某型核电汽轮机高压主汽调节阀组稳定性研究

Study on Stability of High Pressure Main Steam Regulating Valve Groupfor a Nuclear Power Steam Turbine

研究某ARABELLE型百万千瓦级核电汽轮机高压主汽调节阀组的稳定性,提出优化运行措施。以某ARABELLE型核电汽轮机为研究对象,根据高压主汽调节阀组的配汽方式和布置特点分析其运行特性;建立阀组振动测试系统,测试高压调节阀在不同开度下阀杆的振动情况,研究阀组的稳定性。结果表明:高压调节阀开度在约2.9%时,阀杆存在共振现象;随着阀门开度增加,阀杆振动幅值略有升高,但基本保持稳定,振动以流体高频湍流诱发振动为主,激振力频率集中在0~5000Hz频段;满功率下阀组内部蒸汽流速符合行业标准,具有良好的气动性能和整体稳定性。但该型核电汽轮机在夏季满功率工况时容易进入高压调节阀流量特性曲线的陡峭区域,存在阀位抖动、高压进油管油压脉动和进油管爆裂等缺陷,采取适当提高功率设定值的运行方式等,有助于维持阀门开度稳定和机组安全运行。

The stability of high-pressure main steam regulating valve group for a millions-kilowatt ARABELLE nuclear power steam turbine is studied,and the optimal operation measures are put forward.Taking a ARABELLE nuclear power steam turbine as the research object,according to whose steam distribution mode and structural characteristics of high-pressure main steam valve group,the valve group's operation characteristics are analyzed theoretically;then valve group's vibration test system is set up to test its vibration when valve group at different openings,and the valve group's stability is studied at last.The results show that the valve stem has a resonance phenomenon when the valve's opening is about 2.9%;with the increase of the valve's opening,the vibration amplitude of the valve stem increases slightly but remains stable basically.The vibration is mainly induced by high frequency turbulence of fluid,whose excitation force frequency is concentrated in the range of 0-5000Hz;the steam flow velocity in the valve group meets the industry standard and so it has a good aerodynamic performance and stability overall.However,the flow characteristic curve of the valve group is easy to enter the steep region of when full powered in summer by this type steam turbine,which has some defects such as valve position jitter,high pressure oil's pressure fluctuation and the bursting of the intake pipe.It is helpful to maintain the valve opening's stability and the operation's safety by adopting the operation mode of increasing the power setting value properly of the unit.