过流部件参数变化对水轮机性能的影响

发布时间：2018-05-05 12:40

本文选题：混流式水轮机 + 导叶分布圆直径　；参考：《西安理工大学》2017年硕士论文

【摘要】：中小型电站的技术改造在现在的水电发展事业中担任着极其重要的角色,借助CFD软件来研究过流部件参数变化对水轮机性能的影响对于水电站的改造具有一定的借鉴意义。本文以HLX180-LJ-36水轮机为研究对象,通过CAD、UG等软件对机组进行改型,借助CFD软件对改型前后的水轮机进行流动分析。首先,根据所给的CAD图纸对水轮机进行三维全流道建模,然后对建立好的模型进行网格划分,最后通过CFX软件进行计算及后处理。通过修改导叶分布圆直径,下环以及转轮出口直径研究过流部件参数变化水轮机性能的影响。得出以下结论:(1)导叶分布圆直径的变化对最优工况和大流量工况下水轮机的内部流动影响不大,但是对小流量工况下的叶道涡影响较大;水轮机的效率随着导叶分布圆直径的增大而增加,小流量工况表现尤为突出,与原转轮相比,小流量工况时,方案5的效率提高了1.87%,在大流量工况时,效率提高了 0. 17%,最优工况时提高了 0. 04%;随着导叶分布圆直径的增大,活动导叶和转轮之间无叶区的压力脉动有所减轻。(2)下环形状和转轮出口直径对不同工况下水轮机性能的影响不同。增大转轮出口直径和下环锥角可以提高水轮机的过流能力,但是在小开度工况下,由于效率下降太多导致水轮机的出力整体下降;最优开度下,水轮机的效率会有所下降,但是由于过流量的增加,水轮机的出力整体增加,相比于原方案,方案4增容5.4%:大开度工况下,水轮机的效率和过流量都增加,相比原方案,方案4增容8. 3%。(3)增大转轮出口直径和下环锥角,水轮机的最优工况将向大流量方向偏移,水轮机的空化性能略微有点下降。(4)适当的增大转轮出口直径和下环锥角可以减小小开度工况下水轮机转轮的出口环量,减轻尾水管的压力脉动。
[Abstract]:The technical transformation of small and medium-sized power stations plays an extremely important role in the development of hydropower stations at present. The study of the influence of the parameters of the flow passing components on the performance of the turbine by means of CFD software has certain reference significance for the transformation of hydropower stations. In this paper, HLX180-LJ-36 turbine is taken as the research object, the turbine is modified by CAD / UG software, and the flow analysis of the turbine before and after the modification is carried out with the help of CFD software. Firstly, according to the CAD drawings, the three-dimensional full-channel modeling of the turbine is carried out, then the established model is meshed, and the calculation and post-processing are carried out through the CFX software. By modifying the diameter of the guide vane distribution circle, the lower ring and the outlet diameter of the runner, the influence of the parameters of the overflowing parts on the performance of the turbine is studied. The following conclusions are drawn: (1) the variation of the diameter of the distribution circle of the guide vane has little effect on the internal flow of the turbine under the optimal condition and the large flow condition, but has a great effect on the vortex of the blade under the condition of small flow rate; The efficiency of the turbine increases with the increase of the diameter of the distribution circle of the guide vane, and the performance of the small flow rate is particularly prominent. Compared with the original runner, the efficiency of the scheme 5 is increased by 1.87 in the case of small flow, and by 0. 7 in the case of the large flow rate. In the optimal operating conditions, the increase of 0. 5%. With the increase of the diameter of the guide vane distribution circle, the pressure pulsation in the vaneless zone between the active guide vane and the runner can be alleviated.) the influence of the lower ring shape and the runner outlet diameter on the performance of the turbine is different under different working conditions. Increasing the diameter of runner outlet and the cone angle of the lower ring can improve the overflow capacity of the turbine, but under the condition of small opening degree, the efficiency of the turbine will decrease as a whole because of too much decrease in efficiency; under the optimal opening, the efficiency of the turbine will decrease. However, due to the increase of overflow rate, the output capacity of the turbine increases as a whole. Compared with the original scheme, scheme 4 increases the capacity of the turbine by 5.4: under the condition of large opening, the efficiency and overflow rate of the turbine increase, compared with the original scheme, the capacity of the fourth scheme increases by 8. Increase the diameter of runner outlet and the conical angle of lower ring, the optimal working condition of the turbine will shift to the direction of large flow rate, The cavitation performance of the turbine is slightly decreased. 4) increasing the outlet diameter of the runner and the cone angle of the lower ring can reduce the outlet ring quantity of the turbine runner under the condition of small opening and reduce the pressure pulsation of the draft tube.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV734

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