Analysis On Character Of Butterfly Valve Extraction Pipeline Of The Cogeneraton Units

In cogeneration steam turbine, especially the applications on heating supply renovation project, the general method is layout extraction valve in the over-cross pipe to achieve steam from the main steam path, by adjusting the valve opening to meet the requirements of flow and pressure. However, in engineering practice, often can't extracted steam from the turbine to meet the parameters(pressure / flow) require, even if the valve is fully closed and can't be extracted steam from the turbine that the parameters meet required. In some pipeline, due to flow separation on portion of the opening of the butterfly valve, produce highly unstable movements vortex after the butterfly valve, it may cause vibration and noise radiation throughout the pipeline which is not conducive to the safety management of the system.Therefore, in this thesis study, for cogeneration steam turbine over-cross pipe extraction capacity and security issues, Mainly use of computational fluid dynamics to creating one 3D model of extraction valve piping. And the inlet and outlet of this extraction valve piping 3D model using 1D model to analysis, finally formed from 1D-3D-1D mixture model to analysis of extraction valve piping to assess whether it can meet the requirements. Simulation of four typical conditions under extraction pressure to meet the requirements, predicted different extraction conditions required to butterfly valve opening size, and condition of the flow field inside the pipe. And comparative analysis of butterfly valves installed position. Improved pipeline flow field in front of butterfly valve, but the low-pressure cylinder inlet flow field turbulent kinetic energy increases.Finally, through the research of this paper, Using 1D-3D-1D mixed model analysis method that can be used in analysis on butterfly valve extraction pipeline of multi inlet and outlet. Through the analysis of the actual case to find out the underlying causes that can't be extracted steam from the turbine to meet the requirements in actual project. For the latter to develop a reasonable extraction plan, improvements butterfly valve control requirements and arrange to provide data supporting and theoretical basis.