LAI Ming-zhu，DAI Ye，ZHANG Guo-yin

赖明珠， 戴 野， 张国印

(1.College of Computer Science and Technology，Harbin Engineering University，Harbin 150001，China;2.School of Mechanical＆ Power Engineering，Harbin University of Science and Technology，Harbin 150080，China)

Nuclear power valves are referred to the ones which are used in nuclear power station N1，conventional island CI and power plant auxiliary facilities BOP system in nuclear power plants.As the medium conveying control equipments of nuclear power plants，they have the high temperature，high pressure，and the unique characteristics of the seal design compared with other valve products，so it makes this kind of valve products gain the characteristics that the other products cannot replace［1－2］.In the traditional process，the nuclear valve design needs to experience the prototype，performance experiments and repeating the process.However，by using digital design methods for the performance analysis of the prototype，we can predict the performance of the valves，and the pressure drop，flow properties generated by internal fluid flow，hence the possible design flaws can be eliminated in the schematic design stage，it is of great significance in saving the prototype test cost and shortening develop period［3－4］.At present，the domestic nuclear power valve enterprises have done very few in digital integrated designs;most work has been limited to the simple parametric design and characteristic analysis by using universal design and analysis software.Due to the lack of the integrated support environment，this kind of scattered design method exists some shortages in the application integration of CAD/CAE/MDO，so it is not suitable for the current fast response design requirements of nuclear valve products［5］.

According with the performance requirements of nuclear valve products and the demand of computer supported cooperative work(CSCW)，we can develop multidisciplinary optimization design system by using the existing CAX/MDO design software，and then achieve the collaborative design between different departments，and it will become the design development trend of nuclear power valve products［6－7］.Therefore，on the basis of integrated development framework，the integrated platform is constructed in this paper，which integrates design，simulation，and optimization of nuclear power valves together with the comprehensive application of CAD，CAE and MDO technology and database technology.

1 System General Design

1.1 General Framework and Function

For the same type of nuclear power valve products，the contents and methods of characteristic analysis are basically the same.Hence，it can greatly improve the development ability and efficiency of nuclear power valve by setting up the numerical analysis and evaluation system for nuclear power valves.According to the specific structure characteristics and working requirements of the nuclear power valve products，the nuclear power valve numerical analysis and ev aluationare divided into four aspects:the structure strength analysis，the thermal change analysis，the circulation ability of body cavity and valve seismic performance［8］.The digital design system structure is constructed to satisfy the need of the performance simulation analysis of nuclear power valve products(as shown in Fig.1);the system structure are described herein according to level structure，and it mainly consists of three major components，including the supporting layer，function layer and application layer，the functions of each part are described as follows:

1)Supporting layer:this layer is the foundation of the whole system constructed by using current mainstream technology，and it is responsible for transferring the data between the functional level and the application layer in order to realize data sharing;and it is used to support related data and knowledge physical storage and management services in the process of nuclear valve design development，including the product design database，finite element model library，standard parts library，simulation database and other shared resource database，etc.

Fig.1 Integration system framework of nuclear power valve

2)Function layer:based on the support of software environment foundation，the logic modules are developed according to the business needs of the nuclear power valve products digital design，such as the parametric design logical processing based on UG，the comprehensive characteristic analysis logical processing based on ANSYS;the structure optimization design logical processing based on the iSIGHT.These logical modules，developed in UG，ANSYS and iSIGHT platform，is integrated together to the tool software.The interactive information of each module can be turned into middle format to store in a database through ADO technology，and it can be directly used for knowledge management system to ensure the information sharing and unity between modeling，characteristic analysis and optimization design.

3)Application layer:this layer is the description of usage mode in nuclear power valve design.The application of nuclear power valve products digital design can be integrated to modeling，characteristic analysis and optimization calculation software，and according to the business process and business function，various function items can be customized in the system:parameterized modeling and assembly of all kinds of nuclear power valve based on UG，characteristic analysis based on ANSYS and comprehensive properties optimization analysis based on iSIGHT.

1.2 Main Interface of the System

Through providing a unified the data access interface，the system makes each simulation system be flex-ible to define and publish the data set which are needed to share so as to realize the information integration in the multidisciplinary simulation process.

The main interface of the integrated system for valve products is shown in Fig.2，which is divided into four functional areas，viz.navigation area(a)，which contains task bar button access into the three design platform;parts list area(b)，the system will list the main parameters of the components after the choice of valve type or model number;system management list area(c)，which is used to save and manage the results from the three design systems;parts diagram area(d)，which provides the diagram of the parts for the operator，including 3D modeling graphics and engineering drawing.

Fig.2 Main interface of the integration system

2 Finite Element Analysis and Optimization of Valve Products

2.1 Multi-discipline Characteristics Analysis of Valve

The system structure of multi-discipline characterristics analysis is shown in Fig.3.The system chooses ANSYS software as the tool of multi-discipline characteristics analysis，encapsulates the complicate operate into the program according to the APDL［9］，operates human-computer interaction by means of interface window provided by VC++，completes the complicated process of multi-discipline characteristics analysis，and realizes the process of static analysis，fluid mechanics analysis，thermodynamics analysis，modal analysis.Finally，system can store the analysis results into the database in the form of texts and pictures.The system provides the monitoring function of analysis process，transfers supervisory instruction to ANSYS，and obtains the feedback information，calculates the residual time，and then completes the monitoring of analysis process.Because ANSYS doesn’t provide secondary development interface，this system chooses VC++to build the background operating interface in order to provide a good visualization operation window of human-computer interaction.The secondary development principle of VC++ integrated ANSYS is shown in Fig.4，including data communication between VC++and APDL，ANSYS program operation and transmission of after treatment file，and the concrete realize method is:

Fig.3 Structure diagram of multidisciplinary finite element analysis

Fig.4 Schematic diagram of ANSYS integrated by VC++

1)The communication data between VC++program and APDL:VC++program encapsulations the APDL data files that needs to be calling into its window.Operators can modify each parameter in the table，and the system will read modified parameter value and regenerate APDL files according to VC++program.

2)ANSYS program operation:start ANSYS command through VC++program by calling background.The content of this processing file is:"%ANSYS110-DIR%inintelansys.exe"-b-i* .txt，the function of"%ANSYS110-DIR%inintelansys.exe"is to start ANSYS software，-b-i* .txt is to run background and input APDL files，and complete the whole analysis process of ANSYS according to APDL files.

3)Transmission of after treatment file:because ANSYS program is automatic operation in the background，it cannot display the analysis results in the foreground.In order to display the analysis results in-tuitively，VC++program is used to put ANSYS postprocessing into service，and then save and display the text and picture of analysis results in the window of dialog box.

2.2 Multi-discipline Optimization Design of Valve

In order to conduct multi-discipline optimization，this system integrates iSIGHT with ANSYS.iSIGHT，opened to CAD，CAE，VC++and other environment，can connect software together conveniently［10］.In this integration process，it first analyzes the APDL command flow files，builds the mapping relation between iSIGHT and design variable of ANSYS files，and completes the modification of parameter and definition of optimization problem，and then starts ANSYS by operating batch processing files.Finally，iSIGHT calls internal mapping function，judges whether the result satisfies the optimum conditions according to the optimization algorithm selected by operator，and completes one optimization design cycle.

As shown in Fig.5，when conducting the coupling operation of valve’s model analysis and structural analysis，it can realize the coupling analysis by introducing command flow files(Structure.txt and Modal.txt)，carrying out batch files of application(ansys-str.bat and ansys-mod.bat)，and compiling the output result files by using*Get command and/output command of command stream files.Finally，iSIGHT compares present function value with the target expected value to determine whether to iterative again.

Fig.5 Operation flow chart of coupling modal and structure analysis

3 Example Analysis

Combining with the related design tasks of the power station valve，he functions of integrated platform are analyzed through the design task of J61Y-25 stop valve.The user can select the series of J61Y-X stop valves after login the platform，and the analysis model of J61Y-25 stop valve can be established rapidly through applied template of parametric modeling.And then，the user can enter the navigation interface of characteristic analysis of parts by clicking the analysis button of dynamic and static thermal characteristics.The process is shown in Fig.6.

Fig.6 Navigation interface of analysis characteristics

After modeling valve parts and entering the platform of multidisciplinary finite element analysis，the multidisciplinary characteristics analysis can be carried out.The results of each characteristic analysis are shown in Fig.7.

Fig.7 Extract results of multidisciplinary characteristic analysis

Entering the platform of multidisciplinary optimization design，and then the modal analysis and the structural analysis for this valve are coupled.According to the valve structure，the parameters of D6，D8，D12 and D13 are selected as optimal design variables.The value range of each parameter variable is defined，and the boundaries are filled in respectively in accordance with given variables and structural requirements of optimal design in parametric modeling.The current initial value of each parameter is inputted.And the optimal constraints are defined as follows:the maximum load pressure of the valve body(Pressure)，the first order modal of assembly(Modal)and the mass of thevalve body(Mass)are stetted as the objective functions.Among them，pressure can be defined within 106 MPa，and the first order modal is more than 33 Hz for avoiding resonance by earthquake，and the mass of value getting minimum value is to reduce cost.

The optimal results are shown in Tab.1 with the optimization constraints above(A:initial design，B:optimal design).It can be seen that the mass is decreased by 5.52%，and the wall thickness at the passageway of valve body reduced by 3.6%.Meanwhile，the capacity of valve body is expanded so as to improve the flow field performance of the valve，and the first order natural frequency is still higher than 33 Hz that matches the requirements of seismic.

Tab.1 Optimization results

4 Conclusions

The platform that integrates the design，simulation and optimization of nuclear valves is developed by combining with the actual engineering projects in this paper.Through integration of heterogeneous CAD/CAE software，such as UG，ANSYS and iSIGHT，the analytical efficiency is enhanced by coupling respective and unique advantage of various software systems，which is benefit to shorten the development period of nuclear power valve products and realize the rapid response to customer demands.The design process of J61Y-25 stop valve verifies that multidisciplinary simulation analysis function provided by system solves the multidisciplinary optimization problems effectively，and makes designers comprehensively appraise and improve of valve by combining with multidisciplinary characteristic analysis so as to improve the product quality.The integrated platform has been applied successfully in certain valve corporations，and achieved good economic benefits.

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