fluctuation coefficient is greater than a preset threshold, it is determined that the nozzle needs to be optimized for control, and the nozzle adjustment opening of each nozzle is obtained. Based on the nozzle adjustment opening of each nozzle, pressure optimization control is performed on the opening of multiple basic nozzles.

8. The pressure optimization control system for a multi-nozzle steam ejector according to claim 7, characterized in that, The second acquisition module includes: The first acquisition unit is used to acquire the number of nozzles, throat diameter, outlet diameter, diffusion angle, and steam property correlation coefficient based on the basic structural parameters. The second acquisition unit is used to acquire the throat diameter ratio based on the throat diameter and the outlet diameter; The third acquisition unit is used to acquire the cavity volume that steam can occupy in the injector mixing chamber; The fourth acquisition unit is used to acquire the critical ejection ratio based on the number of nozzles, the throat diameter ratio, the diffusion angle, the cavity volume, and the correlation coefficient of the steam properties.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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