Modeling method and analysis model for kinetic analysis of nuclear power main pump rotor

Abstract

The invention provides a modeling method for kinetic analysis of a nuclear power main pump rotor, and the method comprises the following steps: S1, building a rotor part of a kinetic analysis model of the nuclear power main pump rotor, and creating a node representing a hydraulic effect at the rotor part; s2, establishing a stator part of the kinetic analysis model of the nuclear power main pump rotor, and creating nodes representing the hydraulic effect on the stator part; s3, establishing a connection part of a hydraulic dynamic effect between dynamic and static parts in the nuclear power main pump rotor dynamic analysis model, and selecting hydraulic dynamic parameters to simulate the hydraulic dynamic effect between the dynamic and static parts according to working conditions and rotating speeds; and S4, according to the hydraulic dynamic parameters, the connection relation of the impeller wear ring, the radial bearing and the clearance circulation is established. The method is improved based on a traditional rotor dynamics method, interaction between a main pump component and hydraulic power is increased, influences of different parameters of the hydraulic power action under different working conditions are considered, and the calculation precision can be improved by scientifically selecting proper parameters.

Description

Technical Field

[0001] This invention relates to the field of nuclear power plant reactors, and in particular to a modeling method for the dynamic analysis of the rotor of a nuclear power plant main pump. Background Technology

[0002] In existing technologies, the reactor coolant pump, or main pump for short, is the most important core component of the primary loop pressure boundary of a nuclear power plant. It is used to drive the circulation of coolant inside the reactor, and its operating condition directly affects the safe and stable operation of the nuclear power plant.

[0003] Generation III passive nuclear power plants have multiple loops, each with one or two steam generators, and each steam generator is equipped with one or two main pumps. AP series passive nuclear power plants use fully sealed pumps, and a common arrangement for main pumps is a vertical cantilever beam structure. Generally, the main pump inlet is connected to the steam generator via a transition section, and the outlet is connected to the cold section, arranged relatively horizontally. While the vertical cantilever beam structure is advantageous for a compact plant layout, it places high demands on the stable operation of the main pumps. Considering the safety and stability of the power plant, the design specifications for the main pumps will specify certain critical speeds and operability requirements. Therefore, the rotor dynamics of the main pumps is a crucial analysis related to their safety.

[0004] Currently, the rotor dynamics modeling method for nuclear power plant main pumps mainly considers rotating components, calculates the critical speed only for rotating components, and appropriately increases the mass coefficient caused by additional fluid to prove that the critical speed of nuclear power plant main pumps meets the requirements of the specification.

[0005] However, existing rotor dynamics analyses of nuclear power plant main pumps still lack sufficient research on the hydraulic interactions between moving and stationary components, leading to a series of related problems. For example, the use of conventional circular bearings results in a large amplitude of half-speed whirl in the main pump. While using tilting pad bearings avoids half-speed whirl, it imposes stricter requirements on manufacturing tolerances to prevent rubbing.

[0006] The vertical suspended arrangement used in third-generation passive nuclear power plants leads to a strong coupling effect between the main nuclear pump and the main circuit. Furthermore, the vibration control of the main nuclear pump itself places higher demands on the accuracy of vibration analysis based on rotor dynamics models and the modeling of the hydraulic interactions between moving and stationary components. This is something that previous rotor dynamics models could not achieve, and research on the hydraulic interactions between moving and stationary components of nuclear power main pumps urgently needs to be strengthened.

[0007] In view of this, the inventors of this application have designed a modeling method for the dynamic analysis of the rotor of a nuclear power plant main pump in order to overcome the above-mentioned technical problems. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the problem that the traditional rotor dynamics modeling method in the prior art underestimates the first critical speed, the difficulty in obtaining the accurate first-order rotor bending mode frequency by adding an additional fluid mass coefficient, and the defect of fault diagnosis based on the first-order rotor bending mode frequency. The present invention provides a modeling method for rotor dynamics analysis of nuclear power plant main pumps.

[0009] The present invention solves the above-mentioned technical problems through the following technical solution:

[0010] A modeling method for the dynamic analysis of a nuclear power plant main pump rotor, characterized in that the modeling method includes the following steps:

[0011] S1. Establish the rotor part of the nuclear power plant main pump rotor dynamic analysis model, and create nodes representing hydraulic effects in the rotor part;

[0012] S2. Establish the stator part of the nuclear power plant main pump rotor dynamic analysis model, and create nodes representing hydraulic effects in the stator part;

[0013] S3. Establish the connection part of the hydraulic dynamic effect between the dynamic and static components in the rotor dynamic analysis model of the nuclear power plant main pump, and select hydraulic dynamic parameters according to the working conditions and speed to simulate the hydraulic dynamic effect between the dynamic and static components.

[0014] S4. Based on the hydraulic dynamic parameters, create the connection relationship between the impeller inlet ring, radial bearing, and gap circulation.

[0015] According to one embodiment of the present invention, in step S1, the rotor portion creates nodes representing the hydraulic effect, including the impeller side of the mouth ring and the bearing.

[0016] According to one embodiment of the present invention, in step S2, the nodes representing the hydraulic effect created in the stator portion include the guide vane side of the mouth ring and the bearing housing.

[0017] According to one embodiment of the present invention, the nuclear power plant main pump rotor dynamics analysis includes rotating components, symmetrical stationary components, and asymmetrical stationary components of the nuclear power plant main pump.

[0018] According to one embodiment of the present invention, the rotating components of the nuclear main pump include an impeller, an upper radial bearing, a rotor assembly body, and a lower radial bearing.

[0019] According to one embodiment of the present invention, the symmetrical stationary portion includes an upper flange, a stator assembly body, and a lower flange.

[0020] According to one embodiment of the present invention, the asymmetric static portion includes a pump housing, a heat exchanger, and a junction box.

[0021] According to one embodiment of the present invention, the rotating component of the nuclear main pump, the symmetrical stationary component, and the asymmetrical stationary component are assembled into the overall mass, stiffness, and damping matrix using one-dimensional or three-dimensional finite element units.

[0022] According to one embodiment of the present invention, step S3 uses a connection unit between nodes with mass, stiffness, and damping, the parameters of which are related to the main pump operating conditions and speed.

[0023] According to one embodiment of the present invention, the dynamic parameters caused by the bearing force at the upper radial bearing and the bearing force at the lower radial bearing change with the rotational speed of the main pump.

[0024] The positive and progressive effects of this invention are as follows:

[0025] The present invention provides a modeling method for the rotor dynamics analysis of nuclear power plant main pumps. Based on the traditional rotor dynamics method, this method improves upon it by adding the interaction between the main pump components and hydraulic forces, and considering the influence of different parameters of hydraulic action under different operating conditions. By scientifically selecting appropriate parameters, the calculation accuracy can be improved. Attached Figure Description

[0026] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:

[0027] Figure 1 This is a flowchart of the modeling method for the rotor dynamics analysis of nuclear power plant main pumps according to the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of an embodiment of the nuclear power main pump in the modeling method for rotor dynamics analysis of the nuclear power main pump of the present invention.

[0029] Figure 3 This is a schematic diagram of another embodiment of the nuclear power main pump in the modeling method for rotor dynamics analysis of the nuclear power main pump of the present invention.

[0030] Figure 4 This is a schematic diagram of another embodiment of the nuclear power main pump in the modeling method for rotor dynamics analysis of the nuclear power main pump of the present invention.

[0031] [Attached image labels]

[0032] Impeller 10

[0033] Upper radial bearing 20

[0034] Rotor assembly body 30

[0035] Lower radial bearing 40

[0036] Pump casing 50

[0037] Upper flange 60

[0038] Stator assembly body 70

[0039] Lower flange 80

[0040] Heat exchanger 90

[0041] Junction box 100

[0042] Impeller inlet ring force 110

[0043] The bearing force at the upper radial bearing is 120.

[0044] The circulating force between the stator and rotor assemblies is 130.

[0045] Bearing force at the lower radial bearing: 140 Detailed Implementation

[0046] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0047] Embodiments of the invention will now be described in detail with reference to the accompanying drawings. Preferred embodiments of the invention will now be described in detail, examples of which are shown in the drawings. Wherever possible, the same reference numerals will be used in all the drawings to denote the same or similar parts.

[0048] Furthermore, although the terminology used in this invention is selected from commonly known and used terms, some terms mentioned in this specification may have been selected by the applicant in his or her judgment, and their detailed meanings are explained in the relevant sections of the description herein.

[0049] Furthermore, the invention should be understood not only through the actual terminology used, but also through the meaning implied by each term.

[0050] like Figure 1 As shown, this invention discloses a modeling method for the dynamic analysis of a nuclear power plant main pump rotor, which includes the following steps:

[0051] Step S1: Establish the rotor section of the nuclear power plant main pump rotor dynamics analysis model, and create nodes representing hydraulic effects within the rotor section. The rotor section may preferably include components such as an impeller, shaft, upper flywheel, lower flywheel, rotor assembly, and thrust disk.

[0052] Preferably, in step S1, the nodes representing the hydraulic effect created in the rotor portion include the impeller side of the mouth ring and the bearing.

[0053] Step S2: Establish the stator section of the nuclear power plant main pump rotor dynamics analysis model, and create nodes representing hydraulic effects within the stator section. The stator section may preferably include components such as the pump casing, suction duct, upper flange, guide vanes, heat shield, stator top cover, stator assembly, lower flange, flange bolts, stator bottom cover, heat exchanger and its piping, and junction box.

[0054] Preferably, in step S2, the nodes representing the hydraulic effects created in the stator section include the guide vane side of the mouth ring and the bearing housing.

[0055] like Figure 2 In one embodiment, the components of the nuclear power plant main pump include an impeller 10, an upper radial bearing 20, a rotor assembly body 30, a lower radial bearing 40, a pump casing 50, an upper flange 60, a stator assembly body 70, a lower flange 80, a heat exchanger 90, and a junction box 100. The hydraulic dynamic effects between the moving and stationary components reflect the impeller inlet ring force 110 between the pump casing and the impeller, the bearing force 120 at the upper radial bearing, the bearing force 140 at the lower radial bearing, and the gap circulation force 130 between the stator and rotor assemblies.

[0056] like Figure 3 As shown, in another embodiment, the pump casing 50 or heat exchanger 90 in the components of the nuclear power main pump can be incorporated into the main pump rotor dynamics analysis model in the form of a dynamic substructure.

[0057] Or, such as Figure 4 As shown, in another embodiment, in the components of the nuclear power main pump, the impeller 10 and the pump casing 50 are arranged between radial bearings.

[0058] The layout structures of the aforementioned nuclear power plant main pumps are all applicable to the modeling method of this application. Furthermore, the modeling method described in this invention can be used not only for suspended nuclear power plant main pumps but also for horizontal nuclear power plant main pumps.

[0059] In actual nuclear power plant main pump modeling, the above components can be further divided and modeled in a more suitable manner according to the actual main pump structure. Typically, key components in the nuclear power plant main pump, such as suction ducts, guide vanes, heat shields, upper flywheel, lower flywheel, upper radial bearing housing, lower radial bearing housing, thrust bearing housing, stator top cover, stator bottom cover, stator windings, and rotor windings, are modeled, and the hydraulic dynamic effects at the thrust bearing are considered.

[0060] The nuclear power plant main pump rotor dynamics analysis includes rotating components, symmetrical stationary components, and asymmetrical stationary components. The rotating components can refer to the rotor section, while the stator section generally includes both the symmetrical and asymmetrical stationary components. Preferably, the rotating components include an impeller 10, an upper radial bearing 20, a rotor assembly body 30, and a lower radial bearing 40. The symmetrical stationary components include an upper flange 60, a stator assembly body 70, and a lower flange 80. The asymmetrical stationary components include a pump casing 50, a heat exchanger 90, and a junction box 100.

[0061] Preferably, the rotating component of the nuclear main pump, the symmetrical stationary component, and the asymmetrical stationary component are assembled into the overall mass, stiffness, and damping matrix using one-dimensional or three-dimensional finite element units, such as simplified beam elements, three-dimensional solid elements, and mass point elements.

[0062] Step S3: Establish the connection part of the hydraulic dynamic effect between the moving and stationary components in the nuclear power plant main pump rotor dynamic analysis model, and select hydraulic dynamic parameters according to the operating conditions and speed to simulate the hydraulic dynamic effect between the moving and stationary components.

[0063] Preferably, step S3 employs a connection unit between nodes, specifying mass, stiffness, and damping parameters. The parameters of this connection unit are related to the main pump's operating conditions and rotational speed. Here, the parameters of the connection unit refer to mass, stiffness, and damping parameters.

[0064] For example, the impeller 10, upper radial bearing 20, lower radial bearing 40, and stator / rotor assembly 30 all exhibit corresponding dynamic parameters caused by hydraulic effects at the motor location. These dynamic parameters are beneficial for obtaining more accurate results in the rotor dynamics analysis of nuclear power plant main pumps. These dynamic parameters can be achieved by defining the parameters of the connecting units in the rotor dynamics analysis.

[0065] The stiffness and damping of the connecting unit at a certain rotational speed ω are usually known.

[0066] F1′(u1),F2′(u2),F3′(u3),…,F n ′(u n ) and ξ1(u1), ξ2(u2), ξ3(u3),…,ξ n (u n The input to the connection unit typically requires displacement and load, damping curves, for example...

[0067] F(u,ω)=F(F1′(u1),F2′(u2),F3′(u3),…,F n ′(u n ),ω), u1,…,u n ∈[0,1)

[0068] ξ(u,ω)=ξ(ξ1(u1),ξ2(u2),ξ3(u3),…,ξ n (u n ),ω), u1,…,u n ∈[0,1)

[0069] By using piecewise interpolation and numerical integration, relevant displacement, load, and damping curves can be constructed, satisfying the following:

[0070]

[0071]

[0072] ...;

[0073]

[0074] ξ(u1)=ξ1(u1);

[0075] ξ(u2)=ξ2(u2);

[0076] ...;

[0077] ξ(u n )=ξ n (u n ).

[0078] In the dynamic analysis of the main pump rotor in a nuclear power plant, the dynamic parameters caused by the bearing forces 120 at the upper radial bearing and 140 at the lower radial bearing change with the main pump's rotational speed. The Coriolis force (which is the apparent force generated by inertia in a rotating reference frame and is proportional to the rotational speed) of the rotor components also changes with the main pump's rotational speed. Here, the dynamic parameters mainly refer to stiffness and damping.

[0079] In the dynamic analysis of the main pump rotor of a nuclear power plant, the dynamic parameters caused by the interstitial circulation force 130 between the stator and rotor assemblies change with the operating conditions of the main pump. Based on actual measurements and theoretical formulas, the proportional relationship between the mass parameters of the interstitial circulation under seismic conditions and the mass parameters of the interstitial circulation under normal operating conditions is determined.

[0080] The formula for the interstitial circulation force in a rectangular coordinate system is as follows:

[0081]

[0082] Let the rotor and stator radii be R1 and R2, respectively. Then R = (R1 + R2) / 2, and the average clearance thickness C = R2 - R1. The rotor speed is Ω, the clearance circulation length is L, and the Darcy friction coefficient is f0.

[0083] m H =πρR3 L / C

[0084] F T =0.192f0nΩR / C

[0085] According to the 1 / 7 power distribution law, n is 1.14, which is the ratio of the flow velocity at the center of the flow channel to the average flow velocity of the flow channel.

[0086] Based on the formula for the gap circulation force, when performing stability analysis of the gap circulation under normal operating conditions, m can be used. H / 4.

[0087] Step S4: Based on the hydraulic dynamic parameters, create the connection relationship between the impeller inlet ring, radial bearing, and gap circulation.

[0088] As described above, the modeling method for the rotor dynamics analysis of nuclear power plant main pumps in this invention uniformly incorporates the dynamic effects caused by hydraulics (including bearings, gap circulation, inlet ring seals, and the added mass of the fluid inside the pump casing on the impeller and pump casing) between the rotating components, stationary components, and dynamic and static components of the nuclear main pump. The modeling method selects the hydraulic dynamic parameters between the stator and rotor components based on operating conditions and rotational speed. According to measurements and theory, there is a proportional relationship between the mass parameters of the gap circulation under seismic conditions and the mass parameters of the gap circulation under normal operating conditions.

[0089] The proposed modeling method considers rotating components, symmetrical stationary components, the dynamic effects caused by hydraulics between moving and stationary components, and asymmetrical stationary components in the rotor dynamics analysis model of the nuclear power plant main pump, thus constructing a complete finite element analysis model of the nuclear power plant main pump. This rotor dynamics analysis model of the nuclear power plant main pump can be used for more accurate rotor dynamics analysis and can be connected to the nuclear power plant main circuit for related analyses. It has significant practical implications for addressing the strong coupling effect between the nuclear power plant main pump and the main circuit caused by the vertical suspension arrangement, as well as for mitigating the vibration of the nuclear power plant main pump itself.

[0090] In addition, the dynamic parameters of the nuclear power main pump rotor dynamics analysis model in this invention will be selected according to different operating conditions and different speeds and substituted into the analysis model. The relevant values ​​have a valid theoretical basis and evidence. The calculation results obtained by the analysis model are more accurate than the traditional single rotor model of rotor dynamics.

[0091] The present invention provides a modeling method for the rotor dynamics analysis of nuclear power plant main pumps. Based on the traditional rotor dynamics method, this method improves upon it by adding the interaction between the main pump components and hydraulic forces, and considering the influence of different parameters of hydraulic action under different operating conditions. By scientifically selecting appropriate parameters, the calculation accuracy can be improved.

[0092] For those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application and therefore remain within the spirit and scope of the exemplary embodiments of this application.

[0093] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0094] Similarly, it should be noted that, in order to simplify the description of the embodiments disclosed in this application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of this application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of this application requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of a single embodiment disclosed above. Some embodiments use numbers describing the number of components or attributes; it should be understood that such numbers used in the description of embodiments are modified in some examples by the terms "approximately," "about," or "generally."

[0095] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A modeling method for the dynamic analysis of a nuclear power plant main pump rotor, characterized in that, The modeling method includes the following steps: S1. Establish the rotor part of the nuclear power plant main pump rotor dynamic analysis model, and create nodes representing hydraulic effects in the rotor part; S2. Establish the stator part of the nuclear power plant main pump rotor dynamic analysis model, and create nodes representing hydraulic effects in the stator part; S3. Establish the connection part of the hydraulic dynamic effect between the dynamic and static components in the rotor dynamic analysis model of the nuclear power plant main pump, and select hydraulic dynamic parameters according to the working conditions and speed to simulate the hydraulic dynamic effect between the dynamic and static components. S4. Based on the hydraulic dynamic parameters, create the connection relationship between the impeller inlet ring, radial bearing, and gap circulation.

2. The modeling method for the rotor dynamics analysis of nuclear power plant main pumps as described in claim 1, characterized in that, In step S1, the nodes representing the hydraulic effect created in the rotor section include the impeller side of the mouth ring and the bearing.

3. The modeling method for the rotor dynamics analysis of nuclear power plant main pumps as described in claim 1, characterized in that, In step S2, the nodes representing the hydraulic effects created in the stator section include the guide vane side of the mouth ring and the bearing housing.

4. The modeling method for the rotor dynamics analysis of nuclear power plant main pumps as described in claim 1, characterized in that, The dynamic analysis of the nuclear power plant main pump rotor includes the rotating components, symmetrical stationary components, and asymmetrical stationary components of the nuclear power plant main pump.

5. The modeling method for the rotor dynamics analysis of a nuclear power plant main pump as described in claim 4, characterized in that, The rotating components of the nuclear main pump include an impeller, an upper radial bearing, a rotor assembly body, and a lower radial bearing.

6. The modeling method for the rotor dynamics analysis of a nuclear power plant main pump as described in claim 4, characterized in that, The symmetrical stationary part includes an upper flange, a stator assembly body, and a lower flange.

7. The modeling method for the rotor dynamics analysis of a nuclear power plant main pump as described in claim 4, characterized in that, The asymmetric static part includes the pump casing, heat exchanger, and junction box.

8. The modeling method for the rotor dynamics analysis of a nuclear power plant main pump as described in claim 4, characterized in that, The rotating component of the nuclear main pump, the symmetrical stationary component, and the asymmetrical stationary component are assembled into the overall mass, stiffness, and damping matrix using one-dimensional or three-dimensional finite element units.

9. The modeling method for the rotor dynamics analysis of a nuclear power plant main pump as described in claim 1, characterized in that, Step S3 employs a connection unit between nodes that measures mass, stiffness, and damping. The parameters of the connection unit are related to the operating conditions and speed of the main pump.

10. The modeling method for the dynamic analysis of a nuclear power plant main pump rotor as described in claim 5, characterized in that, The dynamic parameters caused by the bearing force at the upper radial bearing and the bearing force at the lower radial bearing change with the rotational speed of the main pump.

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