不同埋设方式下巨型水轮机蜗壳结构动力特性研究

随着水电机组单机容量的提高,蜗壳日趋向巨型化发展,HD值很高.目前,关于巨型蜗壳结构动力特性的研究在理论和实践方面涉及较少,然而此问题在设计阶段尤其重要.为此,对典型的3种蜗壳埋设方式,即垫层、保压和直埋,以某巨型工程为实例,采用三维有限元方法,从优化设计的角度重点研究和比较了蜗壳结构的刚度、固有振动特性、脉动水压力作用下结构的振动反应和抗疲劳特性.计算与分析表明,蜗壳埋设方式对厂房结构的静、动力特性的影响不显著, 不应成为蜗壳埋设方式选择的制约因素.

Study of dynamic characteristics of a giant spiral case with different embedment manners

With the increase of unit capacity of hydro-generators,the spiral case becomes a giant hydraulic structure with very high HD value,but its dynamic characteristics which should be paid particular attention to in the design stage have rarely been touched both in theory and practice.Three typical manners of steel spiral casing(SC) embedded in concrete,i.e.,manner of SC embedded in concrete with soft cushion layer(MSCL),manner of SC embedded in concrete while holding a certain water head inside SC(MHWH) and manner of SC embedded directly in concrete(MD),were researched on the performances of a giant spiral case performed by 3-D finite element methods.To optimize the design of the giant spiral case,free-vibration and stiffness behaviors,dynamic responses under water pressure pulsation and anti-fatigue performance were analyzed and compared respectively.Results show that the influence of different embedment manners on the static and dynamic performances of the powerhouse is minor and should not be the control factor while selecting embedment manners.