Hydraulic-thermal stability coupling guarantee method, device and medium for small flow working condition of fuel centrifugal pump

Abstract

The application provides a hydraulic-thermal stability coupling guarantee method, device and medium for a small flow condition of a fuel centrifugal pump, the method comprising: determining a design condition parameter and a target minimum continuous operation flow; establishing a parameterized model comprising an impeller and an injection structure or a backflow structure, and setting the parameters as adjustable; determining a first minimum flow meeting hydraulic stability and a second minimum flow meeting thermal stability based on the model; taking the larger value of the two as a minimum allowable continuous operation flow; when the first minimum flow is greater than the target value, reversely optimizing the geometric parameters of the impeller, and when the second minimum flow is greater than the target value, reversely optimizing the parameters of the injection structure or the backflow structure; and iterating until the requirements are met. The application unifies the hydraulic stability and the thermal stability as a coupling criterion, solves the problem that the small flow operation boundary is difficult to accurately determine due to the mutual separation of the two, and is suitable for small flow stable operation guarantee of a high-temperature high-speed fuel centrifugal pump.

Description

Technical Field

[0001] This invention relates to the field of fluid machinery technology, and in particular to a method, device and medium for ensuring the hydraulic-thermal stability of a fuel centrifugal pump under low flow conditions. Background Technology

[0002] High-temperature, high-speed centrifugal fuel pumps are widely used in aero-engine fuel delivery, fuel pressurization, and fuel supply regulation systems. In actual operation, these pumps often need to operate continuously under conditions of inlet throttling, low flow rates, variable operating conditions, and high-temperature fuel media. As the pump speed, power density, and medium temperature continue to increase, the flow state within the pump becomes more complex. Especially under low-flow conditions, phenomena such as localized separation, backflow, broken vortices, vortex shedding, and increased flow losses can easily occur in the impeller passage, volute, and sealing gaps.

[0003] Currently, methods to ensure the stability of fuel centrifugal pumps under low-flow conditions are typically implemented from two aspects:

[0004] On the one hand, by optimizing the hydraulic design of the impeller and volute, the head-flow characteristic curve can be kept stable in the low-flow-rate region, avoiding the appearance of humps or upward-sloping sections. Existing technologies often employ methods such as adjusting geometric parameters like blade outlet angle, blade wrap angle, channel diffuser ratio, impeller inlet diameter, and blade height distribution to improve the velocity distribution and pressure gradient inside the impeller at low flow rates. This suppresses unsteady flow phenomena such as backflow, vortex shedding, and local separation, causing the head-flow characteristic curve to tend towards a monotonically decreasing trend across the entire flow range. Related technical approaches typically require numerical calculations across the entire flow range within the pump to analyze the relationship between unstable flow and geometric and flow parameters in the low-flow-rate region, and to establish the correspondence between the head-flow characteristic curve and the geometric and flow parameters.

[0005] On the other hand, by calculating the minimum continuous operating flow rate or minimum thermal continuous operating flow rate, the pump is limited to operate at excessively low flow rates for extended periods to avoid excessive temperature rise caused by the conversion of fuel flow losses into heat within the pump. Existing technologies generally calculate the minimum allowable flow rate (minimum thermal continuous operating flow rate) for long-term stable pump operation without overheating based on parameters such as pump flow losses, fuel specific heat capacity, fuel flow rate, and allowable temperature rise. For high-temperature fuel media, if the fuel cannot promptly remove the heat generated by friction losses, diffusion losses, and backflow losses within the pump during low-flow operation, the fuel temperature at the pump outlet may continue to rise, thereby affecting fuel properties, cavitation performance, sealing reliability, and the safe operation of the pump.

[0006] Therefore, there is an urgent need for a hydraulic-thermal stability coupling guarantee method, device, and medium for fuel centrifugal pumps operating at low flow rates, in order to solve the problems existing in the current technology. Summary of the Invention

[0007] This invention provides a method, device, and medium for ensuring the hydraulic-thermal stability of a fuel centrifugal pump under low-flow conditions. It addresses the problems in the prior art where hydraulic stability design and thermal stability calculation are disconnected and the coupling relationship between the two is not fully considered, making it difficult to accurately determine the continuous stable operating boundary of the fuel centrifugal pump under low-flow conditions.

[0008] The core technology of this invention is to establish a parameterized model that includes an impeller and an ejector or recirculation structure, determine the first minimum flow rate that satisfies hydraulic stability and the second minimum flow rate that satisfies thermal stability, and take the larger of the two as the minimum allowable continuous operating flow rate. When either minimum flow rate does not meet the target requirements, the corresponding impeller geometric parameters or ejector structure parameters are optimized and adjusted in reverse and iteratively converged.

[0009] In a first aspect, the present invention provides a method for ensuring the hydraulic-thermal stability of a fuel centrifugal pump under low-flow conditions, the method comprising the following steps: Determine the design operating parameters and target minimum continuous operating flow rate of the fuel centrifugal pump; A parameterized model of a fuel centrifugal pump is established, which includes an impeller and an ejector or reflux structure for thermal management. The impeller geometry and ejector or reflux structure parameters are set as adjustable parameters. Based on the parameterized model, the first minimum flow rate that meets the hydraulic stability requirements and the second minimum flow rate that meets the thermal stability requirements are determined respectively across the entire flow range. The larger of the first minimum flow rate and the second minimum flow rate is determined as the minimum allowable continuous operating flow rate; When the first minimum flow rate is greater than the target minimum continuous operating flow rate, the impeller geometry parameters are adjusted in reverse; when the second minimum flow rate is greater than the target minimum continuous operating flow rate, the ejector structure or recirculation structure parameters are adjusted in reverse. Repeat the above determination steps until both the first minimum flow rate and the second minimum flow rate are not greater than the target minimum continuous operating flow rate.

[0010] Furthermore, the first minimum flow rate required to satisfy hydraulic stability is determined, including: Select multiple operating points within the full flow range and calculate or test the head and flow field state at each operating point. Based on the head at each operating point, generate head-flow characteristic curves and determine whether the head-flow characteristic curves meet the hydraulic stability conditions in the low flow range. If the requirement is not met, increase the flow rate until it is met, and use the flow rate at this point as the first minimum flow rate.

[0011] Furthermore, the hydraulic stability conditions include at least one of the following: The head-flow curve for low flow rates does not have local humps. There is no positive slope rising segment in the low flow range; The head change does not occur abruptly between adjacent operating points; There is no large-scale backflow or strong vortex in the impeller inlet, outlet, and volute tongue area; The pressure pulsation amplitude does not exceed the preset threshold.

[0012] Furthermore, the second minimum flow rate that satisfies the thermal stability requirement is determined, including: Calculate the flow loss power and medium temperature rise in the pump under various flow conditions; Based on the flow loss power, the thermal properties of the medium, and the preset allowable temperature rise, combined with the proportional coefficient of the heat entering the medium and causing the temperature rise, the minimum flow rate that can promptly remove the heat generated in the pump to avoid the medium temperature rise exceeding the limit is determined and used as the second minimum flow rate.

[0013] Furthermore, determining the second minimum flow rate that satisfies the thermal stability requirement also includes verification using thermal stability criteria, which include at least one of the following: The overall temperature rise of the medium does not exceed the first preset threshold. The local maximum temperature rise shall not exceed the second preset threshold. The volume fraction of the high-temperature retention zone shall not exceed a preset proportion of the flow channel volume; The volume fraction of the low-speed recirculation zone shall not exceed a preset proportion of the impeller inlet flow channel volume; The high entropy production zone did not form a continuous thermal accumulation zone at the impeller inlet, impeller outlet, or volute tongue.

[0014] Furthermore, the impeller geometry parameters are optimized in reverse, including at least one of the following methods: When a hump appears on the head-flow curve, adjust the blade outlet angle; When the positive slope is obvious in the low flow range, increase the blade wrap angle; When there is severe backflow at the impeller outlet, adjust the impeller outlet width; When the diffusion in the flow channel is too strong, reduce the diffusion ratio of the flow channel; When the impeller inlet vortex is obvious, adjust the blade inlet angle.

[0015] Furthermore, the parameters of the ejector structure or recirculation structure are optimized in reverse, including at least one of the following methods: When the temperature rise is too high at low flow rates, increase the return flow rate; When local heat accumulation is significant, adjust the reflux inlet position to near the impeller inlet or the low-speed stagnation zone; When the entrainment capability is insufficient, optimize the entrainment coefficient; When backflow causes inlet disturbance, adjust the nozzle angle; When mixing losses are too high, optimize the geometry of the mixing chamber; Furthermore, the reverse optimization adjustment simultaneously satisfies the following constraints: removes heat loss due to small flow rate within the pump, does not disrupt impeller inlet flow, does not introduce new head-flow curve instability, does not significantly reduce design point efficiency, and does not increase cavitation risk.

[0016] Secondly, the present invention provides a hydraulic-thermal stability coupling protection device for a fuel centrifugal pump operating at low flow rates, comprising: The parameter determination and modeling module is used to determine the design operating parameters and target minimum continuous operating flow of the fuel centrifugal pump, and to establish a parameterized model of the fuel centrifugal pump. The parameterized model includes the impeller and the ejector structure or reflux structure for thermal management. The parameter determination and modeling module sets the impeller geometric parameters and the ejector structure or reflux structure parameters as adjustable parameters. The stability analysis module is used to determine the first minimum flow rate that meets the hydraulic stability requirements and the second minimum flow rate that meets the thermal stability requirements, based on a parametric model, over the entire flow range. The coupling decision module is used to determine the larger of the first minimum flow rate and the second minimum flow rate as the minimum allowable continuous operating flow rate, and to determine whether both the first minimum flow rate and the second minimum flow rate are not greater than the target minimum continuous operating flow rate. The optimization control module is used to perform reverse optimization adjustment of the impeller geometry parameters when the first minimum flow rate is greater than the target minimum continuous operating flow rate, and to perform reverse optimization adjustment of the ejector structure or recirculation structure parameters when the second minimum flow rate is greater than the target minimum continuous operating flow rate. It also controls the stability analysis module to re-analyze until both the first minimum flow rate and the second minimum flow rate are not greater than the target minimum continuous operating flow rate.

[0017] Thirdly, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to execute the above-mentioned hydraulic-thermal stability coupling guarantee method for low-flow-rate fuel centrifugal pumps.

[0018] Fourthly, the present invention provides a readable storage medium storing a computer program, the computer program including program code for controlling a process to execute the process, the process including the hydraulic-thermal stability coupling assurance method for low-flow-rate operation of a fuel centrifugal pump as described above.

[0019] The main contributions and innovations of this invention are as follows: 1. This invention abandons the method of determining the minimum flow rate solely based on hydraulic characteristics or thermal balance. By establishing a hydraulic-thermal stability coupling criterion, it selects the larger value between the minimum hydraulic stability flow rate and the minimum thermal continuous working flow rate as the minimum allowable continuous stable operating flow rate, thereby taking into account both the risks of hydraulic instability and thermal accumulation, and solving the problem of inaccurate boundary determination caused by the separation of the two in the prior art.

[0020] 2. This method, through flow field and thermal analysis across the entire flow range, can simultaneously identify unstable flow phenomena such as backflow and vortex shedding in areas such as the impeller outlet and volute, as well as the location of heat accumulation. It can then optimize the flow channel structure or ejector parameters in a targeted manner, effectively preventing excessive fuel temperature rise while suppressing unstable flow phenomena, and significantly improving the overall stability of the pump under harsh operating conditions.

[0021] 3. Based on the type of instability (hydraulic or thermal), this invention adopts different reverse optimization paths to adjust the impeller geometry parameters or ejector structure parameters respectively, avoiding blind adjustments. At the same time, the clearly defined minimum allowable flow rate provides a quantitative basis for pump design verification and actual operation control, which is convenient for engineering applications, effectively reduces the risks of vibration, cavitation and local overheating, and extends the service life of the equipment.

[0022] Details of one or more embodiments of the present invention are set forth in the following drawings and description, so that other features, objects and advantages of the invention will be more readily understood. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of a method for ensuring the hydraulic-thermal stability of a fuel centrifugal pump under low-flow conditions, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of this specification. Rather, they are merely examples of apparatuses and methods consistent with some aspects of one or more embodiments of this specification as detailed in the appended claims.

[0025] It should be noted that the steps of the corresponding methods are not necessarily performed in the order shown and described in this specification in other embodiments. In some other embodiments, the methods may include more or fewer steps than described in this specification. Furthermore, a single step described in this specification may be broken down into multiple steps in other embodiments; and multiple steps described in this specification may be combined into a single step in other embodiments.

[0026] The hydraulic-thermal stability coupling guarantee method for fuel centrifugal pumps under low flow conditions provided by this invention is based on the core idea of ​​incorporating the hydraulic stability boundary and thermal stability boundary of the fuel centrifugal pump under low flow conditions into a unified coupling criterion system. For example... Figure 1 As shown, the basic process of this method is as follows: First, determine the design operating parameters and establish a parameterized model. Then, within the entire flow range, obtain the head-flow characteristics (to determine the first minimum flow rate) and calculate the thermal balance state (to determine the second minimum flow rate). Take the larger of the two values ​​as the minimum allowable continuous operating flow rate. If this value is greater than the target minimum operating flow rate, then perform reverse optimization on the impeller hydraulic parameters or ejector / return structure parameters, and re-perform the full process analysis until the convergence condition is met.

[0027] Example 1 This invention aims to propose a method for ensuring the hydraulic-thermal stability of a fuel centrifugal pump under low-flow conditions. Specifically, refer to... Figure 1 The method includes: S1: Determine the design conditions and constraints Obtain the basic design parameters of the fuel centrifugal pump to be designed or optimized. The fuel is a liquid fuel medium with low compressibility under high temperature conditions, significant viscosity variation with temperature, and specific heat capacity that can be used for heat balance calculations, preferably high-temperature fuel such as aviation kerosene.

[0028] The recommended ranges for each parameter are shown in Table 1 below: Table 1

[0029] S2: Establish a parameterized model of the pump's internal flow channel Establish a three-dimensional parametric model of the impeller, front and rear cover clearance, volute or diffuser, return channel, and ejector (if an ejector scheme is used) of the fuel centrifugal pump, and parametrically process the key structural parameters. In this step, the impeller geometry and ejector or return channel structural parameters are all set as adjustable parameters; among them, Q... p Q is the total flow rate through the impeller in the pump. s Q is the net flow rate that the pump outputs to the external oil supply system. rThis refers to the return flow rate from the high-pressure zone inside the pump, through the ejector or return channel, back to the pump inlet or low-pressure zone; under steady-state conditions, it satisfies Q. p =Q s +Q r And 0≤Q r ≤Q p .

[0030] The recommended ranges for impeller and flow channel parameters are shown in Table 2 below: Table 2

[0031] The recommended ranges for ejector or recirculation structure parameters are shown in Table 3 below: Table 3

[0032] When using a simple reflux structure without ejectors, the parameters of the reflux channel may include the reflux pipe diameter, reflux inlet location, and reflux flow rate.

[0033] S3: Obtain head-flow characteristics across the entire flow range. like Figure 1 As shown, full-process CFD calculations are performed across the entire flow range. At 0.03Q... d Up to 1.20Q d Multiple flow rate operating points are selected within a given range to calculate or test the head, efficiency, shaft power, pressure distribution, velocity distribution, and internal backflow of the fuel centrifugal pump, obtaining the head-flow rate (HQ) curve. Preferably, there are no fewer than 8 flow rate operating points, more preferably no fewer than 12. For example, the following flow rate operating point can be selected: 0.03Q d 0.05Q d 0.08Q d 0.10Q d 0.15Q d 0.20Q d 0.30Q d 0.50Q d 0.70Q d 1.00Q d 1.10Q d 1.20Q d .

[0034] In this step, it is determined whether the HQ curve meets the hydraulic stability requirements for low flow rates. The hydraulic stability condition includes at least one of the following criteria: 1. The head-flow curve does not have local humps in the low-flow-rate section; 2. There is no positive slope rising segment in the low flow rate segment; 3. The head changes do not change abruptly between adjacent operating points; 4. There is no large-scale backflow or strong vortex in the impeller inlet, outlet, and volute tongue area; 5. The pressure pulsation amplitude does not exceed the preset threshold; If the HQ curve does not meet the above conditions below a certain flow rate, it indicates that hydraulic instability exists at that flow rate. The lowest flow rate that satisfies all hydraulic stability conditions is determined as the first minimum flow rate. .

[0035] S4: Calculate the thermal stability during continuous operation at low flow rates. Under the same flow conditions as in step S3, calculate the flow loss, entropy production distribution, input power, effective hydraulic power, and fuel temperature rise within the pump.

[0036] Power loss Determine by the following formula:

[0037] in, The input power of the pump, Effective hydraulic power:

[0038] Where ρ is the fuel density, g is the gravitational acceleration, Q is the volumetric flow rate, and H is the head.

[0039] Minimum continuous thermal operating flow rate The basic heat balance formula is:

[0040] in, The specific heat capacity of fuel at constant pressure. To allow for temperature rise.

[0041] If some heat is to be carried away through the pump body, bearing cavity, housing, or reflux system, a heat proportionality coefficient can be further introduced. Its physical meaning is the proportion of heat entering the fuel medium and causing the fuel temperature rise to the total heat loss, with a value ranging from 0.50 to 1.00. Therefore, the heat balance relationship is:

[0042] When the pump body has poor heat dissipation conditions Take a higher value (close to 1.00); when the pump body has a good heat dissipation structure or the return system removes a lot of heat, A lower value (such as 0.50~0.70) can be selected.

[0043] The thermal stability criteria include the following items: Table 4

[0044] Based on the above calculations and verifications, the second minimum flow rate that meets the thermal stability requirements has been determined. .

[0045] S5: Establishing a coupled hydraulic-thermal stability criterion The first minimum flow rate obtained in step S3 The second minimum flow rate obtained in step S4 The two values ​​were compared, and the larger value was determined as the minimum allowable flow rate for continuous and stable operation of the fuel centrifugal pump at low flow rates. :

[0046] The significance of this coupling criterion lies in the fact that when hydraulic stability constraints are more stringent ( > The minimum allowable flow rate is determined by hydraulic conditions; when thermal stability constraints are more stringent ( > The minimum allowable flow rate is determined by thermal conditions. In either case, taking the larger value ensures that the pump meets both hydraulic and thermal stability requirements within a small flow range.

[0047] S6: According to Reverse optimization of impeller hydraulic parameters when Greater than the preset target flow This indicates that the pump's hydraulic stability at low flow rates is insufficient, requiring adjustment of the impeller geometry parameters. Based on the specific problem symptoms, the preferred adjustment methods are as follows: Table 5

[0048] The optimization objective is: (1) The HQ curve in the low flow range has no hump; (2) There is no positive slope rising segment in the low flow segment; (3) The impeller inlet and outlet recirculation zones are reduced; (4) The amplitude of pressure pulsation decreases; (5) Without significantly sacrificing design point efficiency.

[0049] The optimized stopping condition is: Table 6

[0050] S7: According to Reverse optimization of ejector or reflux parameters when Greater than the preset target flow This indicates that the pump's thermal stability at low flow rates is insufficient, requiring an improvement in heat removal capacity or a reduction in low flow rate losses. Based on the specific problem manifestations, the preferred adjustment methods are as follows: Table 7

[0051] The core of ejector or reflux structure matching is not blindly increasing Q. r Instead, it is in satisfying Q p =Q s +Q r This simultaneously reduces localized heat buildup while ensuring overall enthalpy balance, hydraulic stability, and vaporization safety. The adjustment should simultaneously satisfy: (1) Promote the high-temperature fuel to leave the local stagnation zone and mix fully with the system flow, so that the pure internal return flow is not repeatedly counted as external heat dissipation; (2) The volume fraction and vortex intensity of the impeller inlet recirculation zone do not deteriorate to the limit; (3) No new positive slope range of the HQ curve is introduced; (4) The efficiency drop at the design point shall not exceed the preset threshold (the preset threshold shall be selected in the range of 2% to 5%, preferably 3%). (5) The local absolute static pressure p at any point in key areas such as the impeller inlet, blade suction surface, ejector throat, and reflux mixing zone inside the pump. min The difference p between the local fuel temperature at that point and the saturated vapor pressure. v(Tloc) All are not less than the preset vaporization safety pressure margin Δp safe .

[0052] S8: Recalculate and iteratively converge. After adjusting the impeller parameters or ejector / recirculation parameters, repeat steps S3 to S7 until all of the following conditions are met: (1) ≤ ; (2) ≤ ; (3) ≤ ; (4) The HQ curve in the low flow range has no hump; (5) The temperature rise during continuous operation at low flow rates shall not exceed the allowable value; (6) The design head and efficiency meet the design requirements.

[0053] Preferably, the number of iterations is 2 to 20.

[0054] Example 2 This embodiment takes a medium-sized fuel centrifugal pump in a high-temperature fuel supply system of a certain type of aero-engine as an example. It adopts an ejector structure to achieve heat management under low flow conditions and describes in detail the complete implementation process of the method of the present invention.

[0055] Step S1: Determine the design load and constraints The basic design parameters of the fuel centrifugal pump to be optimized are as follows: Table 8

[0056] All of the above parameters are within the range recommended in the general description of step S1.

[0057] Step S2: Establish a parameterized model of the pump's internal flow channel A three-dimensional parametric model of the fuel centrifugal pump was established, including the impeller, the clearance between the front and rear cover plates, the volute, the sealing cavity, and the ejector. The initial structural parameters of the impeller and flow channel are as follows: Table 9

[0058] The initial structural parameters of the ejector are as follows: Table 10

[0059] The impeller geometry parameters and ejector structural parameters mentioned above are all set to adjustable parameters so that subsequent reverse optimization can be performed based on the hydraulic stability and thermal stability analysis results.

[0060] Step S3 (First Iteration): Obtain the head-flow characteristics across the entire flow range. At 0.03Q d Up to 1.20Q d Twelve flow rate operating points were selected within the range for full-channel numerical calculation (CFD), with operating points of 0.15, 0.25, 0.40, 0.50, 0.75, 1.00, 1.50, 2.50, 3.50, 5.00, 5.50, and 6.00 m³ / h. For each operating point, the head, efficiency, shaft power, pressure distribution, velocity distribution, and internal recirculation were calculated, generating HQ characteristic curves.

[0061] The hydraulic stability criteria were checked on the HQ curves, and the results are as follows: 1. Within the flow rate range of 0.15~0.50 m³ / h, the HQ curve shows a significant local hump phenomenon, with the head first increasing and then decreasing, which does not meet criterion (a). 2. Within the flow rate range of 0.15~0.25 m³ / h, the head increases with the increase of flow rate, and there is a segment with a positive slope increase, which does not meet criterion (b). 3. In operating conditions with a flow rate below 0.75 m³ / h, a large-scale backflow occurs in the impeller inlet area, and there are broken vortices and strong vortex structures in the impeller outlet and volute tongue area, which does not meet criterion (d). 4. In operating conditions below 0.50 m³ / h, the pressure pulsation amplitude in the volute tongue region exceeds 12% of the design head, which exceeds the preset threshold (set at 8% of the design head), and does not meet criterion (e). When the flow rate increases to 0.28Q d When the flow rate is 1.40 m³ / h, the HQ curve resumes its monotonically decreasing trend, backflow and vortices are significantly reduced, and pressure pulsation decreases to an acceptable level. Therefore, the first iteration determines the first minimum flow rate. =0.28Q d =1.40 m³ / h. Because =1.40 m³ / h greater than =1.00 m³ / h, hydraulic stability does not meet the requirements.

[0062] Step S4 (First Iteration): Calculate the thermal stability during continuous low-flow operation. Under the same flow conditions as in step S3, CFD calculations were performed on the pump flow loss power, entropy production distribution, and fuel temperature rise at each operating point. The calorific value was taken as the proportionality coefficient. =0.85.

[0063] With a flow rate Q = 0.30Q d Taking a flow rate of 1.50 m³ / h as an example, at this operating point, the head corresponding to the HQ curve is H=138m (the pump head is higher than the design head under low flow conditions; this value is obtained by CFD calculation). The calculation process is as follows: Input power P in P was obtained through numerical calculation. in =3500 W.

[0064] Effective hydraulic power:

[0065] Power loss:

[0066] The minimum continuous thermal flow rate corresponding to this operating point (i.e., the limit flow rate required only when the overall temperature rise reaches the allowable value) is:

[0067] It should be noted that the above The limiting flow rate calculated based on the heat balance formula at a single operating point only reflects the single factor of overall temperature rise. Actual... The determination also requires comprehensive consideration of other thermal stability criteria (local maximum temperature rise, volume fraction of the high-temperature retention zone, volume fraction of the low-velocity recirculation zone, distribution of high entropy production areas, etc.). A comprehensive thermal stability check was conducted for each flow condition, and the results are as follows: 1. When the flow rate is below 0.32Q d When the flow rate is 1.60 m³ / h, the overall fuel temperature rise inside the pump exceeds 20°C, which does not meet the thermal stability criterion. 2. When the flow rate is below 0.30Q d At a flow rate of 1.50 m³ / h, the localized maximum temperature rise near the impeller outlet and the volute tongue exceeds 25°C. 3. When the flow rate is below 0.28Q d When the flow rate is 1.40 m³ / h, the volume fraction of the high-temperature retention zone exceeds 5% of the channel volume. 4. When the flow rate is below 0.35Q d =1.75 m 3 At / h, the high entropy production region forms a continuous thermal accumulation zone in the tongue of the volute. Based on all the above thermal stability criteria, the second minimum flow rate is determined. =0.32Q d =1.60m 3 / h. Due to =1.60m 3 / h greater than =1.00 m³ / h, thermal stability does not meet the requirements.

[0068] Step S5 (First Iteration): Establish Coupling Criterion

[0069] because =1.60 m 3 / h greater than =1.00 m 3 / h requires reverse optimization. In this embodiment... > This indicates that the thermal stability constraints are more stringent, with both values ​​exceeding the target values. Therefore, it is necessary to perform hydraulic optimization and thermal stability optimization simultaneously.

[0070] Step S6 (First Iteration Optimization): Backward Optimization of Impeller Hydraulic Parameters Based on the hydraulic instability problem identified in step S3, the impeller geometry parameters are adjusted as follows: 1. The HQ curve shows a hump in the low flow rate range: Reduce the blade outlet angle β2 from 28° to 22°. 2. Significant positive slope in low flow rate section: Increase the blade wrap angle φ from 120° to 145° 3. Severe backflow at the impeller outlet: Reduce the impeller outlet width b2 from 3.5 mm to 2.8 mm. 4. Excessive diffusion in the flow channel: Reduce the diffusion ratio of the flow channel from 1.35 to 1.20. 5. Obvious vortex at the impeller inlet: Adjust the blade inlet angle β1 from 22° to 18°. Step S7 (First Iteration Optimization): Backward Optimization of Ejector Parameters Based on the thermal buildup problem identified in step S4, the ejector structural parameters are adjusted as follows: 1. Excessive temperature rise at low flow rates: Adjust the return flow rate Q. r From 0.15Q d Increase to 0.22Q d =1.10 m 3 / h; 2. Significant localized heat buildup: Adjust the reflux inlet position to be closer to the low-speed stagnation zone near the impeller inlet; 3. Insufficient ejection capability: The ejection coefficient μ was optimized from 0.25 to 0.42; 4. Backflow disturbs the flow at the impeller inlet: Adjust the nozzle angle from 15° to 30° (angle with the mainstream); 5. Excessive mixing loss: The aspect ratio of the mixing chamber was optimized from 5 to 7; While making the above optimizations and adjustments, it was verified that the ejector parameters still met the following constraints: they were able to remove the small flow loss heat in the pump, did not disrupt the impeller inlet flow, did not introduce new HQ curve instability, the efficiency drop at the design point did not exceed 3%, and did not cause a significant increase in cavitation risk.

[0071] Step S8 (Second Iteration): Recalculate and verify convergence. After adjusting the impeller and ejector parameters, repeat steps S3 to S5.

[0072] Step S3: Reanalyze the results: The optimized HQ curve shows a monotonically decreasing trend across the entire flow range, with no hump or positive slope rising segment in the low flow range; The volume of the recirculation zone in the impeller inlet and outlet areas is significantly reduced, and the vortex intensity in the volute tongue area is significantly weakened. The pressure pulsation amplitude was reduced to 5.5% of the design head, a reduction of approximately 28% compared to before optimization; The minimum flow rate required to satisfy all hydraulic stability conditions is reduced to 0.16Q. d =0.80 m 3 / h; Therefore, the updated first minimum flow =0.16Q d =0.80 m3 / h. =0.80 m 3 / h ≤ =1.00 m 3 / h, hydraulic stability meets requirements.

[0073] Step S4: Reanalyze the results: At 0.20Q d =1.00 m 3 At a flow rate of / h, the overall fuel temperature inside the pump rises and falls to 16.5℃, meeting the requirement of ≤20℃; The local maximum temperature rose to 21℃, meeting the requirement of ≤25℃; The volume fraction of the high-temperature retention zone decreased to 3.2%, meeting the requirement of ≤5%; The volume fraction in the low-speed reflow zone is reduced to 6.5%, meeting the requirement of ≤10%; The distribution of high entropy production areas tends to be dispersed, and no continuous thermal accumulation zone is formed at the impeller inlet, outlet, or volute tongue. Therefore, the updated second minimum flow =0.18Q d =0.90 m 3 / h. =0.90 m 3 / h ≤ =1.00 m 3 / h, thermal stability meets requirements.

[0074] Step S5 Coupling Criterion:

[0075] Convergence condition check: 1. =0.80 m³ / h ≤ =1.00 m 3 / h, satisfied; 2. =0.90 m³ / h ≤ =1.00 m 3 / h, satisfied; 3. =0.90 m³ / h ≤ =1.00 m 3 / h, satisfied; 4. The HQ curve in the low flow range has no hump, which meets the requirement; 5. Temperature rise during continuous low-flow operation does not exceed the allowable value, which meets the requirement; 6. Design point (Q=5 m) 3The head is 97.5 m (deviation -2.5%, within ±5%), and the efficiency decreases by 1.8% (within 2%~5%), which meets the design requirements; The iteration terminates when all convergence conditions are met. The final determined impeller and ejector parameters represent the optimal design scheme for this embodiment.

[0076] The final optimized impeller parameters are summarized below: Table 11

[0077] The final optimized ejector parameters are summarized below: Table 12

[0078] This embodiment achieves convergence after only two iterations, demonstrating that by using the hydraulic-thermal stability coupling criterion and the dual-path reverse optimization method, a design scheme that meets the requirements can be determined within a relatively short iteration cycle.

[0079] Example 3 This embodiment takes a high-temperature fuel centrifugal pump with a large design flow rate in the fuel pressurization system of a certain type of high-power aero-engine as an example. It adopts a simple reflux channel structure (without using an ejector) to achieve heat management under low flow rate conditions, further illustrating the versatility of the method of the present invention.

[0080] Step S1: Determine the design load and constraints Table 13

[0081] The fuel inlet temperature in this embodiment is relatively high (185°C), and the allowable temperature rise is relatively low (18°C), which places more stringent requirements on thermal stability.

[0082] Step S2: Establish a parameterized model of the pump's internal flow channel A three-dimensional parametric model of the fuel centrifugal pump is established, including the impeller, the gap between the front and rear cover plates, the volute, and the return flow channel. In this embodiment, a simple return flow pipe is used to guide the high-temperature fuel in the high-pressure zone of the pump back to the low-pressure zone, using the return flow to remove the heat accumulated in the pump.

[0083] The initial structural parameters of the impeller are as follows: Table 14

[0084] The initial parameters of the reflow channel are as follows: Table 15

[0085] Set both the impeller geometry parameters and the return channel parameters to adjustable parameters.

[0086] First iteration (S3 to S5) Numerical calculations were performed on the entire flow path at 12 flow rate points. Hydraulic stability criteria were used to check the HQ curve of the initial design scheme, which exhibited a hump and a rising positive slope in the low flow rate range, indicating severe backflow at the impeller inlet. At 0.20Q... d The pressure pulsation amplitude exceeds a preset threshold when the following conditions are met. The minimum flow rate that satisfies all hydraulic stability conditions is determined as follows. =0.24Q d =3.60 m 3 / h.

[0087] Take the heat ratio coefficient =0.85, thermal balance calculations and thermal stability criteria were performed for each operating point. Due to the high fuel inlet temperature (185℃) and low allowable temperature rise (18℃), when the flow rate is below 0.25Q... d The overall fuel temperature rise exceeded 18°C, with localized maximum temperature rises exceeding 25°C, and the volume fraction of the high-temperature retention zone exceeded 5%. This was determined comprehensively. =0.28Q d =4.20 m 3 / h.

[0088] = max(3.60, 4.20) = 4.20 m 3 / h> =1.50 m 3 / h does not meet the requirements.

[0089] First optimization (S6 to S7) Addressing insufficient hydraulic stability: 1. Reduce the blade exit angle β2 from 30° to 22°; 2. Increase the blade wrap angle φ from 110° to 140°; 3. Reduce the diffuser ratio of the flow channel from 1.50 to 1.25; 4. Reduce the impeller outlet width b2 from 4.5 mm to 3.6 mm; Addressing insufficient thermal stability: 1. Return flow Q r From 0.08Q d Increase to 0.15Q d =2.25 m³ / h; 2. Adjust the return flow entry position from in front of the inducer to the low-speed stagnation zone near the impeller inlet.

[0090] Second iteration (S8) After optimization and recalculation, the results improved but still did not fully converge. =0.14Q d =2.10 m 3 / h, =0.12Q d =1.80 m 3 / h, =2.10 m 3 / h> =1.50 m 3 / h still does not meet the requirements.

[0091] Second round of optimization 1. Further reduce the blade exit angle β2 to 18°; 2. Further increase the blade wrap angle φ to 160°; 3. Return flow Q r Increase to 0.18Q d =2.70 m 3 / h; 4. Increase the diameter of the return pipe from 4 mm to 5.5 mm to reduce the return resistance; Third iteration (S8) Optimized and recalculated: The HQ curve decreases monotonically across the entire flow range, with no hump and no positive slope rising segment. The impeller inlet and outlet reflux zones have been significantly reduced; At 0.10Q d At a flow rate of 1.50 m³ / h, the overall fuel temperature rise is 17.2℃, which meets the requirement of ≤18℃; The local maximum temperature rose to 22℃, meeting the requirement of ≤25℃; The volume fraction of the high-temperature retention zone is 4.1%, which meets the requirement of ≤5%. =0.09Q d =1.35m 3 / h ≤ =1.50m 3 / h, satisfied; =0.095Q d =1.43m 3 / h≤ =1.50 m 3 / h, satisfied; =1.43 m 3 / h ≤ =1.50 m 3 / h, which meets the requirements; the design head is 243 m (deviation -2.8%), and the efficiency decreases by 2.5%, both of which meet the requirements. All convergence conditions are met, the iteration terminates, and a total of 3 iterations are performed.

[0092] This embodiment demonstrates that even without using an ejector and employing only a simple return channel, the coupling criterion and dual-path optimization method of this invention can still effectively determine the low-flow operating boundary that satisfies hydraulic and thermal stability. However, compared to Embodiment 1, it requires more iterations (3 times compared to 2 times), indicating that the ejector structure has better flexibility and adjustability in terms of thermal management.

[0093] Example 4 This embodiment provides a hydraulic-thermal stability coupling protection device for a fuel centrifugal pump operating at low flow rates, corresponding to the method described above, for executing the method of Embodiment 1 or Embodiment 2. The device includes the following functional modules: The parameter determination and modeling module is used to determine the design operating parameters and target minimum continuous operating flow rate of the fuel centrifugal pump, and to establish a parametric model of the fuel centrifugal pump. This parametric model includes an impeller and an ejector or recirculation structure for thermal management, and both the impeller geometry and the ejector or recirculation structure parameters are set as adjustable parameters. The function of this module corresponds to steps S1 and S2 of the method.

[0094] The stability analysis module, based on a parametric model, determines the first minimum flow rate that meets hydraulic stability requirements and the second minimum flow rate that meets thermal stability requirements across the entire flow range. This module contains a hydraulic stability analysis submodule and a thermal stability analysis submodule. The hydraulic stability analysis submodule calculates the head and flow field state at multiple flow rate points, generates HQ characteristic curves, performs stability criterion checks, and determines the first minimum flow rate. The thermal stability analysis submodule calculates the flow loss power and fuel temperature rise within the pump, and determines the second minimum flow rate based on the heat balance relationship and thermal stability criterion. The functions of this module correspond to steps S3 and S4 of the method.

[0095] The coupling decision module is used to determine the larger of the first minimum flow rate and the second minimum flow rate as the minimum allowable continuous operating flow rate, and to determine whether both the first minimum flow rate and the second minimum flow rate are not greater than the target minimum continuous operating flow rate. The function of this module corresponds to step S5 of the method.

[0096] The optimization control module is used to perform reverse optimization adjustments on the impeller geometry parameters when the first minimum flow rate is greater than the target minimum continuous operating flow rate, and to perform reverse optimization adjustments on the ejector or recirculation structure parameters when the second minimum flow rate is greater than the target minimum continuous operating flow rate. A closed-loop control is formed between the optimization control module and the stability analysis module: the optimization control module transmits the adjusted parameters to the stability analysis module for re-analysis, and the stability analysis module feeds back the updated first and second minimum flow rates to the coupled decision module for judgment, until both the first and second minimum flow rates are no greater than the target minimum continuous operating flow rate. The function of this module corresponds to steps S6, S7, and S8 of the method.

[0097] The modules interact with each other via a data bus. The output of the parameter determination and modeling module is connected to the input of the stability analysis module, the output of the stability analysis module is connected to the input of the coupling decision module, the output of the coupling decision module is connected to the input of the optimization control module, and the output of the optimization control module is connected to the feedback inputs of both the parameter determination and modeling module and the stability analysis module, forming a closed-loop iterative control loop.

[0098] The above functional modules can be implemented using application-specific integrated circuits, field-programmable gate arrays, digital signal processors, or general-purpose processors combined with software programs.

[0099] Example 3 This embodiment also provides an electronic device, see reference. Figure 2 It includes a memory 402 and a processor 401, wherein the memory 402 stores a computer program and the processor 401 is configured to run the computer program to perform the steps in any of the above method embodiments.

[0100] Specifically, the processor 401 may include a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of the present invention.

[0101] The memory 402 may include a mass storage device for data or instructions. For example, and not limitingly, the memory 402 may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), flash memory, an optical disk drive, a magneto-optical disk drive, magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 402 may include removable or non-removable (or fixed) media. Where appropriate, the memory 402 may be internal or external to a data processing device. In a particular embodiment, the memory 402 is non-volatile memory. In a particular embodiment, the memory 402 includes read-only memory (ROM) and random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable read-only memory (PROM), an erasable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), an electrically alterable read-only memory (EAROM), or flash memory, or a combination of two or more of these. Where appropriate, the RAM can be Static Random-Access Memory (SRAM) or Dynamic Random-Access Memory (DRAM). DRAM can be Fast Page Mode Dynamic Random Access Memory (FPMDRAM), Extended Data Out Dynamic Random Access Memory (EDODRAM), Synchronous Dynamic Random-Access Memory (SDRAM), etc.

[0102] The memory 402 can be used to store or cache various data files that need to be processed and / or communicated, as well as possible computer program instructions executed by the processor 401.

[0103] The processor 401 reads and executes the computer program instructions stored in the memory 402 to implement any of the hydraulic-thermal stability coupling guarantee methods for low-flow conditions of fuel centrifugal pumps in the above embodiments.

[0104] Optionally, the electronic device may further include a transmission device 403 and an input / output device 404, wherein the transmission device 403 is connected to the processor 401 and the input / output device 404 is connected to the processor 401.

[0105] The transmission device 403 can be used to receive or send data via a network. Specific examples of the network described above may include wired or wireless networks provided by the communication provider of the electronic device. In one example, the transmission device includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 403 may be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0106] Input / output device 404 is used for inputting or outputting information. It can be a speaker, microphone, monitor, or keyboard.

[0107] Example 4 This embodiment also provides a readable storage medium storing a computer program, which includes program code for controlling and executing a process, the process including the hydraulic-thermal stability coupling guarantee method for low-flow-rate operation of a fuel centrifugal pump according to Embodiment 1.

[0108] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated here.

[0109] Generally, various embodiments can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of the invention can be implemented in hardware, while others can be implemented by firmware or software executed by a controller, microprocessor, or other computing device, but the invention is not limited thereto. Although various aspects of the invention may be shown and described as block diagrams, flowcharts, or using some other graphical representation, it should be understood that, by way of non-limiting example, these blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0110] Embodiments of the present invention can be implemented by computer software, which may be executable by a data processor of a mobile device, such as a processor entity, or by hardware, or by a combination of software and hardware. Computer software or programs (also referred to as program products), including software routines, applets, and / or macros, can be stored in any device-readable data storage medium, and they include program instructions for performing specific tasks. A computer program product may include one or more computer-executable components configured to perform embodiments when the program is run. One or more computer-executable components may be at least one piece of software code or a portion thereof. Additionally, it should be noted that any block in the logical flow of the figures may represent a program step, or interconnected logical circuitry, blocks and functions, or a combination of program steps and logical circuitry, blocks and functions. The software may be stored on physical media such as memory chips or blocks of storage implemented within a processor, magnetic media such as hard disks or floppy disks, and optical media such as, for example, DVDs and their data variants, CDs, etc. The physical medium is a non-transient medium.

[0111] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0112] The above embodiments are merely illustrative of several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A method for ensuring the hydraulic-thermal stability of a fuel-fired centrifugal pump under low-flow conditions, characterized in that, Includes the following steps: Determine the design operating parameters and target minimum continuous operating flow rate of the fuel centrifugal pump; A parameterized model of the fuel centrifugal pump is established, which includes an impeller and an ejector or reflux structure for thermal management, and the impeller geometry and ejector or reflux structure parameters are all set as adjustable parameters. Based on the parameterized model, a first minimum flow rate that meets the hydraulic stability requirement and a second minimum flow rate that meets the thermal stability requirement are determined within the entire flow range. The larger of the first minimum flow rate and the second minimum flow rate is determined as the minimum allowable continuous operating flow rate; When the first minimum flow rate is greater than the target minimum continuous operating flow rate, the impeller geometry parameters are adjusted in reverse. When the second minimum flow rate is greater than the target minimum continuous operating flow rate, the parameters of the ejector structure or return structure are adjusted in reverse. Repeat the above determination steps until both the first minimum flow rate and the second minimum flow rate are not greater than the target minimum continuous operating flow rate.

2. The hydraulic-thermal stability coupling guarantee method as described in claim 1, characterized in that, Determine the first minimum flow rate that satisfies the hydraulic stability requirements, including: Select multiple operating points within the full flow range and calculate or test the head and flow field state at each operating point. Based on the head at each operating point, a head-flow characteristic curve is generated, and it is determined whether the head-flow characteristic curve meets the hydraulic stability condition in the low flow range. If the requirement is not met, the flow rate is increased until it is met, and the flow rate at this point is taken as the first minimum flow rate.

3. The hydraulic-thermal stability coupling guarantee method as described in claim 2, characterized in that, The hydraulic stability condition includes at least one of the following: The head-flow curve for low flow rates does not have local humps. There is no positive slope rising segment in the low flow range; The head change does not occur abruptly between adjacent operating points; There is no large-scale backflow or strong vortex in the impeller inlet, outlet, and volute tongue area; The pressure pulsation amplitude does not exceed the preset threshold.

4. The hydraulic-thermal stability coupling guarantee method as described in claim 1, characterized in that, Determining the second minimum flow rate that satisfies the thermal stability requirements includes: Calculate the flow loss power and medium temperature rise in the pump under various flow conditions; Based on the flow loss power, the thermal properties of the medium, and the preset allowable temperature rise, combined with the proportional coefficient of heat entering the medium and causing the temperature rise, the minimum flow rate that can promptly remove the heat generated in the pump to avoid the medium temperature rise exceeding the limit is determined and used as the second minimum flow rate.

5. The hydraulic-thermal stability coupling guarantee method as described in claim 4, characterized in that, Determining the second minimum flow rate that meets the thermal stability requirements also includes verification based on thermal stability criteria, which include at least one of the following: The overall temperature rise of the medium does not exceed the first preset threshold. The local maximum temperature rise shall not exceed the second preset threshold. The volume fraction of the high-temperature retention zone shall not exceed a preset proportion of the flow channel volume; The volume fraction of the low-speed recirculation zone shall not exceed a preset proportion of the impeller inlet flow channel volume; The high entropy production zone did not form a continuous thermal accumulation zone at the impeller inlet, impeller outlet, or volute tongue.

6. The hydraulic-thermal stability coupling guarantee method as described in claim 1, characterized in that, Reverse optimization of impeller geometry parameters includes at least one of the following methods: When a hump appears on the head-flow curve, adjust the blade outlet angle; When the positive slope is obvious in the low flow range, increase the blade wrap angle; When there is severe backflow at the impeller outlet, adjust the impeller outlet width; When the diffusion in the flow channel is too strong, reduce the diffusion ratio of the flow channel; When the impeller inlet vortex is obvious, adjust the blade inlet angle.

7. The hydraulic-thermal stability coupling guarantee method as described in claim 1, characterized in that, Reverse optimization adjustment of the parameters of the ejector structure or recirculation structure includes at least one of the following methods: When the temperature rise is too high at low flow rates, increase the return flow rate; When local heat accumulation is significant, adjust the reflux inlet position to near the impeller inlet or the low-speed stagnation zone; When the entrainment capability is insufficient, optimize the entrainment coefficient; When backflow causes inlet disturbance, adjust the nozzle angle; When mixing losses are too high, optimize the geometry of the mixing chamber; Furthermore, the reverse optimization adjustment simultaneously satisfies the following constraints: removes heat loss due to small flow rate within the pump, does not disrupt impeller inlet flow, does not introduce new head-flow rate instability, does not significantly reduce design point efficiency, and does not increase cavitation risk.

8. A hydraulic-thermal stability coupling protection device for a fuel centrifugal pump operating at low flow rates, characterized in that, include: The parameter determination and modeling module is used to determine the design operating parameters and target minimum continuous operating flow of the fuel centrifugal pump, and to establish a parameterized model of the fuel centrifugal pump. The parameterized model includes an impeller and an ejector structure or reflux structure for thermal management. The parameter determination and modeling module sets the impeller geometric parameters and ejector structure or reflux structure parameters as adjustable parameters. The stability analysis module is used to determine, based on the parameterized model, the first minimum flow rate that meets the hydraulic stability requirements and the second minimum flow rate that meets the thermal stability requirements within the entire flow range. The coupling decision module is used to determine the larger of the first minimum flow rate and the second minimum flow rate as the minimum allowable continuous operating flow rate, and to determine whether both the first minimum flow rate and the second minimum flow rate are not greater than the target minimum continuous operating flow rate; The optimization control module is used to perform reverse optimization adjustment on the impeller geometry parameters when the first minimum flow rate is greater than the target minimum continuous operating flow rate, and to perform reverse optimization adjustment on the ejector structure or return flow structure parameters when the second minimum flow rate is greater than the target minimum continuous operating flow rate, and to control the stability analysis module to re-analyze until both the first minimum flow rate and the second minimum flow rate are not greater than the target minimum continuous operating flow rate.

9. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to run the computer program to perform the hydraulic-thermal stability coupling guarantee method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program including program code for executing a process, the process including the hydraulic-thermal stability coupling guarantee method according to any one of claims 1 to 7.

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