超（超）临界疏水阀内部流动特性与开启动态特性研究

Aiming at the current situation of the ultra supercritical traps lacking of basic theory research, the problems in the work process are analyzed,which are high temperature and high pressure-drop cavitation, cavitation damage in the trap and water hammer in opening process. Based on the vapor liquid mass transport theory, a mathematical model for the cavitation of high tempreture water is presented by introducing a source term of reflecting thermodynamics effect, which include thermodynamic effects,the vapor/liquid ratio,the difference between the local static pressure and the saturated vapor pressure. Taking the steam trap and pipeline as a system, a mathematical model of coupled nonlinear vibration as a description of water hammer induced vibration due to trap open shut actions is set up. The internal flow characteristics and open pipeline system dynamic characteristics of the trap are revealed. Along with the changing of the parameters of multi-stage cage type throttling components, the influence and the change rule of the trap internal flow field, the vibration and noise of the pipeline system are emphatically researched. The parameters of multi-stage cage type throttling components include the number of layers, the clearance between the layer and layer, the shape and diameter ratio of the hole, the thickness per level , the quantity and size of the hole and the arrangement of factors and so on. The presented models are verified and corrected by numerical simulation and experiment analysis methods. Thus, better theory foundation of valve design is laid and a method for high parameter valve design theory is provided, which would promote its reliability and stability.

针对超（超）临界火电机组疏水阀缺乏基础理论研究现状，研究其工作过程中存在的高温水高压降空化、气蚀破坏以及开启时诱发的水击等问题。基于气液传递理论,考虑局部气/液相含量、局部压力与饱和蒸汽压之差及空化的热力学效应，通过引入反映热力学效应的源项, 建立疏水阀内高温水空化流计算的空化模型；把疏水阀与管路作为系统，建立开启瞬间水击非线性振动模型。揭示疏水阀内部流动特性及开启管路系统动态特性。着重考察多级笼式节流元件的节流级数、层与层的间隙、开孔的形状、孔的长径比、每级孔的大小和数量及小孔排布方式等因素对阀的内部流场、管路系统振动及噪声的影响和变化规律。结合数值模拟与试验的手段加以验证并修正模型，为该类阀门设计基础理论的完善奠定基础，为高参数阀门设计理论提供方法借鉴，促进其可靠性、稳定性的提高。

本项目针对超（超）临界火电机组疏水阀工作过程中存在的严重空化、汽蚀破坏及开启时诱发的水击振动等问题展开研究。基于气液传递理论，建立了超（超）临界疏水阀内部高温水空化模型进行模拟实验，获得了不同参数模型条件下的阀内压力、速度分布及汽液两相含量等流场信息，研究了阀门内部空化流动特性的主要影响因素及变化规律。基于特征线法建立了疏水阀开启瞬间水击动态特性非线性振动模型，通过模拟实验得出了在不同模型条件下疏水阀开启时管道中流量和水击压力的时域曲线，分析了管路系统振动的主要影响因素和变化规律。本项目研究结果揭示了超（超）临界高温水高压降工况下疏水阀内部流动特性及开启管路系统动态特性，可为该类阀门设计基础理论的完善提供一定参考，为高参数阀门设计理论提供方法借鉴，促进其可靠性、稳定性的提高。通过本项目研究共发表文章3篇，其中EI期刊收录1篇（已录用），国际会议1篇，中文核心期刊1篇（已录用）；申请发明专利2项。培养青年教师1名，硕士研究生3名。