Method, device and computer equipment for determining boundary of flow instability of heat transfer tube

Abstract

The present application relates to a method, device, computer device, storage medium, and computer program product for determining the boundary of flow instability of a heat transfer tube. The method includes obtaining the operating parameters of a once-through steam generator; sequentially selecting each parameter in the operating parameters to perform an adjustment step until the critical parameter value corresponding to each parameter is obtained; the adjustment step includes continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters, and if the alternating stress obtained based on the adjusted operating parameters is greater than the critical stress corresponding to the current moment, then taking the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, where the critical stress is obtained based on the thermal fatigue life of the heat transfer tube; determining the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each parameter. Thus, the flow instability boundary of the heat transfer tube is obtained by combining the thermal fatigue phenomenon of the OTSG heat transfer tube, providing a reliable numerical basis for the design of the OTSG operating parameters.

Description

Technical Field

[0001] The present application relates to the technical field of thermal-hydraulic control, and particularly to a method, device, computer equipment, storage medium, and computer program product for determining the boundary of flow instability of heat transfer tubes. Background Art

[0002] Once-through steam generators (OTSGs) are key components connecting the primary and secondary sides of a reactor. They transfer the heat of the primary-side coolant to the secondary-side feedwater to generate superheated steam at a certain pressure and temperature. Due to the intense phase change of the secondary-side fluid in the OTSG and the existence of a large number of parallel channels, under specific operating conditions, flow instability may occur, resulting in thermal oscillations of the flow rate and system pressure, as well as continuous cyclic changes in the wall temperature. The continuous cyclic changes in the wall temperature can lead to problems such as thermal fatigue and mechanical vibration of the component structure, and may further cause heat transfer failure of the pipeline. Therefore, studying the flow instability of OTSGs is crucial for the safety and operation of the reactor.

[0003] Currently, the boundary of flow instability is mainly delimited by the maximum pulsation amplitude (such as 10%) of the steam flow rate at the OTSG outlet, and then the operating parameter range is limited according to the above-mentioned boundary of flow instability. However, if flow instability occurs, the thermal fatigue of the heat transfer tube is the main consequence, and the above discriminant criterion does not establish a direct connection with the thermal fatigue phenomenon, and cannot fully reflect the limitation of thermal fatigue on flow instability. Summary of the Invention

[0004] Based on this, in view of the above technical problems, it is necessary to provide a method, device, computer equipment, storage medium, and computer program product for determining the boundary of flow instability of heat transfer tubes based on the thermal fatigue phenomenon.

[0005] In a first aspect, the present application provides a method for determining the boundary of flow instability of heat transfer tubes. The method includes:

[0006] Obtain the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters;

[0007] Successively select each of the parameters in the operating parameters to perform an adjustment step until the critical parameter value corresponding to each of the parameters is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters. If the alternating stress obtained according to the adjusted operating parameters is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube;

[0008] Boundary parameters for determining the flow instability boundary of the heat transfer tubes based on the critical parameter values corresponding to the respective parameters.

[0009] In one embodiment, in the adjustment step, after using the parameter value at the previous moment of the parameter to be selected as the critical parameter value of the parameter, the method further includes:

[0010] Updating the operating parameters of the once-through steam generator according to the critical parameter values.

[0011] In one embodiment, the operating parameters include at least two of the inlet throttling pressure drop, the subcooling degree of the secondary side feed water inlet, the feed water flow rate, and the operating pressure.

[0012] In one embodiment, the alternating stress obtained according to the adjusted operating parameters includes:

[0013] Determining the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters;

[0014] Determining the alternating stress corresponding to the adjusted operating parameters according to the thermal-hydraulic parameters.

[0015] In one embodiment, determining the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters includes:

[0016] Performing time-domain analysis on the adjusted operating parameters to determine the thermal-hydraulic parameters of the once-through steam generator.

[0017] In one embodiment, the thermal-hydraulic parameters include at least one of the steam pressure, temperature, and flow rate at the outlet of the once-through steam generator.

[0018] In one embodiment, the once-through steam generator is used for a reactor, and obtaining the operating parameters of the once-through steam generator includes:

[0019] Obtaining the operating parameters of the once-through steam generator at a low power step of the reactor.

[0020] In one embodiment, the method for determining the critical stress includes:

[0021] Based on the current moment, obtaining the service life of the heat transfer tube;

[0022] Obtaining the critical stress according to the service life and the thermal fatigue life of the heat transfer tube.

[0023] In a second aspect, the present application further provides a device for determining the flow instability boundary of a heat transfer tube. The device includes:

[0024] A parameter acquisition module, configured to acquire the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters;

[0025] A critical value determination module, configured to sequentially select each of the parameters in the operating parameters to perform an adjustment step until the critical parameter value corresponding to each of the parameters is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters, if the alternating stress obtained according to the adjusted operating parameters at the current moment is greater than the critical stress corresponding to the current moment, then stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube;

[0026] A boundary parameter determination module, configured to determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each of the parameters.

[0027] In a third aspect, the present application further provides a computer device. The computer device includes a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0028] Acquire the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters;

[0029] Sequentially select each of the parameters in the operating parameters to perform an adjustment step until the critical parameter value corresponding to each of the parameters is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters, if the alternating stress obtained according to the adjusted operating parameters is greater than the critical stress corresponding to the current moment, then stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube;

[0030] Determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each of the parameters.

[0031] In a fourth aspect, the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program thereon, and when the computer program is executed by a processor, the following steps are implemented:

[0032] Acquire the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters;

[0033] Select each of the operating parameters in sequence and perform an adjustment step until the critical parameter value corresponding to each of the parameters is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain an adjusted operating parameter, and if the alternating stress obtained according to the adjusted operating parameter is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter and use the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube;

[0034] Determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each of the parameters.

[0035] In a fifth aspect, the present application also provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the following steps are implemented:

[0036] Obtain the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters;

[0037] Select each of the operating parameters in sequence and perform an adjustment step until the critical parameter value corresponding to each of the parameters is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain an adjusted operating parameter, and if the alternating stress obtained according to the adjusted operating parameter is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter and use the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube;

[0038] Determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each of the parameters.

[0039] The method, device, computer equipment, storage medium and computer program product for determining the flow instability boundary of the heat transfer tube first obtain the operation parameters of the once-through steam generator; the operation parameters include at least two different types of parameters; each type of parameter in the operation parameters is sequentially selected to execute the adjustment step until the critical parameter value corresponding to each type of parameter is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operation parameters, if the alternating stress obtained according to the adjusted operation parameters is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of this parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube; based on the critical parameter values corresponding to each parameter, determine the boundary parameters of the flow instability boundary of the heat transfer tube. Thus, in combination with the thermal fatigue phenomenon of the OTSG heat transfer tube, the critical values of each parameter in the operation parameters of the once-through steam generator are determined one by one to obtain the flow instability boundary of the heat transfer tube, providing a reliable numerical basis for the design of the OTSG operation parameters. At the same time, this method can automatically search for the OTSG flow instability boundary without experiments, saving labor costs. Brief Description of the Drawings

[0040] Figure 1 It is an application environment diagram of the method for determining the flow instability boundary of the heat transfer tube in an embodiment;

[0041] Figure 2 It is a flowchart of the method for determining the flow instability boundary of the heat transfer tube in an embodiment;

[0042] Figure 3 It is a flowchart of the alternating stress obtained according to the adjusted operation parameters in the method for determining the flow instability boundary of the heat transfer tube in an embodiment;

[0043] Figure 4 It is a flowchart of the method for determining the flow instability boundary of the heat transfer tube in another embodiment;

[0044] Figure 5 It is a structural block diagram of the device for determining the flow instability boundary of the heat transfer tube in an embodiment;

[0045] Figure 6 It is an internal structure diagram of the computer equipment in an embodiment. Detailed Description of the Embodiments

[0046] In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0047] The method for determining the boundary of flow instability of a heat transfer tube provided by an embodiment of the present application can be applied to, for example, Figure 1 the application environment shown. Among them, the heat transfer tube is a heat transfer tube of a once-through steam generator. The terminal 102 communicates with the server 104 through a network. The data storage system can store the data that the server 104 needs to process. The data storage system can be integrated on the server 104, or can be placed in the cloud or on other network servers. The server is used to obtain the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters; each type of parameter in the operating parameters is sequentially selected to execute an adjustment step until the critical parameter value corresponding to each type of parameter is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters, if the alternating stress obtained according to the adjusted operating parameters is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of this parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube; determining the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each parameter. Among them, the terminal 102 can be, but is not limited to, various personal computers, laptop computers, smart phones, tablet computers, etc. The server 104 can be implemented by an independent server or a server cluster composed of multiple servers.

[0048] In one embodiment, as Figure 2 shown, a method for determining the boundary of flow instability of a heat transfer tube is provided. Taking the server in Figure 1 as an example, the following steps 200-step 600 are included.

[0049] Step 200, obtain the operating parameters of the once-through steam generator.

[0050] The once-through steam generator is a heat exchange device. Its working principle is to use the reactor power device to push the coolant in the reactor to the core, thereby increasing the pressure, heating the core, and then transferring the heat obtained in this way to the secondary loop working medium to turn it into steam, and then return, in a continuous cycle. The heat transfer tube in this embodiment is a heat transfer tube of a once-through steam generator. The method for determining the boundary of flow instability of the heat transfer tube is not limited to being applied to the heat transfer tube of the once-through steam generator of a reactor, and once-through steam generators in other application fields and scenarios are still applicable. For the sake of explanation, in this embodiment, the heat transfer tube of the once-through steam generator is taken as an example of the heat transfer tube of the once-through steam generator of a reactor for description.

[0051] The types of operating parameters of the once-through steam generator need to be determined in combination with the specific usage scenarios of the once-through generator. Generally, the operating parameters include at least two different types of parameters. In some embodiments, the once-through steam generator is used in a reactor, and its operating parameters include at least two of the inlet throttling pressure drop, the subcooling degree of the secondary-side feed water inlet, the feed water flow rate, and the operating pressure. For example, in some embodiments, the operating parameters may include two parameters, namely the inlet throttling pressure drop and the subcooling degree of the secondary-side feed water inlet; or, in some embodiments, the operating parameters may include three parameters, namely the inlet throttling pressure drop, the subcooling of the secondary-side feed water inlet, and the feed water flow rate; or, in some embodiments, the operating parameters may further include four parameters, namely the inlet throttling pressure drop, the subcooling of the secondary-side feed water inlet, the feed water flow rate, and the operating pressure. Of course, the operating parameters may also include other parameters, which are not limited herein. In this embodiment, the obtained operating parameters of the once-through steam generator can be used as the initial operating parameters of the once-through steam generator. The initial operating parameters can be determined according to the operating conditions of the once-through generator. Optionally, the initial operating parameters can be determined according to the operating conditions under which the once-through generator is prone to operating instability phenomena. For example, when the once-through steam generator is used in a reactor, step 200 may include: obtaining the operating parameters of the once-through steam generator at a low power level of the reactor. This is because the flow instability phenomenon of the once-through steam generator is likely to occur at the low power level of the reactor (such as 20% FP). Therefore, after determining the boundary parameters of the OTSG flow instability boundary based on the overall operating parameters of the OTSG at the low power level of the reactor as the initial operating parameters, operating according to the boundary parameters at the low power level of the reactor will not reach the OTSG flow instability boundary. Then, operating according to the boundary parameters at the high power level of the reactor will also not reach the OTSG flow instability boundary.

[0052] Therefore, determining the initial operating parameters according to the operating conditions under which the once-through generator is prone to operating instability phenomena and exploring the critical value of the flow instability of the heat transfer tubes can better ensure the operating safety of the heat transfer tubes and the OTSG.

[0053] Step 300: Sequentially select each parameter in the operating parameters and execute the adjustment step until the critical parameter value corresponding to each parameter is obtained.

[0054] During the process of determining the flow instability boundary of the heat transfer tubes, first, based on the initial operating parameters, the value of the first parameter in the operating parameters is adjusted individually, and the values of other types of parameters are kept unchanged during the adjustment process until the critical parameter value of this parameter is determined. Then, based on the initial operating parameters, the value of the second parameter is adjusted until the critical parameter value of the second parameter is determined, and so on, until the critical parameter value corresponding to each parameter is obtained.

[0055] Taking the operating parameters of a once-through steam generator, including four parameters: inlet throttling pressure drop, subcooling degree at the secondary side feed water inlet, feed water flow rate, and operating pressure, as an example, when determining the boundary of the flow instability of the heat transfer tubes, it is necessary to adjust these four parameters sequentially to obtain the critical parameter values corresponding to these four parameters. When adjusting these four parameters, the adjustment order of the four parameters can be set according to the actual situation, and this embodiment does not limit this.

[0056] When adjusting each parameter, it can be implemented by performing an adjustment step. The adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameter. If the alternating stress obtained according to the adjusted operating parameter is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of this parameter.

[0057] It should be noted that during the process of continuously adjusting the selected parameter, each time the parameter value of the selected parameter is adjusted, an adjusted operating parameter can be obtained. Each time an adjusted operating parameter is obtained, it is judged whether the current alternating stress obtained according to the adjusted operating parameter is greater than the critical stress corresponding to the current moment. If after a certain adjustment, the current alternating stress obtained according to the adjusted operating parameter obtained from this adjustment is greater than the critical stress corresponding to the current moment, stop continuing to adjust the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of this parameter.

[0058] Specifically, in this embodiment, after selecting a parameter based on the initial operating parameters, adjust the parameter value of this parameter to obtain the adjusted operating parameter; then obtain the current alternating stress according to the adjusted operating parameter, and judge whether the current alternating stress is greater than the critical stress corresponding to the current moment. If the current alternating stress is less than or equal to the critical stress corresponding to the current moment, it indicates that the adjusted operating parameter will not cause the heat transfer tube to exceed the fatigue life, then continue to adjust the parameter value of the parameter currently being adjusted to obtain the re-adjusted operating parameter; update the current alternating stress according to the re-adjusted operating parameter, and judge whether the updated current alternating stress is greater than the updated critical stress corresponding to the current moment. If the updated current alternating stress is less than or equal to the updated critical stress corresponding to the current moment, then adjust the parameter value of the parameter currently being adjusted again until the updated current alternating stress is greater than the updated critical stress corresponding to the current moment; if the updated current alternating stress is greater than the updated critical stress corresponding to the current moment, then use the parameter value at the previous moment as the critical parameter value of this parameter.

[0059] Exemplarily, still taking the operating parameters of the OTSG including four parameters: inlet throttling pressure drop, subcooling degree of the secondary side feed water inlet, feed water flow rate, and operating pressure as an example. Assume that the initial parameter values of the inlet throttling pressure drop, subcooling degree of the secondary side feed water inlet, feed water flow rate, and operating pressure obtained based on step 200 are all a. Assume the selection order is to adjust the inlet throttling pressure drop, subcooling degree of the secondary side feed water inlet, feed water flow rate, and operating pressure in sequence.

[0060] First, adjust the parameter value of the inlet throttling pressure drop (assume it is adjusted from a to b), and keep the subcooling degree of the secondary side feed water inlet, feed water flow rate, and operating pressure as the initial parameter value a. Then the adjusted operating parameters include: the inlet throttling pressure drop is b, the subcooling degree of the secondary side feed water inlet is a, the feed water flow rate is a, and the operating pressure is a. Calculate the intensity of the alternating stress based on this operating parameter, and determine whether this alternating stress is greater than the critical stress corresponding to the current moment (this current moment is the moment when the inlet throttling pressure drop is adjusted from a to b).

[0061] If this alternating stress is not greater than the critical stress corresponding to the current moment, it indicates that the operating parameters with the inlet throttling pressure drop of b, the subcooling degree of the secondary side feed water inlet of a, the feed water flow rate of a, and the operating pressure of a will not cause the heat transfer tubes to exceed the fatigue life. At this time, the numerical value of the parameter currently being adjusted can be continued to be adjusted, that is, continue to adjust the parameter value of the inlet throttling pressure drop (assume it is adjusted from b to c). The adjusted operating parameters include: the inlet throttling pressure drop is c, the subcooling degree of the secondary side feed water inlet is a, the feed water flow rate is a, and the operating pressure is a. Recalculate the intensity of the alternating stress based on this operating parameter, and determine whether this alternating stress is greater than the critical stress at the current moment (this current moment is the moment when the inlet throttling pressure drop is adjusted from b to c). If it is greater, it means that the operating parameters with the inlet throttling pressure drop of c, the subcooling degree of the secondary side feed water inlet of a, the feed water flow rate of a, and the operating pressure of a will cause the heat transfer tubes to exceed the fatigue life, and the critical parameter value of the inlet throttling pressure drop is b. At this time, stop adjusting the inlet throttling pressure drop, and take the parameter value of the previous moment as the critical parameter, that is, determine the critical parameter value of the inlet throttling pressure drop as b.

[0062] Next, adjust the parameter value of the subcooling degree of the secondary side feed water inlet (assume it is adjusted from a to b), and keep the inlet throttling pressure drop, feed water flow rate, and operating pressure as the initial parameter value a until the critical parameter value of the subcooling degree of the secondary side feed water inlet is obtained. The specific adjustment process can refer to the above adjustment process of the inlet throttling pressure drop and will not be elaborated. After the critical parameter value of the subcooling degree of the secondary side feed water inlet is determined, adjust and obtain the critical parameter values of the feed water flow rate and operating pressure in sequence.

[0063] It should also be noted that in actual implementation, the critical parameter values of each parameter under various operating conditions can also be determined according to various operating conditions of the OTSG.

[0064] Among them, the critical stress is obtained based on the thermal fatigue life of the heat transfer tube. The thermal fatigue life refers to the life that the heat transfer tube can reach under the condition that thermal cyclic stress is generated inside the material due to temperature change and restraint. The critical stress is the maximum thermo-mechanical stress that the heat transfer tube can withstand before fatigue failure.

[0065] The alternating stress is specifically the strength of the total alternating stress in the fatigue analysis of the OTSG heat transfer tube during the period from the start of parameter adjustment to the current calculation moment, determined according to the requirements of the pipeline design code, such as the design requirements for nuclear class 1 pipelines in the Boiler and Pressure Vessel Code of the American Society of Mechanical Engineers (ASME) or the RCC-M "Design and Construction Code for Mechanical Equipment in the Nuclear Island of French Pressurized Water Reactors". The specific implementation manner for determining the alternating stress strength is not limited.

[0066] Step 400, determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each parameter.

[0067] Among them, the critical values of the flow instability of the heat transfer tube include each parameter and the critical parameter values corresponding to each parameter, thus providing a theoretical basis for the design of the OTSG operating parameters.

[0068] It can be understood that when determining the critical parameter values of each parameter under various operating conditions, the boundary parameters of the flow instability boundary of the heat transfer tube can include the ranges of the critical parameter values of each parameter.

[0069] The above method for determining the flow instability boundary of the heat transfer tube first obtains the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters; sequentially select each type of parameter in the operating parameters to perform the adjustment step until the critical parameter value corresponding to each type of parameter is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters, if the alternating stress obtained according to the adjusted operating parameters is greater than the critical stress corresponding to the current moment, then take the parameter value of the selected parameter at the previous moment as the critical parameter value of this parameter, where the critical stress is obtained based on the thermal fatigue life of the heat transfer tube; determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each parameter. Thus, it realizes determining the flow instability boundary by combining the thermal fatigue phenomenon of the OTSG heat transfer tube, provides a theoretical basis for the design of the OTSG operating parameters, and at the same time meets the mechanical design requirements. Moreover, this method can automatically search for the OTSG flow instability boundary without experiments, saving labor costs.

[0070] It should also be noted that there are mainly two criteria for judging the flow instability of traditional OTSGs. The first is to establish the flow instability boundary through the dimensionless subcooling number Nsub and the dimensionless phase change number Npch. The second is to delimit the flow instability boundary by the maximum pulsation amplitude of the OTSG outlet steam flow rate (such as 10%). However, both of the above two criteria have obvious deficiencies: the flow instability boundary is mostly obtained based on experiments, with a large number of experimental conditions and high costs. If the flow instability phenomenon occurs, the thermal fatigue of the heat transfer tubes is the main consequence, and neither of the above two criteria has a direct connection with the thermal fatigue phenomenon, and it is impossible to fully reflect the limitation of thermal fatigue on flow instability.

[0071] The method for determining the flow instability boundary of the above heat transfer tubes, combined with the thermal fatigue phenomenon of the OTSG heat transfer tubes, automatically determines the flow instability boundary, which can fully reflect the limitation of the thermal fatigue phenomenon on the operation of the OTSG and reduces the experimental and labor costs.

[0072] In one embodiment, in the adjustment step, after taking the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, that is, after obtaining the critical parameter value of the selected parameter, the adjustment step further includes: updating the operation parameters of the once-through steam generator according to the critical parameter value.

[0073] In this embodiment, after each critical parameter value of a parameter is determined, the initial operation parameters of the OTSG are also updated according to the critical parameter value of the parameter. When determining the critical parameter value of the next parameter, the parameter value of the next parameter is adjusted according to the updated operation parameters of the OTSG.

[0074] Exemplarily, still taking the operating parameters of a DC steam generator including four types of parameters: inlet throttling pressure drop, subcooling degree of feed water at the secondary side inlet, feed water flow rate, and operating pressure, and assuming that the first parameter to be adjusted is the inlet and outlet throttling pressure drop, and the second parameter to be adjusted is the subcooling degree of feed water at the secondary side inlet as an example. Suppose the initial parameter values of the inlet throttling pressure drop, subcooling degree of feed water at the secondary side inlet, feed water flow rate, and operating pressure obtained are all a. And by performing an adjustment step on the inlet and outlet throttling pressure drop parameter, the critical parameter value of the inlet and outlet throttling pressure drop is determined to be b. The operating parameters of the OTSG updated according to the critical parameter value of the inlet and outlet throttling pressure drop, that is, the updated operating parameters of the OTSG include: the inlet throttling pressure drop is b, the subcooling degree of feed water at the secondary side inlet is a, the feed water flow rate is a, and the operating pressure is a. Subsequently, the subcooling degree of feed water at the secondary side inlet parameter is adjusted. For example, the subcooling degree of feed water at the secondary side inlet is adjusted from a to d, while keeping the inlet throttling pressure drop at b, the feed water flow rate at a, and the operating pressure at a unchanged, to obtain the adjusted operating parameters. At this time, the adjusted operating parameters include: the inlet throttling pressure drop is b, the subcooling degree of feed water at the secondary side inlet is d, the feed water flow rate is a, and the operating pressure is a. Based on these operating parameters, the intensity of the alternating stress is calculated, and it is judged whether the alternating stress is greater than the critical stress corresponding to the current moment (this current moment is the moment when the subcooling degree of feed water at the secondary side inlet is adjusted from a to d). If the alternating stress is not greater than the critical stress corresponding to the current moment, continue to adjust the subcooling degree of feed water at the secondary side inlet (suppose it is adjusted from d to e). The adjusted operating parameters include: the inlet throttling pressure drop is b, the subcooling degree of feed water at the secondary side inlet is e, the feed water flow rate is a, and the operating pressure is a. Based on the intensity of the alternating stress calculated from these operating parameters, it is judged whether the alternating stress is greater than the critical stress corresponding to the current moment (this current moment is the moment when the subcooling degree of feed water at the secondary side inlet is adjusted from d to e). If it is greater, then stop further adjusting the subcooling degree of feed water at the secondary side inlet, and determine that the critical value of the subcooling degree of feed water at the secondary side inlet is d. And the operating parameters of the OTSG updated according to the critical value of the subcooling degree of feed water at the secondary side inlet, that is, the updated operating parameters of the OTSG include: the inlet throttling pressure drop is b, the subcooling degree of feed water at the secondary side inlet is d, the feed water flow rate is a, and the operating pressure is a. Next, based on these updated operating parameters, the feed water flow rate and operating pressure are adjusted in sequence, and the adjustment process will not be elaborated here.

[0075] Actually, when determining the critical parameter value of each type of parameter, the search workload is very large. In this embodiment, after determining the critical parameter value of one parameter, the initial operating parameters of the OTSG are updated according to the critical parameter value of this parameter, and then the next parameter is adjusted based on the updated operating parameters, which can greatly reduce the search workload and shorten the search duration.

[0076] In one embodiment, as Figure 3As shown, the alternating stress obtained according to the adjusted operating parameters includes step 321 and step 322.

[0077] Step 321: Determine the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters.

[0078] Step 322: Determine the alternating stress corresponding to the adjusted operating parameters according to the thermal-hydraulic parameters.

[0079] According to different actual application scenarios, the thermal-hydraulic parameters may include at least one of the steam pressure, temperature, and flow rate at the outlet of the once-through steam generator.

[0080] Among them, the method of determining the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters does not need to be limited. In one embodiment, determining the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters includes: performing time-domain analysis on the adjusted operating parameters to determine the thermal-hydraulic parameters of the once-through steam generator.

[0081] It can be understood that a time-domain analysis program can be preset in the server to perform time-domain analysis on the operating conditions of the once-through steam generator obtained according to the adjusted operating parameters. Since time-domain analysis is a method of directly analyzing in the time domain and has the advantages of intuitiveness and accuracy, the thermal-hydraulic parameters obtained based on this are also more accurate and intuitive.

[0082] In another embodiment, a thermal-hydraulic parameter determination model can also be preset in the server. When the adjusted operating parameters are obtained, the corresponding thermal-hydraulic parameters are obtained based on the adjusted operating parameters and the thermal-hydraulic parameter determination model.

[0083] When determining the alternating stress corresponding to the adjusted operating parameters according to the thermal-hydraulic parameters, those skilled in the art can select a suitable method according to the actual situation to determine the intensity of the alternating stress in the OTSG heat transfer tube fatigue analysis during any two time periods starting from the most recent parameter adjustment to the current calculation moment. For example, the moment of the most recent parameter adjustment is m, and the current calculation moment is n. When calculating the intensity of the alternating stress, first select moment i and moment j, where moment i and moment j are any two moments between moment m and moment n, and then calculate based on moment i, moment j, and the thermal-hydraulic parameters to obtain the intensity of the alternating stress, that is, the intensity of the alternating stress corresponding to the adjusted operating parameters.

[0084] In one embodiment, the method for determining the critical stress includes: based on the current moment, obtain the service life of the heat transfer tube, and obtain the critical stress according to the service life and the thermal fatigue life of the heat transfer tube.

[0085] In this embodiment, the manifestation form of the thermal fatigue life can be a fatigue curve (S-N curve) or a parameter comparison table of the service life and the critical stress, etc. When the manifestation form of the thermal fatigue life is an S-N curve, the service life of the heat transfer tube can be determined based on the current time first, and then the maximum stress that the heat transfer tube can withstand can be obtained on the S-N curve according to the service life, that is, the maximum stress corresponding to the current time, so as to determine the critical stress corresponding to the current time according to the maximum stress corresponding to the current time.

[0086] When determining the critical stress corresponding to the current time according to the maximum stress, the maximum stress corresponding to the current time can be directly used as the critical stress corresponding to the current time; or on the basis of the maximum stress corresponding to the current time, a certain safety analysis margin can be reserved, and the result obtained by subtracting the safety analysis margin from the maximum stress corresponding to the current time can be used as the critical stress corresponding to the current time. The safety analysis margin needs to be set in combination with the actual situation, as long as it can ensure that the once-through steam generator operates according to the critical value without exceeding the fatigue life of the heat transfer tube, so as to ensure the safe operation of the once-through steam generator.

[0087] In order to better understand the above embodiment, the following will be explained in detail in combination with a specific embodiment. In one embodiment, the method for determining the flow instability boundary of the heat transfer tube of the once-through steam generator is a method that can automatically search for the flow instability boundary of the heat transfer tube. In this method, in combination with the thermal fatigue phenomenon of the OTSG heat transfer tube, the critical values of the various parameters in the operating parameters of the once-through steam generator are determined one by one to obtain the flow instability boundary of the heat transfer tube, providing a theoretical basis for the design of the OTSG operating parameters. At the same time, this method can automatically search for the OTSG flow instability boundary without tests, saving labor costs.

[0088] Specifically, please refer to Figure 4 , the method for determining the flow instability boundary of the heat transfer tube of the once-through steam generator includes the following steps:

[0089] (1). Determine the overall operating parameters at the low power step of the reactor (such as 20% FP), mainly including the OTSG inlet throttling pressure drop, the secondary side feed water inlet subcooling degree, the feed water flow rate and the operating pressure.

[0090] (2). Taking the overall operating parameters obtained in step (1) as the initial operating parameters, fixing other parameters, and gradually adjusting one of the parameters of the inlet throttling pressure drop, the secondary side feed water inlet subcooling degree, the feed water flow rate and the operating pressure separately to obtain the operating parameters of a series of working conditions. For example, fixing the inlet throttling pressure drop, the secondary side feed water inlet subcooling degree, and the feed water flow rate, and separately adjusting the operating pressure within the reasonable operating range, thereby obtaining a series of initial working conditions.

[0091] (3) Use a system analysis program to conduct a time-domain analysis on a series of initial operating conditions obtained in step (2) to obtain the results of main thermal-hydraulic parameters such as the steam pressure, temperature, and flow rate at the OTSG outlet.

[0092] (4) According to the requirements of the pipeline design specification, and in combination with the results of the OTSG thermal-hydraulic parameters obtained in step (3), calculate the total alternating stress intensity in the fatigue analysis of the OTSG heat transfer tubes during any two time instants i and j.

[0093] (5) Judge whether the intensity of the alternating stress of the heat transfer tubes calculated in step (4) under this initial operating condition meets the critical stress determined by the S-N curve of the OTSG heat transfer tubes.

[0094] If the result obtained in step (5) shows that the stress intensity meets the S-N curve of the OTSG heat transfer tubes, it indicates that the initial operating condition in step (2) will not cause the OTSG heat transfer tubes to exceed their fatigue life. Return to step (2) to continue adjusting the input parameters until the result obtained in step (5) shows that the stress intensity does not meet the S-N curve of the OTSG heat transfer tubes, that is, the initial operating condition in step (2) will cause the OTSG heat transfer tubes to exceed their fatigue life. Thus, the critical values of each parameter are obtained, and the flow instability boundary is determined accordingly.

[0095] The method for determining the flow instability boundary of the once-through steam generator heat transfer tubes can automatically search for the flow instability boundary of the once-through steam generator heat transfer tubes based on the thermal fatigue phenomenon. It can automatically search for the flow instability boundary of the OTSG operation based on the S-N curve of the OTSG heat transfer tubes, fully reflecting the limitation of the thermal fatigue phenomenon on the OTSG operation, and reducing the test and labor costs.

[0096] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are shown in sequence according to the arrows, these steps do not necessarily need to be executed in the order indicated by the arrows. Unless clearly stated in this article, there is no strict order limit for the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages. These steps or stages do not necessarily need to be executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential either, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0097] Based on the same inventive concept, an embodiment of the present application further provides a device for determining the boundary of flow instability of a heat transfer tube, which is used to implement the method for determining the boundary of flow instability of the heat transfer tube involved above. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the device for determining the boundary of flow instability of the heat transfer tube provided below can refer to the limitations on the method for determining the boundary of flow instability of the heat transfer tube in the above text, and will not be repeated here.

[0098] In one embodiment, as Figure 5 shown, a device for determining the boundary of flow instability of a heat transfer tube is provided, including: a parameter acquisition module 500, a critical value determination module 600, and a boundary parameter determination module 700, where:

[0099] The parameter acquisition module 500 is configured to acquire the operating parameters of a once-through steam generator; the operating parameters include at least two different types of parameters.

[0100] The critical value determination module 600 is configured to sequentially select each parameter in the operating parameters to perform an adjustment step until the critical parameter value corresponding to each parameter is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters. If the alternating stress obtained according to the adjusted operating parameters at the current moment is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of this parameter, where the critical stress is obtained based on the thermal fatigue life of the heat transfer tube.

[0101] The boundary parameter determination module 700 is configured to determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each parameter.

[0102] In one embodiment, the critical value determination module 600 is further configured to update the operating parameters of the once-through steam generator according to the critical parameter values.

[0103] In one embodiment, the critical value determination module 600 is further configured to determine the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters;

[0104] Determine the alternating stress corresponding to the adjusted operating parameters according to the thermal-hydraulic parameters.

[0105] In one embodiment, the critical value determination module 600 is further configured to perform time-domain method analysis on the adjusted operating parameters to determine the thermal-hydraulic parameters of the once-through steam generator.

[0106] In one embodiment, the parameter acquisition module 500 is further configured to acquire the operating parameters of the once-through steam generator at a low reactor power step.

[0107] In one embodiment, the threshold determination module 600 is further configured to obtain the service life of the heat transfer tube based on the current time; and obtain the critical stress according to the service life and the thermal fatigue life of the heat transfer tube.

[0108] Each module in the above-mentioned device for determining the flow instability boundary of the heat transfer tube can be implemented in whole or in part by software, hardware, and their combination. The above-mentioned modules can be embedded in the processor in the computer device in the form of hardware or independent of the processor, or stored in the memory in the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above-mentioned modules.

[0109] In one embodiment, a computer device is provided. The computer device can be a server, and its internal structure diagram can be as Figure 6 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store the data that the processor needs to process, such as various critical parameters. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, it realizes a method for determining the flow instability boundary of a heat transfer tube.

[0110] Those skilled in the art can understand that Figure 6 the structure shown in

[0111] is only a block diagram of some structures related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0112] Obtain the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters;

[0113] Select each parameter in the operating parameters in sequence to execute the adjustment step until the critical parameter value corresponding to each parameter is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameter. If the alternating stress obtained according to the adjusted operating parameter is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube;

[0114] Determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each parameter.

[0115] In one embodiment, when the processor executes the computer program, the following steps are further implemented: update the operating parameters of the once-through steam generator according to the critical parameter values.

[0116] In one embodiment, when the processor executes the computer program, the following steps are further implemented: determine the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters;

[0117] Determine the alternating stress corresponding to the adjusted operating parameters according to the thermal-hydraulic parameters.

[0118] In one embodiment, when the processor executes the computer program, the following steps are further implemented: perform time-domain analysis on the adjusted operating parameters to determine the thermal-hydraulic parameters of the once-through steam generator.

[0119] In one embodiment, when the processor executes the computer program, the following steps are further implemented:

[0120] Obtain the operating parameters of the once-through steam generator at the low power step of the reactor.

[0121] In one embodiment, when the processor executes the computer program, the following steps are further implemented:

[0122] Based on the current moment, obtain the service life of the heat transfer tube;

[0123] Obtain the critical stress according to the service life and the thermal fatigue life of the heat transfer tube.

[0124] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0125] Obtain the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters;

[0126] Select each parameter in the operating parameters in sequence to perform the adjustment step until the critical parameter value corresponding to each parameter is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameter. If the alternating stress obtained according to the adjusted operating parameter is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube;

[0127] Determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each parameter.

[0128] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: update the operating parameters of the once-through steam generator according to the critical parameter values.

[0129] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: determine the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters;

[0130] Determine the alternating stress corresponding to the adjusted operating parameters according to the thermal-hydraulic parameters.

[0131] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: perform time-domain method analysis on the adjusted operating parameters to determine the thermal-hydraulic parameters of the once-through steam generator.

[0132] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: obtain the operating parameters of the once-through steam generator under the low power step of the reactor.

[0133] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented:

[0134] Based on the current moment, obtain the service life of the heat transfer tube;

[0135] Obtain the critical stress according to the service life and the thermal fatigue life of the heat transfer tube.

[0136] In one embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by the processor, the following steps are implemented:

[0137] Obtain the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters;

[0138] Select each parameter in the operating parameters in sequence and execute the adjustment step until the critical parameter value corresponding to each parameter is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters, and if the alternating stress obtained based on the adjusted operating parameters is greater than the critical stress corresponding to the current moment, stop adjusting the selected parameter and use the parameter value of the selected parameter at the previous moment as the critical parameter value of the parameter, where the critical stress is obtained based on the thermal fatigue life of the heat transfer tube;

[0139] Determine the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each parameter.

[0140] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: update the operating parameters of the once-through steam generator according to the critical parameter values.

[0141] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: determine the thermohydraulic parameters of the once-through steam generator according to the adjusted operating parameters;

[0142] Determine the alternating stress corresponding to the adjusted operating parameters according to the thermohydraulic parameters.

[0143] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: perform time-domain method analysis on the adjusted operating parameters to determine the thermohydraulic parameters of the once-through steam generator.

[0144] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: obtain the operating parameters of the once-through steam generator under the low power step of the reactor.

[0145] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented:

[0146] Based on the current moment, obtain the usage duration of the heat transfer tube;

[0147] Obtain the critical stress according to the usage duration and the thermal fatigue life of the heat transfer tube.

[0148] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0149] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0150] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for determining the boundary of flow instability of a heat transfer tube, characterized in that, The heat transfer tube is a heat transfer tube of a once-through steam generator, and the method includes: Obtaining the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters; Sequentially selecting each of the parameters in the operating parameters to perform an adjustment step until the critical parameter value corresponding to each of the parameters is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters, if the alternating stress obtained according to the adjusted operating parameters is greater than the critical stress corresponding to the current moment, then stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of this parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube; Determining the boundary parameters of the flow instability boundary of the heat transfer tube based on the critical parameter values corresponding to each of the parameters.

2. The method according to claim 1, characterized in that, In the adjustment step, after using the parameter value of the selected parameter at the previous moment as the critical parameter value of this parameter, it further includes: Updating the operating parameters of the once-through steam generator according to the critical parameter value.

3. The method according to claim 1, wherein The operating parameters include at least two of the inlet throttling pressure drop, the subcooling degree of the secondary side feed water inlet, the feed water flow rate, and the operating pressure.

4. The method according to claim 1, characterized in that The alternating stress obtained according to the adjusted operating parameters includes: Determining the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters; Determining the alternating stress corresponding to the adjusted operating parameters according to the thermal-hydraulic parameters.

5. The method according to claim 4, characterized in that Determining the thermal-hydraulic parameters of the once-through steam generator according to the adjusted operating parameters includes: Performing time-domain method analysis on the adjusted operating parameters to determine the thermal-hydraulic parameters of the once-through steam generator.

6. The method according to claim 5, characterized in that, The thermal-hydraulic parameters include at least one of the steam pressure, temperature, and flow rate at the outlet of the once-through steam generator.

7. The method according to claim 1, wherein The once-through steam generator is used for a reactor, and obtaining the operating parameters of the once-through steam generator includes: Obtaining the operating parameters of the once-through steam generator at the low power step of the reactor.

8. The method according to claim 1, wherein The method for determining the critical stress includes: Based on the current moment, obtaining the service life of the heat transfer tube; Obtaining the critical stress according to the service life and the thermal fatigue life of the heat transfer tube.

9. A device for determining the boundary of flow instability of a heat transfer tube, characterized in that The heat transfer tube is a heat transfer tube of a once-through steam generator, and the device includes: A parameter acquisition module for obtaining the operating parameters of the once-through steam generator; the operating parameters include at least two different types of parameters; A critical value determination module for sequentially selecting each of the parameters in the operating parameters to perform an adjustment step until the critical parameter value corresponding to each of the parameters is obtained; the adjustment step includes: continuously adjusting the parameter value of the selected parameter to obtain the adjusted operating parameters, if the alternating stress obtained according to the adjusted operating parameters at the current moment is greater than the critical stress corresponding to the current moment, then stop adjusting the selected parameter, and use the parameter value of the selected parameter at the previous moment as the critical parameter value of this parameter, where the critical stress is obtained according to the thermal fatigue life of the heat transfer tube; A boundary parameter determination module, configured to determine boundary parameters of a flow instability boundary of the heat transfer tube based on critical parameter values corresponding to the respective parameters.

10. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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