A Study On Dynamic Modelling And Virtual Prototype Of 600MW Supercritical Steam Turbine Reheat-Stop-Valve

The reheat-stop-valve assembly is the essential steam turbine auxiliary, which is significant for the proper running and secure production of steam turbine sets. The reheat-stop-valve of 600MW supercritical steam turbine's middle heat steam-cylinder is a type of lopsided mechanism, which mainly depends on the rotation of valve stem relative to the fixed bushes to carry out the valve opening/closing function and requires a strict assemblage with high precision. In practice, there are common run-time problems of opening/closing due to the effects of working medium when the valve is during of the performance test or in the working condition, that is, valve-sticking phenomenon. So the systemic and comprehensive analyses/evaluations of the multi-issues effects on reheat-stop-valve are performed in this current research. On the basis of the analytical results, the essence of valve-sticking phenomenon is defined as such an issue that the dynamic performance of one type of mechanism with clearance can not meet the requirement of design any more due to the effects of reheat steam-gas, that is a basic principle issue on the research of mechanism with clearance. From the point of view of multi-effects on the dynamic performance of reheat-stop-valve mechanism with clearance, a series of simulation analyses and academic research are achieved with a broad-based of related native and abroad researches. The main content of this current research includes:1. The virtual prototyping analysis methodology of reheat-stop-valve.In order to analyze the valve-sticking issue systemically, a methodology of multi-domain-simulation-based virtual prototyping for reheat-stop-valve is put forward firstly in the light of the reheat-stop-valve configuration and the environmental issues. The methodology with concrete implement is discussed in detail which provides a foundation for the subsequent research work.2. The hydrodynamic torque characteristics of reheat-stop-valve and its effects on the dynamics properties of reheat-stop-valve.The computational fluid dynamics analysis for the reheat steam-gas inner reheat-stop-valve is performed based on the theory of fluid dynamics, and the influential characteristics of reheat steam-gas on reheat-stop-valve has been drawn out with the analysis results. The flow characteristic of reheat steam-gas is defined as the reheat-stop-valve hydrodynamic torque characteristics. The effects of the reheat-stop-valve fluid dynamic torque characteristics on the dynamic properties of reheat-stop-valve also have been discussed.3. The thermal expansion behavior of reheat-stop-valve and its effects on the dynamics properties of reheat-stop-valve.Aiming at the high temperature load's effects on dynamic behavior of reheat-stop-valve that derived from reheat steam-gas, the thermal-structure coupled finite element analysis is carried out with finite element method. The axial uneven thermal expansion characteristic is presented with the finite element analysis. Furthermore, the radial thermal expansion's effects of the valve stem on the dynamic properties of reheat-stop-valve have been analyzed deeply.4. The kinematic relationship and mutual contact-impact force model between the valve stem and bush in working situation.Based on the contact dynamics theory, a revolute clearance joint model for the configuration of valve stem and bush is presented according to the practical related motion and the environmental issues in working condition. The revolute clearance joint model includes nonlinear normal contact force model and tangential friction force model, which is used for the research on the interaction behavior between the valve stem and bush.5. The dynamic modeling and dynamic properties analysis of reheat-stop-valve.Based on the multi-body dynamics theory, the kinematic/dynamic analysis is accomplished in consideration of the revolute clearance joint. The kinematic/kinetic control equations are presented and the dynamic analysis for the reheat-stop-valve influenced by multi-issues also has been carried out.6. The secondary development of software module for reheat-stop-valve virtual prototype analysis and the virtual prototype modeling and parameterized analyzing of the reheat-stop-valve are performed.For the high fidelity simulation analysis of the reheat-stop-valve, the software module for the virtual prototyping analysis and parameterized modeling of the reheat-stop-valve is implemented based on the ADAMS code. A rational design/assembly parameter has been obtained for the running of reheat-stop-valve with the parameterized analysis for the reheat-stop-valve assembly.Finally, a series of improved solutions for the existing design/assembly scheme are put forward with the results and conclusion of simulation analysis and academic research. The reseach conculsion and improved solutions are also verified by the comparison with the practical analyzing report and application for the valve-sticking problem. The practical analyzing report shows that the research conclusion and improved solutions in current research are consistent with the practical analyzing results and confirms that the current reaearch can explain the multi-effects on reheat-stop-valve in working situation effectively. As a result, the practical valve of the current research is also validated.